Pro Stock John

iTrader: (34)

That would kick *** on the street.

MIGHTYMOUSE

iTrader: (59)

maybe north of 850.. i don't have direct experience.. but i can assure you that displacement will hurt your mileage more than the compression

Websy21

iTrader: (34)

Ya, thats what I am beginning to think too. I am leaning more your way now MM, it makes more sense. By dropping CR you are able to run alot more boost on pump gas and have that safety factot too. I have meth, but don't want it to be on all the time and filling it up etc. I think I will set something up like you did, have it kick in under higher boost, etc. I think I am liking your setup more the more I think of it. Makes sense that high CR is more for the pure race crowd. Plus, like you said you aren't slamming your head of the steering wheel b/c your losing at stop lights I really think this is the way to go, 8.5-9 for turbo's anyways and 9-9.5 for S/C. Done deal, thanks guys!

MIGHTYMOUSE

iTrader: (59)

consider how much power you want to make

5-6-700 you can keep highish compression and run around on pump gas without much sweat

8-9-1000 hp and you want to 'enjoy' the car on regular fuel i would def. drop the compression.

Websy21

iTrader: (34)

Wow, its so much better when a pro explains it, LOL. That makes so much sense, sacrifice a little down low and maximize power output with pump gas. Lower CR is the way to go unless all out race application, meth/race gas.

Just for curiousity any takers guessing here what someone on average would be leaving on the table motor alone by dropping one point in CR? Obviously it doesn't get out weighed by what extra boost you will be able to run though.

This is a very interesting topic as I always pondered this when I was going to go with a S/c on stock cubes. It didn't make sense to me to run 6.0 heads and drop to 9.5 just to run maybe one or 2 more psi. You're only limited to a certain power level within stock cubes so why go the extra mile for giving up efficiency, etc.

bifster

well guys looking into my build here a little farther seems like im almost limitied to 9:1 compression unless there are head gaskets out there i can use that will drop a full point for me haha. and with boost it seems like head askets are a problem to start with on a FI gen III but MM you are using the new felpro's correct? buuilt even with the addition for the extra 2 bolts? have you had time to check them out yet and see how they perform? what would be the best bet to deal with high boost numbers so far gasket wise??

Websy21

iTrader: (34)

I can't speak for the gaskets but I wouldn't worry about running 9:1 CR. You should be fine, I decided to go with 8.5 instead of 9.5 but if 9 was option for me I think I'd do it. Kinda the happy medium so to speak.

KWIKKAR

iTrader: (15)

Well guys I talked to Tony at AFR and my SCR is not were I want it. I think I would want atleast 9.5 SCR. Here the set-up Ls2 402 with -12dish pistons and heads are AFR 225 72cc. I know I need a gasket size of 4.125 but what thickness do I need. Would 6.0L gaskets work or do I need something else. Thanks. I'll be using 93 oct fuel and it will be a street car. I may drive it about 100 miles a month. I would like about 750+rwhp. Thanks

mahhddgtp

Has anyone swung low 700rwhp with 15psi on a 346ci motor on 93pump? What CR for that? 8.1?

TAQuickness

iTrader: (28)

You'll need a gasket thickness that give the desired quench. Much better to drop compression by changing the pistons.

Pro Stock John

iTrader: (34)

I think that might a little hard, maybe you could get there with twin turbos but I doubt you'd get there with a blower and an A3 trans.

KWIKKAR

iTrader: (15)

Well I can't change the pistons so what gasket would you say I should get.

MonkeyBoneSS

iTrader: (7)

If one were to run a 347 on 93 fuel with a 10:1 ratio. What would be the advised max boost to run 10 - 12? Also how much would a cam play in this factor. Would you use a EPP blower cam 232/240 or a TR blower cam 214/230 ?

Pro Stock John

iTrader: (34)

I'd go with the bigger cam and boost less with 10:1 personally. But I think you can get into the low 600's at 10:1, and beyond that it's a matter of tunings and inlet air temps.

cablebandit

iTrader: (37)

also a matter of dynamic compression

rjw

iTrader: (3)

Hmmm....this thread has me curious as well

MonkeyBoneSS

iTrader: (7)

PSJ how many pounds would you think 10 at the most?

cablebandit

iTrader: (37)

quit thinking boost and think horsepower. you guys need to consider your dynamic compression as well.

rjw

iTrader: (3)

Which is hard to consider in some cases due to mytsery cam specs

But in that you mentioned it twice in this thread, what do you considerto be the threshold?

thx

bte: Were you happy with your Darts?

cablebandit

iTrader: (37)

i went higher static. lower dynamic. Every cam is different...do you not know the specs of your cam?