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beertracker
Cochise

387 Posts

Posted - 14 Sep 2018 :  7:28:08 PM  Show Profile  Reply with Quote
I wanted to ask for a cam recommendation for my 70 LeMans. It's going to be a weekend, pump gas, street car. I am looking for a HFT cam that will give me the most torque.

So far I have been looking at Voodoo and Comp XE cams but don't let that influence you.

So what is the biggest cam you would use?


My setup;

.060" over 455.
Ported 6x-8 Heads at 102cc.
Four tube 1 5/8" headers.
CR is 9.1:1. I can mill the heads to achieve 9.5 CR if necessary for better cam selection.
800 CFM Qjet with Cliff recipe.
Edelbrock RPM intake.
Power brakes so vacuum is a concern.
2300 rpm stall converter.
2.78 axle ratio.
1.6 rocker ratio.
HEI recurved distributor.
SpeedPro pistons and 5140 rods.

Thanks,
bt



Steve C.
Chief PONTIAC

1882 Posts

Posted - 14 Sep 2018 :  8:25:35 PM  Show Profile  Reply with Quote
A Voodoo cam. Pay little attention as to the RPM range listed in a catalog for a specific cam. That is generic information only !

Paul Carter has quite a bit of experience with Voodoo cams, note his comments here....

"That cam will have a smooth idle in a 455. The 703 has a smooth idle and makes plenty of vacuum in a 455. The 702 will probably be all done by 4800-5000 RPM. It is small, IMO, for a 455. If you go with it, I would install it on a 106 ICL."

http://forums.maxperformanceinc.com/forums/showthread.php?t=813264&highlight=Voodoo+702


Edited by - Steve C. on 14 Sep 2018 8:26:48 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 15 Sep 2018 :  11:08:48 AM  Show Profile  Reply with Quote
I am with Steve on the cam pick. The voodoo 268/276 looks like a very nice cam for that combo. I have been around 268xe comp in a 468, 9.8:1 with ported 96, 260 cfm heads, ram air manifolds and a performer rpm intake. It runs really good, but it is very inconsistent the way it idles, and has a lot of valve noise when it is cold. It hits a wall at 5000 rpm, which is fine considering it has about the same torque as a cat deisel. The engine had a ud275/283 246/254 solid cam with headers in a gto and would hit 6 easy. It has the same valve springs only the cam was changed becuase it is now in a 4wd pickup. Very border line on pump gas now, would run a 87 with the solid cam.

The 268 voodoo revs a little more than the 268xe, about the same torque. I think becuase it has a slower ramp closing rate and a little more area under the curve. The slower ramp closing rate seems to works better on 30 intakes seats past 5000rpm. Seems to be able to run a little more compression than an xe268. Below 9:1 and 5k, I think the xe268 reigns king. Especially on 45 degree valves. I have contemplated runs Rhoades vmax on the xe 268 and run the lash very tight too make the valve noise more consistent. Never seen that done that I can think of, at least on the 268. The 274xe would be the biggest cam pick for your combo, imo.

The summit 2802 would also be a good cam imo. Could use some vmax rhoads, adjusting them to have better bottom end and very little noise. It has lazy ramps which seem to like rhoads. Would work good with stock lifter too. But imo a better cam for exh manifold, and more compression, it is better with compression than the xe or voodoos. Imo. Jay
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 15 Sep 2018 :  12:16:59 PM  Show Profile  Reply with Quote
I've posted this before but worth a repeat. Keep in mind Harold Brookshire was responsible for the Voodoo lobes and considered them a improvement over his UltraDyne lobes. Also as a reminder pay attention to the spring pressure that Paul Carter recommends for the Voodoo lobes. Do not skimp on the pressure nor the quality of spring used.

For interest and somewhat related, below are comments made by Harold Brookshire years ago regarding UltraDyne lobes. Note his comments on opening and seating velocity and about 'sewing-machine' sound.....


"Although I have done only a few Buick cams, I have done an awful lot of Pontiacs and Oldsmobiles. Jim Butler, famed Pontiac engine builder, was my largest buyer of camshafts at UltraDyne, doing over $65,000 a year. He thought they worked very well, until the Recession of 2000 left us with an inability to keep him supplied.
As was said, I do all my cam designs as unsymmetrical cam designs. Although I design my hydraulics just like I do my roller profiles, The information I will give applies just to my hydraulic flat profiles.
Using Harvey Crane's Hydraulic Intensity formula, ALL my .842" tappet designs have an Hydraulic Intensity of 53.88 degrees.
This is the duration at .050" subtracted from the duration at .004", where the SAE has decided that hydraulic durations begin and end.
This Hydraulic Intensity of 53.88 is considered to be very aggressive, yet the cams do not have that 'sewing-machine' sound to them.
The opening side of the cam has a 45.26 degree equivalent Hydraulic Intensity, and the closing side is 62.50 degrees Hydraulic Intensity. The SEATING velocity of the valve is only 37% as fast as the OPENING velocity. This seating velocity is only slightly faster than GM uses on all their engines. At UltraDyne, I have had many hydraulic, as well as solids, go over 100,000 miles on the street. I keep the edge of the tappet about .018" away from the point of contact between the cam and tappet.
That 'sewing-machine' sound is caused by the valves hitting the valve seats too fast. The original High Energy cams, which I designed, produced that sound. I was shutting the valve at .0007"/*, only .0002"/* faster than GM. After hearing about the noise, a little thought made me realize the .0002"/* was only 40% faster than GM.
You do not have to shut the valve faster to keep the charge from getting out.
You have to design the cam so the charge, or inertia ram, is still filling the cylinder when you shut the valve.
Every cam I design, hydraulic, hydraulic roller, solid, solid roller, is designed using the same theory I have used for the past 29 years, and they all make excellent bottom-end torque for their duration."

