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High Compression E85 401 Build

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farna View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Topic: High Compression E85 401 Build
    Posted: Apr/29/2012 at 1:41pm
Since my J-10 isn't going to be doing any heavy towing I'm thinking a 232 six with 5-7 psi will be good. After looking at some figures I'm actually considering putting the little Ford (Merkue XR4ti) 2.3L turbo motor I have in it. About the same power levels as a NA 302 V-8, just at a bit higher rpm. Hmm.... would make the J-truck crowd pull hair out and swear at me for sure!


Edited by farna - Apr/29/2012 at 1:42pm
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote A0M797X112187 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/29/2012 at 10:19am
Originally posted by farna farna wrote:

I wasn't even considering a turbo! That would be the way to go. Turboing is basically the same as adding compression, you're just stuffing the air in. Normally you wouldn't be able to go but 5-6 psi on a 8.5-9.0:1 engine, but with E85 you can turn the boost up (10-15 psi) and get your power and gas mileage back. That is probably the best way to go.
To paraphrase a favorite movie of mine, turbo's and E85 go together like peas and carrots....
 
One of my non-AMC cars has a turbocharged, 8.6:1 compression 357" engine with Accel DFI engine management that I recently converted to E85.  I had been running 11psi manifold pressure on 91 octane pump gas and that pushed my 3500lb car to the 10.80's and a dyno verified 543rwhp with my timing limited to 22 degrees. 
 
I began mixing in 110 octane unleaded race gas for a 25% blend and bumped the boost up to 15psi which put me in the 10.40's.  I only mention this because my next step was a switch to E85 with no change to my tune whatsoever other than increasing fuel by 50% accross the map and my times dropped to 10.20's at the same 15psi.  At 17psi and 2 more degrees of timing, it has run a best of 10.03 @ 136mph.  I have run as high as 23 psi with no improvement in ET because, I believe, I am "blowing through" my converter at this power level.
 
Several people I know are running as high as 11:1 compression AND 25psi of manifold pressure on E85 as high as 7000rpm with no problems whatsoever and a nearly stock timing curve.
 
All this leads me to believe that a high compression NA motor will thrive on E85 just like the turbo cars.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote muttnïk Quote  Post ReplyReply Direct Link To This Post Posted: Apr/29/2012 at 8:45am
Thanks Frank, for the response.  It sounds like I need to get myself an O/D on my truck.  My numbers in direct drive (ignoring any torque converter response):

3.54 w/ 31"
45: 1824
55: 2230
65: 2635
75: 3040

3.54 w/ 33"
45: 1714
55: 2095
65: 2475
75: 2856

After speaking some more with different cam grinders, and catching a bit of guff from Howards Cams we finally had a very good discussion with the guys at Lunati.  They carefully considered our use case and helped us select a cam that should work well to build low/mid torque and efficiency at our 13.5:1 CR.  It is their 64502 cam: 220 / 226 duration @ .050 with a .507 / .527 valve lift with a 1.6:1 rocker and a 112* lobe separation.

I talked yesterday with my engine builder about the AMC 502 head flow numbers, particularly those published by Ken Parkman.  I told him that those numbers appear to be reliable.  He has never built an AMC engine and was absolutely blown away by the head performance.  I also showed him the numbers for Bulltear's CNC ported 502 heads.  What impressed him most is that the flow does not drop off at higher lifts up in to 600 and 700 range.

