Premium aftermarket heads vs. Stage 2 LS6 heads
09-04-2009, 12:15 PM
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Premium aftermarket heads vs. Stage 2 LS6 heads I am seriously considering doing a heads and cam package. I live under California's smog laws so I can't be too radical. My car will be mainly street driven.
While doing my research I feel myself being pulled in two general directions. Premium after market heads, or ported and polished LS6 heads. The after market heads have a geat pedigree with a premium price, PP'ed heads look stock with a practical price.
But my main concern is the volume of the intake runners and their effect on throttle response. Most aftermarket heads for my application have intake runners in the 205 - 215cc range. While most PP'ed LS6 heads seem to have runners in the 230cc range. Now big runners make for big flow numbers which translate to big dyno numbers. But my car will be mainly street driven with some spirited weekend driving, I'm more interested in better throttle response across the full operating rpm range and big heads can result in sluggish performance at low rpms.
So how much does the bigger intake runners effect low rpm throttle response. Should I be concerned about an extra 15 - 25cc increase in intake runner volume?
I know this isn't your typical which part is best question. But I appreciate any insight everybody can give me.
While doing my research I feel myself being pulled in two general directions. Premium after market heads, or ported and polished LS6 heads. The after market heads have a geat pedigree with a premium price, PP'ed heads look stock with a practical price.
But my main concern is the volume of the intake runners and their effect on throttle response. Most aftermarket heads for my application have intake runners in the 205 - 215cc range. While most PP'ed LS6 heads seem to have runners in the 230cc range. Now big runners make for big flow numbers which translate to big dyno numbers. But my car will be mainly street driven with some spirited weekend driving, I'm more interested in better throttle response across the full operating rpm range and big heads can result in sluggish performance at low rpms.
So how much does the bigger intake runners effect low rpm throttle response. Should I be concerned about an extra 15 - 25cc increase in intake runner volume?
I know this isn't your typical which part is best question. But I appreciate any insight everybody can give me.
09-04-2009, 12:29 PM
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I'm in the same boat out here in SoCal. So I'm looking at the TR cheater packege with AFR heads.
http://thunderracing.com/catalog/?ac...vid=3&pcid=226
Supporting mods:
Eldebrock shorty's, Random Tech high flow cats and Y pipe, TR has them also.
What year car do you have? Ported TB & LS6 intake are a must at least.
http://thunderracing.com/catalog/?ac...vid=3&pcid=226
Supporting mods:
Eldebrock shorty's, Random Tech high flow cats and Y pipe, TR has them also.
What year car do you have? Ported TB & LS6 intake are a must at least.
09-04-2009, 01:29 PM
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I have a '04 C5 coupe. So I already have the LS6 intake manifold. I also have a ported throttlebody and a Callaway CAI.
My tuner has recommended either of these two directions. He grinds his own cams. I am just looking for some insight from people who may have some experience with these two set-ups (aftermarket vs. CNC LS6).
My tuner has recommended either of these two directions. He grinds his own cams. I am just looking for some insight from people who may have some experience with these two set-ups (aftermarket vs. CNC LS6).
09-05-2009, 11:03 AM
#5
It's all about the combination.. but if the budget permits I would prefer the premium head. AFR 205's are great street performaners for a 346 for price and you can use your stock rockers. TFS 215's are a little more money and you need an aftermarket rocker. The AFR 205's have the CARB# ? and are legal in Cali IIRC, not sure about the TFS but I would think so.
Here is customer of mine results as well... He had ported OEM heads and a big cam. Put down x amount on the dyno and ran so fast at x mph in the 1/4.
Went to AFR 205's and a smaller cam and lost power on the dyno but was quicker in the 1/4 and gained 3 mph. Dyno number's can be deceiving. Read the sticky it has excellent info about airspeed.
Here is customer of mine results as well... He had ported OEM heads and a big cam. Put down x amount on the dyno and ran so fast at x mph in the 1/4.
Went to AFR 205's and a smaller cam and lost power on the dyno but was quicker in the 1/4 and gained 3 mph. Dyno number's can be deceiving. Read the sticky it has excellent info about airspeed.
Last edited by 99blancoSS; 09-05-2009 at 03:36 PM. Reason: sp