Edited by - Steve C. on 15 Sep 2018 12:18:35 PM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 15 Sep 2018 :  12:20:07 PM  Show Profile  Reply with Quote
Also Paul Carter has posted valuable information regarding a Voodoo cam with a 110 lobe separation with very specific information presented on that subject as to why they are much different than other cams, such as the Comp XE flat tappet lobes.

I believe he touches base on that subject here:

http://forums.maxperformanceinc.com/forums/showthread.php?t=817316&highlight=Voodoo&page=2


And one of many related comments originally Posted by Paul Carter:

"We all know that wider lobe seps make less peak power than narrower lobe seps, but in a broader RPM range. More average power. Certain lobe designs, by nature, benefit from wide lobe seps, while other lobes benefit from tighter lobe seps. If you have a lobe design that when ground on a 110? LSA, has a power band as broad as another lobe design ground on a 112? or 114? LSA, why not take advantage of the extra power if your not running the cam out of it's power band in the first place?"

"Let me make one thing perfectly clear. When I talk about narrower lobe sep cams in big engines, I am specifically talking about Harold cams. Not Comp XE or anyone else's tight LSA cams. Harold did many things differently to his lobes. Things NO ONE ELSE DID! These subtle little things created lobes that when ground on a 110 LSA, gave the power band performance of a cam ground on a 112-114 LSA. Just look at some of the Voodoo lobes."

http://forums.maxperformanceinc.com/forums/showthread.php?t=775018&highlight=Voodoo+lobe+separation&page=16

Edited by - Steve C. on 15 Sep 2018 12:21:11 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 15 Sep 2018 :  2:13:21 PM  Show Profile  Reply with Quote
How rough do you want the idle?

Bullet and comp both have a wide selection of custom profiles in hydrualics. Comp are not all in there catelog though.

To me the more power with tighter lsa only hold true if you change the lsa only on the same cam. Can usually change the engine in another area and make up the hp or surpass it. Cams are always making compromises somewhere imo jay

Edited by - Corncob2061 on 15 Sep 2018 2:17:58 PM
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beertracker
Cochise

387 Posts

Posted - 15 Sep 2018 :  7:33:56 PM  Show Profile  Reply with Quote
I haven't had time to read all the responses but to answer your question. Some idle lope would be good but it's not a deal breaker on cam selection. I wonder if there is a way to make a non-lopey cam lopey in a 455?

Here is another data point that I don't know is valid or not. On Desktop Dyno 2000 I ran a simulation with a XE274h and VooDoo 268/276 and the XE274h had slightly higher hp and torque. I don't know how accurate Desktop Dyno 2000 is compared to a fly wheel dyno or if Desktop Dyno 2000 comprehends fast ramp cams?

bt
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Corncob2061
Cochise

USA
266 Posts

Posted - 16 Sep 2018 :  01:23:50 AM  Show Profile  Reply with Quote
I had a desktop dyno 2000 at one time. It seems like it did have a ramp rate that you could increase manually for a more accurate simulation for the faster rate cams. It had some other issues if I remember correctly, it would not accurately represent the gain in intake air volocity from big strokes very well. I bet if you plug a 3.75 stroke in instead of the 4.21 it would say the 3.75 makes about 15 more hp, which is not at all correct real world. Compcams cam quest is the same way. You can make them work but you have to find a real world dyno example and calibate the numbers with either flow or make the bore bigger and with shorter stroke. Then make small changes and look for trends.

The 274xe usually fairs well on simulators. I ussually add 5 degrees to the voodoo cams to get more accurate comparisons to the xe comps. Not sure if it is becuase they are rated conservatively, or if it is the way they are ground. I know I have seen old cam cards on the 704 voodoo that said advertised duration is 281/ 289 when they were advertise it as 276/284. Which to me fits more the way they act. Either way, they simply tolerate more compression than an xe and rev more for the same .050 specs.

To make a cam lope more leave the intake closing and exhuast opening the same and increase the overlap. Which tightens the lsa up increases the duration a few degrees. Rocker arms at another good way to make it lope more. A summit 2800 with 1.73 sounds like a 2801 with 1.5s. That combined with different ramp rates and LSA changes you can do all kinds of stuff.

Fuel mileage would be the next question. The bigger exhaust duration on the split cams do no favors too low end torque or mileage. Leaving the intake centerline and overlap same, you can open the exhuast valve later and help torque and economy. But it comes at the expenses of hp up top. I have had cars get in the 20s doing that, but I ussually go back to a split cam becuase I would rather have the hp.

Picking Cams are a lot like the fella on Happy Gilmore trying too explain too Happy how to get the golf ball in the whole. In the end you just want to pull the shirt over the guys head, punch him, and send him rolling down the hill. :) Jay

Edited by - Corncob2061 on 16 Sep 2018 01:54:52 AM
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Corncob2061
Cochise

USA
266 Posts

Posted - 16 Sep 2018 :  08:07:07 AM  Show Profile  Reply with Quote
I think a custom xe or voodoo grind would be good possibity too. A xe274 cam, with the intake lobe exactly like an out of the box xe274. But paired up with the 268xe exhuast lobe. So it would be 274 on 106 ICL, 230 @ .050 on the intake. And 280 on 111 EXh centerline with 230 at .050. The LSA would be 108.5 if I am thinking correctly. That would open the exhuast valve 6 degrees later in the power stroke., but everything else would be the same as an out of the box xe or voodoo. It would have close to the xe274 power and the xe268 torque and economy. And work fine with 9 compression. Could do the same with a voodoo too.

