My 300rwkw Adventures

[The Mafia]

I'd probably lose about 30rwkw - 40rwkw.

I'd hae to take at LEAST 10 degrees timing out.

If I get some time on the dyno, I'll disconnect the system and pull timing out and do a run.

[skyguy61]

Thanks Mafia,

well worth the expense,please dont go to the trouble of doing a run without WI i think your estimate would be very close to the mark. ive been reading a lot and there is heaps of info about WI and lots of differing opinions about before or after the turbo WI,some guys even worry about the safety of Methanol verus Denatured Alcohol.See Excerpt below

"The water/alcohol mix: Many people use methanol for the alcohol portion of their fluid, but I have found a few drawbacks. First, methanol is highly toxic and a known carcinogen. Second, it can be hard to come by. Third, it's highly corrosive. So, I decided to use denatured alcohol which is available at the local hardware store ($7 a gallon). Denatured alcohol is ethanol with a little methanol added so you can't drink it. Although it's still toxic, it's far less poisonous than straight methanol. You'll probably just go blind if you drink it, but maybe you won't die. Ethanol, by the way, is just good old booze in it's purest form. But again, don't drink denatured alcohol. For the water portion, use only distilled water. You don't want to clog the misting nozzle. You can adjust the mixture percentage as you see fit, but I recommend at least 20% water to get some of it's cleaning and in-cylinder cooling benefits"

Im very keen on installing and running a WI system on my car.......i think the benefits and the gains are well worth the cost, cheers

[SilverECR33]

To Mafia, Cubes, Disco, Dale.

If the 7 Blade would acheive more response down low. But suffer from 20rwkw up to possibly, what kind of characteristics would be expected then, if you sacrificed the rear a/r sumwhat. for example.

Using the 7 blade option rather than 6, on the GT3076R in mafia's turbo configration (56Trim 60mm cover 76mm comp, .063 rear a/r in 84 trim.) to boost response, but using a rear housing arrangement of 0.71 a/r in 84 trim. to flow that extra bit up top.

could this be a more benificial Ideal turbo configuration for this GT3076R.. I was thinking about getting one made up and giving it a try.

ps. the .71 housing isnt a off the shelf item, its engineered thru CGC. and with housing made to suit the rb25det standard manifold. It seems a feasible option though, especially if they actually make them up and keep them on their shelves, people must be using them. But havnt read anything about them here on sau yet.

Edited July 22, 2007 by silverbulletR33

[Dale FZ1]

The interesting thing in having a look at the flow maps side by side for a 6 blade vs 7 blade configuration is that the 7 blade pushes more air at virtually any shaft speed. That's just because there is another blade (primary + don't forget the smaller secondary) getting a "grab" on what is coming into the inducer. An example is that the 56T 6 blade can push 53lb/min @ 2.5PR @ 130000rpm, while the 56T 7 blade can do 53lb/min @ 2.5PR @ 111000rpm. (rider: that is only one point on the map)

But what goes with that is extra turbine grunt required at any given shaft speed to push that extra air mass. It's a bit like throwing a few extra bricks into a wheelbarrow. Alright to do, but you need the grunt to shift it efficiently. So the turbine must have enough "headroom" to handle the load and make it all work together.

When you upsize the turbine A/R you effectively introduce a reduction in gas velocity and inlet pressure through the snail at lower engine speeds and loads. This directly impacts on your transient response and lag.

If you were to get the spec suggested, you may well find that the bigger flowing compressor will need extra drive, but not get it until higher rpm. I'd still say that the internally gated turbine exactly as used by Mafia is a pretty good unit, and would mate pretty well with a 7 bladed comp to possibly give a more punchy mid rpm torque. It may however be a bit more abrupt in its sign-in delivery.

[Cubes]

I don't remember the exact specs of Mafia's 7blade GT30 but I believe it ran the cropped 56mm turbine wheel + a machined up RB25 turbine housing. Both of which would most definitely improve its lively feel at the lower rev's compared to the 60mm + .63 hotside.

Until these two variables are removed only then would we truly see the 7blade vs 6blade comparison.

