Supercharging an LT4?
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Joined: Apr 2005
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From: Grand Rapids Michigan
Supercharging an LT4?
I have had my LT4 coupe since May and the car is fast already, but I want it to go faster. I'd like to supercharge it but I have talked to some people and they say it not a good thing to do with the LT4 because it burns the engine up? Is this true or do they not know what they are talking about? Would it be better to turbocharge it? or not doing any forced induction at all? Help me out!
Thanks,
Jake
Thanks,
Jake
Safety Car
Joined: Sep 2003
Posts: 3,692
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From: Hayward CA
Supercharging is not a good ideal when you have a 10.8:1 compression ratio.... and hypereutectic pistons.
If you want to supercharge it, build a forged bottom-end and lower the compression ratio. Otherwise, have the heads/intake ported, get a custom cam, a full 3" exhaust and tune, and you'll get 380-395rwhp. Several guys on this forum with LT4's have gone the N/A route and have very impressive numbers.
If you want to supercharge it, build a forged bottom-end and lower the compression ratio. Otherwise, have the heads/intake ported, get a custom cam, a full 3" exhaust and tune, and you'll get 380-395rwhp. Several guys on this forum with LT4's have gone the N/A route and have very impressive numbers.
Racer
Joined: Dec 2004
Posts: 427
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From: Albuquerque New Mexico
If you can't afford the engine rebuild when it eventually blows you probably shouldn't supercharge the LT4. Though after my rebuild things weren't so bad as the compression was lowered to a functional 9.2:1.
For what it's worth, if I started from scratch I would probably go the N20 route instead. Build the heck out of the motor and drop a 250+ shot, or maybe a couple of stages of N20. Woulda been alot cheaper plus a heck of lot less headaches.
My .02
Le Mans Master
Joined: Jul 1999
Posts: 8,683
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From: Phoenix AZ
Originally Posted by zelement
just leave it alone. unless you got $30K laying around and don't know what to do with it.
But you'd have to admit, once it's done it's worth the effort!
Safety Car
Joined: Oct 2002
Posts: 4,277
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From: Austin Texas
2018 C6 of Year Finalist
It can be done. Talk to Greg with Blower Works at www.carrollsupercharging.com/ . He has a kit developed for the LT-4 and makes aroud 500 HP. I am getting ready to install the kit on my 383 LT-4.
Michael
Michael
Last edited by GS057; Sep 22, 2005 at 11:23 PM.
Melting Slicks
Joined: Sep 2000
Posts: 3,150
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From: Carlsbad, CA CA
Originally Posted by Zix
Are you speaking from experience?! But you'd have to admit, once it's done it's worth the effort!
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Michael S. Palmer
Pro
Joined: May 2003
Posts: 682
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From: Annapolis MD
it can be done but it is very tricky. i know where a LT4 vette is with a procharger setup on it putting out 7 lbs of boost on the stock long block and runs damn good. pulled 460 to the wheels. take alot of timing out and add alot of fuel and it can be done.
our first top alcohol dragster we ran was 12:1 compression with a 1471 psi blower. anything can be done but you better have deep pockets cause if 1 cylinder goes alittle lean there is no give in a 10.8:1 street application.
our first top alcohol dragster we ran was 12:1 compression with a 1471 psi blower. anything can be done but you better have deep pockets cause if 1 cylinder goes alittle lean there is no give in a 10.8:1 street application.
Burning Brakes
Joined: Nov 2003
Posts: 914
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From: Redding Ca
First look in your wallet and decide how fast you want/can afford to go. Be specific: How fast in mph and how quick an ET (if drag racing is what you are talking about). 
Also consider state smog compliance. 
The alternatives to reach that level of performance will become apparent as the parts necessary to do it are known commodities.
If you read the supercharger button on this forum, there are a lot of unhappy supercharger owners and a few who go like stink and are thrilled. I think the latter stepped up to the pay window.
Also consider state smog compliance. The alternatives to reach that level of performance will become apparent as the parts necessary to do it are known commodities.If you read the supercharger button on this forum, there are a lot of unhappy supercharger owners and a few who go like stink and are thrilled. I think the latter stepped up to the pay window.
Safety Car
Joined: Sep 2003
Posts: 3,692
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From: Hayward CA
If you're dead set on supercharging the LT4, get the compression down. Either go with a set of AFR 195cc heads with a 62cc (or bigger) combustion chamber, or have your LT4 heads worked to increase the size of the combustion chambers. Add some 1.7 rockers, a bigger TB, full exhaust, a Carroll (Vortech) supercharger, bigger injectors, and a bigger fuel pump...... with a tune, you'll have one nice street-able 450+hp combination.
Race Director
Joined: Feb 2001
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From: Manassas VA
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St. Jude Donor '14
Originally Posted by GS057
It can be done. Talk to Greg with Blower Works at www.carrollsupercharging.com/ . He has a kit developed for the LT-4 and makes aroud 500 HP. I am getting ready to install the kit on my 383 LT-4.
Michael
Michael
What did the kit cost you???
Which kit did you buy from him?
What's the compression ratio of your 383?
thanks
robert
Race Director
Joined: Dec 1999
Posts: 10,230
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From: Alexandria, Virginia, USA VA
with a good tune you could run some boost but the pistons aren't designed for it. if you want to put a kit on the car, get it tuned well and consider alchy operation for higher boost.
chances are the pistons won't last very long, and I agree it would be better to freshen it up with the right compression, run a bit more boost rather than low boost and high compression.
the little turbo buick runs pretty good at 26 psi, but we break alot of stuff too. :o
chances are the pistons won't last very long, and I agree it would be better to freshen it up with the right compression, run a bit more boost rather than low boost and high compression.
the little turbo buick runs pretty good at 26 psi, but we break alot of stuff too. :o
Supporting Vendor
Joined: Oct 2004
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LT4 S/C Kit
I've Been Making A Kit For The LT4 Since It Came Out. Boost Restricted To Around 6-7 Pounds And Of Course It Includes My "Gaseous Intercooling". When Done Properly And You Limit The Boost, It Screams. Of Course The Engine Potential Is Far Greater With Forged Pistons And A CR Reduction.
Regards Greg
Regards Greg
Supporting Vendor
Joined: Oct 2004
Posts: 761
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If it's done right (boost limited to 5-7 lbs) and it includes water/alcohol injection along with a proper 'PCM' re-flash it'll last as long as a stock LT4: all things being equal (like running the injection reservoir empty and still stumping on it). I've got customers with LT4's that have been running since 1996. The pistons are plenty strong as long as you don't let it detonate !!!
Regards Greg
Regards Greg