LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Lt4 Corvete Vs Lt4 Ss Camaro (or Lt4 Firehawk)?

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Old Apr 12, 2008 | 02:14 PM
  #1  
mcjaxon's Avatar
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Lt4 Corvete Vs Lt4 Ss Camaro (or Lt4 Firehawk)?

Guys,

I've never heard anyone comment on this. To the best of my knowldge the LT4 grand sport Motor used in 1996 6-speed Corvettes was a factory issue assembly line motor. However, I have also read that the few LT4 SS Camaros and Firehawks that were built used SLP balanced and blueprinted ('hand massaged if you will') LT-4 motors. If this is the case I would think SS/Hawks got more power out of their LT4s than did the LT4 96 Vettes.

Any logic to my thinking? Better yet, any evidence that this might be the case (race or dyno)?

Very interested to hear your collective thoughts on this one

MCJ

PS Also, who would have the weight advantage? Vette or F-body? Amongst F-bodies are there any weight or mechanical differences between the LT-4 Hawk and SS?

Last edited by mcjaxon; Apr 12, 2008 at 02:18 PM.
Old Apr 12, 2008 | 02:49 PM
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Weren't the Firehawks and SS's 345hp vs the LT4 vette's 330hp.

I remember seeing the build sheet for an LT4 SS and the LT4 motor was expensive, like $17K.
Old Apr 12, 2008 | 02:52 PM
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http://s16.photobucket.com/albums/b2...=IMG_24411.jpg

http://s16.photobucket.com/albums/b2...=IMG_24401.jpg

looks like it says 330hp.

yep.
http://s16.photobucket.com/albums/b2...t=IMG_2450.jpg


A quote from another site,
The year is 1997 and GM has quite a few of the LT4 motors that were used in the 1996 Grand Sport and Collector's Edition Corvettes available. Knowing this SLP approaches GM looking to do a special edition Firehawk and SS to send out the Gen II (LT1) based f-bodies (Firebird and Camaro) with a a bang. After some negotiating GM agrees to have SLP do a limited production run of LT4 equipped Camaro SS and Firebird Firehawk cars. This run is initially set to be 100 cars of each model. The SS LT4s actually reach this production limit and exceed it by 6 cars to provide cars to six Canadian buyers. However due to the late start on the LT4 Firehawks, SLP ends up producing only 29 production models and 1 prototype car. Needless to say, the LT4 Firehawk is one of the rarest cars ever produced in the history of the f-body and if not already, will definitely be a collectible in years to come.

The general idea of the LT4 SS and Firehawk, was to take an LT4 engine, balance and blueprint it and then install it in an SS/Firehawk with every option that was available from SLP. This car would then be rated with 330HP to match the rating of the 96 LT4 Corvettes and dyno tested at SLP to verify the HP rating on each car. To address concerns regarding the car being able to handle the additional HP and Torque of the LT4 motor, these cars could only be ordered in a hardtop with the six speed manual transmission. So you will never see a factory LT4 t-top, convertible or automatic equipped car

Last edited by Zepher; Apr 12, 2008 at 03:00 PM.
Old Apr 12, 2008 | 03:58 PM
  #4  
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I once heard that the LT4 Camaro's used the LT1 computer tune due to emission regulations, and GM not wanting to get the car recertified if they used the LT4 tune. I think it was Alvin at PCMforless that had a chance to dyno tune a factory LT4 camaro and it picked up waaaay more power than a stock car should with a dyno tune. That being said I think a 96 LT4 vette would spank an SLP LT4 camaro based on that reasoning and of course weight advantage. Just one opinion. And one based on rumors at that
Old Apr 12, 2008 | 04:23 PM
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They were actually almost exactly the same HP stock vs stock. While the LT4 Hawk/SS did get B&B engines, they were severely limited in a couple of ways, which held it to the advertised 330HP:
1) They had to use the stock LT1 ECM tune due to emissions
2) They used the stock LT1 knock module
3) Even with the extrude honed exhaust manifolds, they still used a more restritive exhaust than the Vettes (The Vette use basically shorty headers and true dual exhaust from the facotry).
My car bone stock dynoed 280RWHP, 300TQ, which figuring 15% driveline loss works out to almost exactly 330HP (flywheel). After going to the LT4 ECM tune, I jumped to 300RWHP & 317TQ (now roughly 350HP flywheel). After adding the LT4 knock module to that, it was 311RWHP & 326TQ (roughly 365HP). I haven't checked it since I added long tube headers, but it feels WAY stronger on the top end now, I'd guess somewhere around 330-335RWHP (~390HP).