Better yet, since it is a 455 with ported heads and headers, jump up a size too the xe 278 on the intake, run the exhuast from the xe274, which is 286. And do the same thing with the Icl on 106 and the lsa on 108.5. 278/286 234/236 106/109 But put rhoads vmax on and set the lash at about .010. Or the voodoo 704, 276 with the 703s exhuast lobe.

Jay
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Corncob2061
Cochise

USA
266 Posts

Posted - 17 Sep 2018 :  10:40:22 AM  Show Profile  Reply with Quote
Steve, I was thinking about the 53.88 avg intensity number that Harold mentioned on your post above. Comparing that info to the old cam card from the 704 voodoo. 233@.050 plus 53.88 is 286.88 at .004 tappet lift. EDIT: Harold said from an old post to add 3 degrees to valve timing events to convert from .006 to .004 ratings on voodoo cams. So that is 6 degrees, that according to UDHarold gives gives you the .006 rating.

286.88-6=280.66 The old cam card said 281....

Just looking at static numbers for cam designs. No more no less. Jay

Edited by - Corncob2061 on 20 Sep 2018 12:33:08 AM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 17 Sep 2018 :  2:07:13 PM  Show Profile  Reply with Quote
My post was more toward the choice between the XE cam and the Voodoo cam regarding valve train noise, aka "the sewing machine" sound many don't like with XE cams. I neglected to say that, sorry for the confusion. That said, like the older UltraDyne lobes the Voodoo lobes are supposed to be quieter.

And as brought up here the intensity is difficult to measure because with most cams today the opening side is different that the closing side. Also related, note David Vizard's comments here regarding hydraulic intensity that might be of interest....

http://www.enginebuildermag.com/2006/07/vizards-view-avoiding-flat-tappet-cam-and-lifter-failure/

Not directly related here because of the type of cam in the subject and concerns with valve lash but note Mike Jones comments about intensity and the suggestion it's a marketing tool....

https://www.yellowbullet.com/forum/showthread.php?t=455257


.

Edited by - Steve C. on 17 Sep 2018 2:10:51 PM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 17 Sep 2018 :  10:04:53 PM  Show Profile  Reply with Quote
Edit of my last post, I meant to say:

That said, like the older UltraDyne lobes the Voodoo lobes are supposed to be quieter than the XE lobes.


.



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Corncob2061
Cochise

USA
266 Posts

Posted - 18 Sep 2018 :  10:30:32 AM  Show Profile  Reply with Quote
No confusion Steve, you are on target, I am the one that took the detour. It is amazing how much we can see Harolds fingerprints through out the aftermarket cam world now from his time at comp, UD, Lunati, and the consulting he did for other companies. There is a ton of info in that first post about cam design. And those posts from Jones and Vizard just reinforce it.

Back to topic, looking at cams from different companies

Summit, and more generic grinds
Summit 2801 and similar grinds would work good in a 9:1 455 with 1.6 rockers, smallest cam pick for this , max power all in at 4600rpm or so. Crower has a similar grind, as does lunati, melling, speed pro, etc,etc. The 1.6 help wake it up. The 2802 makes more power but will not make the low end torque of the 2801, the 2802 likes more compression due to the 114 lsa. The 2802 and Rhoads lifters would be ok, out performing the 2801 easily. Crane has a nearly identical cam to the 2802, as does Speed pro.

Lunati
Voodoo 702 is a great cam for a highway geared low compression 455, but if you do not mind a little rougher idle, I would move up to the 703, the narrower lsa boosts hp and does not loose much low end torque. The 703 is a big as I would go with 1.6 rockers. 704 would need more converter and the 1.6 ratio is getting to the point valve springs are a bit problematic on the exh lift.

Comps cams
Comp 268xe, absolutely the smallest xe grind for this imo, and my choice over the xe274 as long as you have 1.6 rockers. 276 ah10 another good choice if your looking at comp cams. With rhoads and the 1.6 rocker it would run really good.

Crower
The crower 60243 would be great with 1.6 rockers and Rhoads lifters, better power wise than the summit 2801/Crower 60918 imo, and close to the comp 276ah10, more compression would be better though, maybe 9.5. And the 60919 needs more compression 9.7+ and converter, rhoads would be a must, but it and the ram air 4 type grinds have been good combos with the rhoads.

Bullet
Bullet has a bunch of profiles that would work good here too. Especially if you want a cam custom to your own combo.. With the 1.6 rockers there are some profiles the would work better than the voodoos, especially if your considering bigger cams up in the 230 to 235 at .050 range. You can tailor the lift more becuase they have more choices for hyd grinds, at least ones that you can look at from their profile list. Imo Jay



Edited by - Corncob2061 on 18 Sep 2018 10:47:26 AM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 18 Sep 2018 :  12:08:24 PM  Show Profile  Reply with Quote
With the mention of Summit and Crower that brings up another topic of interest.
In conjunction with a LOWER static compression ratio note how the seat timing (advertised duration) will make a difference between two similar cams. How it can affect the cranking compression, effective compression ratio, dynamic compression ratio, overlap, etc.

For conversation note these two cams below, both with a similar amount of intake duration at .050" and with the same 112 lobe separation. But note the difference in their seat timing. Yes, there could be some apples-to-apples conflict as to what tappet lift they both are rated it. Example, I've called Crower tech on two different occasions and asked at what tappet lift they rate their hydraulic flat tappet cams. One said .005" and one stated .006" ! Set this aside and for evaluation just use the published numbers here.

