Significant exhuast HP difference or what?

[Stang7900]

I know alot of people here are using hi flowcats and aftermarket 3" exhaust. But what is the performance difference (HP)compared to deleting the muffler and adding hi flow cats? maybe even different bullet mufflers in the sills.
the reason I ask is that if you dont change to headers with the larger dia. the hp/torque should be about the same and alot cheaper.
true or false?

Steve
-----
1999 RT/10 Silver/Black

 

[Chuck 98 RT/10]

True. IMO and experience deleting the muffler and installing hi-flow or removing cats entirely will produce the same performance gain as a $1,500 cat back.

Exhaust note however, is a subjective matter.

 

[genXgts]

Re: Significant exhuast HP difference or what?

True Steve, and even moreso in your case, you have a decent header on your 99 already, unlike our 60 pound cast iron dogs that came OEM in 96 and 97.

I tossed mine and put on your header, rear **** delete and Roe Oval Hi Flows, very nice, sounds perfect in my book. The el cheapo (I'm Canadian eh?) budget exhaust that makes 90% of the gains for 1/3 the price. (debate on the header gain however, some feel only the weight savings).

Dyno in the next few weeks, as I lost 3 horse with just the headers and cats, leaving the restrictive rear **** in place, not good.

Start unbolting and tossing!!

 

[Stang7900]

Re: Significant exhuast HP difference or what?

Thanks for the responses. How does the 99 stock header compare to an aftermarket header/ combo?
Anybody?

Steve
---------
1999 RT/10 Silver/black

 

[Sam 01 RT10]

Re: Significant exhuast HP difference or what?

That's good news on the exhaust. I just recieved my Roe high flow ovals w/ tubes and filters on Saturday. The exhaust will be as mentioned, HF cats and !mufflers.
The tubes and filters are already on.

 

[cgmaster]

I just spoke with a friend And he told me not to waste my money on 3" exhaust until I change the headers. He told me to just put high flow cats or gut them and put dynomax bullet mufflers. The headers go down to about 2.5" so no use in 3". Only you can decide what you want it to sound like. He also said he could change my stock headers so that they would not get smaller than 3". I plan to wait until I comlete building the engine to put on headers and 3" exhaust.

 

[sbkim]

What tips do you recommend with dynomax muffler or even without mufflers? How are is high flow cat to install - I take it, you need to do some tact welding?

 

[FUSCUCLA1]

Let me throw an additional wrench here. If you had to choose losing either cats or mufflers which would it be?

I am guessing no cats with less restrictive mufflers will produce more power versus high flow cats with no mufflers.

Vice versa for volume of sound.

Yes?

 

[cgmaster]

I would start out just deleting the cats 1st. This seems to give the best flow and sound in my opinion. You can always do more later or put them back if the person doing it does a good job.