Nismo R-tune Intake Duct Vs. Pod Filters

[MLCrisis]

Hi, all,

I have just had a Power Fc installed on my R34 GTR (still getting used to that phrase - "my R34 GTR" .........). I had also fitted a Nismo R-Tune intake duct, which was promoted as a good thing in various places. The guys at the workshop were dubious about its likely performance, because the flow area at the mouth is really quite restricted. My understanding is that the idea of it is to introduce some level of ram effect into the airbox. (I had also put a Midori panel filter in the box, which was supposed to give enhanced flow over standard - I could not get a Nismo Sports Element.)

When it was being tuned on the dyno, the guys reports that from about 5,500 rpm the intake started whistling, it was so restricted. The power curve also flattened off. This was also influenced by the boost declining from an initial 18 psi or so to about 13 psi. (This is temporarily controlled by a bleed valve, with an EBC going in next week - hopefully.) The suggestion from the workshop is that the intake is responsible for much of the flattening of the power curve (I will post up the dyno graph tomorrow).

I am now considering installing an APEXi Power Intake pod system instead. I am swayed by the argument that the ram effect would be marginal compared to the available flow area - which the pod system will win hands down. Naturally, tuning on a dyno, there will be no ram effect, because the car is not moving. So it is difficult to tell conclusively.

My doubts on all this stem from the fact that Nismo know what they are doing and they have had some pretty high output cars running with this intake. Does anyone else have any experience of this or can they offer an explanation of the differences involved? The R-Tune intake duct sits on the standard airbox, which is unmodified. I have the standard intake pipes. I note that the Nismo cars all have the Nismo intake pipes, which offer improved flow - but they are all downstream of the mouth of the intake. So if this presents a restriction, this will dominate the performance of the overall intake system.

I would appreciate any comments.

Cheers.

[djr81]

I think you should be looking elsewhere for the cause of the lost boost.

This is a useful thread which will explain much.

http://www.skylinesaustralia.com/forums/in...=181061&hl=

Lastly, having seen the Nismo duct on a 34 I was suprised by how crappy it is. Nonetheless is its cross sectional area is larger than stock it will be plently big enough.

[Beer Baron]

there is a very simple way to find out what's happening. run it up on the dyno with everything hooked up. then remove the box, intake etc just leaving the two AFMs there. now run it up and see if it's any better. if it is, then get the pods, if it's not stick with the box and nismo intake and keep chasing the problem.

[sewid]

If your 34's airbox is truly unmodified then the first thing you should do is remove the blocking plate in the secondary airbox intake (the one from the wheel well). Mine still had this when it came from Japan as well so it's possible yours does too. Opens up the intake and should be the first thing anyone does when they buy one.

It's there to quieten down the intake but easily removed with a bit of elbow grease.

[MLCrisis]

If your 34's airbox is truly unmodified then the first thing you should do is remove the blocking plate in the secondary airbox intake (the one from the wheel well). Mine still had this when it came from Japan as well so it's possible yours does too. Opens up the intake and should be the first thing anyone does when they buy one.

It's there to quieten down the intake but easily removed with a bit of elbow grease.

Thanks, Sewid, I'll take a look at it. Thanks to the other guys for their comments too.

Cheers.