Thread: Intake pipe size?

My setup has 2' piping hot and cold on the ol' T25.

Now that I am running a Z32 MAF, I'm wondering if the 2' intake is my new bottleneck and may be causing funny MAF readings.. Should I leave it or fab up a new pipe?

My piping is all 2". I don't have a z32, but I do have an n60 which looks very similar. Runs fine. I'm running draw through. Idk if it matters being blow thru or draw thru, but 2" works nice for me.

There could be a few things wrong there. A lot of people run 2" pipes without any problems, especially on a T25.

Firsts things first, are you blow through or draw through? What are you using for maf readings and how low is you voltage at idle?

I'm draw through. I don't have any MAF readings yet. I noticed after I switched to STI 520/605cc/4bar/Z32 setup there has been a slight bucking going on at light to partial throttle.

I went ahead and regrounded the MAF to the ECU's ground. It helped alittle. but still kinda there.

No boost leaks besides the very slight one at the dist.

I installed a WB this week, but I don't have AFR data yet.

TPS is at .45v

No CEL's

So now that I have a big bottleneck right after the MAF, my theory is that the air is rushing and getting bottled up at the MAF by the reduction.

Do you have a 2" pipe right after the MAF going to the turbo?

I would say 2" would be fine after the turbo, I would suggest 2.25-3" before the turbo, depending on how much space or serious you want to get.

Even then, you need to get your MAF voltages at idle, if it's below 1.0v you need a new MAF.

Yep I have 2" before the turbo. I have 2.5" stock sitting around. I have give it a try. I will check the MAF voltages after I get the car interior back together.