I saw an interesting comment in a GMhighperformance article. The article was about an LS7/ZR1 Supercharger build but on the engine dyno they used OEM LS7 manifolds and said that although they gave up a few lb/ft of tq that they actually produced more HP.....

I'm always looking to learn more on here. Any ideas as to why this may be true?

 

It would really come down to the specifics of the build, including what type of headers were used, and the diameter of the primaries & x-pipe.

For example, with our 1 3/4 tri-y headers on a stock ls7, you will see significant increases in TQ and HP. What were the details of the supercharged build? I do know that GM is using a tri-y shorty manifold on the new z-28. Not sure if they will carry the technology over with other models though:



http://www.car-engineer.com/the-ls7-...14-camaro-z28/

 

Maybe on a supercharged motor but it's been my experience that shorty headers never produce as much HP or TQ as long tubes on a NA motor.

 

No way no how...

A number of members and shops on the board, including ourselves have posted before and after numbers using LS7 manifolds/cats/H pipe over the base Corvette items.

Are the LS7 manifolds better than an LS2 or LS3 setup? Sure, they have almost consistently shown 10-14 hp and about the same on torque. Given that a good set of headers will pick up 28-32 hp and 30-40 ft-lbs of torque.....no they are not as good as, or even better than headers but they are better than stock base car manifolds if you want to keep the car 'stock' looking.

As for the LS9's....typically with a supercharged application a bigger tube primary header is going to loose a little bit of boost measured at the engine due to the reduction in back pressure in the system. It should also drop chamber temps slightly. They will increase HP but possibly not to the degree of what you might think given that they are more reliant on boost than anything else to make big gains. What you will typically be able to do however it put more timing in it and/or increase boost levels after the headers and make a very big jump in power. So you may only see a 20-25 hp increase with just headers on an LS9 (depends on the setup) but you could change a pulley size on the blower and end up maybe another 1-2 psi of boost over what it was stock and see a 50-65 hp gain. So it is typically a bit more involved with a supercharged engine to make sure you are comparing apples to apples.


At any rate...a good long tube header will always make more HP and TQ over a cast manifold.

 

 

My '08 LS3 bolton ran a best of 10.82/125.82 with a full Z06 system, except the over-the-axle pipe, in -760 air. I later changed to a ported IM and 2.5" LG Streets and ran 10.85/126.80 in -100 air on a .03 softer launch. If you correct for DA and a slower 60', there was a power increase. I can't say how much more HP or what was responsible, but it certainly runs stronger now.

 

This.

 

yeah but lets remember headers and tune give you that much, alot of it is the tune on the z06 that is picking up. Headers about 15-18whp on their own usually. So yes the ls7 manifolds are good, but no way are they better than good all fashioned long tubes...

 

I can't wait to see what the SPL Headers do to my HP & Torque on my ZO6 tomorrow... Feeling Excited!

 

ya the engineers at GM don't have a clue, right?

 

I would like to read this article, can you direct me to it?

 

I'm on my phone now and don't have the link. Look up GM high tech performance mag and then search for LS7 supercharged. It's a fun read.


Found it..... http://www.gmhightechperformance.com..._engine_build/

 

Not sure that's a very fair way to compare the two Changing pullies because you the vacuum gauge at the manifold reads different....

 

I have LS9 exhaust manifolds and they are not cast.

 

EPA

While Chevy engineers are great they are not designing a car for track junkies, they are designing it for average people.

The beancounters and EPA have a huge say in what gets to the dealer.

Could Chevy have a 1000HP ZR1 yes, could they have great brakes yes, could they have fixed the LS7 valves yes. Did they?

Headers work great and even better without CATs if you are willing to put up with the stink and noise.

 

Gee back in the 70's we did not have cats and I do not remember stink and noise, then again there is a lot I don't remember about the 70's LMAO.

 

Non alcohol race gas still smells good, but the stuff at the pump now?

 

Another good article below comparing headers and manifolds.

http://www.carcraft.com/techarticles...t/viewall.html

 

so $1800 headers for what a handful of HP all I can say is wow.

 

It's about the same as buying the $1800 option for a set of wheels that don't add any performance, but just look different than the base wheels.
$50K will buy you lots of hookers and drugs or 3 smart cars or 1 Corvette. Freedom of choice still exists to some degree.