10.1:1 Compression with 12lbs

Would running a fmic and meth(how much would be needed?) give me the capability to run 12-15lbs of turbo boost on a motor with forged componets with 10 to 1 compression? or is a liquid intercooler needed?

you will want 9:1 or so compression to make it last.

But, yes, you could make it work with careful tuning, but its not recommended

i just dont want to go out and buy new pistons again. my wife is already about to shoot me.

i just dont want to go out and buy new pistons again. my wife is already about to shoot me.

Reason with her that your new pistons would probably save you the cost of a new engine, and you could sell the old pistons on line and it wouldn't cost that much overall so she might as well give you kitchen clearance to get the new dish pistons.

im gonna run 10-12ish on 94+octane meth and a front mount.

Jay

what compression are you at? I'm thinking about running e85. i think e85, meth/water and a fmic will be enough. anyone agree or disagree?

Yes, It can definitely be done, especially with 100+ octane E85.

Run e85 with a fmic and you shouldn't have a problem at all, then sell your meth kit to recoupe some of the money for the bigger fuel system you'll need. What times are you shooting for and what is the rest of the setup? 15lbs can be a HUGE difference depending on what turbo you run.

Opps sorry im 9.78 to 1 sorry hahaha

Jay

i got a great deal on 83lb injectors and a forged 3.75" crank, so the motor will be a 383. i have two 57mm t4 turbos. i have an afpr that can go up to 70lbs.

what heads are on this motor? Why not toss some heads on it and drop the compression down? Or where the heads already done?

But that also requires spending another 1000+ lol
I wanna sell my LE2s and get some trickflows but I wanna get it running first before wasting more money I dont have.

Jay

I've got some eric bradby ported lt1 heads on it. they flow 291 but there 55cc. if i could get a little more than 1k for them i'd get some 70cc afr heads.

I've got some eric bradby ported lt1 heads on it. they flow 291 but there 55cc. if i could get a little more than 1k for them i'd get some 70cc afr heads.

you might be able to. those should flow as well as a set of LE3s than, and those go for about that on here I believe. Post em up!

Tune it well - Run e85 or switch to race fuel at higher levels and it will last ok. I wouldn't do it on a daily driver but would have no problem doing it on my toy.

Yes boost is relative. I sometimes see 23ish psi on a cold day - But probably only need 10 to make the same power on a bigger turbo.

Start low. 8psi on a well built higher compression motor could still be nasty. Fill it up with good stuff at the track and run your 15 - I'm about to do it with an 11:1 ls1 motor and an 88mm. Looking for 800+ at the tires (hopefully on pump)

car is a weekend cruiser. i just put my heads up for sale so we shall see. wish me luck.

I am running 9.5:1 on an all forged 383ci (JE -28cc pistons). AFR 190 heads 54cc chambers. Use a Procharger D1 series with a 7.6 --> 3.4" pulley ratio. I see about 14-15 psi. I have no problems, but I also run a large Spearco IC and Meth/ H20 spray in hot weather. Also, I have converted to Evans waterless coolant and do not run a thermostat. I am sold on Evans NPG. (97ss 383ci - D1 - M6) B.

is it 30% more fuel required with E85?

11:1 10psi LS7 = 812rwhp.

you should run a thermostat.. otherwise... restrict the flow...

With Evans, do NOT run a thermostat. You must block the WP internal bypass circuit. Restriction of flow will not remove more heat load. As an Engineer, I advise you to go ahead and run a heat transfer load. Restriction of fluid flow is a true falsehood for increased removal of heat. A good read is Ray Bohaz's book on cooling systems. Available from Summit. The LT1 cooling system is very bad for FI modification. Also, go to the evenscooling.com site. Not only do they critique heat load, they also document the LT1 and reverse cooling theory. HTH. B.

thank you,

but... then why does removing the thermostat increase the failure rate of engines??? Specially on the back side... Most of the engines that I have opened that didn't fail had severe scratches to the cylinder walls on the 7 and 8 pistons....

its nice to someone else running "more" compression and forced induction. I am 11:1 with 12 psi (396ci and D1SC)..conservative tune making 660 rwhp. I am in the process of get the NOS set up....:yes:

what would be the limit of e85 at ~10:1 compression? 15lbs? 20lbs?

i say do it... i pushed 16.5#'s to a stock 5.3 (NOT FORGED... untouched engine... 9.4/1) and it never even hiccuped (besides running out of fuel!!).

If anything im willing to bet it takes 10#'s forever.

There is actually quite a few guys on other forums who believe in higher compression and boost. Tuning is a lil different and if you want to crank it up at all then race fuel will be mandatory.

I personally wouldn't be scared at all. Good tuning with decide if it lives (like anything).

buddy runs 10.8:1 and 12psi on his c5 vette with a vortech t trim if he dont use his meth that motor will explode!! oh his motor is a 381 fyi...

buddy runs 10.8:1 and 12psi on his c5 vette with a vortech t trim if he dont use his meth that motor will explode!! oh his motor is a 381 fyi...

mainly cuz of timing... pull tons of timing and it will more than likely live with the boost.

few guys on ls1tech run 10.5 and 16psi (albiet race gas.... but still).

Really you can go both ways.

with good IAT's and decent octane (meth or gooood gas) it will be fine. Just make sure to setup a fail safe with the boost controller. Use a pressure switch in the meth line to allow the boost controller to run it up 12psi.

If there is no pressure in the meth line then it will only hit it with (lets say) 6psi.

Then you have nothing to worry about. ;)