Jump to content
SAU Community

Recommended Posts

Hi guys. Please help me here any advice would be appreciated. This was my set up: RB30det block honed out to 3.2L< forged rods and pistons, port and polished rb25 head, stock cams and cam gears, bosch coils, cheap s*** GT45 turbo and waste gate, top mount manifold, greedy plenum, 80mm throttle body, 800cc injectors, jun oil pump, microtec ltx12s ecu. Was running perfect at 450hp at the wheels tuned by dyson rotary.

That's how i bought the car:

Now i stripped the rb25 head off and replaced it with a r32GTR head from spool import. CNC ported, Good valves(not sure what type), HKS 282 cams, tommie cam gears, Turbonetics GTK1000 turbo, Turbonetics waste gate, 6BOOST top mount manifold, STANDARD GTR PLENUM ( not sure if this is a let down), sard fuel rail, sard 820cc twin spray injectors, One in tank bosch fuel pump that feeds to a catch can with 2 bosch 040 taking fuel from catch can to fuel reg. Eboost2.

So that's a list of what i have added to it. It now only makes 430hp at the wheels on 24psi and runs like shit. where or what have I done wrong. Or what have I left out. Maybe it's my tuner. Any good tuners that are recommended around Brisbane or gold coast Please let me know as well.

Thanks for your help. And please email me at [email protected]

Thanks

post-40332-1245075213_thumb.jpg

post-40332-1245075237_thumb.jpg

post-40332-1245075278_thumb.jpg

have you got anyway of looking at the map inside the microtech? swapping from a microtech to a vipec (or anything) is not going to fix your root issue as the ecu swap wont make any more power if the microtech is tuned properly (Granted a vipec/LINK is a better ecu though).

If you do have the ability to view the maps feel free to take screen grabs of the timing curve and boost compensation curves and email them to me [email protected] it will soon be obvious if it is tune related. Another thing to check is cam timing, was it dialed in properley? or just installled at zero? ive had a few aftermarket cam gears be up to 12 degees out and then when the workshop does the install they guess the best cam setting without properly finding zero (3degrees advance on the intake and 3 retard on the exhaust seems to be a favourite) the cam timing is way out.....

Edited by URAS
have you got anyway of looking at the map inside the microtech? swapping from a microtech to a vipec (or anything) is not going to fix your root issue as the ecu swap wont make any more power if the microtech is tuned properly (Granted a vipec/LINK is a better ecu though).

If you do have the ability to view the maps feel free to take screen grabs of the timing curve and boost compensation curves and email them to me [email protected] it will soon be obvious if it is tune related. Another thing to check is cam timing, was it dialed in properley? or just installled at zero? ive had a few aftermarket cam gears be up to 12 degees out and then when the workshop does the install they guess the best cam setting without properly finding zero (3degrees advance on the intake and 3 retard on the exhaust seems to be a favourite) the cam timing is way out.....

Thanks trent. I belive that the cams are left on 0 and they havent touched them. But ill double check that. And ill get back to you with these graphs. Thanks lots for you honest help.

why did you retain the RB25 cam covers? and 450hp seems a bit low for a GT45.

With the cheap chinease GT45 it was running 20psi and making 450. Now with what i think is a better setup its only running 430 on 24psi

have you got anyway of looking at the map inside the microtech? swapping from a microtech to a vipec (or anything) is not going to fix your root issue as the ecu swap wont make any more power if the microtech is tuned properly (Granted a vipec/LINK is a better ecu though).

If you do have the ability to view the maps feel free to take screen grabs of the timing curve and boost compensation curves and email them to me [email protected] it will soon be obvious if it is tune related. Another thing to check is cam timing, was it dialed in properley? or just installled at zero? ive had a few aftermarket cam gears be up to 12 degees out and then when the workshop does the install they guess the best cam setting without properly finding zero (3degrees advance on the intake and 3 retard on the exhaust seems to be a favourite) the cam timing is way out.....

whats a Link ?

It now only makes 430hp at the wheels on 24psi

At what RPM?

My guess is tuning, that's where I would start looking. Post up the dyno graphs with A/F ratios is a good place to start.

The 282 cams are bit long in duration for an RB30, unless you are intending reving it to 10,000 rpm of course. which is not a good idea with a standard crank.

The standard GTR inlet won't be the problem, most certainly not at 430 rwhp, maybe at 730 rwhp.

How's the blow by? To get 3.2 litres (rounded) the smallest bore size is 88.2 mm (2.2 mm oversize) which is rather large for an RB30 block to handle, 87 mm (1.0 mm oversize) is the most I would go. So it may pay to check the leak down at 3 or 4 piston heights just in case the bores are oval.