Crower 60916
278 / 289 advertised
221 / 220 at .050"
112 LS
.455" / .470" lift

Voodoo 702
262 / 268 advertised
219 / 227 at .050"
112 LS
.468" / .489" lift

Use the necessary calculators here:
http://www.wallaceracing.com/Calculators.htm

For timing events, when the intake valve closes, use this calculator:
http://www.wallaceracing.com/cam-deg-calc.php

Also note the Voodoo lobe has additional, and beneficial, valve lift. A separate topic in itself, why a typical 2-valve engine responds to high lift.

.

Edited by - Steve C. on 18 Sep 2018 12:35:33 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 18 Sep 2018 :  11:45:33 PM  Show Profile  Reply with Quote
When you run the numbers the dynamic compression on the voodoo 702 and 703 are nearly identical.

Of all the out of the box cams listed I think my top two picks are 1st the 703, and 2nd the 276ah10 Comp. I would run vmaxs on both, can always zero the lash if you do not like what they do.

One think I do like about the comps is they seem to spend more time developing lobes that are designed for the exhuast only. Were as the lunati use the same profiles on either intake or exhaust. At least it appears that way looking at the specs. I could be wrong. Jay
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Corncob2061
Cochise

USA
266 Posts

Posted - 20 Sep 2018 :  12:25:46 AM  Show Profile  Reply with Quote
I made some edits above after doing some thinking, finding some old UDharold posts, and spending a little time on a simulator for this combo. When I put in the lunati numbers for the 268 voodoo using the new cam card number 268/276 I was coming up with the same hp and tq numbers as the comp 274 xe. 415@5000 rpm. And the 276ah10 was a 422 hp at 5000. When I changed the seat timing to the old numbers on the cam card 273/281 it said 420 hp. I thought that was interesting, simulator was wanting more seat timing. Jay

Edited by - Corncob2061 on 20 Sep 2018 12:26:50 AM
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beertracker
Cochise

387 Posts

Posted - 25 Sep 2018 :  3:33:08 PM  Show Profile  Reply with Quote
Good cam company summary. I can use a 1.6 rocker ratio. I am leaning toward the Comp XE274H. I like the Voodoo 703 but I read Paul C. said the 703 in a 455 has a smooth idle. I would like a little lopey or roughness & I don't haven enough axle ratio for the 704. So this rules out Voodoo 703 & 704.

FWIW, I can mill my 6x-8 iron heads to achieve 9.5 CR.

bt


quote:
Originally posted by Corncob2061

No confusion Steve, you are on target, I am the one that took the detour. It is amazing how much we can see Harolds fingerprints through out the aftermarket cam world now from his time at comp, UD, Lunati, and the consulting he did for other companies. There is a ton of info in that first post about cam design. And those posts from Jones and Vizard just reinforce it.

Back to topic, looking at cams from different companies

Summit, and more generic grinds
Summit 2801 and similar grinds would work good in a 9:1 455 with 1.6 rockers, smallest cam pick for this , max power all in at 4600rpm or so. Crower has a similar grind, as does lunati, melling, speed pro, etc,etc. The 1.6 help wake it up. The 2802 makes more power but will not make the low end torque of the 2801, the 2802 likes more compression due to the 114 lsa. The 2802 and Rhoads lifters would be ok, out performing the 2801 easily. Crane has a nearly identical cam to the 2802, as does Speed pro.

Lunati
Voodoo 702 is a great cam for a highway geared low compression 455, but if you do not mind a little rougher idle, I would move up to the 703, the narrower lsa boosts hp and does not loose much low end torque. The 703 is a big as I would go with 1.6 rockers. 704 would need more converter and the 1.6 ratio is getting to the point valve springs are a bit problematic on the exh lift.

Comps cams
Comp 268xe, absolutely the smallest xe grind for this imo, and my choice over the xe274 as long as you have 1.6 rockers. 276 ah10 another good choice if your looking at comp cams. With rhoads and the 1.6 rocker it would run really good.

Crower
The crower 60243 would be great with 1.6 rockers and Rhoads lifters, better power wise than the summit 2801/Crower 60918 imo, and close to the comp 276ah10, more compression would be better though, maybe 9.5. And the 60919 needs more compression 9.7+ and converter, rhoads would be a must, but it and the ram air 4 type grinds have been good combos with the rhoads.

Bullet
Bullet has a bunch of profiles that would work good here too. Especially if you want a cam custom to your own combo.. With the 1.6 rockers there are some profiles the would work better than the voodoos, especially if your considering bigger cams up in the 230 to 235 at .050 range. You can tailor the lift more becuase they have more choices for hyd grinds, at least ones that you can look at from their profile list. Imo Jay




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Corncob2061
Cochise

USA
266 Posts

Posted - 25 Sep 2018 :  10:44:50 PM  Show Profile  Reply with Quote
I was curious to hear the xe274 and lunati 703 side by side, I think the xe does sound a little rougher considering the 703 I found is a 400. I think I would leave the compression at 9ish if you go with the 274xe.

XE 274 in a 455
https://m.youtube.com/watch?v=xBtwPqlSH7c

703 lunati in a 400

https://m.youtube.com/watch?v=w_RmgPVNwMI

Edited by - Corncob2061 on 25 Sep 2018 10:59:54 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 27 Sep 2018 :  12:40:46 AM  Show Profile  Reply with Quote
For 9.5 compression:

If you do end up with 9.5 static compression with the 274xe I think you should have 180 psi or higher cylinder pressure. I think it would be ok most of the time on 91 octane, but it is right at the threshold of having problems from my experience. At 9.5 compression I would do a custom comp and use the xe 278 intake and the 274xe exhaust lobe at 110lsa. It would behave like the xe 274 at 9 to 1 with more top power and similar torque. It would idle a little choppier than the xe 274. It is easy to have comp grind a custom cam. The last time I did it it took longer to give them the credit card info than the cam grind number.

