R33 Sii - My Gt30 Upgrade Is Done. Lots Of Pics

[The Mafia]

as I said before I am not worried about top power at the moment due to fuel.

I just want to get rid of this lag!

Edited December 25, 2005 by The Mafia

[Cubes]

I drove my uncles VT II 6speed 250i Clubsport, that has top end... lol it felt as if it was struggling as it nudged over 4000rpm.

I was quite suprised how lazy and slow reving it was, a very unexciting car indeed. Wide power band but rather gutless overall.

And I did give it quite a bit of shit, he said to rev and dump it. Nice smokey all the way through first and a bit of second.

Still its a slow rev'r and boaring to drive, nearing the end of second at approx 90km/h it just feels boaring and slow. No top end really, well not compared to mine.

My old VS 5ltr with ecu, mild cam, 3.5" exhaust, 5speed was more fun.

I don't think you will get rid of lag Mafia.. Maybe bring it down to 4000rpm full spool but thats about as low as you will get with the vg30 gt30 setup.

Edited December 25, 2005 by Cubes

[The Mafia]

well, bhdave is getting 20psi at 3200rpm with the same setup. I highly doubt not having an external gate has anything to do with the lag. He's got the same compressor housing, TO4S wheel, and .63 housing.

20psi at 3200rpm...I want that... How do I get it...

I tested the tension on the wastegate actuator, and it took both hands to pull the gate and arm open even just a little bit. I think its pretty damn tight.

Edited December 25, 2005 by The Mafia

[Cubes]

BHDave runs a different setup.

Not a VG30 GT30 setup.

I have a t300s, which is the same t04s comp wheel as you and a .63 T3 rear turbine that looks to be identical(ex gate though). However it is a hks low mount setup.

The VG30 turbine is slightly larger than a .63, estimated by ATS to be around the .7 mark. Then take in to consideration the machining of the nozzles etc. All of which will no doubt cause the setup to be just that little bit less efficient than a properly designed turbine housing.

The fact is others running the VG30 GT30 setup from GCG which is no doubt very similiar to yours makes all their boost by approx 4000rpm. They run the smaller comp cover which will improve response and spool time ever so slightly, you run the larger .7.

I've lost track.... Do you run an aftermarket manifold? I assume BHDave would as he runs an external gate.

Edited December 25, 2005 by Cubes

[The Mafia]

so really, if I wanted the same spool time, I'd need a HKS rear and external gate?

I don't want to do this....

But if I have to...................

Thanks for explaining that cubes.

[Cubes]

It sucks... I'm hanging off and trying not to jump in to it.

Even then I think I will be dissapointed with its results.

[BHDave]

There is no stamp on my turbo stating it is a hks (which is a bit of a worry) Though it is a garret stamped t3 rear housing, which leads me to beleive that it is a common enough housing if you want to get a hold of one.

I previously ran a stage 2 gcg highflow and the response was near enough to identical to the current setup. This had a machined rear housing that looked to be about the same size as my old r32gtst turbo. Maybe that housing, once machined, is pretty close to the .63 you are looking for? I know the vg30 rear housing highflows have much poorer response than the regular highflows. It may be worth having an r33 rear housing machined up to suit. It couldn't cost more than a few hundred dollars and should improve response significantly.

I have an hks kit, which is the low mount cast manifold and ex wastegate. As i said previously, i think that a log style manifold (stocker) should offer better response at the cost of some top end power.

[The Mafia]

dave, you are right on the money.

I was thinking this in my f**king sleep!

My mate has about 10 Standard R33 Exhaust housings - I will get one machined up to suit this GT30 and see whatit does.

It should be more than happy to provide 250rwkw, with a bucket load of torque.

What was the top end like though? Did it feel tired? Or did it pull, just limiting the power level to something like 260rwkw like the hi flows are maxing out on?

[Cubes]

BHDave,

Care to share any pics of the engine bay.. I'm interested to see how the low mount cast manifold looks and positions the turbo.

