Lithium

Zilch - Nice man I'll have to have a look at your thread. Yeah, at the boost and power level you are making the GT3076R has no major advantage over the GT3071R on a stock RB25 looking at the map. Its more the potential when I start getting more aggressive that the GT3076R has. WTF mate?? You had nothing at all to do with it. Neither you or Dale FZ1 deserve an ounce of my thanks. I had the 56T GT3076R for ages before you got yours, and had decided way before then. As far as I am concerned there is more of a chance that you copied or got inspiration from my or DP's ramblings. DiscoPotato deserves some credit for swaying me for .82 and Cubes a lot ... so thanks you guys for your opinions and help. And you are welcome for my input when you were thinking about what to change with your setup and were still fighting with the 52t: http://www.skylinesaustralia.com/forums/t1...um#entry2857161 For an additional reference, here is a dyno plot of my car running the .63a/r housing with a .6bar spring and creeping to nearly 20psi: Mr Mafia - you do realise you NEED a spacer to space a turbo too big to fit on the stock manifold away from the motor? Its not to copy you, its because you need to do it. I have no spacer now either....

I actually think a GT3076R .82a/r has MORE power potential on a fairly stock RB25 than a GT3040 .63 on the same boost level. Reason is, it breathes out the rear better and at higher boost levels will result in far lower exhaust pressures which ultimately means less restriction and you can as a result often get away with a bit more timing and therefore more power. The 82mm compressor of the GT3040 (aka GT3082R) only really has an advantage in higher flow capacity for a given boost level. If the engine isn't being choked by the compressor - which you aren't likely to get with the GT3076R ESPECIALLY if you are running stock cams, you aren't going to be in a position where the GT3040 has any advantage. The .63a/r GT3040 I'd imagine would be a tad lazier than a .82a/r GT3076R given the extra inertia from the 82mm wheel. I won't swear by that however haha. At best it would comparable- though thats just theory, someone on here who has exposure or more knowledge may be able to shed some light.

Not quite sure what you are looking for with that question. I basically bought a laser cut flange for a XR6-Turbo and effectively a pair of separate dump pipes were made up - one for the turbine outlet and a 2" one for the wastegate outlet. When the main exhaust bends to the back of the car the wastegate dump pipe merges into the main exhaust flow. You can clearly hear when the wastegate opens, even though it flows with the rest of the exhaust stream. I'll see if I can get a photo of it Why did you change your setup?

