Jump to content
SAU Community

Recommended Posts

Daz was saying this is on a Hubber. Anyone care to have a guess at what the difference is between a hub and roller dyno?

My last figures were 375 kw at 4500, 425 kw at 5000 and 470 (6500) odd up top. Boost was 27 tapering back to 25 top end.

Interestingly was the difference between setting "2" and "3" on my controller. Setting 2 is 23 PSI (give or take) and the midrange was 50 KW less than setting 3.

It would be interesting to have both cars there, get out of one and into the other.

They're 63's IIRC.

Damn stout effort. I'm too wonder if the standard compact housing is/will hamper the GTX's. Power wise it seems up there but it's the apparent surge that might be an issue.

I'm fairly sure that chequered tunings dyno is setup so it's spot on with local roller dynos.

Gav made 500 on less boost, guess we won't really know without similar spec engines

Yeh, Trents is a RWD hub dyno, still he shouldn't need to justify his figures, it is on par with most of the other local tuners machines, but obviously dispenses with the wheelspin and over strapping required at that sort of power.

If you ran it on a roller I would expect to see minimal losses, although I still haven't been on Trents to compare my figures. As you say though, same dyno same day, or take them to the drags together is the only way to know.

Yeh, Trents is a RWD hub dyno, still he shouldn't need to justify his figures, it is on par with most of the other local tuners machines, but obviously dispenses with the wheelspin and over strapping required at that sort of power.

If you ran it on a roller I would expect to see minimal losses, although I still haven't been on Trents to compare my figures. As you say though, same dyno same day, or take them to the drags together is the only way to know.

Yeah, I was soley referencing to real gtx2863 compared to 2.5" gtx2863 with similar spec engines.

At a guess, the GTX stuffed into the stock housings will flow more air in the midrange compared to the anti-surge ones, which is why I heard what I assume was surge. (unless it was a cooler pipe or gasket, but it was only as it hit boost)

I would prefer the real housings myself, the slot is there for a good reason. Garrett wouldn't have added the complexity to the casting and machine work otherwise. But this was a stealth stock setup.

At a guess, the GTX stuffed into the stock housings will flow more air in the midrange compared to the anti-surge ones, which is why I heard what I assume was surge. (unless it was a cooler pipe or gasket, but it was only as it hit boost)

I would prefer the real housings myself, the slot is there for a good reason. Garrett wouldn't have added the complexity to the casting and machine work otherwise. But this was a stealth stock setup.

Thats right, 500kw, stock. even 450kw, stock is a good outcome. considering not many people crack 400 with -5's.

At a guess, the GTX stuffed into the stock housings will flow more air in the midrange compared to the anti-surge ones, which is why I heard what I assume was surge. (unless it was a cooler pipe or gasket, but it was only as it hit boost)

I would prefer the real housings myself, the slot is there for a good reason. Garrett wouldn't have added the complexity to the casting and machine work otherwise. But this was a stealth stock setup.

Okay so with all the GTX talk lately, here is my experience:

Put them on late last year when I built my engine. GTX2860's and keep in mind these are 400hp per turbo rating.

Used the anti surge compressor housings and added flanges to outlets etc to bolt to original pipework.

The good:

They are quiet,

They don't surge

After 4800RPM they really take off

Dynoed around the 480hp+ on Godzilla motorsports dyno

The bad:

Anti surge housings are not bolt in for GTR's

Don't come with turbine housing but you just use your busted -5, -10 bits that probably shit their bearings out from crap plastic bearing cages.

Laggy/lazy coming on, after a gear change due to anti surge ports.

Not suited to pump 98 as you really gotta pump some psi (25+) to take advantage of the stronger billet compressor wheel.

So the gun setup to get some sort of lower response with surge as a trade off would be the GTX's with a -5 front housing. Or run E85 or put em on a 3+litre engine.

I have some -5's ready to go onto my car, but still contemplating whether to give the GTX another chance with a different front from the -5's or just put the -5's in and enjoy. Ahh the joys...