If you were going with the lunati at 9.5 compression I would jump up to the 704 from the 703. It is a tall gear with a low stall. But it is also a 455. It is still going to blaze the tires.
Jay


Edited by - Corncob2061 on 27 Sep 2018 01:10:26 AM
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tjs44
Crazy Horse

USA
533 Posts

Posted - 27 Sep 2018 :  5:46:13 PM  Show Profile  Reply with Quote
Or instead of putting it in at 5 degree advance like im sure they would recommend put it in a 2.I had to do that with a SPII in my 455 and also with the 068 in my 421.The 455 also made more HP when we did it.Had the 421 on a run stand and not the pump.Tom
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Corncob2061
Cochise

USA
266 Posts

Posted - 27 Sep 2018 :  7:20:22 PM  Show Profile  Reply with Quote
The 2 degrees of the timing instead of 5 would be a good idea with the the xe274 or xe278 if the compression is pushed up. Not much difference in those cams.

Tom, did advancing the 068 work out for you? I remeber seeing you did that recently. Jay
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tjs44
Crazy Horse

USA
533 Posts

Posted - 27 Sep 2018 :  8:24:44 PM  Show Profile  Reply with Quote
Yes,got me up about 10lb.Runs great.Tom
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beertracker
Cochise

387 Posts

Posted - 27 Sep 2018 :  8:38:13 PM  Show Profile  Reply with Quote
Here is a Voodoo 704 in a Pontiac 455. Definately some loping.
https://www.youtube.com/watch?v=aMi5XAQUYME

I wonder what the street manners would be with this cam and my setup?
With this cam my cr would be 9.5. I am concerned about vacuum for PB, 2.78 gear and 2300 rpm stall converter.

bt



quote:
Originally posted by Corncob2061

I was curious to hear the xe274 and lunati 703 side by side, I think the xe does sound a little rougher considering the 703 I found is a 400. I think I would leave the compression at 9ish if you go with the 274xe.

XE 274 in a 455
https://m.youtube.com/watch?v=xBtwPqlSH7c

703 lunati in a 400

https://m.youtube.com/watch?v=w_RmgPVNwMI


Edited by - beertracker on 04 Oct 2018 5:58:24 PM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 28 Sep 2018 :  10:28:08 AM  Show Profile  Reply with Quote
"I put the 703 in a 9.2:1 455 that was basically stock with iron D-port heads. It made 400 HP from 4700-5200 RPM, and made like 528 ft. lbs.. According to the customer, it makes 14" of vacuum at 5000 ft. elevation. Works his brakes good. It has a real good idle also. The Lunati description of the 702 cam as being choppy idle is totally wrong. I put that cam in a 328 and it wasn't choppy. It will be baby smooth in a 455. The 703 was smooth in a 455. The 704 has a slightly noticeable idle in a 455. The 702 will probably come out somewhere in the 108-109 degree range if you install it straight up. But there are so many variables that could affect the cam timing that it is best to degree them. The Voodoos are especially sensitive to where they are installed. They like to be advanced at least 4-6 degrees."

Paul Carter
Koerner Racing Engines
520-294-5758


Call him !

.

Edited by - Steve C. on 28 Sep 2018 10:29:47 AM
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Corncob2061
Cochise

USA
266 Posts

Posted - 01 Oct 2018 :  12:11:30 AM  Show Profile  Reply with Quote
It is a custom profile in a Pontiac. The lobe number 5446 in the xe section of the lobe profiles and it has the ex274 exhuast 5208 lobe put on it. It is 278 at .006 and 234 at .050 in your simulator, intake closing 65, 33 open if the Icl is 106, .498 lift with 1.5 rockers.
Could go higher than 9 on that. Up to 9.5. Desktop 2000 is problably going to like it retarded to a fair amount . 108 Icl if 9.5.

All the catalog cams have the lobes listed in the comp masters catalog, Jay

http://www.compcams.com/Technical/Catalogs/CamLobeMasterCatalog.pdf

Edited by - Corncob2061 on 01 Oct 2018 09:20:15 AM
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beertracker
Cochise

387 Posts

Posted - 02 Oct 2018 :  5:47:23 PM  Show Profile  Reply with Quote
Here are the Desktop Dyno 2000 results for the Comp Custom Profile and stock XE274 cams. One test parameter has been changed per test run. My goals are a lopey or rough idle, 112 LSA and 500 lb ft of torque. I know can't have every thing.

Comp Custom Cam lobes 5446 & 5208.
CR LSA I\E Lift adv\ret ICL
9.5 110 .498\.491 0 108
429hp @ 5000rpm 493 lb ft @ 4000 rpm

112
425hp @ 5000rpm 499 lb ft @ 3500 rpm

110 .531\.523
433hp @ 5000 rpm 495 lb ft @ 4000 rpm

112
429hp @ 5000 rpm 501 lb ft @ 4000 rpm

Comp Cams XE274H
CR LSA I\E Lift adv\ret ICL CR is 9.1 to keep cylinder pressure in check.
9.1 110 .523 0 106
422hp @ 5000 rpm 496 lb ft @ 3500 rpm

112
413 hp @ 5000 rpm 499 lb ft @ 3500 rpm

110 .488\.491
418hp @ 5000 rpm 495 lb ft @ 3500 rpm

112
408 hp @ 5000 rpm 498 lb ft @ 3500 rpm

I don't see a great deal of difference in these numbers. Retarding the cam did not help performance however a slight advance did improve the numbers slightly.