I still feel in the dark a little as to the exact specs of Mafia's 7blade turbo.

On garretts website the only 76mm comp wheel I was able to find was on the GT2835's; it uses a 48trim comp wheel that is paired with a 53mm turbine wheel.

Under the GT30 listing garrett only had the 71mm 56t comp wheels both with the full 60mm turbine wheel and 56mm turbine wheel.

So what exactly did Mafia have?

A hybrid Gt30 56mm turbine with a GT2835 48trim 76mm compressor or was it simply the Gt2835 76mm 48t, 53mm turbine?

Also.. I don't believe the split pulse turbine housings are a special 'for' GCG as they are available through ATP in the US. So I'd say GCG are simply getting the same T3 .7 split pulse turbine housing that the others are also getting.

As can be seen here ->> http://www.atpturbo.com/Merchant2/merchant...tegory_Code=GRT

[Cubes]

I found the post where I asked Mafia for the size difference between the rb housing and garrett .63.

http://www.skylinesaustralia.com/forums/in...7572&st=20#

Interesting.........

How did the RB housing look size wise compared to the garrett .63 housing?

Maybe the combination of the slightly smaller rb housing + cropped turbine wheel made it just that bit nicer to live with every day.

mafia..

rbhousing looked quite small.

I think that was a limiting factor to the 7 blade config I had.

Also, I had the cropped 54mm turbine. If someone was going to go for a 60mm turbine in the 7 blade family, I'd shove it in a .63 garrett housing. I reckon it would go HEAPS better. Oh, and I highly doubt my 2.5inch pipe off the back of the turbo helped.

Now if Mafia had the 54mm turbine wheel that would make the turbo a GT2835 as they run with a 53.8mm turbine wheel which is damn close to 54mm.

The GT30 cropped turbine wheel is 56.5mm which is almost 3mm larger and easy to distinguish between if one was to measure.

SO.... That would explain why the '7 blade' felt so much more lively in the lower rev's.

[discopotato03]

Cubes the story with designations works like this .

HKS GT2835 . The "GT28" means GT28 turbine housing , forget for a sec the cropped "GT30" turbine .

GT35 in Garrett and HKS speak means GT35 compressor family and they are all ~ 71.1mm OD .

Garrett compressors :

GT30 = 60.1mm

GT35 = 71.1mm

GT37 = 76.2mm

GT40 = 82 or 88mm

The thing to remember with those 7/14 blade T04S compressors is the physical size of their native compressor housing . Because they have more blades and a less aggressive angle of attack on these blades they are a lower speed wheel (in comparison to the same sized GT37 series wheels which didn't exist when they were new) . T series compressors were designed to work with T series turbines though as we know they were paired with GT30 turbines in some early spec "GT30R's" . Sorry Mafia this is way OT but I'll finish what I started .

Geoff tells me that the twin scroll system can have distinct effects on a GT BB turbos characteristics , remember how I prefer turbos that have turbine size in the ball park with compressor size ? An example of this would be a real GT3071R or a hybrid GT3576R . Geoff finds that turbos speced this way often feel lazy in single scroll form and very responsive in twin scroll form . I tend to think its a sad fact of life that single scroll turbine housings are very sensitive to A/R ratio because they feed the sum total of cylinder exhaust shots into one common passage and you get a constant flow effect at the housings turbine nozzle (for a given engine speed and load) . Divided housings don't have this because of the divider they get pressure rise and fall across the nozzles . Geoffs way of describing this is high manifold pressure when its required and low when low is required . So its probably a given that turbos like GT3076R's and GT3582R's work reasonably well with their single scroll GT30/35 turbine housings , the but is that GT truck bush/plate bearing turbos are almost always twin scroll and have a fairly large turbine for similar compressors ie the GT3571 and GT3576 . Actually I pulled down the compressor side of a GT3576 yesterday and it has the same compressor as a GT3076R with the diesel spec HP 84T GT35 turbine . Its turbine housing is split T4 flange 1.17 A/R and also twin divided integral wastegate as well . One wonders how this would work on a hybrid GT3576R ball bearing cartridge , the HKS manifold can mount this housing and the wastegates in the bag . I'd prefer the 1.05 A/R housing but we'll see what turns up .

