dezz Posted March 16, 2009 Share Posted March 16, 2009 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 Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/ Share on other sites More sharing options...
Tangles Posted March 16, 2009 Share Posted March 16, 2009 perhaps try: dyno with cat convert on/off test to see if there is a reasonable exhaust restriction going on? Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481166 Share on other sites More sharing options...
dezz Posted March 16, 2009 Author Share Posted March 16, 2009 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... Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481171 Share on other sites More sharing options...
and3_3 Posted March 16, 2009 Share Posted March 16, 2009 EBC? Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481175 Share on other sites More sharing options...
wolverine Posted March 16, 2009 Share Posted March 16, 2009 what boost control are you using dezz? Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481177 Share on other sites More sharing options...
Wacky Dee Posted March 16, 2009 Share Posted March 16, 2009 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 Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481180 Share on other sites More sharing options...
dezz Posted March 16, 2009 Author Share Posted March 16, 2009 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.. Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481185 Share on other sites More sharing options...
Wacky Dee Posted March 16, 2009 Share Posted March 16, 2009 (edited) 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 Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481194 Share on other sites More sharing options...
dezz Posted March 16, 2009 Author Share Posted March 16, 2009 It's more like 19psi to 17psi... Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481204 Share on other sites More sharing options...
Tangles Posted March 16, 2009 Share Posted March 16, 2009 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?) Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481351 Share on other sites More sharing options...
l0WRB Posted March 16, 2009 Share Posted March 16, 2009 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. Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481375 Share on other sites More sharing options...
joeyjoejoejuniorshabadoo Posted March 16, 2009 Share Posted March 16, 2009 I have an extremely high flowing cat... lol me too double Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481400 Share on other sites More sharing options...
_Ryan_ Posted March 16, 2009 Share Posted March 16, 2009 tried http://www.skylinesaustralia.com/forums/Rb...yno-t55845.html ? Chuck you sheet in there anyway! Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481531 Share on other sites More sharing options...
silva33 Posted March 16, 2009 Share Posted March 16, 2009 A 2 psi drop isnt bad, My gtrs drops from 18psi to 17psi and that is with an EBC Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481819 Share on other sites More sharing options...
joeyjoejoejuniorshabadoo Posted March 17, 2009 Share Posted March 17, 2009 what happens when you run it just off the actuator? i.e. ebc turned off Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481903 Share on other sites More sharing options...
R33GTRKid Posted March 17, 2009 Share Posted March 17, 2009 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. Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4481941 Share on other sites More sharing options...
NickR33 Posted March 17, 2009 Share Posted March 17, 2009 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? Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4482157 Share on other sites More sharing options...
Dose Pipe Sutututu Posted March 17, 2009 Share Posted March 17, 2009 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. Link to comment https://www.sau.com.au/forums/topic/261410-hks-gt-rs/#findComment-4482166 Share on other sites More sharing options...
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