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heads vs supercharger

ms38w

Full Member
Joined
Oct 12, 2007
Messages
4,169
Location
Bent Mountain, Virginia
The heads on my 6.7L LS2 were ported/polished for maximum flow...claimed to be better than ZR1 Corvette (can't back that up though). The motor was originaly built for forced induction, so the compression ratio was kept a bit low to accomodate that.  I no longer have those turbos ( insert comment here  :E:  ) and had planned on going with a twin-screw supercharger, but I am toying with the idea of  staying N/A.  If I stay N/A, I will likely want to up the compression to squeeze some horses out of it.  I need to keep final cost and involvement in mind, so I'd like some QUALIFIED opinions here.  dollar for dollar and HP for HP and all that good stuff, would I be better off changing my heads or just going with the SC?  Please include your argument to back up what you say, not just your opinion or personal preferrence.

Thanks...
 
MS38w- You have several things to m. This is a 6000lb truck not a 3300 lb corvette. So you need low end TORQUE. The supercharger will give you that- upping compression means you will probably end up with a higher rpm torque curve and that is not what you want. A low boost (4-5 psi) system will give you the torque. You will have to go custom tune but you know that. Ther may be used maggies out there that is what I would recommend.

Avalon
 
Thanks, I was thinking along those same lines.  When I had the motor built, I specified that low end tq was more important than hi end HP.  Makes sense about not upping the compression then.  The only problem with a maggie is that they don't make them big enough.  I am at 6.7L on the motor and the maggie is only good to 5.7...6.0 is really pushing the envelope.  I was trying to stay away from a $7000 unit. I was wondering about the heads, and getting more tq.  I am running short headers for the tq.  I have been having issues with the custom tune.  It really needs to get on a dyno, as the email tunes can only get you so far.  Allen has been very patient with me and I appreciate all he has done...but it's time for the next step I think.  I have HPTuners, but it's not really user friendly and if you don't know what to look for or change, it is useless.  Real world dyno results are the most reliable.
 
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