On topic there is someone at the Bluebird site manufacturing Torsen style diff centres for Nissan H190's and may be willing to do R200's if the market was there . I think the price was a little under 1G and those using them seem very happy . One persons view was "works like an open centre when you want it to and not when you don't" . It may be possible to have your cake and eat it in a road car with serious poke .

Cheers A .

[Cubes]

Howdy ho Disco.

Ahh shiet.. Sorry my bad; not sure why I was referring to it as a GT2835 when I really should have been quoting GT2876.

My bad sorry for the confusion.

So in saying that.. I really do think Mafia had what Garrett call their GT2876r CHRA 446179-18.

The specs of that being:

Comp Side - 76mm 48t .7 comp cover

Turbine Side - 53.8mm 76t

http://www.turbobygarrett.com/turbobygarre...6R_705330_2.htm

So no wonder it felt more willing at low rpm than the Gt3076r.

[The Mafia]

nah it was definately a GT30. it was a 700177 - 5011

52Trim Comp, 90 trim "Cropped" Turbine

[The Mafia]

HI everyone, here's a bit of an update.

Put in the Nismo Fuel pump, and the AFR's went from 12.8:1 to 10.9:1 in some areas. The old pump must have been really pushing the limits.

Oh, and the Nismo is such a DAM GOOD setup Factory like items, and factory fitting. Pictures:

[The Mafia]

oh, and I've re-tuned the car to 11.8:1 AFR's and there is not as much power as when running them at 12.8:1. I'm going to try and aim for 12.5:1, and maybe a hit on 13:1 to see how it responds.

I have a feeling that the leaner mixture again might mean I need to increase the water input. I am currently using a 225ml min nozzle and ramming 140psi up its ass once the car hits 15psi.

The Start spray is at 6psi (1% pressure) and 15psi (100% pressure)

I think 13:1 is very doable, but carefully.

One other thing - I'm having heaps of trouble keeping the boost stable. Car will hit 12psi, and then really really slowly make its wat to 18psi. I have a gizzmo controller. I've tighted the actuator arm a bit but its not completely fixed. I'll try and get a higher PSI actuator on there and see what happens.

Maybe I need to pull the turbo off and open up the wastegate hole a bit.

[Cubes]

You mean you finally got the pump from nengun? wow, that was damn quick.

---

Chants... <MOOOOORE BOOST MOOOORE BOOST>

With regards to boost creep. You need to loosen the actuator right off so that there's .5-1mm max preload.

For every mm increase in preload you place on the wastegate you decrease its ability to open as far; which will definitely result in boost creep.

Without a boost controller on my actuator it ramps up quite smoothly; ~12psi by 3000rpmish then by 4000rpm its holding 14psi.

With a cheapo ball/spring boost controller only just nipped up it shifts 14psi peak boost down to a shade under 3000rpm.

I think its just the nature of the garrett actuators to ramp up slowly; I've seen another do it but with a Gt35r. Nice rounded boost knee on the dyno sheet; with the ebc turned on it its a nice sharp knee.

I'm quite surprised yours is only creeping to 18psi in the higher rev's being a .6 and all.

Push 18+ pounds in to it from the word go and you won't notice it creeping.

MTQ (who are all over AUS) enlarge the wastegate for around $250 which isn't too bad. Mine 'appears' to be ok at the moment but time will tell once its tuned.

[The Mafia]

I will definately be talking to these MTQ guys.

Anyone had any experience with them?

[Cubes]

MTQ = the biggest turbo mob in AUS.

http://www.mtqes.com.au/locations.php

Most of the turbo workshops source their turbo's and parts from MTQ. ATS etc.. Unsure if GCG do.

My dealings with them have been great; they threw in gaskets and charged me considerably less when the time came to pay for bits on multiple occasions.

[Dale FZ1]

I've re-tuned the car to 11.8:1 AFR's and there is not as much power as when running them at 12.8:1. I'm going to try and aim for 12.5:1, and maybe a hit on 13:1 to see how it responds.

