Yet another direction for the Z28 possibility?
08-06-2009, 03:32 PM
#91
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Join Date: Apr 2002
Location: All around
Posts: 2,154
I put the GMPP Wbody kit on my GTP and it made a pretty good difference. The kit was cheap and helped take a 10 year old tired chassis and inject some life into it. Sure, it handles a bit rougher on potholes now, but it handles and feels quite a bit better. If I put in better brakes, wheels/tires, and new springs and shocks I could probably get it to handle *really* well...
But...
GMPP products put on in the factory is a bad idea as it means they all have to meet crash/emissions/etc. Even changing a cat-back exhaust on some modern vehicles will mess with the engine operation and require a new tune - longtubes are out of the question. Not to mention issues from an NVH or ground clearance perspective.
Installing such parts at the dealership is extremely expensive for the consumer and creates waste parts. Having a company do the work like SLP is also rather expensive, even though they specialize on the installation.
Not to mention people cannot agree on what a Z28 should or should not be!
I agree. All those "theoretical" savings dont work. 15lb out of a seat means all new crash testing for such seat. Carbon hood? New crash testing. Lightweight battery? Optima has had some bad dealings with manufacturers before and their batteries are not consistent or reliable enough. Titanium suspension? The price of Titanium right not condusive AND all those pieces would have to go through durability and safety testing.
And back to my GMPP kit. For all those ratings/testings/legality issues, the parts all come with a giant "For Offroad use only!" labels. That is the ONLY way to get around the testing - but it also means that the factory cannot install them and the dealership shouldnt if they know whats good for them. Putting them on voids your warranty - and GM must put a warranty on the Z28 - a car even *we* cannot agree on how we'd want it.
And GM is still in the poor house.
But...
GMPP products put on in the factory is a bad idea as it means they all have to meet crash/emissions/etc. Even changing a cat-back exhaust on some modern vehicles will mess with the engine operation and require a new tune - longtubes are out of the question. Not to mention issues from an NVH or ground clearance perspective.
Installing such parts at the dealership is extremely expensive for the consumer and creates waste parts. Having a company do the work like SLP is also rather expensive, even though they specialize on the installation.
Not to mention people cannot agree on what a Z28 should or should not be!
Originally Posted by Z28Wilson
-160 (realistically now, not just throwing out theoretical weight savings), I am still not sure....
And back to my GMPP kit. For all those ratings/testings/legality issues, the parts all come with a giant "For Offroad use only!" labels. That is the ONLY way to get around the testing - but it also means that the factory cannot install them and the dealership shouldnt if they know whats good for them. Putting them on voids your warranty - and GM must put a warranty on the Z28 - a car even *we* cannot agree on how we'd want it.
And GM is still in the poor house.
08-06-2009, 05:06 PM
#92
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Join Date: Nov 2000
Location: Chicagoland IL
Posts: 16,179
I think the 5.5L will be based on the GenV 6.2L.
08-07-2009, 04:23 AM
#93
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Join Date: Oct 2000
Location: Kilgore TX 75662
Posts: 3,372
Why? You are giving up a bunch of available valve size (which is really quite important in a racing engine) to gain ~2mm of stroke? 
Not in a class this competitive.
The 6.2L has a 4.065" bore compared to the 4.125" in the LS7. With the big bore, you are looking at about a 3.15" stroke. With the smaller bore you are looking at about a 3.25" stroke. The longer stroke puts more stress on the rods at higher RPM. I realize that with those restrictors, the engine isn't going to be turning a lot of RPM, but over a 24hr period of racing, that is a HUGE difference in stress on those rods.
Not in a class this competitive.The 6.2L has a 4.065" bore compared to the 4.125" in the LS7. With the big bore, you are looking at about a 3.15" stroke. With the smaller bore you are looking at about a 3.25" stroke. The longer stroke puts more stress on the rods at higher RPM. I realize that with those restrictors, the engine isn't going to be turning a lot of RPM, but over a 24hr period of racing, that is a HUGE difference in stress on those rods.
Last edited by AdioSS; 08-07-2009 at 04:27 AM.
08-07-2009, 09:59 PM
#95
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Join Date: Jun 2004
Location: SeVa
Posts: 2,977
Well I don't see the V8 dying anytime soon either. I'm sure direct injection, displacement on demand and probably a reduction in cubic inches will probably happen but there will still be a need for them. Cars like the Mustang at Ford and the Corvette at GM will still need a performance variant even if they share parts with truck V8's. That's when it's good to be the Camaro and get hand me down V8 power!
Funny you should mention sharing truck parts - Mustang has a history of just that. the 5.0HO stuff along with the PI heads and most recently the 3v heads were all truck APPS. To bad Ford didn't do an AL 5.4 for the trucks, that extra 49 cube would have been real nice in 2005 when the S-197 debuted.
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