Jump to content
SAU Community

Recommended Posts

Hey guys,

I've tried searching but couldnt really find much.

Currently making 347 rwkw

hks2540's i think - full boost of 22psi at around 5500 ish

powerfc

tomei adj gears

bosch 044

ported manifolds

hks dumps

hi-flow cat

z32 afms

sard 800's

Running standard internals

NOW to my question... How can i increase turbo response? Cams? What cams would be suitable Im hoping something along the lines of drop in i.e. keeping everything else stock.

I want a reliable driver also - and im 100% sure this car wont see a track day or drag strip plus i have shift light set at 7000rpms.

Lag is starting to annoy me and i really don't know what to do.. i cant afford to take out the turbos and buy and sell -9's or -5's.. What can i do to make the lag a little bit better/bearable?

Please don't flame, I'm asking a genuine question.

Thanks all

Edited by kinggtr

If you don't want to change your turbos then its just a matter of tuning to get as near as possible to the result you want. I would guess cams should stay stock but timing would need adjusting via the two adjustable gears (that's what they're for!)

Seems like you are in the same town as Status tuning so give them a ring and make an apointment - be prepared to spend around $1000 more or less for a decent tune.

I know you said you don't really want to change turbo's, but those 2540's are probably the worst lowmount setup on a GTR for any type of "'response". Cam timing and tunes are only gonna help so much.

A set of type R Poncams if you must buy a set of bumpsticks would be the go.

And make sure your exhaust doesn't have "step downs" that'll cause unnecessary back pressure

Turbos that size and an engine only revving to 7000rpm would be a dog to drive...

As already mentioned, well aware that you said a turbo change is not what you are wanting to look at doing - but at the end of the day the cams aren't going to be a budget mod and are really going to make so little difference you're going to wonder why you bothered imho, and will eventually have to do something drastic to polish the turd that is GT2540s (if you don't just replace them).

Honestly the most logical thing to do is change the turbos, as funnily enough anything else you do is not going to change that they are GT2540s and as such are going to behave like them.

Can I ask if you can't afford to spend the time removing the turbos or is it just a matter of money?

If it's just money i'm sure you can make a decent bit of cash back selling those and buying second hand -9s/-5s.

But yeah otherwise, who tuned the car and got a dyno graph of it currently? And have the adjustable cams been used to lower the power range?

Edit: What front pipes and cat back are you running?

Edited by Serpandrew

I'm not an RB26/GTR person but I'd look at it like this .

HKS effectively replaced the old "GT2540s" , which in todays speak are actually GT2876Rs , with turbos called GTRSs which are a GT2871R in 52 compressor trim .

People here say that it takes a specific combination of parts and good tuning to make GTRSs work on an RB26 and they actually use smaller but more modern compressor wheels than the old 2540s .

You could try all kinds of ways to work around those turbos but at the end of the day they are not a well though out turbocharger and you can do better .

Simply too big a compressor for the turbines to drive and thats what makes them lazy .

I think the designed for the purpose GT2859R (GTSS) are the go because they make boost and torque in the rev/speed range you can use in a street GTR .

Pretty sure you'd still make 300+ Kw but you'd drag the power range down possibly 1000 revs if not more .

So your call , either GTSS or inaptly called GT2530s I think .

A .

-9's are SS' s

-5' are close enough to 2530's.

Spend the money and rip those turbos off mate. You're about to drop a bomb of money and really, you're not gonna get the result you're after.

what are your cam gears dialled in as?

You could "possibly" get them to spool a tad earlier if you advanced the intake cams and retarded the exhaust cams a tad. A few people have gotten their GTS-ts to spool a tad earlier by retarding the exhaust cam gear only.

Hey guys

Firstly thanks for all your input on this matter - ill upload the tune soon.

Not to sure what's been improved from the cam gears other then an obvious lift on all parts on the graph.

I swapped out the gfb manual Bc and swapped it over for an eboost street and don't a few adjust I'm getting a rushing boost feeling from 3000 rpms and full boost at 4800 5000

Could they be 2530s? I also noticed an intercooler pipe leaking which I sorted out.

Lastly I spoke to my tuner and he explained how opts for a smooth graph and smooth power delivery. Maybe im just used to the standard response of the ceramic turbs?

Peak torque is 3/4 up the powerband, no wonder your not happy..

Im really with the others and will say spend wisely and just get real turbos. To match the peak you will need -5s. Check serial numbers before you do anything, obviously..

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

    • Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place. Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!
    • Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
×
×
  • Create New...