3071 Garrett

[skylinecouple]

to a degree pressure maps and numbers can get you close but throughout time man has always fallen back on the age old way, "suck it and see". Personally, I'm not a big fan of instant boost, which is why I've steered slowly away from small A/R turbines as they just run out of puff too early. I'm told the 3076 with .63 housing will give brilliant results but I know it will be limited by the small housing and stop around the 250-260kw mark. Besides, if the car is barely moving and hits boost hard it's wheel spin city......instantly. No, I think the .82 housing will be perfect but, the compressor, now, thats another story. Guess I'll find out soon enough.

[Cubes]

Skylinecouple;

I wouldn't be concerned if power comes on too hard; a little time spent on the dyno and its easy as pie to tune it to transition softer.

All though that spoils have the fun with improving your throttle control skills.

The 3ltr with the GT30 has some pretty mean mid range power; after a few tweaks am now finally able to get all of second gears power down.

I still find it difficult to get off the line clean in first, usually short shift in to second and let the early boost build soak it up.

The 12mm subframe rake has made a massive improvement to traction; even when it is spinning the arse sits down and accelerates the car fairly quick.

Prior to the rake it felt as if the wheels where just dangling in the air wheel spinning and road speed was hardly increasing.

[jnr32r]

im keen on knowing any fellow RB20 owners using GT3071r and seeing what their comments are...

[skylinecouple]

I thought rather than start a whole new post I'd resurrect my old decision post and continue from there. Hey Cubes, thanks for the PM. Yes there is a problem with boost falling away because we didn't put enough tension on the actuator. I know for a fact having seen the behaviour on the dyno that this power was achieved with 16lbs not 19. On the actuator only we had 243kws at 13lbs. I think if I put a bit more tension in to hold it at, say, 18lbs all the way to redline we could see 270kws very comfortably. You see Yavus had it up another 15kws but we agreed for track work to make it very safe. I know I can thrash it on a hot day and bad batch of fuel and not worry. Couple of issues we need to address is the dump not being 3" but just under as it has a slipper pipe which has to be slightly smaller to fit into the 3" exhaust. The turbine outlet alone is 3" and the waste gate is I think 1 & a half. So we will saw off the end of the dump and weld on a 3.5" or 4". Also working on a fully enclosed alloy air box with temp proof lining, should look good and with the biggest air filter I can find may make breathing easier.

http://www.skylinesaustralia.com/forums/uploads/1215946577/gallery_23164_2695_13951.jpg' alt='gallery_23164_2695_13951.jpg'>

[Dale FZ1]

Congratulations on the good overall result. Similar to a few guys with the HKS 2835 Pro S, but I think they might be tuned/boosted a bit more aggressively. Be interested to see what it would look/go like if you let the tuner play further.

I'd thought the fuelling was richer than that. A consistent 12.2 looks pretty tidy to me

Depending on how quiet (restrictive) the muffling is, you may find the boost drop related to rising back pressure within the exhaust. My removable baffle 20kW, but is worth it to keep road legal and also avoid tinnitus. The odd thing is that the increased back pressure from it only stops it making more maximum power and does not induce a sharp nose over.

Shape of the graph to me looks great - very linear looking and holds maximum across a decent range without falling away. It's good to know that you have extra grunt to access if you wanted to play with ignition. For the odd track day would it be better/desirable to use an octane boost eg. toluene and take advantage of it? That would take care of concerns about the dreaded knock and give a few more herbs. It's pretty evident that the ignition mapping is the only thing holding it back.

A 3.5 inch dump/front pipe will fit in, but reasonably tight. 3 inch should be ample at the power level though. With your fabrication skills try doing the dump with a half-pipe attached similar to the HKS Pro S arrangement. I split open a 3 inch bend and shaped to suit. That would allow a bigger venting volume for the wastegate and perhaps reduced turbulence.

Edited July 17, 2008 by Dale FZ1

[skylinecouple]

Have to agree on the dump pipe. May just fit a 3.5" pipe in there though, seems to be enough room. There is definately more room to play with the timing but will put another full turn on the actuator first and make sure the bottom line is actually 14lbs. I have a thing about track day fuel mixing, Ferrari or Lambo's don't have to worry about it so I don't want to either. I always drive on the full boost setting because I want a car that is fast all day every day, not to use it but for the satisfaction of having nothing to prove. Which brings me to the driving performance.

The boost comes on fast, how do I explain, boost hits at 3,500rpm but it happens so quickly like as quick as you push the go pedal it has a one second pause before it's all happening. And when it hits, wow ! Each gear there is no pause or lag and more to the point the lag is non existant at part throttle. As long as revs are above 3,500rpm you have instant response. I guess this is attributed to the small compressor compared to the 3076, or more to the point the smaller comp housing. It just seems to have response everywhere. As for fuel consumption the improvement is great. Went down the coast and did 300k's with half a tank. Have done a hundred k's around town after filling up again and only just moved off full. Thank you to Yavus as he did a little fine tuning at lower revs and part throttle. All up very happy but room to play further then work on emissions and fuel consuption further.

Would I get the 3071 again ? Hmmm, yes I think so but with cams before tune. Look, I know I'm going to put cams in, I can't stop changing stuff, so that will be the next step. How about 256inlet and 264 exhaust ?

[BHDave]

The hks 256/264 cams are good.

They work for me. I'm not saying you need them as you could probably max the turbo with out them but you would make your 260rwkw with less boost, with a slight trade off in light throttle drivability around the 2k rpm mark.

Good for a track nugget if you want to look at it that way

[skylinecouple]

As I said, I can't stop changing stuff. Cams are just a matter of time. Now if I could just get some really big brakes......

