Got my MS4/PRC Stage 1 LS6 dynoed today. All mods are in sig. The flowmaster catback rocks......ok not really. Dynoed through the flowmaster 401RWHP, with my cutout open.....drumroll......433RWHP. Yes that correct folks, a 32RWHP restriction. Thats a ton in my book. Anyway, I was shopping for a new catback anyway so now that I have the dyno proof, it can push me that much harder (like I need it) hehe

 

Damn thats a lot HP that the flowmaster is eating up! Thats unbelievable.

 

damn thats almost unbelieveable. I'm glad I got rid of mine.

 

what series muffler is on the flowmaster?

 

I dont really know. I think its the 80 series. Either way, I wont cap my cutout till I replace the system. Prob gonna magnaflow or B&B. I know they dont flow the best but I love the look and its gotta be better than 32RWHP.

 

Wow, very interesting. Just for comparison I had dynoed my Hooker exhaust a couple of years ago the same way. I don't recall the before/after numbers (roughly 320 rwhp closed cutout A4) but the gains to open cutout were like 4rwhp/7rwtq.

 

What was the tq diffenrce,I would bet it made more tq through the muffler.but nice hp gain.

 

wowow----I use my qtec half the time anyway though and my 6 year old flow/80 sounds very low and mean so i am gonna keep it anyway..at least for awhile.Good to know though.thanx for info.

 

Unbelievable. I remember when you promised you were going to dyno and get some hard data ... I think this pretty much ends the argument. The conventional wisdom proves true: flowcrapper, chokemaster, etc., etc.

 

Try SpinTech. They flow much better.

 

I have been posting this dyno sheet a lot of times, but noone seems to pay attention to it. This was on my pretty much stock car done in 3rd gear since my car came with a speed limiter that cut the fun on the dyno short prematurely in 4th gear. Mods are the same except the exhaust...Flowmaster 80 series vs B&B



And this is without any other mods. With my current cam and LS6 intake and long tube headers, I am sure the difference would be much more substantial, just as Beasst8 is seeing.

Manny

 

wow thats unreal and hear i am, trying to buy another flow-crapper muffler.. well i will be going with a slp lm2 for sure now

 

Remember folks, the Flowmaster was costing 30HP on a near 500bhp motor. You WILL NOT see those gains on a stock or bolt on setup. This is because on these setups there is much less exhaust flow, thus the restriction is less. Remember keep things in perspective.

 

Do you have the dyno chart at all?

Also what type of dyno? Dynojet, Mustang. And are these SAE corrected numbers?

 

See MannyZ28's Post above.

 

Yes it's nice isn't it.

But all I see is a slightly suspect dyno as it was not done using a 1:1 gear ratio. And I also don't see a 30rwhp difference.

 

I have the dyno sheet for open cutout, its in the dyno section. That was all SAE corrected on a Dynojet.

 

Ive seen 12rwhp gain through a cutout over a Magnaflow(I believe it was), its on my website before and after(422 to 434).

 

The 80 series is always going to be a restriction. I'll only use the 1-chamber race mufflers or 2-chambers on my vehicles. Maybe their race bullets, but I've never heard them in person.

 

No i am really thinking about switching it up. My car feels slow but thats kinda a dumb statment since i have never taken it to the track or the dyno and the flowmaster cant be forcing me to loose that much. But now i really feel like i want to.