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The Mafia

My 300rwkw Adventures

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Mafia... So why 18psi? Didn't make any more power with anything more?

Steve an old member of these forums had a HKS3037S on his stock internal rb25det. That ran a shade over 20psi with a set of baby cams and made 320 something rwkw. Given it was running the hks .8 turbine housing.

Then there's the other bloke on here I forget his alias; hks3037s also recently pushed 323rwkw on 20 something psi.

Sooo... Was it the GT2876r 48t with the machined up rb housing you had previously?

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Sorry guys, I've missed a few questions

Mafia, what is your view on the 0.63 A/R housing? Any reason you would go to the smaller size when there seems to be a preference amongst other owners for the 0.82 or 0.87 offered by Garrett/HKS in this turbocharger range? Is it possible that the smaller 0.63 is holding the engine back from its maximum potential at higher rpm? (and this is not a slag of "you haven't got the best out of your car") Just looking for some discussion on the specs you've settled on and how it equates to the driving experience.

The 0.63AR housing didn't really have much of a difference in lag to the .82ar housing which surprised. The .63 just got onto boost quicker, the .82 started at the same time, but took a little longer. Probably a bit more engine friendly actually. But for the RB25 - the 0.63 i definately a decent size. 82 is just a little too big if you only want to make 300rwkw.

I really don't think this housing is restricting the car yet. I mean, its still on a Standard manifold. Which is surprising me. I think I am getting close to its peak, but I don't think I am there yet.

Mafia... So why 18psi? Didn't make any more power with anything more?

Steve an old member of these forums had a HKS3037S on his stock internal rb25det. That ran a shade over 20psi with a set of baby cams and made 320 something rwkw. Given it was running the hks .8 turbine housing.

Then there's the other bloke on here I forget his alias; hks3037s also recently pushed 323rwkw on 20 something psi.

Sooo... Was it the GT2876r 48t with the machined up rb housing you had previously?

Not really sure cubes. I had an idea in my head that 18psi would be good enough, and it is. I've gone up to 22psi, and the car made heaps more power, but at what cost? 300rwkw is more than enough for now. I know that getting over 20psi on stock cast pistons might get a little hot for them, even with the water meth, its better to be safe than sorry.

But yeah, I just thought 18psi sounded like a good number. haha weird way of setting the boost eh? 18psi made 300rwkw, and I was only expecting 280rwkw at the most. I guess I Was just lucky? I ran 22psi on the street and it went spastic. I think its nearly peak efficiency there, but I don't need to go that far due to -

1. Engine Life

2. Internal WG

3. 0.63 housing and standard manifold maxing out

4. 300rwkw - its enough!

Edited by The Mafia

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Its interesting to view your result happening as mine on about 16.7 psi is only running 221 rwkws, Dyno figures i tell ya there a curse, mind you with a slightly larger hks 0.68 housing with the same wheels and trim as your turbo well hks 3037 ProS anyway, Does water/meth increase power and torque that substantially? Must have a look at this sytem :S Main diffence is that mine is a Series 1 33 Interesting though ill keep an eye on this thread.

Good luck with that actuator too

Cheers

A

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on a stock engine being around 12 and above AFR for most of the run seems a little risky.

especially running a walbro.

new fuel pump is on the cards if you want your ringlands to live...

As above!

The Walbro is a danger from my testings. 270rwkw/17psi and it was all over as it went nasty lean.

That was corectly wired aswell.

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so do you think I should get a Bosche 040 or somthing? What are they rated at?

Why is everyone so scared of the walboro? I thought they were ok?

Also, everyone take note - This is a 56trim 3037 from Garrett. The HKS is a 52 trim, and most likely have a slightly different setup. The larger trim gives the top end at the sacrifice of bottom end.

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Also, everyone take note - This is a 56trim 3037 from Garrett. The HKS is a 52 trim, and most likely have a slightly different setup. The larger trim gives the top end at the sacrifice of bottom end.

Not the case buddy. :D

The HKS3037 is a 52trim, the HKS3037S is a 56trim.

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People are scared cause they are.

Well i am because ive seen more than just mine not live upto the task its given.

I ended up just using it as a lift pump to the surge tank and an external 044/040 (whatever the part number is) and used that as the main feed pump and i went from 14AFR's instantly into the 10's and i changed a fuel pump only.

That was enough to make me sweat a bit.

Yours might be ok, not saying it isnt. But i'd be very mindful of it more than anything

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With stock internals?

I was under the impression 300kw was practically suicide with stock internals...

nah...mine has run 100% for over a year with over 300rwkw on a stock bottom end. Like Mafia said, I think it is more down to the tune than a specific power point where the rb25 lets go. Mine is tuned very conservatively with AFR's and ignition timing to protect the stock parts and still got a result of over 300rwkw with a lot more available if I want to lean on the internals a bit more...and only on 15psi.

As others have mentioned to me on cruises, it runs totally clean, no smoke on any throttle application at all, and knock is almost non existant with it not going over teens even when pushed hard beyond redline...all down to the tune (thanks Lumpy :D)

my 2 cents

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Is there a compressor map laying around for this 7blade 76mm comp wheel?

It wasn't the GT2876 you had?

Maybe the .63 is wasting a little of the additional compressor flow of the 6blade 76mm 56t comp wheel where as the previous setup was a little better matched? Its always a compromise. :D

Well after dredging through a fair bit amount of old notes, I found that his first unit had a CHRA # 700177-5011. That made it a 52T T04S compressor, with the cropped 90T 56.5mm turbine.

Mafia's dissatisfaction with that unit came (I believe) from a mismatch of compressor:turbine, after the RB spec turbine housing was fitted to it. And there was no real joy with the VG spec housing either.

So, no. Not a 2876 based high flow.

