Lithium

The fastest GTSt know of running an RB20DET in NZ was running standard internals and did around 12.1 with a huge turbo. There was a GTS4 running RB20DET that ran 11.8 but required NOS to get a launch without bogging. I think HPI vol 1 or 2 shows a RB"24"DET GTSt doing a ten if I remember correctly.

I've been researching, but at the moment I am quite interested trying a Holset HX35 with a 9cm (.63a/r) Bullseye racing housing. Its a T3 flanged truck based turbo which has a similar sized compressor housing to the GT30R, its a fully rebuildable turbo which costs HEAPS less than the Garrett BB turbos and seems to lose nothing to them in spool.

My apologies if this has been asked already - I've done a search and haven't been able to find anything.... I expected the topic to have already been covered. I know there are quite a few people running GT30Rs, GT3037S and GT2835Rs etc on their R33 GTS25ts.... are they all high mount setups - or is it possible to mount them to the standard manifold? I was having a look at my engine bay last night - and as a rough estimation I guessed I'd need ~9inch across at least at the widest point to make it realistic, and it looked mighty tight if not impossible to find a spot - though I could have been looking at it wrong. Any other issues to be aware of if it does actually fit?

Thats really really interesting, I used a Passport GTimer before and after my S-AFC (which when I got, I tuned to ~10.5psi as well). Before hand I ran a 14.0 @ 101mph (0-60mph in about 5.6s) and backed that up at the dragstrip with a 14.1 @ 103mph... poor track condition the day I raced. The GTimer btw, seems to try and give a trap speed more indicative of the strip.... I used to have a GTech, and that would give on average 4mph higher trap speeds than were realistic in my experience. After I got the car tuned, I ran 4.9s 0-60mph and 1/4 in 13.4 @106mph on the GTimer.... and my car dynod at 190rwkw on a local dyno. As much as anything I just thought it was quite cool how close all the results were.

My apologies - the turbo is no longer in the workshop. The guy reckons the turbine housing was the only part on the HKS turbo which seemed different from an "equivalent" spec Garrett GT30/40R...

I know someone who had one around their workshop - if its still lying around I'll see if they can give some info..

ITS are not a cheap dodgey brand...

The Mafia - That Dyno outfit seemed to start getting results which read much higher after dynapack (hub dynos) started becoming more common in NZ. It seems like the figures have been "tweaked" to more closely match results obtained on hub dynos. Dynos are a tuning tool, blah blah blah

Cheers guys, I have a much much clearer idea on things now Discopotato, I didn't mean to look for a power band that starts in the 4000rpm area - which is what the GT30 sounds like it does. I mean something that is already making good power at 4000rpm, and is still making good useable power at 7000rpm. I'm sure the GT2540R or GT2871R can't drop off THAT badly at the top end if you're running under 1bar? Ie, no worse relative to peak power level than the stocker?

That was really really good information (the whole post, not quoting it all for ease of reading for other people...), thanks for that!!! If you were to guess what would get the best average power between 4000 and 7000rpm out of these turbos when used on a stock RB25 running 13psi with supporting mods and tuning for each - which order would you put these: a/ GT25/40R b/ GT2871R c/ GT3071R Mikka33 - if you are still watching, when do you get full boost with your turbo? Cheers both of you, I feel my picture getting both broadened and filled in quite nicely Fortunately I'm not going to be buying until late next month - so there will be no hasty purchase.

Thats interesting, ATP rate the compressor wheel as a 60trim 60mm, that isn't consistant with all else I know about the turbo. Its interesting that Garrett rate that turbo at 450hp, and Horsepowerinabox (and most other places) refer to it as having a 76mm 48trim wheel... Why have you listed the GT28Rs compressor map as the GT25/40Rs "correct" compressor map? It doesn't really make sense.... especially when ATP have the GT25/40Rs compressor map on there. They definately don't run the same cold side as a GT2510 or GT28R, and most certainly don't flow less than the GT28RS either. I already know people using the GT25/40R on 4cyl 2l engines to make between 250 and 300kw @ wheels (albeit 300kw on C16 and lots of boost...), in NZ there is a 10s street EVO running one.... I agree, the turbine side is on the small side - but I don't think too small, considering its around the same size as various other turbos used in the RB25 dyno results thread which have made up to 270kw @ wheels.... keeping in mind I am only after 400hp @ flywheel, I think it looks to be more than sufficient. Given that, it seems to me a positive thing that the turbine is a bit small as it will get the compressor up to speed a bit quicker, so long as there isn't some dark reason beyond sheer flow potential that I shouldn't go for a smallish one on a bigger motor?