While all this was going on, I had been talking to fellow SAU'er Cubes who was looking for a decent turbo setup for his RB30DET powered R32. I had sung my praises about how good off throttle the GT3076R was, and how well it spooled and how willing I could tell it would be to make lots more power. There is also how cool the anti-surge whistle is.... hehe Anyway, after some deliberation HE went for a .82a/r internally gated version of the GT3076R which made ME watch with great interest. He finally got his car going, and I'm sure a few people here know the results. In short, it made good power, drove awesomely, and most importantly for me - it held boost. After muttering and swearing about my efforts and theories as to how I was going to fix my problems, I PMd Mr. Cubes and told him about what I was pondering. He was extremely helpful, and even went to the effort of hooking up a deal with ATS to get me a turbine housing and actuator from them - as in NZ we don't have people who stock such things separately. THANKS CUBES!!! I got my nice new package in the mail, and amped for the next few days about getting it on haha. Somewhere along the line I also impulse bought a low mount stainless steel exhaust manifold because they are cheap and I was on a bit of a drop-exhaust-manifold-pressure mission. Interestingly enough, with the new exhaust manifold and the new turbine housing - I didn't need any spacer. I don't know how much to do with the design of the turbine housing that was, and how much to do with the new manifold - but either way, it sat a little lower and was a much nicer fit. Also gave the exhaust a pretty sweet tone haha. As soon as I drove it, I was stoked. In normal driving its barely noticeable, on the motorway in 5th gear from 100kph it has SLIGHTLY less urge, almost like what you'd expect driving at a higher altitude. Who really wants brisk acceleration from 2600rpm anyway? Its nice not having the thing hissing like a hissy thing the moment you get under a slight bit of load. The BEST thing was when I gave it a bootful and the needle stopped climbing after it hit full boost. COOOOOOL!! So, I drive it around a bit getting used to it - and in to the dyno. Dyno tune was a mix of good and bad news. Basically, the wastegate would open at around 10psi - I wanted to run ~15psi and I had no form of boost control other than the adjustable preload on the wastegate. We wound up the preload until it seemed like it was going to be silly going any further. As it is now, the wastegate opens at 3600rpm at around 13psi and creeps to 15psi by 7000rpm... peak power attained at 6400rpm running 14.2psi so its not TOO bad but could be better. My next purchase is going to have to be an electronic boost controller to fatten up the midrange and maybe get a little more peak power. Nonetheless, was happy being able to get a full tune into the car - make some semi reasonable power and just have a really really driveable car. The tuner asked what kind of fuel was in it, he's tuned R33 GTS25ts with upgraded turbos along the T3/T4, GT2535 and GT2540 lines and has found them to start getting a little iffy above 240kw @ wheels in terms of timing and detonation. I got NO detonation on the dyno. He'd add timing, it'd make more power. Add a bit more timing, a bit more power. Add a bit more again, and the gain is minimal... ok so thats what it needs. No pinking, no dramas. So - some pics relevant to this stage of modification: New housing Cubes sent over: Dodgey cheap low mount manifold I bought: Wasted spark setup on the firewall: Internally gated turbo on low mount manifold: Dyno plot: Hope this reads as more than a boring wank on about my car actually starting to go properly, and has some informative use. Any questions more than welcome - I post this to hopefully help other peoples mission looking for a nice turbo setup for a stock RB25 that they MAY want to take to the next level at some point... I think this turbo is the best choice for being able to cater for both.

OK - so, first things first - ignition problem kicked in from about 4500rpm.... was a nasty nasty misfire. This was fixed using a Mitsubishi V6 ignition module (Spec2 R33s don't have one ) and a set of wasted spark friendly Buick V6 (Commodore mate) coilpacks. This so far has proven to work a treat! The next and more pressing issue was the boost creep - the first direction of attack was to cut the feed back into the exhaust stream off the wastegate and just have it venting externally. This made a huge racket, and SLIGHTLY reduced the creep - but really all it did was made a bunch more noise. Not cool - I only mention this as it was a path I went down, others might as well. Naturally, I had to road test it to see how it behaved - and now that I've had both the .63a/r and a .82a/r turbine housing I feel qualified to comment on the comparison. I'd love to tell you boost threshold difference on the dyno, or loaded up from low revs in a higher gear - but unfortunately there seems to be none. I don't know if this is because I went to a tubular low mount manifold when I changed to the .82a/r or not, but nonethess with either of them I can get boost from 2000rpm in 4th gear, and on the dyno they both made 9psi by 3300rpm. On the road however, there is definitely a difference - I definitely have a bit more lag. Interestingly enough, I prefer it - it makes a MUCH more streetable car and I wish I went with the .82 in the first place. Basically think of the lag as "how rapidly the turbo winds up once you've got positive pressure". They both feel exactly the same off boost, and seem to get to positive pressure just as easily... With the .63 so long as you are over "reasonable boost" (in my case I consider as 9psi/3300rpm) threshold then if you lean on the throttle the feeling is much like someone has cut a rope tying you back when you are attached to an elastic band at full stretch. You don't instantly get fired off, but you get quite a violent brisk bunch of acceleration. Now if you do exactly the same thing with the .82a/r, imagine a brisk take off in a jet aircraft.... thats the best way I can describe the sensation of them coming on. My experience test launching both setups says a bit -- I tried launching at 3500rpm with the .63, it had enough to get the tires spinning initially - and would snap on to wheelspin as the boost rose. I would gradually back off until the tires were more or less able to hold and try and hold that balance. When the revs went further up, the turbo would get a wiff of more exhaust gas and leap into life again - all keen to start toasting tires again. Basically it felt really really jumpy with this setup. With the .82a/r, launch would be much the same - except imagine the way the turbo reacts to the throttle control as more like how a jet (there goes that metaphor again) engine would react to throttle control. Back off to a point where its nice, and it will give you that thrust. Put your foot down more, and up goes the tires in smoke. With both setups, a gear shift near redline has you sufficient revs that when you put your foot down again the car bursts into life - no worry about falling of boost at all. Soo.... I didn't like the "better spool" of the .63a/r turbine housing as much as I thought I would, and I have a boost creep problem with the setup I have. I can either completely change it all to a high mount and a proper feed to the wastegate, orrr.....

