Hks Gt-rs

[dezz]

I'm after anyone running a HKS GT-RS on an RB25DET, (genuine HKS kit, not a Garret equivalent) to post up their dyno graphs.

Specifically their boost graphs.

I'm running one on my car and have been for some time, but only recently 'finished' the package off with injectors and a Z32 AFM...

It made 253rwkw on 18psi, but boost isn't holding in the top end, which is why I'm after other's GT-RS graphs, as well as any similar experience with boost not holding, and how you overcame it if you did...

My car has all the supporting mods, with most mods being Jap brands and not cheap chinese copies.

Thanks in advance

[Tangles]

perhaps try:

dyno with cat convert on/off test to see if there is a reasonable exhaust restriction going on?

[dezz]

perhaps try:

dyno with cat convert on/off test to see if there is a reasonable exhaust restriction going on?

I have an extremely high flowing cat...

[and3_3]

EBC?

[wolverine]

what boost control are you using dezz?

[Wacky Dee]

do you have an electronic boost controller? Honestly every dyno graph I've seen I always seem to see the boost pressure starting to drop off at the top end mine included. My tuner said that it's very common for skylines. I'm sure someone will disagree and probably has more useful advice.

How much is the boost dropping off and how quickly ? Post up your dyno graph if you have it handy

[dezz]

Sorry, should've mentioned...Blitz SBC Spec-R, so again, no shortcuts taken there either...

There's the latest, as you can see, dropping off from the set 18ish to 15ish...

Does the same on the lower boost settings as well..

[Wacky Dee]

more like from 18psi to 17 .. that's very typical of what I see on most peoples graphs. Have a look in the stickied section in all the RB25 upgrades ..lots of graphs there

Edited March 16, 2009 by Delta Force

[dezz]

It's more like 19psi to 17psi...

[Tangles]

not that much of a loss, but a loss is a loss nonetheloss

time to replace any cracked / old-looking silicone joiners in the intake system (small leak?)

[l0WRB]

just wind it up a tiny bit more so u hit 20psi and bring it back down to 18 and woolah ya done trust me it will love it.

[joeyjoejoejuniorshabadoo]

I have an extremely high flowing cat...

lol me too

double

[_Ryan_]

tried http://www.skylinesaustralia.com/forums/Rb...yno-t55845.html ? Chuck you sheet in there anyway!

[silva33]

A 2 psi drop isnt bad, My gtrs drops from 18psi to 17psi and that is with an EBC

[joeyjoejoejuniorshabadoo]

what happens when you run it just off the actuator? i.e. ebc turned off

[R33GTRKid]

I am interested in this as mine is also dropping off albeit on GTSS on a 26, but the same question ponders, I am going to replace the EVC6 to see if it is defective failing which I will wind up the HKS actuators to set them at 14 psi (currently at 11) so the evc only has to hold 4 psi above the actuator pressure rather than 7.

I hit and about 18ish for say 1,000 rpm and then as with the above, it tapers off a couple of psi down to low 16's.

[NickR33]

Dezz my GTSt was doing the same but with a HKS 2835... dropping from 18psi to 15psi... Benno reckoned it was an exhaust restriction... maybe drop your exhaust for a run and see if it improves?

[Dose Pipe Sutututu]

I have the same problem as well, it peaks at like 19psi then falls to like 17psi, no matter how much I stuff around with the duty cycle settings.

I thought my BOV was leaky, so I put a rubber sheet between the stock BOV & the cross over pipe, no difference. I thought it was the actuator, but after seeing dyno graphs, it seems to be the norm.