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Mafia... So why 18psi? Didn't make any more power with anything more?

Steve an old member of these forums had a HKS3037S on his stock internal rb25det. That ran a shade over 20psi with a set of baby cams and made 320 something rwkw. Given it was running the hks .8 turbine housing.

Then there's the other bloke on here I forget his alias; hks3037s also recently pushed 323rwkw on 20 something psi.

Remember that it's always very important to compare apples with apples.

Changed cams = altered breathing ability = altered volumetric efficiency.

Upsized tiurbine A/R = altered breathing ability (less turbine inlet pressure @ given airflow) = altered volumetric efficiency

Either change is going to allow the torque curve to carry through to higher rpm (developing more power) than one running stock internals or with the same A/R.

I'd done a fair bit of mathmatical reviews of matching this particular 3076 to RB25 over the past 12 months, and it was interesting to see that Mafia had come to a similar conclusion that just under 20psi would get close to the best from that particular compressor + stock engine combo. Working on Sydneykid's rule of thumb of 80hp losses, the engine is likely to have about 480 crank hp, with the turbo capable of about 500hp. So maybe (and only just maybe) there is another 10-15rwkW hiding there if he wanted to bump boost up 1-2psi. I will confess that I didn't believe it would get to 300 however.

A thinking man would be mindful of the integrity of stock conrods though, with extended loading increasing the chances of a bent rod at some stage I would suspect.

BTW Mafia, is this thing a dyno queen, or a Drag Queen??

Edited by Dale FZ1

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Are the stock rods really that weak though?

I can't say i've heard of an rb25 rod going banana.

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May i ask what ignition advance you are running up above 5000rpm under full load?

im curious to know how much help the WMI is at curing the evil ping.

im only able to run around 18 dergrees to make it to 300 kws with a gt3582-iw with a .82 ar.

but thats at 22psi running the auto with a high stall.

youve got me thinking that i may be able to run the WMI set up on my car to increse the ignition advance up into the low

to mid 20's and with a bit of boost should see me up around the 350kw region.

surely that would come close to getting me a 10 second pass.

4 Door shopping trolley FTW....

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May i ask what ignition advance you are running up above 5000rpm under full load?

im curious to know how much help the WMI is at curing the evil ping.

im only able to run around 18 dergrees to make it to 300 kws with a gt3582-iw with a .82 ar.

but thats at 22psi running the auto with a high stall.

youve got me thinking that i may be able to run the WMI set up on my car to increse the ignition advance up into the low

to mid 20's and with a bit of boost should see me up around the 350kw region.

surely that would come close to getting me a 10 second pass.

4 Door shopping trolley FTW....

I'm running 20 degrees, but thats not a real figure because who knows where the cas is compared to yours.

I also have a smaller turbine housing.

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Are the stock rods really that weak though?

I can't say i've heard of an rb25 rod going banana.

Very worthwhile question to pose, and I don't have a definitive answer.

Still, the engine is now running at effectively double its rated output from the factory. It's a testimony to the integrity of the basic engineering, but refer back to my comment and the question as to where the car is used.

Extended power loading such as racetrack environment would highlight any weakness quickly. Perhaps some of the guys who are doing lots of track work or racing their RB25s can comment?

It's more about thinking where the weak points are, given a tune that won't break pistons and revs that won't stretch rod bolts or break the rods.

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I'm running 20 degrees, but thats not a real figure because who knows where the cas is compared to yours.

I also have a smaller turbine housing.

standard idle advance is 15 degrees i think.

it will give me a ruff idea of if its a benificial mod, for the outlay and up keep.

but by what you have explained it seems very cost effective way of cooling the intake charge.

what WMI setup are you running?

cheers

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standard idle advance is 15 degrees i think.

it will give me a ruff idea of if its a benificial mod, for the outlay and up keep.

but by what you have explained it seems very cost effective way of cooling the intake charge.

what WMI setup are you running?

cheers

Darren, I would have to say that a properly engineered water (or water-meth) system is the key to hitting the results Mafia has got. FWIW, he did nominate the system type, but that's only the part of it. Sorting out the volume and rate of delivery relative to the mass-air intake charge, and the fuel mass is critical. Given the amount of time he's spent playing around with that setup. he's obviously got it optimised for the engine/turbo combination.

There is some proper engineering literature around on these systems, but the essence of it is that (when properly matched) WI can improve the knock resistance of a given fuel by up to 10 octane (MON). And yes, in my view it is ALL about cooling the combustion chamber and controlling the rate of the combustion event. He's basically got the same end result as those guys who play around with Elf Turbomax rocket fuels and other similar brews, but by a different means.

Rather than focusing on Mafia's actual max timing, it might be interesting to hear how many degrees he wound into the map, and what he observed on the dyno? That might give some idea of just what the water/meth did to his tune?

Edited by Dale FZ1

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well said.

finding out what ignition he can run without the WI and then with the WI would be priceless.

obviously every engines timing will change a degree either way but in general its the same rb doing the same revs with around the same air flow, so it should be comparable.

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Almost, but given you have the GT35 turbine I would draw a distinction between the two. The difference in volumetric efficiency of the engine with decreased pressure in the exhaust manifold (pre-turbine) will give you even better scavenging, and to some extent the ability to run more max timing than (say) Mafia's GT30. Not much, but enough to make a difference. And 2 degrees could easily equal 15-20 rwkW gain/loss.

That aside, I think he's obliged to let a couple of secrets out here on just what went on with his timing.

Edited by Dale FZ1

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I'ma noob about Water Methanol Injection systems or Boost Coolers. I understand the basic theory - are the kits bolt on? I was in the middle of making my own race fuel which would appear to be similar.

btw Dale. best info I have read for ages...always good to read shit which takes me 3 google seraches to understand :(

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