[notquitegto]

Researching them, that is!

I have a 70 GTO, mildly built with the ram-air manifolds and 2.5" pypes system. I went the the Pro-Vs. The sound is awesome, they never fail to turn heads. However, from 2000-3000 RPM, the resonation screws up my ears. After one longer trip, I couldn't hear well for a couple days.

I'd like to go with something that has a nice, deep, tough tone, but without all the interior noise. I've read about every thread on the subject and there is no crystal clear answer. I'd love to hear people's opinons on these models that supposedly should fit the bill.

The candidates are...
Welded Ultraflows
Race Pros- Pypes
Super Turbos

[69*Goat]

Go buy yourself some Groelich X-Celrators. I have these on my Can Am with an X-pipe. These things are great. When you first get into it it sounds like all hell is breaking loose. I have scared many people with these things. At highway speeds, and constant throttle it is a very quiet, and mellow.

Just my $0.02

[David Jones]

20" Dynomax Super Turbos.
I had a set of 50 Series Flowmasters on my 69 GTO with a 2 1/2" mandrel bent Flowmaster pipe kit. H pipe. From 1800 to 2800 rpm (any rpm you cruise around at) you couldn't hold a conversation in the car. Sounded cool outside though. I swapped to the Super Turbos and couldn't believe the difference. No interior resonation. Totally different car inside and it still sounds good outside.

[Ccass]

Least amount of resonance in order and with a rating so you can tell how close one muffler is to the next.

4-20" Dynomax Super Turbo
5-14" Dynomax SuperTurbo
6.5- 18" Xlerator
7-20" Race Pro
7.5- DynoMax Ultra Flow
7.5 14" Race Pro
9- 14" Pro V

The numbers are not sound ratings, just a comparison between each other muffler.

[hilljacknm]

That bit of info should be a sticky.

[Tim john]

Ccass, I also purchased the complete pypes system with X change in 2 1/2 inch and I do belive this came with the Pro-V mufflers and I too am very disapointed in their resonance, it is deafining while normal driving say about 2000 RPM. I am sorry to say that I would not reccomend them to anyone, the exhaust pipes were wonderful but those mufflers have got to go. Come spring time these will be removed from my vehicle and discarded, when I called PY and asked for assistance upon ordering the full exhaust system I was told these were an exact duplicate copy of the Flowmaster series that I enjoyed on my vehicle for several years (20). Now that I have cut my pipes to fit your mufflers and am disapointed in them I am forced to replace the pipes to change to something more tolerable. I do belive I will re-visit the Flowmasters unless PY is willing to work with us or myself on a personal basis. I am open for suggestions, advice and help. I have silently watched this and prevsious threads closely for many of the same issues that I am experiecing and this seems to be a contagious problem. Please offer any help if it is available. Am I correct in my assumption that I received the Pro-V mufflers with the complete exhaust system with X change, what ever it is/was the problem is very real. I will pull out my reciept this evening to verify. Thank You. Tim

[69*Goat]

I am telling you..........

Get the Goerlich XLERATOR mufflers you won't be disapponited. As I stated I am running these on my Can Am with a 2.5 inch system and an x-pipe(14" muffler). These mufflers are quiet at 2,000 rpm and higher very little resonance.

Larry Navarro can back me up on this.

[elevatorman51]

I put a set of streetpro's on my 67 firebird with the full 2.5" pypes X sys. with logs and I'm quite happy with the sound, low and throaty very comfortable inside car has a'71 455.

[Larry Navarro]

The G Xcelerators are awesome, i wish I had them back on my car.

I gave Russell "69*GOAT" those mufflers.
I went to a 3" exhaust and installed a set of the Pypes discontinued "V-Tube" mufflers. They are loud and basically a muffler with no baffle plates or packing.
Russell can back me up on that.

[HWYSTR455]

69*Goat/Larry- I was looking at the Xcelerator mufflers for my 71 A-body, and was wondering what the part number would be. They make a 14" & a 16", both stainless or not. Which one did you have 69*Goat? The part number?

[69*Goat]

I went with the 14" mufflers. I do not know the part number.

[Larry Navarro]

you don't need stainless.
The 14" will have a bit louder tone over the 18".
I think the A-body cars will accept the 18" Xcelertaor.

[HWYSTR455]

Cool, I'll look at the regular 18" then, thanks!

[rknrl69]

JUST BACKING UP WHAT 69*GOAT SAID ABOUT THE GOERLICH XLERATORS. THEY ARE FANTASTIC. 500 MILE ROUND TRIP FROM INDY TO NORWALK WITH 3.55 GEARS NO HEADACHE. OUR CAR IS A 69 GTO CONVERTIBLE.

[69*Goat]

The 18" will fit just fine.

[HWYSTR455]

Cool, 18" it is then, and will look for the part number. Just as a refresher, those would be center/offset inlet/outlet correct?

[69*Goat]

I ended up using the offset inlet and outlet, because that is what I was given .

[notquitegto]

After searching through this forum and reading the replies here, I went with the Xcellerators.

Here's my review in comparison to the Pro-V's, Note: I'm running a 400 with RA manifolds and 2 1/2" pipe, no cross-over.

These mufflers are still pretty loud, and have a very tough tone. However, there far less resonance at lower RPMs. All the sound is behind you. Sitting at a stoplight, you hear the rumble, but it is very muted. The Pro-Vs sounded like the engine was in the seat next to you. I found that they still have an annoying drone at around 1800 RPM but goes away.

As far as the tone goes, I find the car sounds healthier. It is a deeper tone (not as deep as your typical turbo muffer) where the pro-V's have more of an open header, blapity blapity sound.

I have to drive with these more, but I have to say, so far, I'm very pleased with the change.

Mike

[yakker]

What length are your Xelerators?

[notquitegto]

I went with the 14"s The Pro-v's are 14s and this allowed for the quick change. I had the car out alot this weekend and the ride was much nicer.

Mike