just wondering what the largest diameter down 0pipe is that can be used with stock turbos?

I guess the lartgest possible and the largest useful.

 

Any downpipe is better then that engine destroying precat that came with the car. Performance wise all the downpipes that you can buy on the market are about the same.

 

Where can I get a four inch downpipe then?

 

why four??? i dont think that you will make any more power than with a three inch... i just think it will be louder...
-Keith

 

You don't need a 4'' dp unless you are in the high HIGH hp rating. Stick with the M2 3'' SS down pipe.

 

to go back to whats been said, take a look at that cast iron contraption called an exhaust manifold, and tell me how anything bigger than a 3" is gonna help? lol, that thing is a monstrosity

 

Rite, I agree tht the manifold is a more urgent upgrade.
But I just wonder if I can do it or if u know where to find a larger than 3" dp. I have a 3" currently.

 

the largest ive ever seen was a 3.5" and i dunno who made it, keep in mind also that there really isnt any way short of going single or an aftermarket twins kit to seriously upgrade the goofy stock cast iron manifold, and when you go single a stock DP doesnt work, all single kits come with a new DP for the turbo...personally id buy the cheapest 3" you can find unless your keeping the stockers, then get the nicest 3", I got an HKS and regret it cuz it has the stock flat square thing at the top, any good "all pipe" downpipe <ie one made with a mandrel bend instead of a cast piece at the turbos> will work the same.

 

Chris at Rotary Performance has 3.75" exhaust on his FD, custom made downpipe, hi-flow cat and catback are all 3.75". He said they had talked about producing the set up and selling it, but I've not seen it on any other car. You could try emailing or calling them

www.rx7.com

good luck!

 

lol

Right, my car is almost finished and I thought I let my stock turbos get a work out before going to a T51R.

I know that the 3" down pipe I have is plent for the stock set up , but I thought it would be interesting to see if anything more happens with a larger 1.

But yeah i guess this is at the limit of the stockers!

maybe i'll just chop my dp up and expand it progressively to 4" as it get closer to the midpipe......hmmmmm

 

so what does the opening actually measure at the outlet going to the dp?

will it make a difference weather i use the 3" and expand it as i go down or will a 4" open that much more room to breath at the top?

 

As luck would have it my new DP gasket is here for reference, and I have a tape measure in my drawer. 3 1/8th by 2 1/2 it looks like...also you'll have a real hard time making the bend with anything much bigger than 3" and clearing the frame rail etc...the DP is pretty tight space wise.
-Mike

 

There is a guy in the 93-95 4 sale section claiming 4" dp and 600+rwhp if he has a 4" then it was specially made