Hey, this isn't super scientific testing....but I figured I'd pass on some quick data.

I posted this a few weeks ago showing the 3.5" exhaust I built under my Vette. I previously had some 3" exhaust under it with some Dynomax Race Bullets..and before that some Flowmasters. The 3" stuff just killed it. Now the total truth is that I also built a new trans crossmember that allowed me to run pipes off headers without as many bends as it required with old Vette setup that requires the pipes to go THROUGH the crossmember.

But that's not really the point of the test. I was trying to build something that would allow me to race it without having to mess with uncapping it...plus I hated the way it sounded with the Bullets. So what we have here is a rough test of open headers with 9" extensions against the new Pypes Mufflers and full exhaust.

My car will run 9.90's at around 139-140+ with open headers in 85*-90* weather. Cooler temps in the 60's will get me more power and worse traction....but put MPH in the 141-142 mph range. I've run it at quite a few tracks all over the place and it's actually pretty consistent right around there. 1/8th mile mph will be in the 111-112 mph range with 113 popping up when it's cool outside.

So last Thursday I ran it at our track rental with no changes other than running it capped up with the full pipes out the back of the car. It even had same oil and plugs in it from last year when I ran it at the same track!

First pass of the day was 9.96@139.47 with 111.98 mph showing up at the 1/8th mile mark! That is absolutey consistent with how it runs with open headers in the same weather. I was seriously impressed to say the least! Now the unscientific part is that even though I installed dumps that I could have uncapped, I never bothered to try it. It was an awful busy day with me working on/driving several cars other than mine.

I think some folks got some video of it so you can get an idea of the sounds...and I'll post them as soon as I see them. But it definitely sounds better to me and is amazingly quiet considering you can just about stick your arm through these mufflers!

I've seen recent posts asking for muffler suggestions for some High HP combos and from what I've seen on my car, I can recommend some big pipes and some Pypes brand mufflers. These are the Race Pro's which they claim are actually the quietest and I can believe it.








JIM

 

I'm glad to hear all of that hard work paid off! Running 9's with full exhaust is quite an accomplishment.

You have been running your current motor combination for quite some time now, isn't it about time for a serious bump in power?


Steve