Lithium

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?

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?