2 1/2" or 2 1/4"

[TNT Bomb]

Is somebody knows why Flowmaster, Mac, Borla, Pypes, Magnaflow offer Cat-Back systems with 2 1/2" pipes if we loose in the low torque end with pipes larger than 2 1/4" ?

I sent an email to Flowmaster customer's service asking them the same question; it never be answered...

It's really confusing...

[Danger Dude]

It is all about money. The kits were originally designed For Mustang GT's. Stock GT pipes are 2 1/4. But everyone goes to 2 1/2 . So when they realized there was a V6 market to tap into they just adapted the GT's kit to ours.

The real problem is only a handful of the big companies understand or know much about 3.8's so they usually mod the V8 stuff to our cars. That is also why you see advertisement claims on the V6 stuff that are totally bogus and an outright shame on the consumers. The fact is they just apply the V8's advertised gains to the V6 ads.

That is why I rarely listen to or believe advertised gain by big companies.

Corey

[Ponycarman]

I quit believeing their gains claims long ago. World Products used to advertise that their heads offered a large gain over stock heads. In the small print you found out that their test engine was a Chevy 350 with "stock" 305 heads on it. NO sh!t you saw gains but 305 heads were never stock on a 350.

Lot's of examples of that, so I see what actually works based on people not trying to make a living selling it, like almost all the Amsoil cheerleaders, darn near everyone that I have met who was a wild enthusiat for Amsoil and would wax poetically over it and arugue with you if you disagreed always turn out to be a dealer.

Steve

[RGR]

It's all about Combo Matching.

If you just plan on keeping the stock cats and get a good deal
on a 2.5" cat back, then I'd say you are going to be fine. But
if you are building a complete system and delete the cats or
get hi-flows, I'd use 2.25" unless you are planning on a stroker
and then I'd consider the 2.5" system. I can tell you exactly
what will be the best arrangement for you if you share your
entire mod plans with us, it is pretty well established what
works on a V6 now. If you are staying close to stock and
just want a local shop to customize a set of true duals
then you could stay with 2" pipe all the way through.
Gets confusing doesn't it? That is why I need to know
what your plans are, so you can do it right the first time.
That makes it cheaper for you in the long run.