Hi all I have been lurking around the SAU forums and gaining information from here and other places from before I owned my R33 GTS25t up until now, and will no doubt continue to. I had (and many others will still) have researched and pondered furiously the not so age old "What turbo should I go for question" and I have ended up with a combination that is so far PERFECT for my needs. Its been brought to my attention that people have been following my progress, and others - and that it might be handy to post my findings.... so here goes After all my research I ended up shortlisting and considering long and hard the HKS GT-RS, the 56Trim Garrett GT3076R, the Garrett GT3071R (which I consider to have been NARROWLY my second choice), and a Holset HX35 (got ruled out when I figured I probably wouldn't fit it low mount). After all my deliberation, I ended up with an initial "winning combination" which consisted of: - Garrett GT3076R with .63a/r Ford Style turbine housing (yay ATPTurbo) - Factory Exhaust manifold with 10mm spacer (needed to clear rocker cover), wastegate mounted off the turbine housing of the turbo (BAD move - don't do it, boost creep galore) - Completely stock RB25DET - Nismo 555cc Injectors (yay Greenline for particularly good service on getting these to me) - Walbro 255lb/hr in-tank pump - TiAL 38mm External wastegate - GTSLink Plugin ECU - Cheap front mount intercooler kit - 3.25" MomoCorsa Exhaust with no cat This setup had a MAJOR boost creep problem, even after porting out the internal gate port the Ford Style wastegate setup provided - it rather sucked. I also ended up with huge ignition breakdown issues which was a big pain in the arse. Nonetheless - here are some pics of this stage being put together and running: Turbo: Turbo test fitted (note spacer): Internal gate housing with ported out wastegate feed: Wastegate fitted to turbo: Engine bay with it all in: end of stage one.... will start writing stage two going straight away..

Stock S2 RB25DET GT3076R .82a/r Internally Gated 1bar boost 600x300x76 Intercooler 555cc Nismo Injectors Walbro Fuel Pump Safe tune

Haha will do that on the dyno (maybe not to 18psi though haha) Thanks HEAPS for all your help! I'd still be trying to find a way to solve my boost creep issue if it weren't for you

Just installed one of these .82a/r IG housings on my GT3076R, its awesome Initial tests show it to hit and hold 13psi SOLID from around 3500rpm all the way through 4th. Going to have it on the dyno on Thursday for a proper tune.

Oh it'll probably have the VQ37HR thing in it - those are pretty damn grunty motors! That'd go damn well!

I couldn't possibly disagree with this all more. S13 + stock internal RB25DET with an upgraded turbo etc is a proven 10s combination at the drags. Even an RB20DET makes a hell of a fun car to drive, if its going into what was originally the CA18. Going by the fact you mention the handling, I am better you have not actually driven an S13 with an RB in it? It is a comment made often and I've never heard it made by people who've actually tried driving one. There are quite a few top NZ drift cars using RB powered S13s, even in Japan its done.

Very nice!! And the calender girl is fantastic!

On the contrary, not at all. They all read too different.

