Velocity spike and HVMC differences
09-13-2007, 07:52 PM
#2
Tech Resident
It basically creates a merge inside the collector. Basically, instead of the flow of air running straight into the collector without organization, the velocity spike/merge collector merges the flow together neatly so it flows out of each primary in an organized fashion instead of big gobs of air crashing into each other. It basically makes the exhaust flow faster, and since you're pulling exhaust out of your motor faster, you reach a better efficiency for increased power and even fuel economy if you can keep your foot out of it.
Here is a dyno of Pacesetter longtubes vs. QTP longtubes with HVMC. This is JUST A HEADER SWAP. No other mods, no extra tune, no nothing.
https://ls1tech.com/forums/dynamometer-results-comparisons/700678-results-qtp-hvmc-vs-pacesetters.html
The QTP's netted a 9rwhp peak gain over the Pacesetters with a whopping gain of 18rwhp/30rwtq at ~3100 rpms.
Granted, it's a H/C motor, so the gains won't be this pronounced on a stock internals engine, but it puts the argument to rest that "all longtubes dyno the same." All longtubes DO NOT dyno the same, and it's painfully clear that the QTP's are head and shoulders above the Pacesetter design.
Here is a dyno of Pacesetter longtubes vs. QTP longtubes with HVMC. This is JUST A HEADER SWAP. No other mods, no extra tune, no nothing.
https://ls1tech.com/forums/dynamometer-results-comparisons/700678-results-qtp-hvmc-vs-pacesetters.html
The QTP's netted a 9rwhp peak gain over the Pacesetters with a whopping gain of 18rwhp/30rwtq at ~3100 rpms.
Granted, it's a H/C motor, so the gains won't be this pronounced on a stock internals engine, but it puts the argument to rest that "all longtubes dyno the same." All longtubes DO NOT dyno the same, and it's painfully clear that the QTP's are head and shoulders above the Pacesetter design.
Last edited by ChocoTaco369; 09-16-2007 at 03:59 PM.
09-17-2007, 03:17 PM
#7
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how much do hvmc run for and where can i get them?? i have a set of pacesetters and wouldn't mind swaping the collectors on them. I know someone that can do the job (welding, etc.) so that wouldnt be an issue
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09-21-2007, 12:38 PM
#11
Tech Resident
Originally Posted by patricksd
So, instead of a running a 13.25, I'd run a 13.24 with the QTP's over the Pacesetters? 
09-21-2007, 09:29 PM
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Originally Posted by patricksd
So, instead of a running a 13.25, I'd run a 13.24 with the QTP's over the Pacesetters?
With that thinking you could assume that with the pacesetters you would run 13.25 vs 13.26 with the stock exhaust manifolds.
The QTP's and American Racing headers are top notch.
https://ls1tech.com/forums/sponsor-sales-specials/780773-quick-time-performance-headers-y-pipe-sale.html
Last edited by MPHmotorsports; 09-21-2007 at 09:35 PM.