[BHDave]

Mine made a touch over 240 during tuning but we took a bit of boost out and a bit of timing too.

Final figure was 238rwkw on 20psi. The dyno ramp rate wasn't bringing the boost on as early as it hits on the road either. There's a copy of my dyno sheet in the rb25 turbo comparison thread near the end.

Basically the car pulls like a train between 3 and 6k and then feels a bit flat at the top end even though it's still making power right up to about 7k. It doesn't really roll off either.

Cubes, pm me your email addy so i'm not clogging up mafias thread with a bunch of my photos.

[discopotato03]

I can relate this smaller RB25 housing from the VG one from one of my own bastard hybrid turbos . That one actually used a Ser 5 RX7 turbine and a -24 B wheel , going down to the smaller turbine housing only made it surge . My turbo was a copy of what Bill from ATS did for the JMS S-13/RB20 DET car .

There are times when going smaller in turbine housing works but its only generally when the compressor is smaller in relation to the turbine . The desire to speed up the rotating group with a small a/r housing is valid but not with compressor being the size and style of that one . In this case the compressor is the culprit , the non native turbine is less than ideal but not the greatest drama .

Its a bad feeling to be in the dark and clutching at straws - been there done that .

The answer is staring you in the face - lose the S compressor and use a propper turbine housing . Nothing you can do with turbine and compressor housings will help much because the cartride is a Garrett factory flop . It may have worked in some obscure diesel app but fails dismally with petrol engines . I can nearly hear people thinking this guys full of shite BUT on a parting note show me a HKS BB turbo that uses 7/14 blade compressors - you won't find any . They had their pick of Garretts full range but you won't see a GT3037 or GT2835 with an "S" wheel .

Cheers A .

[BHDave]

I don't think you're full of it. I know from my experience with the t300s that it requires a heap more boost than an equivalent gt30 to make less power.

But i'm quite happy to accept that as mine is a pretty old second hand turbo and was relatively cheap.

I dont agree that the t04s wheel is the root of all evil as you do though. It's just got an efficiency window the size of a bee's dick.

I don't think surge will be an issue with the smaller turbine housing in this case. The turbo is making boost very high in the rev range which is either a restriction or an overly large exhaust housing. If i can have the same compwheel making considerably more boost 1000rpm earlier on a near enough identical engine without surge, then a smaller exhaust housing is worth a shot in my opinion. (particularly if he has access to a heap of them).

[Dale FZ1]

I dont agree that the t04s wheel is the root of all evil as you do though. It's just got an efficiency window the size of a bee's dick.

If i can have the same compwheel making considerably more boost 1000rpm earlier on a near enough identical engine without surge, then a smaller exhaust housing is worth a shot in my opinion. (particularly if he has access to a heap of them).

<{POST_SNAPBACK}>

Considering that the T04 range was conceived/developed to be tailored to many different applications including diesels, I'd be interested to see a flow map for the 52 trim S with 0.7 A/R housing. How about it? I haven't found one (and have tried) but welcome someone to post either a link or pic. I think BHDave may be right but would be good to confirm. His comments about requiring more boost to make less power are good evidence of flow/pressure ratios/efficiency.

Also as a matter of pure cost containment, if Mafia can get his mate to machine up a std RB25 housing, it's probably worth a go. I wouldn't like to see good money going after bad, but it'd be good to see him hit a happy medium.

cheers

[The Mafia]

yeah I think I can get away with slapping a RB25 housing on this turbo for less than $100.

My uncle and aunt own a very very large trucking company in mackay, and the turbo repair guy is 50 meters away. (they get all of their volvo turbos done there)

I am going to get the turbo guy to grind a Standard RB25 Turbo Exhaust housing to fit a Garrett GT30 cartridge, and then drive my car over one of the truck pits, remove the dump, disconnect the Water and oil lines, remove the turbo intake, undo the 4 bolts that hold the turbo on, and take it to him to fit the housing. This should take less than 2 hours. He should be able to fit the pre prepped housing in less than 5 mins.