Some Bride seats, rear tower brace since nobody makes them for a 4 door, and still working on the rear diffuser. Oh, and a forward facing intake.

[Cubes]

I went with some cheapo 265/263 9mm lift regrinds (221degree @ 0.050"). I've only taken it to 5k but on the same boost I'm now seeing 4.93volts from the z32 vs 4.78volts previously.

Hasn't lost anything down low only feels smoother a few hundred rpm off idle which makes it easier to drive around car parks as the throttle isn't as touchy/lungy in first.

Tune is next week Some sleepless nights ahead.

[skylinecouple]

Never thought of regrinds, if I kept the same rev limit they shouldn't break, should they ? In the old days we reground cams all the time and never snapped one. let me know how it turns out.

[Cubes]

Tighe cams appear to do decent ones.

rbman went with the 708c 254 8.5mm lift (214 @ 0.050") cams and picked up 26rwkw on the 1psi less.

simonr32 went the same as myself and with the std lca's on the rb25det picked up a little over 30rwkw on the same boost. then pushed in some overlap picked up 20rwkw through the mid range and dropped ~10rwkw up top.

His jumped from 260rwkw to 290 something rwkw on the same boost with the gt3071 .7 IW a/r.

[skylinecouple]

How much did they cost ? that is awsome for such an easy install. Where do I find Tighe Cams ?

[Cubes]

http://www.tighecams.com.au/

A good year ago.. $220 for a set of regrinds.

These days. Supply and demand. $380.

But still $380 for R&D.

[skylinecouple]

Can you tell me which rear housing to get any other information you can give me.

I am getting it from GCG.

Hi.

I have the .82 housing and absolutely love it. No problems with boost control at all. That is why I went away from the .63 as too many have had boost spiking or boost continuing to climb because the internal wastegate can't flow enough. I was concerned about lag so went with the smaller 71mm comp wheel too get it to boost ealier and now very happy. If you wanted more power I would suggest the 3076 as it will make the power at lower boost. Bare in mind I will wind the actuator in a little further to hold the wastegate closed for a steady 18lbs at full revs. Notice the current boost is dying off to 16lbs from an initial 19lbs. By the way, the .82 will allow the car to make more power as revs climb so I don't get wheel spin the moment I floor it. That was so frustrating with the GCG high flow. Get the 20mm spacer for the manifold from GCG as it will give you good clearance for the comp housing. If you get the 3071 or 3076 you will need a 4" joiner from turbo to intake then 4" custom alloy pipe to 3" then 3" joiner to AFM. Make sure you get a 3.5" or 4" dump to weld onto the exhaust flange from the turbo housing or as Luis from Drifty Garage did with mine was to weld 3" then 2" piggy backed on that similar to HKS. Actually, Luis will do the lot if your unsure for about $1200 to 1300. If you can leave the car off the road for a week or two then do it at home. I have to work so not an option. Hope you go ahead.

Regards,

Gary.

[Cubes]

I had mine tuned.. no issues with boost creep but plenty with boost drop.

Pushed in 19psi through the mid that would tail off to 17psi by peak power.

Tuner seems to think its airflow restricted. 2" FMIC piping + smallish FMIC + std airbox as the almost certian culprit.

3" bell mouth dump.

Power jumped to 302rwkw at 17psi massive mid range gains (~260rwkw at 4000rpm) that actually hooks up damn well due to the progressive nature of the gt30 + the boost controller setup sedately.

[skylinecouple]

Funny how yours is behaving exactly like mine. I have an initial 19lbs then tapers off to 16lbs. Your cooler piping is killing you and for God's sake get yourself a Hybrid cooler and nothing else, look inside one and you can see an extra 20kws. My Just Jap cooler was great for 230-250kws but then you need something else. When you put the two together there is a clear difference in tube size and therefore flow. Plus an extra tube, 15 I think from the JJ 14 tube. I was lucky to pick it up as a return to the factory then repaired it and weld on new brackets. How much ? $100.

You can have my old cooler if you want but only if it is better than what you have. It's a bar and plate. $50 for you. Piping kit should be everywhere. Just Jap ?

Yeah the standard airbox has to go, Do I hear Blitz or similar ? Recently picked up a few sheets of alloy in 1.2mm for $15 so will get it done soon. Need the biggest filter I can find.

[Cubes]

My core isn't actually too bad. 450x300x90 I've been told to stick with it (its an old spearco bar/plate core) and simply weld 2.5" outlets on to it. But it is a tad short....

Piping I'll have custom stuff done to retain that std factory look.

I really think the taper is most influenced by the 1bar actuator as I experienced the same thing when making less power on the std cams. No doubt the cooler piping and std airbox/filter is hurting it a tad.

The offer is much appreciated but its all sorted.

[skylinecouple]

No worries, yours at 90mm is plenty of flow and I doubt 150mm shorter would make a difference in temps. So what are you saying about the actuator ? 1bar not enough ? If so, I need to get a stronger one. Is there a 17lb actuator ?

[BHDave]

maybe not 17 but close.

I have a 16psi one atm, i know there is a large diaphragm 18psi one on ATP's site too

[skylinecouple]

I think the best way to go here would be to free up the air inlet and see if there is still a drop in boost then go for bigger actuator. I really would like to see boost stay at a perfect 18lbs across the rev range. The only way I can see to check which is causing the problem is to watch the waste gate during a power run and see when it starts to open. I should have taken the lid off the box to see if there was a restriction. I never had a problem with 220kws. Dave, how is your 16lb actuator holding boost, do you have a standard airbox ?