What hp levels do stock tail pipes become restrictive?

[slayerripkdc]

I recently swapped some flows on my car and left the stock tails and was wondering if they will bottle neck at 400 wheel horse?

 

[BurningRubber]

A buddy of mine had a Vortech GT, 8 or 9 psi... made 360rwhp. The tails weren't restricting it, although he had a 2.5" H and a set of Flow 40 series welded in.

 

[bhuff30]

I seriously doubt it will bottle neck you. I am making over 300rwhp with a SINGLE 2.5" crush bent exhaust on my 88 mustang. That's around 360hp at the crank? Granted, it is obviously restrictive at my level because when I open the exhaust cut out, I gain 2mph in the quarter. So double my single exhaust numbers and you can figure your dual 2.5" system will get restrictive around 600+rwhp (700 at the crank). I think you'll be fine.

 

[sneaky98gt]

I have a friend with a 78 Malibu, street car, with a 406 stroker, fully built, with a nice shot of nitrous and all the supporting mods. He has dual 2.5 inch pipes with a set of Flowmasters that are quieter than mine. I'm not sure about horsepower numbers, but he ran 6.20s in the 1/8 a couple weeks ago.

Restrictive? Maybe.

Necessary to have big exhaust to run good times: definitely not.

 

[Winters98GT]

10-15hp on a 480-500hp car. That is my dyno experience, but not on a 4.6.

 

[BK_CAULEY]

Anyone with flow masters doesnt need to worry about the tail pipes becoming a restriction.

 

[SteedaGT9150]

Anyone with flow masters doesnt need to worry about the tail pipes becoming a restriction.

lol.

 

[SaleenGT2001]

Anyone with flow masters doesnt need to worry about the tail pipes becoming a restriction.

TRUE

 

[Stumbaugh]

Anyone with flow masters doesnt need to worry about the tail pipes becoming a restriction.

Agreed. My 99 gt back in the day picked up a little over 1mph with going from weld in flowmasters to weld in magnaflows.