Then once the original housing is back on, I am going to get 3 new T3 flange gaskets, bolt the turbo back on, intake, oil and water lines, and the dump and front pipe...

This should take 3 hours, so I am looking at about a day and around the $100 mark to reduce my lag from 4500rpm to 3200 rpm. Now thats going to make the car drive 1000000000 times better.

Absolutely no adjustments will need to be made, as the flanges on the VG30 and the RB25 turbo flanges are exactly the same.

Think about it, full boost or up to 20psi at 3200rpm? Than means the car starts making power at about 2500 rpm. Nice and low. The larger compressor cover should keep the air nice and cool, and hopefully it won't surge too much. If it does a little, I will get a powerfc boost control kit, that should help it alot.

Will be a nice little experiment.

oh, and I will also get the turbo dude to grind out the wastegate hole to give it a little more flow when it opens as the standard one is only small. He said its not a problem to do. This will also help prevent surging.

Here's one last thing. I am not going to get rid of this VG30 for a damn good reason. You know why? This turbo setup doesn't belong on this block! It belongs on a RB30..... and RB30 should be able to get this VG30 setup spooling at full boost by about 3200rpm....with massive amounts of torque, and the housing should also be efficient enough to drag the RB30's arse up to 280rwkw. They are bigger than you think when ground out to fit a GT30.

So I am gonig to keep it for when I do a RB30 upgrade. Then I'll put it on, as the standard RB25 Exhaust housing would be way too restrictive for a RB30.

hehehe hope I didn't ramble too much.

Oh and Dale, if this works out well,and runs just as I thought, I will be able to source you a GT30 core with a .7 comp cover, the better 6 blade wheel, and and no ex housing for about $1400.

Then all you'll need is a second hand RB25 ex housing, and you'll have the same low down punch as me

I can't wait to see the torque curve, its gonna be fat. I am not really worried about the top power. As long as the setup is good for 250rwkw - 270rwkw, then thats heaps (for a standard bottom end)

Has anyone got any thoughts on all of this?

[Ezz35]

i think mafs that was a very long post lol....but im learnin heaps just reading all of this was thinkin of the same kit for my S1 33

[Cubes]

Mafia, try not to get your heart set on it being all in by 3200rpm because it won't. You are only going to see an improvement by ~500rpm.

Edited December 26, 2005 by Cubes

[discopotato03]

Hokay give it a shot , just remember smaller a/r turbine housings achieve the higher exhaust gas velocity by using smaller passages - and will reach maximum flow capacity sooner .

A little later on you'll come to realise that a smaller compressor can easily lower the boost threshold purely because the turbine can drive it faster sooner . I'm just looking at the 48 and 52 trim TO4S maps and they pass the choke line (60% efficiency) at 2 pressure ratio (1 Bar positive) at ~ 46 and 50lbs . If you assume that 1lb of air for 1 Hp thats enough airflow for 460 and 500 Hp - and Mafia's asking for 270Kw or 360Hp .

The compressor from the GT28RS (60mm 62T 6 blade GT family) pushes 36lbs of air at 60% efficiency but is on its limit . The 56 trim 71mm GT wheel from some 2871's + 2835's does it at ~70-72% and maxes out at ~ 45lbs flow . The 76mm GT compressor from the real GT30R and HKS GT3037 56T maxes out at ~ 50lbs at 1 bar positive and does it 10,000 rpm faster than a 52T TO4S .

Compressor efficiency is important but mainly from a heat rise in the charge temperature point of view . I don't know how else to say this but less blades means less air drawing capacity at low compressor revs . It gives the turbine a better opportunity to zip the compressor up to a workable speed and that's what spool is all about .

Changing to a larger a/r comp cover will do jack for compressor surge because its the inability of the engine to swallow all the air a compressor wants to give that is the issue . Challenge : Disconect a turbos air outlet and rev it to destruction , didn't surge did it ...