Aweeesoommee thats a lot better Mikka33 - thats almost identical to what I laid out for the equivalent + a little more (hence $900) as most of the stuff done with mine will be done at home as well A mixture between me, legendary friends and various hookups I can get is something I am hoping will take the edge off it. Cheers! I'll get info from you if I do buy one though, if thats cool? It'll make it a whole lot easier.. :Pimp2:

Ahh excellent, cheers for clearing that up The GT2871R was actually what I liked the look of as an alternative to the GT25/40R... it seems on paper to be very similar, if not identical to the HKS GT-RS. Do you think the GT3071R would could be used without the need to space the turbo out from the block like the GT25/40R does? Or if the GT28/3071R would have the actuator mounted in such a way to cause the kind of issue Mikka33 described, where he had to remount it to fit?

Cheers DiscoPotato03 - I had initially rationalised that the GT25/40R would be a good turbo to go for in terms of a value for money upgrade, so the fact that the GT25/40R is a dinosaur wasn't going to bother me too much - especially when it looks quite cool too But if it is going to cost that much more to fit, it starts looking like the "expensive" alternatives from HKS etc are not that bad afterall. I want to set up a nice and kinda cool "mild" street combination, 400flywheel hp would be plenty to keep me happy and I want to keep away from running over 1bar. I could be mistaken because I am still new to compressor maps etc - but the GT3071R compressor map didn't look a fantastic amount better to me than the GT25/40R, it looked more suited to higher boost (.. and power...) levels whereas just under and up to around 1bar of boost the GT25/40R looked in a higher efficiency area. While in theory the GT3071R is "better" for a RB25DET if you are going to push it harder, I don't really need the 400+hp the turbine could happily flow with the larger turbine so maybe it would be wasted on me - especially for the ~$200-300US higher price tag? Please correct me if I am wrong, I'm still learning I didn't like the idea of the highflow, the turbine housing from the R33 turbo seems horribly small - though if people think they work fine... I could rethink that?! One issue with dealing with GCG is that I am NZ based, and getting stuff sent from Oz is one thing - but sending bits back and forth starts getting to be a bit more of a headache. One thing I have to factor in which would be worth knowing, is I have stock dump+front pipes on the car and they have to be upgraded if I am going for any reasonable amount of power.... so fabricating one to fit a Garrett turbo isn't going to be an extra cost, as I'd have to do it even with an OEM Nissan turbine.

Wow - $1500, thats more than I had anticipated... I had set aside around $900 - not including intake piping as I've budgeted separated for the intercooler etc. When you say custom made, you did the work yourself and it still cost $1500? You have been an awesome help - very very appreciated

Awesome man - thanks for the input What came with the turbo? Did you have much hassle with space, getting oil to it or anything weird like that?

Pro32 - He specified "RB25DET"... As an additional question (hope this is constructive for the guy who started this thread, otherwise - apologies) if one buys the HKS GT2835 "Turbo", what do you receive? Is it JUST the unit? Oil lines, dump pipe, etc will need to be made up additionally?

Yep, that is the one They are asking US$1075 ATP/Garrett GT25/40R

Has anyone tried this combination? I have been thinking of getting one of these with optional T3 flange with .86 turbine a/r for my R33 GTS25t as they are currently available for a very reasonable price from ATPTurbo.com.

Sorry, my bad

Is that referred to me or the GT30 question? I've been searching on GT2540Rs and not been able to find anything

Has anyone tried what HPIAB sell as a "GT28" or the Garrett GT25/40R turbo, or have any thoughts on them? I have been seriously thinking of getting one of those with a .86a/r turbine side with a T3 flange from ATP-Turbo in the US (US$1070) as it seems like a really good value for money (and not to mention cool looking) turbo which I figure would be good for my 250rwkw target with reasonable delivery.

Am I the only person reading this who thinks its a bit lame buying a car just to beat someone?? If you do that, you are destined for disappointment - there is always a biggest fish. Get something ywhich makes you happy, you'll always be the winner at the end of the day if you take it for a drive and don't want to stop.

Interestingly enough I was talking with someone recently about GT28Rs on an RB26 - and they reckoned that unless you go a large turbine a/r (and therefore a pretty laggy twin setup) they are quite "surgey" turbos as a twin turbo configuration. If you are running ~.64 turbine a/r, then what he was telling me is true...

Thats interesting, someone I know insists to me that the "smaller" a/r turbine housing on the GT2871R (.64 or something?!) is susceptable to compressor surge - and is overall too restrictive for an RB25. I'd be all keen for a 2871R, IF it is able to supply up to around 250rwkw on my RB25DET - do you think that would be a realistic hope?