Yep. I think the "more boost, smaller gate" theory is a bit whack. You basically need enough wastegate to drop the turbine pressure sufficiently to stop spinning the turbo more. GT4088R on an RB25 is an interesting combination - what is the spool like?

Hey man - don't confuse slightly longer spool times with less torque. You will have less torque until its fully spooled of course - so strictly speaking maybe a bit less torque at cruise (<3000rpm) engine speeds, but thats why they are cruise engine speeds. Who races at <3000rpm? Peak power should be reached at the same revs ideally, a bigger turbo can start making more power at lower revs if the smaller turbo is maxed out, or if the bigger turbo is running more boost though.

Have you seen higher than the 310rwkw @ 20psi mentioned in this thread for a GT2835 from a GT-RS?

OK a GT2835R is like an equivalent of a GT3071R from Garrett, more or less the same thing. It basically should flow a bit better than a HKS GT-RS, they use the same compressor but the GT2835R has a bigger comp housing and a bit more turbine wheel if I remember rightly. GT-RS will have much less lag than a GT3076R, but will be working hard to make 270-280rwkw. You are right about HKS being a good option given their turbos are a straight bolt on. From everything you say, I'd go for a GT2835 from HKS - pretty much a bolt on fix if I remember rightly. A GT-RS seems most at home around 250-260rwkw from the threads I've seen. Garrett do an internally gated T3 version of the GT3071R and GT3076R, I'd be looking seriously at the GT3071R from what you've said.... I reckon it'd be really really well suited to it. With a .82a/r turbine housing it'd spool fairly quickly and smoothly, and should be able to do 300rwkw without TOO much more lag than a GTRS. You'll need some custom stuff made up, but its not a new manifold etc type situation. Cubes has done an internally wastegated Garrett GT3076R on his R32...

I'm finding him a bit irritating as a tuner from a few of the things you have mentioned about him haha. Chalk and cheese is funny, as a GT3076R from Garrett IS a HKS GT3037. Or the other way around if you want. Made in the same factory, same wheels and core. It'll spool the same-ish. The only reason there could be any varience is that HKS do 8cm/10cm/12cm style turbine housings while Garrett are .63, .82, 1.06 so they're on a slightly different scale. Other than that, its all just looks (ie, HKS label on the compressor cover etc...). I vote the GT3076R, HKS GT-RS and GT3071R are right up at the max out area of their efficiency at 300kw @ wheels whereas as you say, its beneath a GT3076R. You don't want to be maxing your turbo out to make the power you want, a GT3076R spools fairly well still (.63 a/r is a bit snappy, but in a fun way haha) but has head room for if you do get a little greedy in future etc. I would not go for a GT-RS for a 270-280rwkw R33, personally. It'd be working too hard and working the motor too hard.

The compressor wheel IS a problem on the S2s, quite a few people have had them break under duress. I'm one of those

OK my bad, I must have been put wrong somewhere - I definitely have been put under the impression he had the record for quickest manual shifted.... nonetheless its completely unrelated, and would regardless take nothing from this car doing a 8.69 on DOT tires What is the setup?

Actually I think you are sortof right, the Croyden's GTR WAS a Hollinger sequential - I got my wires crossed, Glenn Sucklings OWN R32 GTR was a manually shifted Hollinger box - running full drag slicks though. The fastest manually shifted GTR I believe, think thats how I got confused.

I can't remember what tires the Croydens R32 was running when it was there, but it was done using an H-pattern box too - and they were definitely some kind of DOT approved tyre. I have it in my head a UAE R32 GT-R built by Sub Zero did something like an 8.2 or 8.3 on DOT tires as well? Either way, an 8s run in ANY form with a 4WD is absolutely nuts, well done - thats awesome news. The 8s GTR club is a very exclusive one

Stock for stock the Z narrowly down the 1/4, and by a solid margain on the track.

Congrats on the awesome time Look forward to seeing how much quicker it goes Quickest RB25 powered thing in the world?

Awesome Thanks! Here's hoping its a RB25DET for a change.