I'm not sure how electronic boost control cant help prevent surge although if it could regulate boost at very low pressures it may not surge - the low boost won't get us much go either .

It's easy to think that a waste gate is a pressure relief valve in the exhaust side but its not the case , its there to by-pass enough gas to control the turbine/compressor speed and hence boost from compressor speed . Waste gates are generally regulated by boost pressure which totally disregards exhaust manifold pressure . Challenge 2 : connect your waste gate actuator to you're exhaust manifold and see if you get ANY boost when its regulating off exhaust manifold pressure . Acid test to see if exhaust manifold pressure is way higher than boost pressure . Gas velocity through the turbine blades dictates how much energy the turbine can recover . Once the flow limit of the housing is reached all that goes up is pressure and heat - bad very bad ...

Someone said earlier that 2-2.5 times exhast manifold to inlet manifold pressure is the thing to aim for . Start crying because the yanks are gettting equal pressure on SR2DET's (front drive Sentra's) with 52T GT3037's and .73 turbine housings . They spool at ~ 25-2700 and make close to 400 at the treads . I think the term they use is crossover to describe equal or even higher boost to exhaust manifold pressure . Every turbo engineer will preach to you the benefits of achieving this , the developement of turbo F1 engines shows it up too . Tis a great pity it ground

to a hault in 1987 when they were banned because turbo development could have continued with the advantage of huge financial resources .

On a parting note , is anyone still awake ? , early truck turbo diesels had no form of waste gate and were said to be free floating . The turbine and housing were sized to allow maximum exhaust flow (minimum restriction) and JUST enough compressor size/capacity to reach the desired maximum boost up near the red line . This is why diesels generally have such large exhaust housings and they don't overboost .

Cheers A .

[Cubes]

I always find your post interesting disco.

With regards to

Challenge 2 : connect your waste gate actuator to you're exhaust manifold and see if you get ANY boost when its regulating off exhaust manifold pressure

The rb20det turboon the rb30det made 6psi at 4000rpm that crept up to 6.5psi by 6500rpm with the wastegate wired all the way open.

I will do the same test with the vg30det turbo just out of curiosity.

One things for sure since I've fitted the vg30det turbo peak torque and around peak power I've been able to dial in another 6degree's ignition timing, just from less back pressure.

Spool is the same when loaded up on the dyno the only real difference is the turbo feels a little more lazy as in it requires that little bit more throttle to get partial boost, it doesn't make boost as easy.

BUT, it appears the top end now pulls well to 5800rpm where it wants a gear change, prior with the rb20t turbo it required a gear change at 5000rpm, no later.

Edited December 27, 2005 by Cubes

[The Mafia]

I'm so confused.

Why is BHDave getting boost so early then?... I want that...

[Cubes]

He's running an aftermarket manifold, and propper garret turbine housing that hasn't been hacked away. Its been designed properly for the turbine wheel.

Very much like R31 Nismoid with his GT30R .82.

The .82 is larger than the vg30 yet its all in by 4000rpm.

We also have to remember spool time is subjective depending on gear. By the sound of it your seeing and feeling a kick in the arse around 4500rpm, drop it in 5th at low rpm and load it up no doubt you will see that same boost/kick at possibly under 4000rpm.

My stock rb20det turbo on the rb20det didn't hit 1bar until around 3500rpm under general street driven conditions. Some state bah load of shit somethings wrong with it then as I see 1bar at 2800rpm.

The difference is I take my spool time readings from the usual gears that you use when giving it a bit of stick. That being second and third out of corners etc. Others take it from fourth gear, which I feel is a bad indication as it doesn't give the true on road experience.

The same was with the vg30det turbo on my rb20det, I didn't see 13psi until around 4200rpm. Others state they see the same boost by 3500rpm, but what gear? Mine was in second, theirs most probably 4th.

The rb20det and vg30det turbos on the 3ltr make very little difference to spool time, its always no matter what gear in between 2000-2500rpm.

Edited December 27, 2005 by Cubes