Since roller rockers are in the plan anyway, we are now considering using a set of Harland Sharp 1.7:1 rockers to take advantage of the higher lift.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Apr/26/2012 at 10:24am
A lot of modern GM V8s are using the "downspeed" theory even with regular gasoline. The engine isn't lugging, but it is being loaded at low rpm. This gives good pulling power without the need to rev the engine much. A GM truck without a load (just a couple passengers) will easily run 65-70 at 1600-1700 rpm in OD on the Interstate, and won't mind running 1400-1500 at 50-55 in OD. Try that in a early 90s vehicle (don't know when GM started this, guessing late 90s) and gas mileage will go DOWN even if the engine will pull without lugging. I tried it with my 4.6L stroker, didn't work. Ran 3.08 gears and would run 65 mph @ 1800 rpm. That wasn't enough for the cam I had (just a little more than stock... stock may have done better!). I've found that most AMC engine (especially the sixes) need to run at least 2000 rpm for an economical cruise with the stock cam. That was 72 mph with 3.08 gears. So I had to run 70 or more to use OD, and 2000 rpm was only 50 mph in direct drive (3rd gear -- using an early Jeep AW4). At 2500 rpm the Jeep EFI computer will start to enrich the mixture for more power. I've found this to be true for the Renix and HO computers, at least through 1995 (Chrysler made some mods in 96 and may have changed this, but I don't think so). At 2400 rpm I was only going 60 mph. The 3.08 gears weren't working! Too many times you can't run 70 but want to run over 55, and I don't particularly like running 2400 rpm for extended periods. Went to 3.55 gears with the same cam and gas mileage went up by 2 mpg on average. I probably gained 1 mpg on the highway and 3 mpg in town. I measured the gain on a long trip with a good bit of driving around at the destination (to and from the 2002 Kenosha Homecoming from Biloxi, MS). With the 3.55 gears I'm running 62 mph @ 2000 in OD, 75 mph @ 2400. This is pretty good, since I prefer to cruise in the 65-70 mph range. I'm seeing another 2 mpg gain on average since I changed back to a 4.0L (but hopped up -- bored out throttle body, bigger injectors, 99 intake -- close to the same power as the 4.6L stroker w/stock TB and "right sized" injectors) and swapped in a low speed torque cam. With the new cam the smaller engine feels a lot better and will pull a bit more gear easily. Would love to have 3.31 gears now, but will settled for going form a 65 series to a 70 series tire next time I need them. That will drop 75 rpm. Not much, but cheap enough. Two series number (from current 215/65R15 to 75) would drop 1300 rpm, but I don't know about the looks with that tall a tire. Going to a 3.31 gear would drop rpm by 143. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote muttnïk Quote  Post ReplyReply Direct Link To This Post Posted: Apr/26/2012 at 9:48am
I have been away messing with my ECU and Flex Fuel sensors, waiting for word from my "build engineer" that the rotating assembly and block are ready.  I heard from him yesterday and we talked cams.  His idea on the target cam profile is 230 to 240 @ .050 duration, a .480 to .520 lift, and 112 to 115 degrees lobe separation.  The feedback he has been getting from several cam manufacturers is that an even higher duration cam, at or above 260 would be more appropriate.  His opinion is that they are just not wrapping their minds around the E85 efficiency/tow vehicle aspects of this project, and are primarily basing their recommendations on the 13.5:1 CR figure.  

From tsanchez' suggestion I have to wonder if the 230 to 240 duration is still too much to maximize efficiency, although I am sure at our CR it would be a fine running engine.
Originally posted by tsanchez tsanchez wrote:

Should run well and a camshaft in the .490 range 215 at .050 on a 112 lobe center should do well (hyd lifters)

I have lately been reading about "downspeeding" on engines optimized for E85.  In essence the engine is built to produce mid/low range torque with high compression.  Higher gear ratios are used to decrease engine speed, basically "lugging" the engine.  My taller 33" tires and 3.54 gears work well with this scenario.  This downspeeding concept seems to me to favor a decreased lobe separation to lower the power band (although not to the point of causing reversion)?

On a side note, I have been looking at the AMC 502 head flow numbers published by Ken Parkman.  Are those numbers legit?  I notice they are included in the Stan Weiss flow table.


