^ realistically could power i could possibly be losing with just the test pipe being a larger diameter be worth it to get another test pipe.

 

let me rephrase, i have a 63mm testpipe and a 70mm exhaust. given that the header is 63 anyway...would i stand to gain or lose from changing the testpipe to 70?

 

^^well people big gains just from the t1r 70mm and 70mm test pipe with stock header, so i think youd be better off with the 70mm, wanna trade! lol

 

The problem lies with going from 63mm piping to 70mm piping. It doesn't matter if it is header piping, test pipe piping or exhaust piping. Anytime you go from a smaller diameter piping to a larger diameter piping without some sort of smooth transition you will lose power.

Case in point: my Toda header is 63mm and my exhaust piping is 76mm. There is no smooth transition from 63mm to 76mm. I lost 13rwhp because of this!

 

^then how come there is still a large gain with the t1r 70mm with stock header? Not doubting you really just wondering why you would lose so much and with the t1r 70mm it gains a good 12 hp

 

I remember a little while ago someone posted there dyno which included intake and exhaust. then they added a test pipe and took the same dyno and just by adding the test pipe the dyno jumped something from 203-4whp to 215-216whp.
Not hard to believe considering a test pipe alone will show more gains then a exhaust itself.

 

[QUOTE=versionJDM,Nov 17 2005, 07:00 PM] i dont plan on lowering vtec, seems like honda has it right.

 

i have to insert foot in mouth here. since that statment i have lowered vtec to 5700 and have had great results with it set there, as we have seen through this thread.

 

oh, and i showed about 5-6 whp from a test pipe.

 

i meant with the complete t1r system test pipe and exhaust, theres no smooth transition from the stock header to the test pipe, but it still has a big gain