skylinecouple

I can say I am very happy with my combination and would go so far as to say it is perfect for every day driving. Put your boot into it and go, any time any place. Even under 3,500rpm there seems to be enough air flow to bring you onto boost very quickly. The point I'm trying to make here is I have no boost control issues at all. If anything I have to wind a bit more tension onto the actuator to get my 14lb actuator to actually BE 14lbs instead of the 13lb it is. I am dropping boost from 19lbs to 16lbs, not good. Ideally I would like 18lbs across the board but I'll fix that this week. As I have mentioned elsewhere in these forums, The RB25 needs a .82 housing. Deciding on 3076 or 3071 is really about if you want 300kws or 260-270kws. I decided I would like 260 and be happy with that. Trouble is, I want more. Should I have taken delivery of the 3076 I ordered as well ? I am kind of glad I didn't, if more power is needed then cams will go in. I have found the .82 gives me bucket loads of torque at low revs but doesn't break into wheel spin yet just loves to rev so freely in the top end. If I had a .63 I know it would light the tires at low speeds and then choke when the revs get serious, not to mention the very real problem of boost control. The RB25 cannot swollow a lot of air at low revs, ok, I know your going to say what about the standard turbo but that doesn't push anywhere near the air a 71mm wheel does. The .82 even handles the 76mm comp wheel no problems from what we have seen.

Just wandering if the AFM is simply not passing enough air as in the States these 3071 compressors are running 22lbs of boost no problems. I want and will have 18lbs across the whole rev range, full stop. Got to get me some cams, 16lb actuator and finish my airbox.

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 ?

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 ?

Something I am very interested in right now. Increase overlap and compression is essentially dropped right ? At what point does the cam become too much for the lifters and springs on a standard head ?

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.

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.

Excellent stuff, much appreciated.

Are you prepared for stronger springs ? At some point the cams will be too agressive for the springs to control so stronger ones are needed, however, for most street setups a mild cam is all that is needed. A bigger turbo will do ninety percent of the work. Look in the RB20 section for other setups as being the first to try something new is over rated.

First up you need to tell us if you mind a little lag. If you don't then go for the vg housing with RB25 turbo. If you find one the owner will probably ask too much for it so your better off looking for a 2532hks or similar. For the money I'd go hks. Without knowing your goals how can we advise ? How much do you want to spend ?

I,000 to 1,100 is normal. It is mostly to power the power steering so you don't need a lot of revs. 1,500rpm would have been too high. The wife's car is an auto R33 which is the same as my manual as far as idle goes coasting.

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

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.

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.

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 ?

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'>

R33GTST 4 door with: GT3071 .82 housing. Bellmouth dump with internal wastegate to 3" exhaust. Power FC Hybrid cooler. 550 Nismo injectors. Stock air box. Stock engine. http://www.skylinesaustralia.com/forums/uploads/1215946577/gallery_23164_2695_174640.jpg' alt='gallery_23164_2695_174640.jpg'>

And I can guarantee I'll let him jam some boost into it. BUT, 270 is what I'm after so we'll see. Buy the way, I'm thinking peak boost on this turbo would be around 22lbs. The compressor map seems to indicate 17lbs as right in the meat of the turbo's potential. What do you think ?

Yes it's a funny thing Dave, some cars have surge, some don't. Cams will definately be on the cards for the future. I'm hoping that will reduce the overlap for more timing. Yeah, I think Yavus is great, takes a cautious attitude to tuning. Don't you just get sick and tired of tuners that shake your hand then tell you to come back in the afternoon to pick it up ? I want to be there to tell them how far to go and make sure tune for drivability, fuel economy, safety and only then power.

A few more for you. http://www.skylinesaustralia.com/forums/uploads/1215299925/gallery_23164_2695_58824.jpg' alt='gallery_23164_2695_58824.jpg'>

I know, but not this little black duck. I strongly suspect GCG screwed up and put a RB20 housing on it, who knows. It would lose urge very ealy at around 5,500rpm in 4th. I could never really put my foot into it as it would just light up the tyres at 2,700rpm. Then lose the plot at 5,500. I once had an SV5000 that was very much the same.