Hey Sean,

After talking to you earlier in the year I also decided to stick with -5s as I'm gonna stick with 98 pump and I wanted a bolt on solution. I've had my fair share of headaches when I did my 3ltr a few years back.

pump some psi (25+) to take advantage of the stronger billet compressor wheel.

So the gun setup to get some sort of lower response with surge as a trade off would be the GTX's with a -5 front housing. Or run E85 or put em on a 3+litre engine.

I'm trying all of the above.

  • Like 1

Hey Sean,

After talking to you earlier in the year I also decided to stick with -5s as I'm gonna stick with 98 pump and I wanted a bolt on solution. I've had my fair share of headaches when I did my 3ltr a few years back.

Yep :) -5 are one of the best 'bolt on' setups if you want 330-470kw at the wheels depending on fuel and setup ;)

  • Like 1

Yep :) -5 are one of the best 'bolt on' setups if you want 330-470kw at the wheels depending on fuel and setup ;)

Did you use the -5 before on the non-built engine?

Or how do you come to the conclusion the GTX are laggier than the -5?

I have used HKS GT2530, GT-RS and now GTX2860 (all in their genuine housings) on a RB30 with stock cams, and the GT-RS were the only one which were REALLY laggy.

As they have been on the car inbetween I can´t really compare the 2530 to the GTX side-by-side, but my impression still is that the GTX are way better spooling etc. than the 2530...am I really that wrong?

BTW all turbos were running with about 1.5 bar / 22psi.

With my -5s converted into GTX 2863's it has really made a big difference to mine, and the lag Sean is talking of is a bit of a mystery, because I actually decreased lag and found a little bit more low down, and heaps from mid range to the top. Even with the cams on my -5s I found my cams to be a bit big 272/9.7 but now with the GTX turbos, the cams really seem to be more efficient, especially the mid range. I was going to take my cams back to a 260 but I don't think I need to as much now, the power delivery from these GTX's is fantastic IMO.

Hey Sean, maybe it's worth giving your 2860's another go, and get it tuned at NextUp, John really got the benefits out of mine quite nicely. And considering you have the same 2.8 as me, it doesn't make sense really that I have decreased lag with the 63's while you saw a decrease?

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

    • HFM BM57 has a "bad" knee point, IIRC. It's not the same thing as the later R chassis MC.
    • The ATTESSA is functionally identical to R34; there were a bunch of JDM models that continued ATTESSA including Fuga/Q70, Skyline/Q50, Cima etc as an option. All with Auto only and I think mostly for snow regions. AFAIK there were no AWD VR30DDTT sold in Australia - it is on my to do list to check regs for racing a LHD car in Targa/ATR/AASA/CAMS events because if I can get the auto to work it would be interesting to run a 4wd car The Ecuteck TCM tuning is the same model as their ECU tuning, they already have it for R35 and Dose's favourite, BMW. You buy "points" to allow your computer to be tuned, buy either a bluetooth (phone app) or bluetooth+USB+Key (phone and PC) dongle, and pay for a tune that will be locked to your tuner ( ). You can also access the tuning software yourself but 1. it is mega expensive and 2. these computers have a billion parameters that intersect, so how could you ever spend enough time on it to get a decent result.
    • Or, is it a case of what it is like owning an R series Skyline? NFI what the previous owner has done or fiddled with... Ha ha ha After reading through this thread, I went on a bit of a research about the Q50/Q60. Now I'm quite intrigued by them! Is the AWD in them more like a WRX where it's always AWD, or is it more like the ATTESSA in the GTRs? By the sound of this TCU tuning, this sounds like a case of someone has made some real software for it, and you just need the right piece of hardware, and then you license that specific vehicle/TCU. Or is this a case of the software will be really expensive so only a few tuners have it, and you still have to pay a license per vehicle?
    • By popular demand.. it was a coil. Got my hands on 1 new OEM coil, replaced with the one that made the less noise difference when I unplugged it while the car was running and started the car up. No stutter and the engine light was gone. I guess I’ll buy the other 5 they have lol
    • No, code 21 is very straightforward. It can only be the things described in that diagnostic flow. In fact it has no way of knowing that the spark plug resistance is out of spec.
×
×
  • Create New...