R34 Gtt Help With Power To Gain More Rwkw

[det034]

Hey guys,

I am getting a lot of different answers from different mechanics and I was hoping if some members on the forum that really know a lot or people with similar mods on a GTT, basically what should I do with my set up... currently on the car:

1999 R34 GTT RB25DET

kms: 104,000

ECU: Apexi Power FC

Turbo: HKS GTRS

Injectors: Nismo 480cc

FMIC: HKS (dont know what model but the size is Length=62cm, Height=29cm, Depth=7cm)

AFM: Z32

Fuel pump is upgraded but dunno what size

Boost Controller: Turbotek manual Boost T (on 15psi)

Coil Packs: Splitfires

Intake: 3A Pod

Exhast: 3" Turbo back (gutted cat) and 1 muffler btw the cat and cannon

I bought this car in April this year and now looking to get it tuned because it hasnt been tuned since 2008, Now with this set up it made 228rwkw on 15psi, Now the turbo, injectors, afm and all these major mods can handle 260rwkw+ ive heard but cant understand why it only made 228... I rang mechanics and they said it could be the fmic lacking because its a return set up which will cause lag, although being HKS generally most people would say thats odd because it should be a decent fmic.. The other thought they had is the exhaust but I doubt thats the issue..

I have been told by another mechanic that the turbo han handle more psi, like 18+... what is a good safe limit for the GTRS turbo considering for the rb25? also some mechanics say manual boost t is better and some say elec boost controller is better, what are your opinions, what is better for this set up and why? also is turbotek unable to put the boost to 18psi, if not what brand should I look into?

If I up the boost to 18psi and get it tuned is this where it can make 260rwkw or is there a problem with the fmic or exhaust or is my car simply missing something to make more power?

If anyone can help thats great, and if anyone has the same or similar set up please tell me what you have and I can possibly work out why mine is lacking..

Thanks heaps

[Bronx]

your settings now sound about right, is yours an automatic or manual? i would have guessed around 240 with the way you are running things now.

15-20psi is still pretty low boost so you shouldnt make big numbers.

go to a good tuner and get a nice tune done, depending where you are in australia, there are quite a few good tuners.

your whole setup should be good enough to run up to 300kw

[det034]

Its manual. Now you say 15-20 is low, does this mean the turbo can take more and is it safe to run such high boost on standard bottom end? I know Race Pace are meant to be one of the best in VIC so I want to take it there for a tune.

[Bronx]

for the average user it is ok, most people on here run that boost, me personally, in the old audis ive had, iv run to 40+psi. but those were stronger turbos.

if its HKS, it should have a Garrett core in which case it should be able to take to 30psi, but dont know how long it would last, dont want to replace your turbo every year or two do you.

get a good tuner to give it a tune and it should show you better numbers, crank it to 20psi see what it gets you, 20psi out of a HKS should be easily had

[det034]

Thanks for your opinion Bronx, anyone else have their opinions on whats good or what the problem is that im having? I especially need help to decide on if the Turbotek boost t is good enough or should I go for a better brand? or is the elec boost controller better? ill probably run it to 18psi... does anyone also think 20psi is safe for the engine and the turbo or is 18 enough?

Any personal experiences with this specific turbo and boost controller would really help.. Thanks guys

[mad082]

at that sort of boost on that turbo i would've expected the power to be closer to 250kw. the lower power output of your car could be due to 1 (or possibly more than 1) of a few things. it could be due to the quality of the tune, condition of engine (compression, etc), the dyno may have been a low reading dyno, if it was hot when it was done then that will affect the power reading as well, and there are a few other things as well which i couldn't be bothered going on about as the ones i listed are the more likely ones. i'd start by getting a dyno run done. this will give you an up to date base to work off. the dyno opperator should also be able to give you a bit of an indication of what the tune is like and whether they think they could get you a bit more power.

[PM-R33]

Ok first of all. Don't bother using the turbotek boost controller, you don't need it. The HKS GT-RS has an adjustable actuator for the wastegate so use that to shorten the rod to increase the boost pressure. The actuator is a 1 bar item so therefore runs around 14.7psi (ie your boost tap is not needed and doing nothing).

The GT-RS gets into its "zone" at around 18-19psi so run this amount. It will start running out of puff around 20-21psi so don't bother pushing it past that as you will start to see diminishing results.

An electronic boost controller will only aid you in ramping the turbo up harder. It does this by keeping the wastegate shut as long as possible and then cracking it open once desired boost pressure is reached. Without one it will slowly creep open as it reaches desired boost pressure. You can obviously also increase the boost pressure with it but once the boost pressure is set and tuned you won't be touching it. So in your case for the time being it isn't really needed.

Now as to your power. There are to many variables to accurately say what power it should be making on 15psi for your car however it's fairly normal. On 1 bar anything around 230rwkw is fairly normal so I wouldn't stress to much at the moment.

To get more power simply ask your tuner to increase the boost pressure as at the moment there doesn't seem to be an issue. However one thing that should probably be always done by every tuner (they don't though) is pressure test the intake to make sure there isn't any slight boost leaks and also drop the exhaust after the final run to make sure there isn't a restriction.

Goodluck.

[det034]

So is adjusting the actuator as good or better than the boost t or having the elec boost controller? out of the 3 ways what gives the best performance? and is there a reason why one is better than the other...

I have also heard that you can air bleed the tube as a boost controller... is this good or bad?

[mad082]

the less work any boost controller has to do the better. setting the wastegate to as close as the desired boost the better.

[Galois]

Also as mentioned above adding an electronic boost controller will give a slightly quicker ramp up as the wastegate actuator won't be moving as the pressure rises. Not sure if it makes a noticeable the difference though?

The rb25 dyno thread would be well worth a peruse for you, it's got lots of different combinations of mods and peoples dyno results.

Edited August 8, 2011 by Galois

[joeyjoejoejuniorshabadoo]

Boost it

Do skids

[Rolls]

Run 18-20psi, it will be fine on a standard engine if tuned safely. Should see 240kw with that boost whatever you do don't just turn it up though, it needs to be done on a dyno and tuned safely.

Your current mods look good and the power for 15psi sounds pretty much spot on.

Electronic boost controller will help you get a flat boost line, if you start maxing the turbo out with a boost tee it will usually drop off in the upper range, this is the only real difference.

Edited August 10, 2011 by Rolls

[det034]

Ok Guys, I took it to get tuned... I didnt change anything.. It made 260+rwkw at peak...

Minus 1 degree for ign timing so it made total of 251.7rwkw on17psi which drops off down to 15 roughly. Was tuned well, I recommend anyone that can take their car to Bayswater, Melbourne.. go to Race Pace Motorsport, they are the best!! They know skylines really well.

Thanks to all that commented on what I should do.

[Rolls]

There you go so it is making great power already.

260kw with a GTRS must be very responsive, what do you want more power for?

[det034]

Yea im happy, well we all want more power lol but for now its perfect!!

Boost kicks in bout 3500 so yea its responsive enough, it actually pulls me back in my seat now! its a really nice drive, Race Pace are really good at what they do..

[Jayden.K]

I'm running about same size injectors, same turbo and apexi avcr boost controller to 1.25bar. And mine starts spooling at 2000rpm and I'm sucked in my seat by 3000rpm and all the way up the rev range. Def just feel the boost straight away no creeping.I think I'm running 240rwkw but not sure. And I'm sure mine is on a safe tune as I too have to see the dyno man about my set up. I think larger injectors (depending on my current highest duty cycle) and a good tune will give alot more power at 18psi. Cams and polish and porting of the head should give a responsive torque set up. Recommend avcr