I like the 1) XE274 numbers of 413hp\499lb ft and 2) Custom Profile 425hp\499 lb ft. So does the difference in numbers justify ordering a Comp Custom Profile cam? Does Comp charge extra for acustom cam?

Given the results I believe my ported 6x-8 heads are the bottleneck. I don't have enough flow to get better hp and torque numbers.

Regards,
bt
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 02 Oct 2018 :  7:29:48 PM  Show Profile  Reply with Quote
Here is the Pontiac XE274H cam:

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1204&sb=2

From it note the specifications listed for the intake & exhaust lobes, then match them up here:

http://www.compcams.com/Technical/Catalogs/CamLobeMasterCatalog.pdf

Actually it uses lobes 5445 & 5208


If you wanted it with a 112 lobe separation Butler could do it for $189.95

https://butlerperformance.com/i-24623475-comp-cams-custom-grind-hydraulic-flat-tappet-camshaft-cca-51-000-5.html

Similar at Summit:

https://www.summitracing.com/parts/cca-51-000-5

Comp Cams or other sources can do the same.


.

Edited by - Steve C. on 02 Oct 2018 7:50:56 PM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 02 Oct 2018 :  7:49:41 PM  Show Profile  Reply with Quote
The Voodoo lobes can easily be custom ground with any lobe separation. Now Compare them with your Desktop Dyno.

http://www.lunatipower.com/ProductGroup.aspx?id=287&cid=75


.

Edited by - Steve C. on 02 Oct 2018 7:50:16 PM
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beertracker
Cochise

387 Posts

Posted - 02 Oct 2018 :  7:53:19 PM  Show Profile  Reply with Quote
Is valve spring instability going to be a concern with a lift of .531"? Lobe 5446 came fron Corncob2061's post above. bt
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 02 Oct 2018 :  8:41:31 PM  Show Profile  Reply with Quote
"Always run enough seat pressure to control the valve action as it returns to the seat. Heavier valves require more seat pressure. Strong, lightweight valves require less seat pressure. When in doubt, run slightly more seat pressure . . . not less."
Crane Cams

That said, seat pressure alone doesn't tell the whole story with valve springs, much will depend on which springs you intend on using. A lot more than the valve lift involved. With the XE flat tappet lobes I'd personally use at least 115-120 minimum on the seat.

And the obvious, Desktop Dyno is just a simulation, but It's still fun To play with. It's value to me would be to note trends with changes made.

.

Edited by - Steve C. on 02 Oct 2018 8:42:12 PM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 02 Oct 2018 :  9:16:59 PM  Show Profile  Reply with Quote
Go back to my previous post regarding a LOWER static compression ratio and the topic of how the seat timing (advertised duration) will make a difference between two similar cams. In addition to this do your homework and note how a wider lobe separation also effects a LOWER static compression ratio.

http://www.compcams.com/Pages/413/cam-timing-lobe-separation-angle.aspx

.



Edited by - Steve C. on 02 Oct 2018 9:21:38 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 02 Oct 2018 :  9:24:34 PM  Show Profile  Reply with Quote
Lift is basically the same between .531 and .523. Not really difficult to find springs until the .57 range. The xe cams struggle more past 5k than the lunati. I would not widen a bigger xe to 112 unless you have 45 degree intake valves like a eddy or Kre head. The 274 probably ok yet, it will lope less, but you would be good up to 9.5 compression imo.

Not much difference power wise between any of those simulations. The 108 lsa xe278 int 274exhuast combo is more a combo I run that seems to do better fuel mileage wise. Not trying to talk you into it though. Most engines that run a 108 lsa cam have a 102 or 104 intake centerline and build to a lot of compression. 106 to 108 is retarded a fair amount, combined with higher compression it seems to be easier on gas. It does gives up some power up top compared to a wider lsa cam.

Is it worth it? Another 50 dollars for a custom cam sound reasonable to me. I guess it depends on how your going to drive it and what you want the idle to sound like. Widening the lsa will make it idle better with higher vacuum. If you want a loppier idle than a xe274 the only good choice I see for comp in an xe is the xe278 intake profile with the xe274 exhuast on 108, 109, or 110..Jay


Edited by - Corncob2061 on 02 Oct 2018 11:37:39 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 02 Oct 2018 :  10:38:09 PM  Show Profile  Reply with Quote
How ported are your heads? Guesstimate?
Jay
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beertracker
Cochise

387 Posts

Posted - 03 Oct 2018 :  12:31:53 AM  Show Profile  Reply with Quote
quote:
Originally posted by Corncob2061

How ported are your heads? Guesstimate?
Jay


I ported my heads per Jim Hand's book. He published numbers for 6x ported heads and I imported these into my flow file. Here are the numbers.

3.10
Jim Hand 6x ported Pont head
0
6
1 2.110000
1 25.000000
1 0.200000
1 0.300000
1 0.400000
1 0.500000
1 0.550000
1 0.600000
1 155.000000
1 203.000000
1 234.000000
1 245.000000
1 247.000000
1 248.000000
1 1.660000
1 25.000000
1 0.200000
1 0.300000
1 0.400000
1 0.500000
1 0.550000
1 0.600000
1 109.000000
1 139.000000
1 180.000000
1 202.000000
1 206.000000
1 207.000000

bt
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Corncob2061
Cochise

USA
266 Posts

Posted - 03 Oct 2018 :  10:23:29 AM  Show Profile  Reply with Quote
I have that file in my simulator to. I have ran a bunch of sumulations with that head. All my current pontiac engine are ported past Hands example, at least they are now. Good heads though, they really keep up with the out of the box aftermarket heads up to the .55 range. It is enough head to make good power on a 469 up to 5500. But unless you either have a bigger converter or Rhoads lifters it is just giving up to much torque for a 2500 stall and 2.78 gears.

