Mine is over 12:1.

 

Yeah but apparently it didn't last too long. That's a lot of compression with boost.

 

12:1 with 12 psi. That's awesome . Just wondering how high Incan build this thing before i get on trouble.

 

11.5 here and loving it.

 

I've been running 10.7:1 with 28-30psi on E98 with little issues. Blew the motor, but not because of fuel or compression (busted a valve spring.)

 

My next motor will be well over 13:1 and I plan on running E98.

 

How are you gonna get to 13:1?

 

^ Im not. Itll be over that.

Big Bore, stroker...and other minor details.

 

It was the timing it didnt like. The block I was running had the head mounting threads repaired. One on each side. This was one that I made myself. This also could have allowed the head"s" lift.

 

Well, the boost/power level you were running wasn't extreme. Judging from the melted spark plug, there was detonation which probably caused the head to lift. I'm sure those threads didn't help. Obviously the tuning window shrinks with really high compression.

To me, with a boosted car, the only thing higher compression does is give a better feeling throttle response when off boost. Either you run higher compression and less boost and timing or lower compression and higher boost and timing. Either way, the blower/turbo is only going to make the power it's rated for. I think there is a happy middle ground with regard to compression.

 

I'm just thinking about doing something fun and maybe at tad different then what I see every day. Don't want the cost of a bb but thinking of a cast stroker crank. Light weight I beam rods, mod max or boss ( if I can ever find the weight if these things). Obviously custom pistons. 13.5:1 or so compression . Some slightly worked over heads and maybe a little bit more cam to take advantage of cr?

Thoughts. Yes I know I can make more power with no2, turbo, blower. Huge power is not really the point here. Is decent power at a decent price.

 

The optimum compression for e85 is 14.5:1. A big bore stroker with flat top pistons will yield 11.8 compression. This is with a 1cc exhuast valve relief, pistons .011 in the hole, stock 51.3cc heads, and a .035" head gasket.

Change the combustion chamber to the frpp or livernois stage 3 heads with 46cc combustion chamber and compression is 12.92. Zero deck it and you get 13.35. This is all with a 3.75 stroke.

Stock stroke with all the above will result in 12.67. All estimates are being made with this calculator: http://www.wallaceracing.com/cr_test2.php

I hope you do it. The 323 stroker with stage 3 heads and 13.35 compression would have alot of potential with e85 imo. Anyone think 500rwhp?

 

Lcaptmorg, if you build that, I'd love the opportunity to tune it. The idea of a high compression E85 NA modular setup turns me on.

 

Interested in tuning my car?
367ci modular overbored darton sleeved 5.4, race ported gt supercar heads. Nasty cams for 8k rpm peak with 367ci. 12:1 compression. Custom 7.5" runner intake. 1 7/8-2" longtubes. Its running and in the car with a basetune. E85.

 

Can the OEM PCM's safely handle 8000 RPM's?

 

If you use a Mach 1 processor, shut off the OBD2 monitors to free up the processor.... I think it would .

 

Cool, didn't realize that.

 

Well as much as I would like to build a max effort e85 bb stroker quite honestly I just dont feel liked droping that kind of cash. I thinking more reasonably budgeted high comp e85 combo. Still very curiouse about the eagle stroker cast crank. Guess I need ot just call them to find weight. Im sure its more than stout enough to handle the power Im just wondering if its worth it for weight savings on a na motor? Can seem to find a single person who has used one. Not surprising though.

 

The 5.0 cammer forged crankshaft weighs about the same as a stock cast crankshaft.

 

You'll find that e85 doesn't work very well over 7500rpm it can't burn fast enough so you start to lose power up high in the rpm!

 

What are you talking about?

 

Sorry but in a n/a specific

 

So you are saying that this happens on on n/a engines?

 

Yes...

 

So what is the difference between high RPM's with forced induction vs. n/a? Just trying to understand how a slow burn would affect an n/a engine at high RPM's but not an FI engine.

 

Hasn't effected my motor... I'd like to see some scholarly evidence that dictates this. Not saying its not true but I shift WOT at 8k rpms and have had no issues or odd readings when datalogging...

 

Let me try and find the links on yellow bullet and you can read it.

 

So what is the difference between high RPM's with forced induction vs. n/a?

Less pressure in the combustion chambers on NA motors?

 

That's one reason but I can't find the article but if you just use google you will see that e85 vs c16 results and e85 always falls off up top vs c16 in high rpm n/a motor

 

Doesn't hurt anything tho just proven

 

I haven't researched this but haven't heard of anything like it before with E85. I'm glad somebody spoke up who has first hand experience and has no issues. If there is an issue with E85 and higher RPM's, I see no difference between a n/a motor and an FI motor with HP/TQ being equal. To me, I would suspect an ignition issue whether n/a or FI because E85 is harder to light.

 

Sorry if I made it sound like it was bad my fault but it just doesn't make power like c16 does high rpm if you want maximum power

 

How do you know this? Are you running C16 or E85? Have any testing data to post up?