Quick_CX

say i have this friend who has a gsr swap in a hatch...and is thinking of going turbo....its got 2.25 mandrel bent piping all the way back for exhaust system if planning on going turbo will i need more back pressure so much that i'd have to swicth to say a 2 inch pipe....turbo guys let me know

EK7_DriftMania

No, the original pipe is 2.25' depending on your boost pressure, that pipe could not take the pressure. Bigger pipe will give more power, but calculate the boost to pipe ratio. Having a smaller pipe could give you problems later on, depend on boost.

Turbo will compress more air into your engine, so it need to let more air out, so to speak. It's all about the efficiency of flow.

On a NA engine, having a smaller muffler will give better accel. but at high speed or high rev. your engine is dying. 2 inch, I don't think any car uses 2 inch pipes any more. Straight mufflers with bigger openings are better, it makes more power and would not kill your engine, back pressure is a bad thing for turbo. It could cause back fire.

crazyhatchback

i heard 2.5 on turbo is optimal

bbarbulo

iTrader: (2)

it's the opposite... turbo wants NO back pressure, NA needs MORE back pressure. I know of a B16A turbo with 3" exhaust, but you can get away with as small as 2.5" if you have to. For turbo, BIGGER is always better. Think... if you had a dam that generated electricity via a turbine...except downstream didn't have the flow that you need... it'll get backed up and the turbine will stop, right?? Hope that analogy makes sense. The boost will force the air out in the same fashion it forces it in. 2.5 is okay for your application. The 3" B16A put out over 300hp.

OcTaNeTeDdY

I run a B18C turbo in a 92 hatch and my exhaust piping is 3 inches all the way to the back... Exhaust = HKS Hiper... You Don't want any back pressure at all.... The turbo spools up much faster when there is no restrictions... If you really want to get crazy don't use any type of exhaust just a down pipe from your turbo.. tee hee....

EK7_DriftMania

What about the turbine? There are defferent ones that can boost better right?

I can understand 3' for 300hp, but what about 200hp or less?

OcTaNeTeDdY

3" still ... let that exhaust flow freely and fast if you want that turbo to spool up faster... ie. my turbo used to spool up at approx 4 g's and the turbo lag was annoying... that was with 2.25" exhaust.... then I changed out to 3"s and now I spool up at 3G's and turbo lag changed dramatically....

Quick_CX

ok cool thanks octane teddy..i hear your the one to beat...what are u pushing at the wheels?? and i want to know how ur car runs for a daily driver? or is it a daily driver??...is turbo reliable....i hear good i hear bad...just really curious....cause i am hearing many thinga re gonna go wrong and its gonna cost all kinds to get it running right ...and its a jhuge hassle...

OcTaNeTeDdY

Last Dyno was done in summer 2002 and since then there has been a couple of more power mods ... at that time I dyno'd at 241 Hp at the wheels, 300 at the crank and 187 Ft/lbs of torque... not bad... Been having lots of bad luck lately with the turbo... Fuel maps off slightly dumping more gas that needed and running too rich gone through 2 high flow cats, because of this (cat being clogged) I fried the O2 sensor and was getting no flow out the exhaust stopping my turbo from working (no boost sux) Finally fixed ... Before I also had some hesitation problems where the car would bog down on full throttle and recently discovered I had 2nd runners on my intake manifold and 4 little butterflies in them an option 94 GSR's had called VVIS ("Variable Volume Induction System")... Well I decided to disable them and now everything is running better than before.... Summers a bitch the engine gets freaking hot... I had to rewire the fan so I control the thing manually (Keep it on ALL the time)... But when you get little things iron'd out it's helluvalotta fun!!!! Especially when you hear the turbo spooling up then the BOV goes off... hehe whasssshhhhhhhh........PHHSSSSSHHHHHH!!!!!! BWAAAAHAHAHAHAHAHAHA..... sorry getting carried away.....

Quick_CX

haha i would too...well i have a 94 hatch, with 2001 gsr...i can do a T3 setup...i just have this car as a daily driver through summer....so i want it to stay reliable...and i could go Blower...but thats less power than turbo

Quick_CX

how much $$$ do u think u've spent on getting ur turbo to run right...or are u there yet??

OcTaNeTeDdY

Well depends on how good your mechanic is and how much dyno time you want to pay.... tuning on a dyno is much more easier and convient but $$$

Quick_CX

very true...

BB1_EG6

lol who is gonna install it......? and how much boost u want to push.......?

oh ya go 3" for sure