1INSANEGTO

iTrader: (13)

Since I will be going with ETP heads I have the option to play a little bit.

Currently have 25cc Wiseco turbo duty pistons. So I am interested what compression would be good and what CC chamber. I am going with the ETP 245's.

1INSANEGTO

iTrader: (13)

More info on current setup....

Bore 4.030
Stroke 4.00
Head Gasket thickness .035 . This is open ended...
Deck Height .004-.009 Really not sure on this I have to check with my builder
Piston top volume 25cc
Combustion Chamber 72CC

Curent range of compression now. 8.87:1 to 8.95:1 again this depends on head gasket and what my deck height is.

99bluefirebird

iTrader: (8)

What type of gas and any meth? Are you limiting boost at all?

DeltaT

iTrader: (5)

I had a similar choice recently when I specced my AFR heads - range was 8.9:1 to about 9.3:1, on 434ci. I decided to go with the largest chambers and the correct gasket thickness to hit a quench target of ~.040". I figure anything over 400ci is not going to suffer on the low end, and the lower CR will be more boost friendly.

Decided yesterday to run E85 instead of pump and meth, since I just found out they opened a couple stations near me.

Jim

EPP

iTrader: (22)

I'd shoot for having the compression ratio as close to 9.5/1 that you can. 9.0/1 will work, it doesn't need to be down in the 8's. A lot of people are running even higher compression ratio's these days, up in the 10.0/1 to 10.5/1 range. Bob

ls1290

iTrader: (20)

I totally agree with Bob. With my 402/F1-R combo, I went with 9.5:1 combo and it is working out well so far.

1INSANEGTO

iTrader: (13)

I will be running E85 if that makes a difference......

With a
70CC it 9.1:1
65CC its 9.5:1
60CC its 9.97:1

cablebandit

iTrader: (37)

10:1 I am running 10.3:1 with 93 + meth.....e85 is gonna let you run whatever you want. I have run mine a few times on low boost with no meth and just 93 and it was still fine on low boost for the street...700ishrwhp. At the track i do use race gas though

1INSANEGTO

iTrader: (13)

Sounds good. Ya E85 will be the everday fuel. I do have a meth kit as well but I am not sure its needed.

LS1x2

iTrader: (11)

I'd go with 10:1 with the E85. It depends how much boost you are going to run, but I think I would still go 10:1 for anything under 25psi on e85. Meth can only help.

john_sblendorio

iTrader: (4)

It is going to depend on what the goals are for the engine. Boost makes more top end power than compression. Compression will give you a faster response time. If you are planning to make a lot of power, I would not recommend e85 because of its inconsistancy. I am making over 1,000rwhp on 93, spraying 100% M3. If you have easy access to e98, I would surely go that route, so you can run more timing. 9-9.5:1 seems to work well with an upper midrange of boost 16-22#. Less than 9:1 works if you are drag racing and launching hard under boost. 10:1 works with lower boost (10-16#). High compression 10-11:1 with low boost 8-12#. There is no need for an F1R if you do not plan on boosting the hell out of the engine, so plan according to your goals.

1INSANEGTO

iTrader: (13)

I am planning and building everything to max the F-1R if I ever want to. I just wanna do it once not keep switching stuff around. .

Slowhawk

iTrader: (12)

Really depends on the Cam too since the overlap with affect it.Our engines ussually end up at 9.8-1 running 12-16lbs of boost on 93 octain/meth. The higher compression really helps the midrange power.

1INSANEGTO

iTrader: (13)

I am having a cam spec'd to the heads.