Outer Limits 4x4 Board

hi all i have 1985 lwb seirra and am thinking 2 inch or bigger exh pipe has any one got any ideas to what is the best for power and performance out of 1.3 spook ????????? thanks brett

dont go any bigger than 2" , have you got extractors? with extractors and 2" system you will get a slight but noticeable increase in proformance, but nothing huge, but you will get a big increase in noise is your engine stock? alot of exhaust shops don't recommend more than 1 3/4" others don't care . i run a 2" system with extractors , but to quieten it a bit around town i put a 1 3/4" reduced tip (my canopy's stuffed and the noise gives me a headache) on it

I have a 2" - 2.25" system on the 1.6 Viagra. Even a full 2" system is probably excessive without extractors - maybe 1 3/4" going into 2" would be better, and with variation in pipe size you get less droning.

The Vitara sounds good with it's new pipe, but it would be way to big for the sierra.

This topic has been discussed before - someone had some real experience on what was optimum for the Sierra - I believe it was 1 7/8"..

Had two inch system on my SWB Zook a few years ago and it didn't seem to work real well. Same system on the 1.6 toyota mill I put in seemed to restricted. ( You can't win ) Inch and a quarter with extractors and high flow muffler would be a better option.
Just stuck a full 2 inch system on the EFI Vit and the improvement is remarkable. Better response down low, motor rev's cleaner and higher and with extractors, high flow Cat and muffler, resonator it sounds the job too
I 'spose the difference in the two is that the Vit is high flow throughout whereas the toyota motor had big muffler and poorly designed extractors.
Once I work the head and stuff in a cam and some other stuff the system will come into its own

I have a 2" straight through system on my 1.3, made a good difference, coupled with I have extractors and a sports cam.

cheers