Edited by muttnïk - Apr/26/2012 at 10:55am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Apr/10/2012 at 5:52pm
I wasn't even considering a turbo! That would be the way to go. Turboing is basically the same as adding compression, you're just stuffing the air in. Normally you wouldn't be able to go but 5-6 psi on a 8.5-9.0:1 engine, but with E85 you can turn the boost up (10-15 psi) and get your power and gas mileage back. That is probably the best way to go.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote smills61074 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/10/2012 at 7:40am
I understand the issue about gas mileage.  The horsepower gains are not significant.  I do believe that some of the turbo engines, and super charged engines have the best possiblilty for horsepower gain, due to the cooling affect crated by the E85 when it is mixed with air.  This is still a good topic, because it makes other aware of something that will probably evolve into more horsepower. 
68 Blue AMX Perfect California Body going for 401/6 speed
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Apr/10/2012 at 6:22am
Modern fuel systems and materials don't have a problem with E85. Old ones (say prior to around 90) do. Most of us with old cars have replaced everything that would be a problem. Steel fuel lines don't have issues with E85, but many have even replaced those. 

With the 9.5:1 motor you'll probably notice a slight drop in power and more than a slight increase in fuel consumption. 3-4 mpg is more noticeable than you would think, especially on a long trip. IIRC gasoline has to be around $5 per gallon before you can break even with the lower cost of E85. That's in a flex fuel vehicle which typically has a compression ratio of 10:1 or 10.5:1. By purpose building an engine with 11-13:1 compression you gain some power an efficiency back, though you still use more volume -- just not as much as with lower compression. You lose the option of running straight gasoline though. I think you can go with 12:1 and use copper or Cometic MLS gaskets. You might want to drill for an additional head bolt for each cylinder. I don't know much about the extra head bolt as far as placement, but it is commonly done on very high compression AMCs. IIRC it's a 3/8" head bolt on the outer edge where there is the biggest gap between bolts.


Edited by farna - Apr/10/2012 at 6:25am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jcisworthy Quote  Post ReplyReply Direct Link To This Post Posted: Apr/09/2012 at 5:02pm
I have talked to a guy who has been running it in his race car for the last 6 years and says he made no changes to his fuel system other than provisions for the necessary volume of E85 and checks the system every year with no signs of corrosion as of yet. He never drains the system or fogs it etc, he is not running anything special for fuel line etc with turbo and a carburetor. I know about the use of more fuel to make the same power but it would be about 24 dollars cheaper right now to fill my tank. Now if the price goes up because of loss of funding then that will be a different story but right now it is much cheaper than high octane and WAY cheaper than race fuel. I suppose if you do not try you will never find out right and I can always switch back easy enough because I am installing a conversion kit in my carb so going back is easy. My fuel system is fine for both set ups and there are inexpensive test kits to check for ethanol content so that should not be much of an issue either. If I have to bump or retard the timing a couple degrees here and there not a big deal. I suspect I will not have to worry about it much, especially with the current 9.5cr motor in the car now. Maybe with the 11:1 stroker motor but I dont think the compression is that high there to worry about it either. If a 85% mixture is 105 octane than a 70% mixture should still support 11:1 just fine but maybe not. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Apr/09/2012 at 2:52pm
One of the reasons you lose gas mileage with E85 is that it takes more to get the same power at the same compression. The higher octane lets you boost compression. Most of the multi-fuel cars run around 10:1 and use the computer to control detonation when running regular gasoline. You should be able to run 11:1 with E85 only easily. I don't know how high you can go, When  the vehicle is tuned specifically to run E85 it should improve a bit, but will still burn 20-25% more by volume than a gasoline engine -- and it won't run on gasoline very well.  I know there are a few on here running in the 12-13:1 range. The old trick was to use copper head gaskets (or o-ring), but the new Cometic multi-layer steel gaskets seal real good at high compression. I think I might would try 12:1 with those, but wouldn't want to go any higher.  Note that I have no experience running anything over 10:1 -- so I might just be overly cautious, but from what I've read 12:1 is a good stopping point as things start to get expensive over 12:1.


Edited by farna - Apr/09/2012 at 3:03pm
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