Lithium

The man himself said he didn't get into top gear - they don't have a reputation of talking shit (maybe this is common in Oz???).... 256kph trap speed when they usually run 270+ is an obvious sign. Apparently they are working on what went wrong with the box with the intent of running tomorrow. I guess that will clear some stuff up?? They've already done an 8.033 @ 172mph already - so no matter what way you look at it, a solid seven second pass is inevitable... if not now, with the new motor.

WTF is that supposed to mean?

Any more happening in the GTR-700 camp? I've been keeping an eye on the website and all has been quiet since July. Reece McGregor ran an 8.03 @ 172mph in NZ this weekend just passed, and backed it up with an 8.09 - 7s should be happening really soon. I can see GTR-700 as the only GTR between him and HKS GTR at the moment...

Yeah - I wasn't 100% sure on that one, I thought the 250wkw cars were possibly running the VG30 turbine housing. There is definate varience between dynos though, is this reading done on a dyno which reads consistant with other ones which have run 250wkw? I know this could sound stupid - but were any runs tried at lower boost - such as the 1.3bar mentioned by paul? Maybe exhaust gas temperatures are becoming insane at 1.4bar, the thing might even be able able to match the power level on a slightly lower boost level? Do you have a decent dump pipe? What kind of intake/intercooler system are you using? Is there any chance that there could be an air leak somewhere?

Wouldn't the tiny R33 turbine housing (~.48a/r) end up creating HUGE amounts of back pressure, and resultantly heat when the exhaust gases from an RB25 breathing 19-20psi of boost at high revs is trying to force its way through? I would just not try to run that kind of power through the RB25 turbine housing.... I wouldn't be surprised if swapping to a VG30 one would make the world of difference.

Thought this would be a good place to make an update - Heat Treatments ran at Masterton Motorplex in NZ this weekend and set his PB, and then reset it again: First run was an 8.33, the second run was an 8.28 @ 167mph. Congrats Reece and the Heat Treatments team

Awesome! Cheers for the information, me and some friends have been discussing the T04Z lately. I was just today trying to find out if anyone anywhere had compressor maps for them - partly because the most recent HPI to hit NZ shores (GTR-Special) had an R32 GT-R with twin T04Zs on it.... what a fascinating combination!! In light of what you say about it compared to a GT2530 - it'd be interesting to compare compressor maps, if the "shape" were similar. I had noticed that someone had compared the boost threshold with twin GT2530s...

Thats interesting - I always thought of boost as a measurement of restriction? If you get higher lift cams (and get the ECU tuned for the change) - won't the engine be able to allow more air in at the same boost level?

Well - if it was my car, the first thing I would be looking at would be the intercooler piping. If its fine off boost, but starting running rough and not boosting when you'd normally hit boost - it implies the turbo is sucking air in through the air flow meter, so while the tune might not be perfect it would suffice as the car is more or less running naturally aspirated. When the turbo has reached the point its sucking in enough air to make boost, the engine will still be drawing in atmospheric pressure and will start overfuelling and retarding. I hope this is the problem, as it will just be a pain in the arse

Roy - I'd misread the full boost thing.... though he did say 14psi by 4000rpm, which is pretty decent spool, no? This is bearing in mind that RB20DETs don't spool turbos overly well, and need a few revs to go - I'd imagine (as Quincy said...) that one should go very nicely on an RB25DET. Mafia - Do you know if there were any modifications to the VG30 wastegate port to allow it to hold boost like that? Are you using a Garrett supplied actuator with it?

Quincy777: How do you find this on the road? What kind of dyno, and at what boost level was that power made? Like the baby-T51R whistles?

Now that we know someone has made 250kw @ wheels with a GT3071R on an RB20DET (other thread) with full boost by 4000rpm, we can agree that the GT3071R is a good unit? I have a VG30DET housing, this can be machined out to fit the GT30 turbine wheel happily enough - and the GT3071R comes with a .5a/r TO4E compressor housing.... shouldn't this combination be able to fit down low easier than the GT30R low mount described in that other thread, and provide some awesome performance for an RB25DET? It sounds like the GT3071R-WG (w/ cut down turbine) was a good combo for the RB20DET.

I have an RB25DET which I blew the standard turbo on and spent a lot of time messing around trying to work out what I wanted to do. I ended up buying a VG30DET turbo to get my car going on the road while I upgrade all the other bits and pieces (ECU, Front mount etc) in preparation for a larger turbo. Your comment on replacing the turbine housing intrigues me - the VG30DET turbo has a noticeably larger turbine housing than the R33 turbo, but a slightly smaller comp wheel? I know the on road impression for one of these on an RB20 is bad, but on an RB25DET it should still spool quite well, aye? Would the smaller compressor wheel be a problem - or would I have all the power of the stock turbo, possibly plus a little more? Additionally, to my understanding - all the turbos from this era for turbo Nissans (R32 GTSt, R32 GTR, VG30DET(T). R33 GTS25t) run the same spec T25G-type turbine wheel? Does this mean that if I got my hands on another R33 GTS25t turbo, I could possibly swap the VG30DET turbo turbine housing onto the RB25DET turbo and made one with the best of everything???

NICE! So is that on the stock exhaust manifold? Does it fit with no mods at all required to fit it there aside from oil and water lines?

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?