When Does Stock Afm/turbo Pipe Become Restrictive

[Robo's]

Does anyone know when the stock R33 AFM to turbo rubber pipe become a restriction?

Im pushing mid 230rkw's and it doesnt seem to be sucking closed, but maybe its becoming a restriction. Ive got a HKS 2535

[paulr33]

bass junky just went to 250rwkw and his workshop put a 3" (or maybe 2.25" or 2.5") section of steel inside the the rubber intake piping and clamped it to prevent it from being sucked closed. i also had a look at the apexi super intake for r33 and it looks very nice, but its basically the same thing. i dont believe you would gain anything from using it other than avoiding the sucking closed thing and nice shiny new intake pipes

[Wazz]

regardless if it sucks fully closed or not it is still a restriction.. me and a few other mates have done comparisions between stock rubber hose and a solid mandrel bent pipe and picked up a car length or 2 (wasnt exactly done on the strip (private road.. apprently)) but the car we tested agains ran consisant times due to being auto and before and after was 3 out of 3 for each so you do pick up a little bit from it

Wazz

[R31Nismoid]

you answered your own question Robo actually hehehe

if the pipe he no sucking shut... then he no problem

You will get no gain if the hose is the same size as the turbo inlet.

Really, how can it be? Only gonna suck what it can fit

So no need if your certain its not sucking shut.

Wazz... definately not a restriction. Drag racing on the street isnt a very accurate way of doing a test. Stupid if you ask me.

GTR's run 350kw+ @ the treads stock piping no worries.

[Ezz35]

i just replaced the rubber piping conecting my pod to the intake(previous owner thought soft rubber was good idea) and felt very restrictive. Had 3" stainless put in there and really noticed the diff. I talked to the guy at the exhaust shop about the rest of the intake and he said that the way its built it should suport round 220-240rwkw..... but the rubber insert conecting them was deffo sucking closed

[Abo Bob]

GTR's have a different setup and so this is not an issue for them.

I had issues at 228rwkw and had to replace the pipe.

[Robo's]

you answered your own question Robo actually   hehehe

if the pipe he no sucking shut... then he no problem

You will get no gain if the hose is the same size as the turbo inlet.

Really, how can it be? Only gonna suck what it can fit 

<{POST_SNAPBACK}>

Not necessarily true. I know with experience LS1's they can gain several kw's with bigger maf to TB pipes as the stockies become restrictive. Its generally in the bends that upsets the flow but i have never seen much info with these RB25's

[paulr33]

gary explained this last time someone was talking of moving the hotwire rb20 afm into a larger diameter airflow meter shell. the restriction in an N/A car is different to that of a forced induction car. The N?A has restrictions all through the intake and inlet system. The turbo/supercharged model restrictions only lie after the compressor/forced unit. So in theory upgrading the intake to a larger diameter at your given power lower wont "unrestrict anything" if that makes sense. well at least thats what i recall.

[R31Nismoid]

the stocker LS1 items though are horrid.

so it the coldair box which comes as part of the kit