So the LT4 Hawk/SS has the ability to make more HP easier than the LT4 Vettes. Most LT4 Vettes really have to spend some big bucks (cam, heads, etc) to make more power, so I'd definitely say the balancing and blueprinting provides a platform for more HP after upgrades.

Having owned a C4 Vette (92 LT1 making 270RWHP, so similar to stock LT4 Hawk), it it weren't for the rarity of the LT4 Hawk and having a back seat, I'd definitely take the LT4 Vette. But then a lot of that has to do with the fact that I do a lot of roadcourse events. While the two have about the same handling limits (almost identicle times at our local roadcourse), the Vette is much easier to drive at the limit than the Hawk (or any f-body). Plus the Vette is actually a better daily driver (better ride due to independant rear suspension), although it is a lot harder to get in and out of. That's why I'm planning on getting an LT4 Vette to go with the LT4 Hawk in the next few years (unless I find a really good deal on a C4 ZR1).

As to an LT4 Vette spanking a LT4 SS/Hawk, not really. The f-body is easier to launch at the dragstrip (and like I pointed out, stock vs stock they do make right at the same HP). Also, like I said above, they will run about the same at the roadcourse too.
Old Apr 12, 2008 | 05:28 PM
  #6  
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Phenomenal responses. Thanks guys! :-)
Old Apr 12, 2008 | 11:50 PM
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Originally Posted by LT4Firehawk
They were actually almost exactly the same HP stock vs stock. While the LT4 Hawk/SS did get B&B engines, they were severely limited in a couple of ways, which held it to the advertised 330HP:
1) They had to use the stock LT1 ECM tune due to emissions
2) They used the stock LT1 knock module
3) Even with the extrude honed exhaust manifolds, they still used a more restritive exhaust than the Vettes (The Vette use basically shorty headers and true dual exhaust from the facotry).
My car bone stock dynoed 280RWHP, 300TQ, which figuring 15% driveline loss works out to almost exactly 330HP (flywheel). After going to the LT4 ECM tune, I jumped to 300RWHP & 317TQ (now roughly 350HP flywheel). After adding the LT4 knock module to that, it was 311RWHP & 326TQ (roughly 365HP). I haven't checked it since I added long tube headers, but it feels WAY stronger on the top end now, I'd guess somewhere around 330-335RWHP (~390HP).

So the LT4 Hawk/SS has the ability to make more HP easier than the LT4 Vettes. Most LT4 Vettes really have to spend some big bucks (cam, heads, etc) to make more power, so I'd definitely say the balancing and blueprinting provides a platform for more HP after upgrades.

Having owned a C4 Vette (92 LT1 making 270RWHP, so similar to stock LT4 Hawk), it it weren't for the rarity of the LT4 Hawk and having a back seat, I'd definitely take the LT4 Vette. But then a lot of that has to do with the fact that I do a lot of roadcourse events. While the two have about the same handling limits (almost identicle times at our local roadcourse), the Vette is much easier to drive at the limit than the Hawk (or any f-body). Plus the Vette is actually a better daily driver (better ride due to independant rear suspension), although it is a lot harder to get in and out of. That's why I'm planning on getting an LT4 Vette to go with the LT4 Hawk in the next few years (unless I find a really good deal on a C4 ZR1).

As to an LT4 Vette spanking a LT4 SS/Hawk, not really. The f-body is easier to launch at the dragstrip (and like I pointed out, stock vs stock they do make right at the same HP). Also, like I said above, they will run about the same at the roadcourse too.
Your a lucky sob, take care of her. Such a nice car.
Old May 19, 2008 | 02:11 AM
  #8  
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First picture shows the dealership as Performance Chevrolet on the window sticker. Back in 1997 I got to test drive 1 of the 2 LT4 CamaroSS cars they had. I wonder if that window sticker is from that same car I got to enjoy 11 years ago
Old May 20, 2008 | 11:18 AM
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With only an LT4 knock module, stock tune and 9k miles my LT4 managed 299 RWHP, don't remember torque figures. I've never driven an LT4 Vette so I can't compare to my Camaro.

Last edited by 97LT4SS; May 20, 2008 at 11:26 AM.
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