Johnv

It will cause the 370 to choke and power to fall off even earlier than the 347.
A bigger AR exhuast housing would help.

I think 17 psi, with a smaller turbo is just too much on straight pump gas,
back pressure and intake temps would be very high, leading to a high chance of detonation.

I personally would add a meth kit for anything on pump gas pushing 15 plus psi boost.

RacerXLs1

iTrader: (14)

I don't think so.. I think it could of been bad fuel or timing! Are you on e85 let me re-read

stoverz28

iTrader: (8)

60's sound pretty small for 750rw...

Whats your base fuel pressure? 1:1 regulator?

black-sinner

Base fuel pressure is at 55psi , twin aeromotive 340 pumps intank , -8 feed line, aeromotive fuel pressure regulator boost referrenced (hits about 75psi on WOT i think) , oem line as return, #60 siemens injectors ( not sure about the brand name) f.a.s.t. Billet fuel rails.

Again fuel was plenty all through dyno tuning never leaned out...

code4

iTrader: (30)

You can only do so much on pump gas. Driving on the street is much different than the dyno.

I would get some race gas and methanol injection. Tune it on the street and watch knock. See what it will take as far as boost and timing.

black-sinner

A race gas tune was in my plan, but i expected the engine to last more than 4 days! Meth isn't something that i would consider at this time.

Low compression+(at least 93 octane) pump gas , should be good for 700-800whp on a good tune and good engine i think

code4

iTrader: (30)

I have smoked a couple of pistons on pump has at that level of horsepower. Once because my intake temperature got too high.

The other time was just two weeks ago, It was a cold night & it ran a little too lean plus I ran out of methanol. It went boom. **** happens on pump gas if you push it hard.

got-a-ls1

iTrader: (12)

11.5 compression with pump gas and 17psi? and your heads lifted?? id start there.

ive run 18psi with my 5.3 on 9.1:1 compression and meth injection with good results.

black-sinner

My C.r. Was at 9.5-9.7:1 with -11 pistons and 67cc chambers, and i just got confirmation from a specialised lab on the pump gas here,it's 98 octane.

white01ss

iTrader: (37)

Ever wonder why even forged motors pop cylinder #7? Surprised no one has said it, but this engine needs REAR STEAM PORTS! Everything thing else looked fine about your setup. Meth/water may have prevented this failure as well.

The other thing is the power handling of different blocks. IMHO, you are pushing an LS1 block beyond it's limit. LS2/LS3 blocks can handle more than LS1, then iron block can handle even more. It's like 650 crank hp for LS1, 950 for LS2/3, and 1150 for LQ9. I'm running a LQ9 block with meth for three years with no issues.

Here's a copy of an e-mail I sent to a friend of mine about steam ports:

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

https://ls1tech.com/forums/generatio...-hp-setup.html

I used an LS6 front crossover pipe on the rear, bent the outlet at a little more angle and ran a hose along the side of the intake up to the front and joined it with the otlet of the other crossover with a brass T fitting...Working great...

GM Part Name: Engine air bleed
12602544

Anyways, 12604711 (two port truck) and 12602544 (two port LS1) are readily available at GM parts stores, Summit, eBay, etc. If you want a 4 to 1, you gotta go used.

If you need the little oblong washer/o-ring setups, they are PN 12551933 which are about $6 each.

(Some of these part #s may not be available)

LS6 part: 12568478

LS1 part: GM part # 12602544
f(ls1) pipe,eng cool air bl(incls 539-542)
(if prior to 2002 vehicle, must us 2 caps p/n 12602540)

4 into 1 tube = GM part# 12557538 Y-body '97-'99 LS1
bolts = GM part# 11514008 (without stud-head)

http://www.kurturbanperformance.com/...or-system.html

http://www.krcpower.com/catalog_i112...l?catId=366482

http://s41657.storefront-solutions.c...l.aspx?ID=3289

https://ls1tech.com/forums/forced-in...4-why-7-a.html

https://ls1tech.com/forums/forced-in...on-system.html

https://ls1tech.com/forums/forced-in...cs-inside.html

The reason gm did it is because they didn't build the engine with 650hp. At 350 hp from the factory those steam vents don't do anything. I melted 2 forged motors on cly 7 not running steam vents on 93 octane at the track.

https://ls1tech.com/forums/conversio...-adapters.html

black-sinner

I've read about this but never gave it much thought, thanks great read, guess it was a heat issue on #7 since every other thing seems ok, my engine has been running a little hot even with an electric water pump and high flow fans, and if steam porting the heads would bring the temps down i can't say it is not worth doing.
Thanks again

white01ss

iTrader: (37)

Honestly, I just found out about the rear steam ports a few months ago. Needless to say, putting them on is my next project. I'm assuming the alky control kit saved my motor these past three years.

Anyway, glad I could help and good luck with your next build.

black-sinner

All great info guys, thanks a lot, i'm still wondering on HP output on my new set up, any guesses?