If it was mine, and I am using a comp and not a lunati. I would sub in the 5240 magnum comp lobe for the 274xe and still run the 274xe 5208 xe profile on the exhaust. Your engine will benifit hp from the extra seat timing over a xe 274 or a xe 278 profile, less valve noise, more hp increase than the simulator is going show after 5000 rpm because of valve terrain stablity, especially with 1.6 rockers. Works much better with the 30 degree intake seat, more compression tolerant, and will be better at the 112 lsa than the 274xe imo. 280/286 232/236 112LSA with 1.6 rockers. Then go for 2 points instead of a field goal, and put rhoads vmaxs on it. Zero them out to make them do nothing, or crank them open at the track and make some really serious torque. Jay

Edited by - Corncob2061 on 03 Oct 2018 10:26:25 AM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 03 Oct 2018 :  11:09:34 AM  Show Profile  Reply with Quote
On the intake side:
The Magnum lobe- 280 degrees seat timing / 232 @.050
The XE lobe- 274 degrees seat timing / 230 @.050
For general conversation or consideration both lobes have the 'same' or very similar .050 duration and both with the 'same' or very similar lobe lift.

Now Jay's statement...

"I would sub in the 5240 magnum comp lobe for the 274xe...."
"Your engine will benifit hp from the extra seat timing..."

Jay,
Not a recommendation here, but for conversation and your thoughts on this. With the above lobe specs and statements in mind would not the following be considered...

If the cams being compared rate the advertised duration at the same lift, the cam with the shorter advertised duration compared to the 0.050 duration should be the cam with the more aggressive ramps, or quicker opening. A quick opening and closing cam will provide better low end performance than one that is slower opening. Also how about the benefit of the shorter seat time aiding a low compression ratio.


.





Edited by - Steve C. on 03 Oct 2018 11:11:53 AM
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Corncob2061
Cochise

USA
266 Posts

Posted - 03 Oct 2018 :  12:04:40 PM  Show Profile  Reply with Quote
I agree that the xe profile is better on low compression and bottom end torque. If the engine has enough head flow to make hp past 5000 that is the point where I give up on the xe with engines that have 30 degree intake seats. In addition to pontiacs, I have a 455 olds that has ported heads and those 30 degree seats too, plus it has 1.6 rockers. It has the same problem as the pontiacs with the 30s. Seen a lot of xe engines give up after 5k with the 30 degree intakes. And if peak power is higher than 5k, it seems to be consistantly lower than it should be. I am not a xe basher, I love them. Huge fan of the hi lift xe versions for mopars.. Just not after 5k with the 30 degree intakes. The Rhoads lifters on a magnum profile would be better than the xe without them, imo. But 9 to 1, no Rhoads, good heads, that is a tough call whether the xe 274 or the 280 magnum, I think 274xe. At 9.5 if the heads flow as good as Hands book I like the 280 magnum. Which I believe is on step bigger than the intake profile for the 280ah10. Jay

Edited by - Corncob2061 on 04 Oct 2018 08:26:51 AM
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Corncob2061
Cochise

USA
266 Posts

Posted - 03 Oct 2018 :  12:48:50 PM  Show Profile  Reply with Quote
I know that last post is nothing new too you Steve. It was one of the reasons we both said Lanati voodoo at the beginning of this thread.

I have not built a Buick 455, but everything I have seen they work great with an xe past 5k. They have 45 degree seats though. Jay

Edited by - Corncob2061 on 03 Oct 2018 12:49:21 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 03 Oct 2018 :  7:40:17 PM  Show Profile  Reply with Quote
Just to narrow up my remarks:

At 9 ish compression, xe274/xe286 110 lsa, good heads but wanting power all in by 5000, higher compression either change to 112 lsa with smoother idle or 108icl at 110lsa

At 9.5, show car type driving, some occasional 5000 rpm blasts, mindful about economy but desire a ruff idle. Xe278/xe286 108 lsa

At 9.3 to 9.5, max effort hft for 2500 stall and 2.78 gears, jim hand port job, good power up to 52-5500. At 9.5 rhoads vmax recommended but opt, or use at 9 with rhoads:
280mag 5240/xe286 5208 112LSA
Jay

Edited by - Corncob2061 on 04 Oct 2018 08:31:54 AM
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Corncob2061
Cochise

USA
266 Posts

Posted - 05 Oct 2018 :  02:43:03 AM  Show Profile  Reply with Quote
I my opinion, on a typical street engine, it is not worth milling heads for a few tenths of static compression unless your trying to blueprint something. Nothing wrong with max power at or before 5k with a highway gear.

A couple 455s I have either built or helped build similar to this: my favorites are the last two, all in A bodies, jay
455, 068, 1.65s, 3.07 gears
455, 041 hft melling ra 4, 1.5s, 3.23, stock converter
455, 281/291 112lsa hft 2200 stall, 3.23
455, 280/280 110 lsa sft, 2200, 2.78
455, 276/283 112 lsa sft, 3.23, stock stall

Edited by - Corncob2061 on 05 Oct 2018 03:15:29 AM
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Phil
The Great White Buffalo

USA
7284 Posts

Posted - 05 Oct 2018 :  10:31:33 AM  Show Profile  Reply with Quote
I didn't see if it has been asked yet but what trans and tire diameter? Also, whose 2300 stall convertor?

