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Velocity spike and HVMC differences

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Old Sep 13, 2007 | 06:53 PM
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Default Velocity spike and HVMC differences

I understand that the High Velocity Merge Collectors are better than a velocity spike.

How does a hvmc work?

How does a velocity spike work?

Why does the hvmc make more power?
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Old Sep 13, 2007 | 07:52 PM
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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.

Last edited by ChocoTaco369; Sep 16, 2007 at 03:59 PM.
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Old Sep 16, 2007 | 09:32 AM
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A while back QTP offered a velocity spike or for more money you could buy a hvmc. They ended up putting hvmc on all headers. Why do HVMC flow better than the velocity spike?
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Old Sep 16, 2007 | 03:57 PM
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There still is a velocity spike in the header.

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Old Sep 16, 2007 | 04:27 PM
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heres some ARH pics I have. for a comparison.

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Old Sep 16, 2007 | 08:55 PM
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Just to make it fair, QTP's collectors:

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Old Sep 17, 2007 | 03:17 PM
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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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Old Sep 18, 2007 | 11:05 PM
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So, instead of a running a 13.25, I'd run a 13.24 with the QTP's over the Pacesetters?
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Old Sep 19, 2007 | 02:31 AM
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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?

pretty much
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Old Sep 21, 2007 | 11:39 AM
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heres a few pics of the Edelbrock longtube collectors (these are off the stepped version)....

HVMC design

turbulence/velocity spike


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Old Sep 21, 2007 | 12:38 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?
Only if you've been brainwashed by the ignorant mass audience into believing that "all longtubes make the same power," because they don't. There are better designs, and you can see significant gains by swapping to another brand. Pacesetters are cheap for a reason. Not many things "Made in Mexico" are of high quality, and Pacesetter longtubes are no exception. They're okay for what they are, but to think they'll show the same performance gains and quality workmanship as the premium headers is nothing short of ignorance.
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Old Sep 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; Sep 21, 2007 at 09:35 PM.
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