For those with Down Pipe Data in Hand
 

Can you tell me what you gained with the addition of a down pipe in power? I am interested in dyno-data specifically....I don't see anywhere in the posts where a single mod increase is documented.

I have a cut airbox and dp, didn't really notice anything but possibly quicker spoolup

It's somewhat hard to gauge, as this is a mod that doesn't make much horsepower if that's the only mod, but gives you increasing amounts of power as you mod the car further. Not to mention it's just a good idea - you get rid of a very heavy, VERY hot, and very in the way pre-cat.

About 5-10 hp is all you should really gain with a downpipe alone versus stock, depending on what kind of shape the pre-cat was in to begin with.

Dale

And probably save your main cat, as I heard the pre-cat falls/fell apart over time.

I couldn't tell you where now, but this is the figure I remember seeing too. Which is really pretty cheap horsepower...isn't it?

I picked up 10hp...

I picked up 10hp...

Same boost right? Mine started overboosting.

Depends on the car. I had boost spiking on my car with just a downpipe and a cat-back. Boost controller will solve that problem no sweat.

Dale

You're also knocking about 13 lb. off the weight of the car since the precat weighs about 18 pounds.