AFM to Turbo Pipe - RB20 upgrade

[Chris32]

Just want to know if anyone has done this and how effective it was

I have a problem at the moment where when I run highish boost i can hear the rubber pipe between the AFM and the turbo sucking shut, and the car drops massively in performance. When running normal boost - 1bar, its fine but when I wind it up a bit further to 1.2bar I can hear it really sucking the intake and restricting the inlet air - really frustrating as the little HKS turbo really want to go, but it is being choked!

So I want to change the pipework to metal to stop this from happening, but want to know if anyone has had any troubles, especially with the AFM playing up due to the pipework being changed?

Thanks for any info

Chris

[BryanB]

yeah its a boost cut i think its 16 psi on a R32 ECU? not too sure but yeah sounds like your getting a cut......

[Chris32]

nah, its been re-programmed so the boost cut is about 22 or 24 psi from memory, definatley pipe sucking shut

When its cold (weather wise) the rubber hose stays quite hard and isn't a problem, I have seen 1.3bar on the gauge in 3rd when it was cold, so its no boost/airflow cut, as they have all been lifted quite high to stop this

[rev210]

the pipe is very similar to the VL turbo. On the Vl you pick up around 7hp just through improved flow , without the pipe suckinh shut issue.

[BIGBLOCKR31COUPE]

This rubber pipe shouldn't close over at those boost levels but installing a nice smooth metal pipe will improve flow. One thing to note is that the original pipe has a section in front of the turbos inlet designed to reduce turbulance in the pipe caused by the turbo. Not having this in place can cause minor airflow meter inaccuracy but will not do any damage.

[Chris32]

Interesting, as I am 100% positive that its causing the problem, to what degree I am unsure but high boost is pretty well useless at the moment

What about using some coiled wire to wind inside the pipe? Has anyone tried this?

[walkoau]

noooooo definetly dont do that!!!!!!!

it may get loose and find its way to the turbo.

just replace it with an alloy pipe

[Brody]

Ive heard this being an issue on some r34ts though their boost wassn't that high. I think frank had this issue?

Im with every1 else on replacing it with an alloy pipe. Probably just as much effort/$ to do anything else also.

[09ONE_32]

Yeah this is a sort of common problem. I know (personally) that the RB20 pipe won't support anymore that about 200rwkw, although they can fail at a fair bit less that this. Mine was replaced with a 3 inch mild steel pipe. It works really well, heaps of flow awersome unrestricted flow capabilities. It should definately be upgraded even if you are not having problems with the stock pipe yet.

[Chris32]

Ok sounds like it would be best to replace it, as at the moment with 1bar its making 200rwkw, so I am guessing with 1.2bar its just to much vacum for the poor old rubber pipe to handle! Should be a good upgrade either way, I'll keep everyone posted of the results

[DJ984]

Can anything be put in the new pipe to replace whatever it is in the standard pipe to reduce the turbulence or is it not worth the hassle....

After reading this i am considering doing the same to my car... 3" mild steel from air-filter to turbo... does it require any other modification....???...

[R31Nismoid]

Just want to know if anyone has done this and how effective it was

especially with the AFM playing up due to the pipework being changed?

Well if your pipe is getting sucked shut, then it would be very effective to put in a pipe that doesnt get sucked shut.

And as for AFM, no worries, the AFM would be before your pipe starts anyhow

[EnricoPalazzo]

replace with pvc