Cats and tune

[Firebirdjones]

Im suprised by removing the cats there are no gains, those cats are big and all the crap thats in there restricting exhuast flow, well i shouldnt say crap. I can see on the other hand that the stock cats and y have good flow for a stock manifolds or a regular bolt on car excluding headers. I think sticking with what i said above with the tune and gears i should be ok for a little while, hopefully. Maybe ill get nitrous down the road since ive done that on my 93Z. I think on my 01 ill go with 100 shot wet and do other supporting mods and i think that will cover me with plenty of power down the road.

Well this is just one example. Fact is though, I tuned the car with and without the cats,,,and saw no measurable gains at the track, only the tune itself got me 3 tenths and 2 mph. This is based off of a stock internal engine though,,,that obviously didn't need any exhaust mods so long as the manifolds were in place.

I did install long tube headers and off road Y-pipe,,,after the cats were already removed,,,and this only got me another tenth and 1 mph. Again a stock internal engine. Something with a cam would have responded better. But it was worthwhile as I needed them to support whats in store later.

[Vexzer]

those cats are big and all the crap thats in there restricting exhuast flow

They are big so that they do not restrict flow. The reason there is so much crap in there is so they do not restrict flow. They are essentially trying to double the capacity of the pipe so as not to cause a restriction.

[Firebirdjones]

Well they probably do restrict,,,I just found they didn't make a difference on a stock motor in my case.

Now if you go building a 5-600 hp monster that requires more exhaust flow then there is probably alot to be had from removing them.

[OMGls1jz]

What Balls! That's awesome, but kinda scares' em at the school zones 'eh?

i don't drive with them open all the time, just when i'm racing.