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 Intake / Carb and Fuel Delivery Tech
 Running on e85 fuel, results
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Aguila1
Buffalo

USA
85 Posts

Posted - 06 Sep 2010 :  11:27:38 AM  Show Profile  Reply with Quote
After studying Cliff Ruggles' excellent book, "How to Rebuild and Modify Rochester Quadrajet Carburetors", I began to rebuild the carburetor with the idea of converting it to a dedicated e85 carb. The trick, of course, is understanding that the carb needs to be "fattened up" somewhere between 17% and 34% to create the proper richer air/fuel ratio. I based this on the recommended 20-40% increase to run pure ethanol and adjusted down to compensate for the 15% gasoline in the fuel.

A great help in understanding tuning and the importance of calculating the metering area was found in the online essay, "How to Tune a Q-Jet" by Lars Grimsrud. He is considered a master tuner and has numerous technical essays online.

The carb I purchased for modification is from a 1976 Pontiac 400 or 455 application, identical part number to the one on the car. I ended up modifying the original carb and the newly rebuilt one, back and forth, until I started seeing improvements.

I am not finished finely tuning both carbs, yet, but I've achieved some interesting results that run contrary to what some have said I should expect from the conversion, namely a loss of fuel economy and a drop in power. Instead, the highway fuel mileage is the same with what the car ran before, that is, on economy conservative driving mode, which is what concerns me. Of course, it sucks down fuel at WOT, just as any powerful engine will, but it doesn't appear to be any worse than on gasoline, nor do I care. The power is roughly equal or even slightly better, judging by testing with the G-Tech performance computer and quarter mile trap speeds.

Driveability is excellent: I had to adjust the idle mixture screws out 6 1/2 turns to get the highest and steadiest vacuum readings. I also advanced the distributor a bit, though some argue e85 likes to be retarded a little and I need to experiment more to see which produces the highest trap speeds. Subjectively, the engine seems to idle more smoothly and also seems to run quieter, especially noticeable at idle and low cruising speeds. The car also seems to produce more bottom-end torque judging by how easily the tires spin, though the computer has not picked up this difference.

Overall, I'm very pleased with the performance on e85 and feel there's still plenty of room for improvement to optimize the engine for this fuel, such as raising the compression. It's like having the luxury of running 105 octane racing fuel all the time with the added benefit of chemical intercooling.

Thanks to Cliff for answering some of my technical questions and great service in getting the rebuild kit I needed and repairing my throttle plate. And thanks to Lars for posting much-needed tuning advice for free.

This is my combo so far for my 455 with 6x heads: #80 primary jets with .044 primary rods, .135 fuel inlet seat, .094 idle mixture screw holes, small nitrophyl float adjusted to within 1/4 of the top, CH secondary metering rods. APT adjusted as per Lars' instructions. I'll post updated modifications if they result in a measurable improvement in performance.

Note: I'd also like to suggest that my fuel consumption may have been much better on the original (before converting to e85) gasoline settings if it wasn't running so rich. The best I've been able to achieve was close to 16 mpg, (4L60 2.73 gears) and that is what I'm getting on e85. Still, I'm skeptical I could ever get 20 mpg on gasoline under even the best circumstances, (though I once got 24 mpg going downhill from the mountains to the piedmont!) Also, I am not tuning with a wideband air/fuel meter, yet, so I can't quantify how lean it is running, however the engine seems to "like" the new fuel and the temperature gauge is cool as always, detonation non-existent.

With e85 able to support 14 or 15:1 compression ratios or high-boost in supercharged applications, the potential for super power increases surpasses pump gas applications.

I'd like others to post their experiences with this fuel, rather than opinions based on unproven assumptions.






1979 Pontiac Firebird Trans Am custom, shaved, House of Kolor Kandy tangerine base coat, airbrush graphics, 462 w/ 1968 #16 heads, 13:1 compression, Ross pistons, Crower Sportsman rods, Pro-Gram billet 4-bolt main caps, Crower 60919 cam, 4L60, powered by e85.

Phil
The Great White Buffalo

USA
7216 Posts

Posted - 06 Sep 2010 :  12:38:46 PM  Show Profile  Reply with Quote
Excellent post! Welcome to PSP. Any chance of seeing a couple pics. of that that tangerine T/A?

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Aguila1
Buffalo

USA
85 Posts

Posted - 06 Sep 2010 :  10:35:15 PM  Show Profile  Reply with Quote
Thank you for your compliment. I've posted this on a few other forums and have met with some hostility for the political forces rallied against this fuel. As I have responded: The question is not why use ethanol, but why switch back to gasoline (as long as it is available)? I will update as I improve the performance of the engine and continue to test and learn more.

