Snorkelface

As I rebuild this motor, this car is really designed to do do everything...a Jack of all trades. It will be a weekend street car, hit the drag strip occasionally, and also do some road race and autox. This is obviously an iron block, and it's built up pretty well with 4 bolt mains, a special Howard's front cap and Pro-gram rear cap.



I've seen a number of people saying they have no problems with partially filling the block on a street car, but do you think it would be okay on a car that will also hit a big track? The car does have a big external oil cooler with a fan, and I am running Evan's NPG coolant.

In the current configuration, the motor should be around 950HP at the crank. After I convert over to a 24x with LS PCM, I'll be upping the boost and hope to be near the 1k HP mark at the crank. This is a full weight car. Do you think with my combo I'd even need to partial fill the block? In case it helps, here's the build below:

Engine: 355, fully forged, balanced and blueprinted by Tom Masek Custom Racing Engines
Turbo System: Customized PTK Gen II LT1 system
Full stainless steel headers
Precision T76GTS-H turbo
A2A front-mount IC
Turbosmart 38mm BO valve
AFR 195cc LT4 heads with port work by Lloyd Elliot
Ported LT4 Intake by Lloyd Elliot (machined for monoblade)
AS&M monoblade throttle body
Lunati Sledgehammer crank
Lunati Pro Mod rods
JE Extreme Duty 23 Degree Inverted Dome Top Pistons (9.08:1 CR). Pistons thermally coated
Howard 4-bolt main billet caps
Pro-Gram rear main cap
Custom Ultradyne cam (CHS 290/290-14NR, 232/232 @ .050, .544lift w/1.6RR)
Morel lifters
Smith Bros custom pushrods
Comp Promag 1.6 Rockers
Isky Gold Stripe Tool Room valve springs
REV Severe Duty stainless steel valves; 2.02" int/1.60" ex
MSD BTM ignition and coil
Canton fabbed-aluminum valve covers
Canton road race oil pan
Mammoth BeCool radiator
85lb/hr Delphi injectors
Custom tuned by Westech

Thoughts?

Black89Z51

iTrader: (2)

The oil cooler is definitely a plus, but I'm not sure how much heat is going to build up in the bottom of the block if you do a partial fill, especially on a ~3 mile road course. I've been racing for around 6 years and I've never heard of anyone running a partial fill block.

Personally, I wouldn't run it very long with a partial fill. Even with low horsepower, a Dewitt's radiator, and an oil cooler with Amsoil 15-50 and straight water with water wetter I still see 240 water and 230 oil temps at VIR, Road Atlanta, and Summit Point. I'm N/A and 3100 lbs putting down 373 tire.

Shownomercy

iTrader: (1)

Accept that you will oblong the bores and run her.

97Z28SS

iTrader: (5)

OP your build is very similar to mine and I am doing a half fill with hard blok, billet 4 bolt splayed caps and a main girdle all in the name of strengthening the block as much as possible. I'm running a 88mm turbo, B&M oilcooler with fan FMIC and looking at the same rwhp/rwtq range as you. My car is also a 97 SS keeping a/c etc mostly street car some drag strip and I don't anticipate any issues so I think you'll be ok.

Snorkelface

Wow, separated at birth, huh! 😃 If I don't do the block fill, the girdle at least might be a good idea

Snorkelface

Also, what stud girdle did you go with?

97Z28SS

iTrader: (5)

I'll ask my engine builder as he spec'ed it out, here's a link to my build my engine is still
at the machine shop. Currently the crank, rods and pistons are out being coated. https://ls1tech.com/forums/lt1-lt4-m...butt-hurt.html

Snorkelface

Nice! I'm def jealous of your plug access. Haha Are you running a stock pcm, or did you jump to an LS computer and coils?

97Z28SS

iTrader: (5)

Yea Jon aka RealQuik does excellent work and I wanted headers but he convinced me to do it his way and I'm glad I listened to him. I have the whole 24x setup including the custom engine harness and I chose it because it's easier to find people familiar with tuning the 0411 pcm. I am also going to run an Eboost 2 electronic boost controller and a trans pump on my faceplated (no syncros in 2-4 gear) T56.

Snorkelface

He certainly does! Yeah, I want to go to 20lbs of boost, but the '97 PCM is really limited going to a 3 BAR setup, so I'm stuck at 2 BAR for now. I'll have to wait for more budget to go to 24X. Are you using a 2pc rear seal crank? Just asking as that will make a difference on the stud girdle question

97Z28SS

iTrader: (5)

No my engine has a Callies Stealth 1pcs RMS 4340 forged crank and I haven't had a chance to get over to the machine shop to ask my engine builder but I think it's this one.

Snorkelface

That's the one I was looking at. Thanks!

Snorkelface

Resurrecting from the dead...haha. Did you ever get to road race with your partial filled block?

gnx7

iTrader: (28)

You are going to have a hell of time keeping that turbo V8 cool on a road course.... Maybe run a 2nd smaller radiator in the back bumper for additional cooling..... That's what I have my LS9 88mm RX-7.... even on low boost you could only get a couple hard laps in before it would overheat. In the 1/2 mile making 1000-1200rwhp (boost by gear) it goes from 165* up to nearly 200*.... in just a 1/2 mile. So on a road course you can imagine the temp spike.

You should have no problem reaching 1000hp. Here is our buddies 240Z with a 383 LT1 (LT4 heads/intake) and 91mm turbo making an easy 1000rwhp on pump e85.

I had an LS7 powered RX-7 and with a fully ducted radiator (Howe 15.5x27.5" dual pass)

, vented hood, distilled water with a splash of Redline water wetter it would be in the 230* range. I had a pretty large ducted oil cooler as well. That's an aluminum block so it runs an easy 10* lower than an iron one. While this picture is with a/c on it... I tracked it without. 49.5% weight up front/50.5% rear at 2840lbs wet without driver.