Bowties are for Pee-wee Herman. LS swaps in Pontiacs should only apply to Fieros.
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beertracker
Cochise

387 Posts

Posted - 07 Oct 2018 :  1:05:35 PM  Show Profile  Reply with Quote
quote:
Originally posted by Phil

I didn't see if it has been asked yet but what trans and tire diameter? Also, whose 2300 stall convertor?



th350, P215-60R15, jegs brand. I know Continental is the best.

Edited by - beertracker on 07 Oct 2018 3:36:40 PM
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Corncob2061
Cochise

USA
266 Posts

Posted - 08 Oct 2018 :  10:49:34 AM  Show Profile  Reply with Quote
Soo, I was looking through comps lobe profile catelog this morning. Working on a cam for Chevy 427 W engine, and I noticed that the exhuast profiles in the xe section are all magnum profiles listed again in xe section with the same numbers. I may have knew that and forgot, but I missed that for some earlier postings here. The Xe series are magnums grinds on the exh with a more aggressive intake. Comps 280ah10 and the xe274 both have the magnum for an exhuast profile. Jay

215/60r15, very short tire, 25.2 inches..

Edited by - Corncob2061 on 08 Oct 2018 3:05:51 PM
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 08 Oct 2018 :  1:40:25 PM  Show Profile  Reply with Quote
Pontiac Magnum 280H

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1197&sb=2


Pontiac XE274H

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1204&sb=2


.

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Corncob2061
Cochise

USA
266 Posts

Posted - 08 Oct 2018 :  3:14:52 PM  Show Profile  Reply with Quote
XE268 runs the 280H on the exhaust. 280ah10 uses one profile bigger than the xe274 on the exhuast. Jay

Edited by - Corncob2061 on 08 Oct 2018 3:44:11 PM
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beertracker
Cochise

387 Posts

Posted - 29 Oct 2018 :  11:38:50 PM  Show Profile  Reply with Quote
Does any one know the minimum gear ratio for a Comp 276ah? http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1211&sb=0
I see it's a bracket cam. bt
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Corncob2061
Cochise

USA
266 Posts

Posted - 30 Oct 2018 :  09:11:44 AM  Show Profile  Reply with Quote
In a 455 that cam should work with about any highway gear. Only reason they list it as a bracket cam is the specs are listed with 1.65 rocker arms. It runs comps magnum profiles on the intake and the exh.
Jay
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Steve C.
Chief PONTIAC

1882 Posts

Posted - 30 Oct 2018 :  1:01:34 PM  Show Profile  Reply with Quote
http://www.lunatipower.com/Product.aspx?id=1776&gid=287

And again, take all these descriptions listed in ALL the cam companies note with a big grain of salt !

.

Edited by - Steve C. on 30 Oct 2018 1:03:27 PM
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tjs44
Crazy Horse

USA
533 Posts

Posted - 31 Oct 2018 :  7:23:01 PM  Show Profile  Reply with Quote
2X Steve!Tom
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beertracker
Cochise

387 Posts

Posted - 07 Nov 2018 :  4:10:39 PM  Show Profile  Reply with Quote
quote:
Originally posted by Corncob2061

For 9.5 compression:

If you do end up with 9.5 static compression with the 274xe I think you should have 180 psi or higher cylinder pressure. I think it would be ok most of the time on 91 octane, but it is right at the threshold of having problems from my experience. At 9.5 compression I would do a custom comp and use the xe 278 intake and the 274xe exhaust lobe at 110lsa. It would behave like the xe 274 at 9 to 1 with more top power and similar torque. It would idle a little choppier than the xe 274. It is easy to have comp grind a custom cam. The last time I did it it took longer to give them the credit card info than the cam grind number.

If you were going with the lunati at 9.5 compression I would jump up to the 704 from the 703. It is a tall gear with a low stall. But it is also a 455. It is still going to blaze the tires.
Jay


When you say "higher cylinder pressure" is this the same as cranking compression? I am looking for a calculator so I re-check this. Shoul d I use Wallace Cranking Compression Calculator? bt
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beertracker
Cochise

387 Posts

Posted - 07 Nov 2018 :  5:38:09 PM  Show Profile  Reply with Quote
With Desktop Dyno I checked UD 288/296, Comp 276ah-10, Voodoo 268, Voodoo 276, Comp XE and a XE custom. Not wanting the valve train noise I ruled out XE series cams. The top two simulation winners are:

LSA/ICl ADV CR Max HP Max Torque Valve Lift

Comp 276ah 110/106 2 9.1 406 @5000 rpm 496 @3500 rpm 1.5 x lobe height
Voodoo 268 110/106 4 9.1 410 @5000 rpm 488 @3500 rpm 1.5 x lobe height

Not much difference between the two. Isn't the 276ah going to have more off seat time than the 268? I need to check cylinder pressure to make sure it's below 180 psi? I wonder if I have my simulator setup right? Do these numbers look valid?

I noticed my numbers for the Voodoo 268 are much lower than Paul Carters crank dyno for the same cam. I suppose this is due to the difference between a software simulator and crank dyno. One crunches numbers whereas the other measures at the crank.

When I started this exercise my goal was 500 lb-ft of torque, hp didn't matter to me. Well, I got close. Unless I learn more my choice is the Voodoo 268. Driveability is a concern.

As mentioned previously a good custom cam may be a combination of UD lobes. Since I don't have much experience in custom cam design I wouldn't know which lobes to begin with?? bt


Edited by - beertracker on 09 Nov 2018 10:29:07 AM
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