What the exhaust like? You shouldn't need anywhere near 24 psi to make 430 rwhp, maybe it's choking the tubine, pumping up the boost and killing the power. Easy to check, turn the boost down to say 19 psi, if it still makes around the same power on the dyno, then drop the exhaust for one quick power run. That'll confirm whether or not the exhaust is the restriction.

Since it is running a Microtec my guess is it has had some work done on the CAS, Mictrotec's don't like the Nissan CAS signal much. You can check the trigger accuracy with a timing light, just make sure that you can see the igntion advance mapped in the Microtec actually agreeing with the timing marks. Try it at 1000 rpm increments up to say 6,000 rpm, if it's accurate then there is a good chance the trigger is OK.

If the above doesn't show anything I would be surprised, the answer is there, you just have to use the right test to find it.

Cheers

Gary

I dont see any mention of valve springs. What are you using?

Also, from my experience with the lt12s you've got to take it to a tuner who's actually used them before. I got mine tuned by a rotory specialist when i first bought it, ran perfectly. Had it retuned by a big sydney workshop with a very expensive reputation and a large amount of R35's there right now. Car ran like shit.

Then back to a guy who does a lot of rotors and what do you know, runs great again.

Note, this was with the stock nissan (mitsubishi) CAS, stock plenum etc

I dont see any mention of valve springs. What are you using?

Also, from my experience with the lt12s you've got to take it to a tuner who's actually used them before. I got mine tuned by a rotory specialist when i first bought it, ran perfectly. Had it retuned by a big sydney workshop with a very expensive reputation and a large amount of R35's there right now. Car ran like shit.

Then back to a guy who does a lot of rotors and what do you know, runs great again.

Note, this was with the stock nissan (mitsubishi) CAS, stock plenum etc

If Dyson tuned it the second time, I'd be surprised if it were a tuning issue.

Does the exhaust manifold and rear housing get red hot at full noise after a couple of runs?

Possibly as Gary has suggested is the exhaust, perhaps the cat has collapsed and is creating backpressure....

or maybe your timing belt is on one tooth out on exhaust side? Your timing might be good, but exhaust cam out by 15 degrees......sometimes silly things happen.

Maybe i missed it, did Dyson tune it the second time?

Nah, It was more of a rhetorical statement rather than a factual comment. Wasn't saying you said otherwise but just making an observation that if he had the second tune done at Dyson, it would more than likely rule out bad tuning.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Just checked in first post and you should be able to bring it home November this year, right? I'm amazed you made it through four years of this. As hard as it feels now the rest will go by in a breeze in hindsight, I'm sure.
    • Realized I haven't been back here in a while. Still here, still alive, still waiting for the car.  I went back again the only time last year from Oct-Nov for R's Meeting and drove it around some more, including a few laps on Fuji Speedway(in the wet, sadly). The car still feels good, but have a couple small things to address. I've been getting more parts but have slowed down still, and most of the bigger purchases are now out of the way. I find myself getting impatient more and more when it comes to getting started on this project; it's quite hard for me not being able to really dive in and start making this car my own because it's halfway across the world. At times it doesn't even really feel like I own one of these. Haven't really been motivated or had the desire to document the last trip on here or social media for, well, reasons... but here's some pics...it's also still alive and well as you can see: I've narrowed down to the last large part purchases(anything over $2k) before the engine build to be: 1) Ohlins Road & Tracks 2) ATS Twin Carbon clutch 3) Endless BBK with some custom options and 4) Kansai Service carbon driveshaft I don't think the budget exists for all of these this year, but I'll try for one or two items I think. Though, every time I look at my spreadsheet I sigh, shake my head, and get depressed just that little bit more.  'til later.
    • It's a stunning location!  I've been to NZ twice but haven't made it to the North Island yet.  Definitely on the cards but the South Island is hard to tear yourself away from too... Looking forward to see what you can wring out of it once you can get it to hold together!  Be awesome to get a low 11 or even sneaking into the high 10's pass out of it.  That's a bloody quick car that most people will never experience in their life.  Enjoy!
    • Nominally yes but I’m not really at that stage yet. Outsourcing to Japan is also a relatively good deal at the moment because their currency has devalued much more against the USD.  You would assume this but a lot has changed from the pandemic. Mechanics are in short supply and demand for fixing old cars has gone up from the cost of new cars. 250-300 USD/hr is not an unusual shop labor rate in California and you’re paying that regardless of whether the guy is competent or not. Coworkers have been quoted 3000 USD for a water pump and thermostat at a dealer on an N54. Oil changes went from ~75 USD to 150 on fairly normal cars like Civics. The cost of the oil and filter hasn’t even kept up with inflation.
    • The downside to that is that the cost of everything, particularly labour, is significantly higher here than it is over there in the Disunited States of Slavery. You can hire 3 tradesmen over there for just the Ranger Raptor allowance of a single 3rd year apprentice over here.
×
×
  • Create New...