Violat0rX

iTrader: (2)

Hey guys, i know this board is mainly for the LS1, but many of you also either know or have owned an LT1 before.

I just need some input on a setup that I'm considering...so here it goes:

I've got a 96z with a forged 383. It was just built last year so it's still pretty fresh...maybe 5k miles. It was a daily driver at the time so the cam is pretty mild, but still has a nice lope. The stock heads have been ported (w/ 1.6 rr, new valves...etc), and so has the intake and throttle body. I've got basically all the bolt-ons (headers, cat back etc.) The compression ratio is pretty much stock at around 10.5:1.

Now I want to put the D1-SC w/ twin high flow intercoolers, on the car. I would really like to run around 10lbs of boost, but the shop that built my motor is telling me to do around 6-7 because the seals on the LT1s are known to leak with high boost. It's not that I don't believe them, but has anyone had any experience with this? Is it safe to run 10lbs w/ the stock compression? I know the ATI kits are made to bolt up to stock motors, but since my is built and I will have the intercoolers I was thinking that I could get away with a little more boost...

My goal is for about 500+ rwhp. They will also be installing 50lb injectors, but I think everything else is going to remain unchanged (cam included).

Thanks for your help.

gator's 99TA

iTrader: (2)

10 psi of intercooled boost on 10.5/1 compression is only going to happen if you run very good race gas and/or very low timing.

Violat0rX

iTrader: (2)

what would a safer CR be to run 10lbs? 9.5:1?

TurboZ28

Your talking about detonation GATOR. I think hes asking about the integrity of the seals on the LT1. What seals are you talking about. Piston rings? Headgaskets? My head gasket had blown and because of it coolant leaked and I got air bubbles in my coolant lines which pretty much screwed everything to hell. But thats the only sealing problem that I've had personal experience with

Violat0rX

iTrader: (2)

i'm not a 100% sure which seals the shop was referring to. I'm guessing seals around any parts that would be affected by increased boost... I'm going to call them later today or tomorrow to talk about the specifics. Thanks for the input so far.

Detonation is also a concern tho. I plan on running on pump gas only (93 octane), so 10lbs is still too much for 10.5:1 stroker motor?

TurboZ28

I wouldn't do it. That's running on the risky edge of detonation. I know that at 10.5/1 CR you can run 6-7psi safely. You might be able to get by with 8-9psi with some timing retard.

LittleRedZ

iTrader: (5)

10 psi should be ok i think if you tune with a Dfi and get someone that knows what the hell they are doing...make sure you have good opti,wires, plugs, also stay away from FMU and get your fuel system upgraded with at least a twin intank set up

Violat0rX

iTrader: (2)

also, boost gauge - recommended or not necessary?

LittleRedZ

iTrader: (5)

necessary!!!! if you pushing that kind of boost you want to make sure you dont spin it too high and push more then 10psi, although it would be hard to watch cuz you'll be most likely trying to watch the road and not boost gauge

gator's 99TA

iTrader: (2)

yes get a boost gauge. i think personally that you need to think out this change of the combo. nothing is without consequences. when you put a motor built for n/a and trying to throw 10 psi at 383" of motor (which is a lot of cfm) you are gonna run into issues. dont cheap out or you will be sorely disappointed with a broken combination.

you will need a great tune, gauge to monitor what is going on, and major fuel upgrades

SSprayn

My car is currently making 10 PSI and has been doing it for a while. I've had now troubles but I also have a 9.2:1 CR and also have it tuned on 100 octance

Got Me SOM

iTrader: (2)

10 lbs is pushing it on pump gas, you'll have to turn your timing way down to like 14 degrees. I'm sure you can run 6-7 lbs of boost just fine, not sure what your shop means by seals..

Violat0rX

iTrader: (2)

thanks for all the input guys. I just talked to the shop to work out some of the details. They are the ones that built my motor btw so I trust their work.

I "revised" my plans a little based on your advise and that of the shop's. I'm going to maintain my current compression ratio and run 6-7lbs of boost from the D1. I also keeping the cam i have in there now here are the specs:

224/230 .503/.510 lift 112 LSA (I should still be able to make decent power with it right?)

As for the fuel system, I had a bigger racetronix in-tank pump put in when the motor was built. Also the 30lbs injectors I have in there now will be replaced by 42lb ones. Let me know what you guys think? I guess it's a little conservative but it's still mainly a street car but not a DD. Thanks