I don't know how to attach a photo so here's a link to CarDomain and my apologies beforehand if this is against the rules:

http://www.cardomain.com/ride/2973935/

1979 Pontiac Firebird Trans Am custom, shaved, House of Kolor Kandy tangerine base coat, airbrush graphics, 462 w/ 1968 #16 heads, 13:1 compression, Ross pistons, Crower Sportsman rods, Pro-Gram billet 4-bolt main caps, Crower 60919 cam, 4L60, powered by e85.
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Chicagogoat
Cochise

USA
823 Posts

Posted - 06 Sep 2010 :  11:17:21 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
Jose, supurb ride!I read your informative post on the other site. I have noticed over the past few years that alot of guys are going to E-85 in our hobby, noticed a lot of good deals on perfectly good used hand me down carbs lately also. But these guys are usually not willing to give away to much info. I think that most of the haters you've encountered our simply going by the fact that E-85 was supposed to be a better alternative for our everyday vehicles. They don't realize that this has truly become an underground breakthough for hi-po street an of course racing.
Funny part is that this was supposed to reduce our reliance on foreign oil and be cheaper, but I've never noticed E-85 cheaper then .25 in my area. Plus the reports of reduced fuel eco. has'nt helped the public perception. Imagine that you can now viably build higher comp. mills with the added cooling effect the fuel provides. Al Gore must be P.O.'ed!
BTW my first car was a gold 79 formula 400. Another story of one that got away....

Pure Pontiac: learn it, live it, love it!

Edited by - Chicagogoat on 06 Sep 2010 11:23:54 PM
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BearGFR
Bear

USA
580 Posts

Posted - 07 Sep 2010 :  12:13:03 PM  Show Profile  Visit BearGFR's Homepage  Reply with Quote
Now there's an idea that got right by me. How available is E85? Enough so to make it 'safe' to go on a road trip to "anywhere" and still be able to refuel? And what about valve seat lubrication --- are the concerns with E85 the same as with unleaded gasoline - (varying from 'ok' to 'bad idea' depending on who you choose to believe)?

I really like the idea of having an engine and not having to sweat about compression ratio/detonation.

Bear
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Phil
The Great White Buffalo

USA
7216 Posts

Posted - 07 Sep 2010 :  2:27:16 PM  Show Profile  Reply with Quote
Most things that have become commonplace in our hobby have been intially met with resistance. Even Henry Ford argued and fought against hydraulic brakes, yet today we would not even consider using a mechanical braking system on a car.

Practically each new development is met with naysayers. People who stand on the sidelines and throw snowballs. Sometimes they are right, but that doesn't matter because they throw no matter what. There are some that resist any change, and others that have the NIBM syndrome (Not Invented By Me).

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 07 Sep 2010 2:33:21 PM
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Aguila1
Buffalo

USA
85 Posts

Posted - 07 Sep 2010 :  3:32:40 PM  Show Profile  Reply with Quote
Thank you for the kind and encouraging words. I don't give much thought to the naysayers and haters, and actually predicted the fallout from what I refer to as cultural indoctrination. At least I haven't been called a liar, yet. (I'll give anyone who cares to visit SC a test drive.) Someone on another Pontiac site thought that I could get over 20mpg on gasoline if I spent as much time tuning and maybe that is the case, but I haven't seen or heard of it - have any of you? I was expecting a drop to around 12 or so - getting the same highway mileage just confirmed my suspicions about misinformation. How many times do you hear that ethanol is corrosive? It isn't. As to valve recession, I've been running my 455 for over ten years without leaded gasoline. I suspect e85 will be comparable, meaning a non-issue, and for those that need it, maybe an occasional shot of Marvel Mystery Oil per tank?

Funny you mention Henry Ford as he built his early cars to run on ethanol, too, and advocated this home-grown fuel. The consequence was Prohibition, until the oil company monopoly established itself.

I don't mean to send any off to another site if that is against the rules, but y'all should check out this site if you are interested in sick power on ethanol:
http://www.raceone85.com/

I'd like to start a car club for those interested in converting their cars and even brewing their own. I'll call it the White Lightning Car Club. Ha-ha! Or was that the Moonshine Runners!?

1979 Pontiac Firebird Trans Am custom, shaved, House of Kolor Kandy tangerine base coat, airbrush graphics, 462 w/ 1968 #16 heads, 13:1 compression, Ross pistons, Crower Sportsman rods, Pro-Gram billet 4-bolt main caps, Crower 60919 cam, 4L60, powered by e85.
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redgtoblue
Tribal Scout

USA
1 Posts

Posted - 08 Dec 2014 :  9:30:30 PM  Show Profile  Reply with Quote
I know this is a relly old thread but is any one still out there
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 10 Dec 2014 :  10:33:24 PM  Show Profile  Reply with Quote
Drove across Iowa once. Nothing but Corn fields for 200+ miles. Smack dab in the middle of all that corn was a BP ethanol plant.

IMO, it dosent make sense to turn food into fuel.

Stop the war on fossil fuels!


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 10 Dec 2014 10:35:41 PM
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