BigWhiteGTP

Here's my goal and or situation. I am having my Lb9 rebuilt to stock specifications. Why not a 350? Because everyone has a 350 and I love my 305. Original matching numbers might be nice later on in life. Anyway, I got to thinking of Supercharging the rebuilt motor. But I want to know if it's worth it.

I have a nice flowing intake, pretty coated headers, and soon get a full 3" catback with a hi-flo cat, and I put in a 3.42 PBR disc rear. I will be doing nothing else. I want 300-ish ( +/- ) wheel horsies and I know TQ will be even more. Torque is more than enough for me now so anything more will give me a **** eating grin.

Will a supercharger bolted on with a conervative pulley, meaning one that won't blow my motor, and quite possibly an alky-kit to keep KR at non-existant levels get me to my goal or should I just skip it and just go on to restoring as much as possible?

Thanks guys.

Sonix

iTrader: (1)

how far into the motor rebuild are you? cast piston and no upgrades?

if you can, use hyper pistons, open up the ring gap, ARP bolts in the bottom end everywhere, and better rods. Then use a simple blower with 4-6psi, intercooled if you want. Should be just fine. oh, and get you grinning

BigWhiteGTP

Well, I will be picking up the car tomorrow or thursday. No upgrades, but the guy assured me that parts were of stock specifications, but better quality, but not what you mentioned I'm sure. I had a limited budget and this SC I'm flirting with won't happen for a few months when I am finally able to refinance my house. Now with that said, are my goals attainable?

Sonix

iTrader: (1)

call him up and ask him what EXACT pistons are in the motor, and what bolts were used for the mains, and rod caps. If he's got any brains at all, he upgraded those.

You can still put on a blower, but you don't have the peace of mind as if it were upgraded. Also you can't run as much boost.

A blower is expensive, make sure you know that. Budget for any other upgrades you'll need too, ie, fuel pump if it's needed.

350FWHP from a blown mild 305 sounds pretty reasonable.

BigWhiteGTP

I'll ask him when I get it back what went in and I'll post it up. I know Supers are expensive, around $3k right?

Also, I would only run low boost 4psi or so, but that was part of my original question, would low boost on a rebuilt stock motor get me to 300whp? I'm not wanting 350-400hp yet. That would require some major $$ work. 200 has been good to me for the last year. 300hp sounds nice.

CrazyHawaiian

From a power aspect I'm not sure if 4-6psi will get you what you want on the LB9. I'm running 6psi on a stock L98 and I don't even think I'm hitting 300whp. Torque is a different story, but HP is kind of lacking in my opinion. Its just that the TPI Intake, stock cam, and stock heads are not a good match for centrifugal blowers. By the time you build boost the TPI engine is running out of steam. I'd say I only have about 1,500 RPM of good powerband on boost. They pretty much have mismatched powerbands. Its a real letdown. An intake and cam change would probably make a world of difference, something I'm in the process of doing myself. Having a powerband thats matched to the blower will definately give the car a better feel, and produce more power.


Reliability aspect, I've been running a Vortech S-Trim @ 6psi on a bone stock L98 for a while now with no problems (motor has 130K miles, blower went on around 75K). Always run 92 octane fuel, still running stock 730 ECM w/ the Vortech FMU kit, MSD 6BTM is set to retard 1 degree timing for every psi of boost. Assuming you run the right octane fuel and have the tuning aspect taken care of, should last a long time on even a stock LB9.

BigWhiteGTP

I understand about the powerband differences, but I was always under the impression that forced induction counteracted the TPI intake at upper rpms as the air is forced into the intake.

Well, what about a roots style blower, anyone make those? CSC are like turbos, but roots are there 100% of the time. My GTP had a roots style blower and the thing was awesome.

3rdGenBlackBird

That theory is true to the effect that it will make more power than a stock tpi, but it still won't be well matched.

There's a tech article on this site about a mini blower, but it won't be fuel injected anymore. https://www.thirdgen.org/weiand142install

How did you like your L67's powerband? (Or whichever GTP....)

BigWhiteGTP

I absolutely love the L67's powerband. You can stomp on the gas from idle and roast the tires. Much like a TPI car except you have an extra 1000 rpms of power. Stock for stock they put down around 195whp and 260wtq, which is very similar to my Lb9's stock 187whp and 270wtq. But sadly, that's where the the advantage of the GTP's cheap mods take over. For $1000, the GTP will do low 13's, whereas the T/A will probably still be in the low 14's.

But at the end of the day I can strap a blower to my car, but I can never put in t-tops or make a GTP rear wheel drive and make it handle like a thirdgen. Also, the roar of the V8 is the best sound in the automotive world. The V8 roar is like a T-rex, and the L67 scream is more like a raptor. One is faster, but isn't as cool.

calebzman

iTrader: (3)

I got 300rwhp out of a stock lg4, but that was with 10psi of boost from a single turbo. It only lasted a few months before 3 pistons broke. Like Sonix already mentioned, you will definately need better pistons and rings, forged being the best. Make sure that the compression ratio is low (~8:1), and if it is too high, swapping out for better pistons will allow you to lower it. Whether you'll need higher quality rods and crank will depend on your power goal. If you plan to stay will 300hp, the stock rebuild ones might be fine. For what it's worth, 5-6psi is pretty much the max boost recommended for an engine with stock internals. Also, make sure you have a way of reducing timing once the boost kicks in. I used an MSD boost timing master like CrazyHawaiian. Good luck.

BigWhiteGTP

Won't a progressive ALky kit help things out? I wouldn't get a SC w/o a form of intercooling, but buying an intercooler is silly if an Alky kit will just as good for cheaper.

3rdGenBlackBird

If you already have experience with meth, you should use it. Usable v8 short blocks are easier to find than l67's if anything does go wrong. Still probably want to limit boost on a stock bottom end.

I agree about f-body vs. w-body. You pretty much nailed the reasons why f-bodies are so much more fun. Plus they aren't stuck with a weak auto.

Scott