TransAm-Z

Now that I'm up and running on E85 I am considering a new High compression engine to take full andvantage of the E85. I am looking for information on how high I can safely go with my dynamic compression ratio. I have read people setting these motors up with 14:1 static compression with no issues but have not been able to find what Dynamic compression to run.

Has anyone seen any info on this?

kgkern01

I am interested to know this as well.

slomarao

+2 on this.

AdioSS

nobody really knows yet. E85 is a relatively new fuel..

TransAm-Z

I really don't want to be the guinea pig here, but I guess I will if needed. Does anyone know what is a good DCR to shoot for with say 100-110 octane racing fuel?

Joe Urban

Actually some people DO know. The ones I asked speak more of SCR than DCR. One engine guy really likes building for E85 if you use nothing else.

Unfortunately I don't see any of them posting on this forum. Too bad.


Joe Urban

WS6T3RROR

Match your cam to your compression, your fuel is secondary to that. If you begin to cross 240-260psi cranking you are likely going to have problems. Just because you probably can run more compression doesn't mean you have to. It will on the other hand let you run a very racy cam and compression on fuel you can get for cheap all over the place.

I've said it many times, people here make way too much of compression. It is not a magic bullet, it does help you out when it matches everything else though. It does improve part throttle and idle. Which is what a big racey cam usually kills off with pump gas compression ratios.

slomarao

anyone else?

AdioSS

Ok, how about this, those that do know, aren't telling

Joe Urban

It depends on who is doing the asking, but they certainly aren't telling on-line.

What you said is true with many (most?) of the people who really make power or fast cars. Some of them will talk to an individual if he keeps the knowledge to himself. Every so often that happens to me. It's fun to see something become general knowledge a couple of years later. Unfortunately you can't even mention that you knew or you'll not get anymore "inside" info. Keeping ears open and piehole closed is the best idea.


Joe Urban

AdioSS

that's very true about a lot of things

tomcowle

ws6t3rror hit the nail on the head, we have a winner.

Joe Urban

Well, it is one opinion anyway. I believe the OP wants to take full advatage of E85's high octane rating and cooling properties. The peope who are doing that are running really well.

I suggest that if you optimize the engine for E85 (compression, cam, timing, etc) it won't like WOT on straight pump gas.

Just another opinion. Not necessarily a winner.


Joe Urban

TransAm-Z

Exactly right. I have heard that for every compression point raised you can expect to pick up 4%, so I want as many points as possible (within a safe limit! Say E70). Also If E85 is always available in my area I will never run pump gas again. And if for some reason E85 tanks in a few years I can allways get new heads.

tomcowle

Let me ask you this, if you ran the equivilent octane rated fuel in relation to what e85 is would the engine run the same as it did on e85? or run better?