ronarndt

For those who have a streetport on their 13B- how much low end torque do you notice has been lost? I am having a rebuild done and am not sure if I want the ports just polished or to actually have a streeet port done. I do not want to lose drivability just to get high rpm gains. Engine is for street use with occasional auto-X. Any advice is appreciated.
Ron A.

Mr rx-7 tt

iTrader: (5)

Polishing won't do anything, can be slightly adverse.
Decide what you want the car for. If you run the car port it. You will make more power up top but you should run a midpipe and full exhaust to get the benifit of a port job. If you are running a cat and don't "run" the car much stay with stock porting. How much you lose on the low end and how much you make up top depends on the porting and the mods. 20-30 rwhp is about what you should see with a "average" port job at the peaks (low end and high end). Gains and losses.

rotary

port

boostedrotor

i think the gains of a streetport far outway anything you may loose, lets just say when my car hits 4k rpms you forget about any tourqe you may have lost down low......and yes, you need a midpipe to reap the full benefits of the streetport which means no airpump....

Street King

Thi shouldn't even be a question. Port IT!

Fd3BOOST

iTrader: (7)

When i did mine, i went huge and the low end power is barely effected.

you might like this thread....http://www.nopistons.com/forums/inde...T&f=81&t=6911&

grinn253

is a midpipe really that necesary? I have to keep the airpump so was considering a high-flow cat instead?

Thanks!
Edgardo
p.s. also i believe there was a thread that indicated a high flow cat was 'good enough' but can someone clarify if a midpipe is absolutely necessary to 'reap full benefits' of street port?

goodbye!

ronarndt

Thanks to all for the replies. I was afraid I might have to lose the cat. Since this area in NC is finally getting strict about their state inspections, I would need to do an annual re-install of the cat convertor, just like you boys in the Sovereign Republic of California. Crap!
Ron A.

boost-in-rx7s93

I do not even have a midpipe on my 93. I have a nurspec exhaust with 3 inch straight pipe running to a now stok downpipe. affter my rebuild I will install a thre inch downpipe keep the three inch pipe and run the nurspec exhuast. should I port and do you think that anything such as a air pump has been lost by using the straighgt pipe?

thanks joe

sacabon

I also don't notice a low end loss with my small street port. (they took out alot of metal for the small port,I'd love to see a large) I even have the upper and lower intake manifold ported. I'm also using stock twins