I think 13:1 is very doable, but carefully.

Agreed.

Unless you target AFR and ignition strategies different from a conventional (non-water/meth injected) tune you definitely won't see the full advantage of your system.

With a correctly sized nozzle and rising rate delivery you should be able to achieve higher power with lower specific fuel consumption and retain VERY effective knock control.

Keep at it and let us know how it progresses.

[discopotato03]

I don't want to sound negative but I think you'll find that the issue is rising turbine inlet pressure and its doing its best to overwhelm the wastegate valve and force it open . What happens is turbine inlet pressure rises out of proportion to boost pressure and all you have is the actuators spring load minus boost pressure to keep it shut .

I've seen instances where enlarging the gates port and valve resulted in more area for exhaust manifold pressure to work on so it didnt achieve the desired outcome . Enlarging the gates area only really works if it formed a restriction .

One idea I was looking into was using the 0.68 A/R HKS GT3037 Pro S turbine housing on a 52T GT3076R because its slightly larger (.68 vs .63) , has a better volute and nozzle shape , more direct wastegate path and a larger valve . The trouble is none of that is cheap and the .68 housing fell through .

The word from FullRace Geoff is that the GT3071R in hybrid twin scroll form can get very close to 500 Hp with awesome response and low turbine inlet pressure so unless anything better materialises thats way to go for me . In fact 500's more than I really need so as long as its a responsive 350 + and free reving - all good .

Cheers A

[Cubes]

Disco;

In mafia's case I believe the problem is with boost creep; unable to keep a cap on boost as rev's increase.

The HKS turbine housings are quite the opposite; they run a considerably larger flap/hole than the garrett's and as a result tend to boost drop as turbine pressure forces the wastegate open.

Grepin battled with this issue on his HKSGT2835ProS .82 IW for years, at one point breaking the actuators arm its self.

So its definitely a fine balancing act between going too big and leaving it too small.

Have you had a play with Engine Analyzer Pro? It has the option to play with twin scroll turbines etc and there is a definitely increase in mid range spool BUT from 'memory' top end didn't change.

500hp is around 300rwkw; I've never seen a GT3071r push 300rwkw on pump; they always seem to top out a little over mid 200's.

Gt3076's push 300-320rwkw but they do it with lots of boost (22-24psi).

There's ~5lbs worth of air difference between the 76 and 71mm compressors; but not only the 5lbs difference but how quickly the 71 comp wheel drops its efficiency off at the higher boost levels on its choke line of which will definitely come in to play when pushing up around 300rwkw where high exh. manifold pressures exist.

Regardless I still believe the 71mm comp wheel is only good for a little over 250rwkw (depending on the dyno) 76mm good for a little over 300rwkw and the 82mm (60mm turbine) good for the same as the 76 on pump but good for a little over mid 300's on good fuel. GT35r good for 400rwkw.

[dangerman4]

not sure if it helps the discussion but with changing my chinese stainless low mount to a highmount Extreme turbo manifold, running a proper merge colector, i not only picked up around 20 kws at the wheels, but i also noticed a lack of knock compared to the previous manifold.

this is running a GT3582R-IW with a .82 rear.

no boost creep or drop to complain about.

[bhappy]

A 3071r is easily capable of 300rwkw. I have one on a s15 sr20det stock bottom end and at 15.5psi its making 280rwkw on CRD's dyno. Just ask jim if you don't believe me, he tuned the car =)

Regards,

Albert

[The Mafia]

A 3071r is easily capable of 300rwkw. I have one on a s15 sr20det stock bottom end and at 15.5psi its making 280rwkw on CRD's dyno. Just ask jim if you don't believe me, he tuned the car =)

Regards,

Albert

That must have been the happiest dyno in the world.

There is no f**king way in the world that a GT3071 would make 280rwkw on a S15 at 15psi.

Mine is making 300rwkw on 18psi, and the turbo is much larger. (bigger compressor and turbine, etc)

Looking at the flow maps will prove this....