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The Mafia

My 300rwkw Adventures

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I'd really like to see the two manifold pressures compared to see if the EMP is significantly higher than IMP .

As far as the "six" blade GT vs "seven" blade T04S compressor families go I'll stand with the people who've spent god knows how long testing these things on flow rigs and know how they perform .

As I'm sure I've said in the past cranking 160 odd Hp/litre out of a production engine designed to make 100/L means there will be some compromises BUT you are not exactly using cutting edge technology to do it either .

Reviewing the compressor maps for the current 56T 6 blade + 0.60A/R vs his previous 52T 7 blade + 0.70A/R, it was clear that both have the same top end flow capacity, so could theoretically support 295+ rwkW. I am in no doubt that turbine efficiency and flow capacity is the basis for the increase of 45-50kW over his old unit, so releasing that log-jam of pressure in the exhaust manifold by using the GT30 turbine just freed the compressor to do its job efficiently. Having the time/inclination to fit a gauge would help, but it is obviously working a lot better than before. Being a production turbo, I'd agree that none of it is cutting edge - but it is affordable.

Where there is some area for discussion is in the actual compressor spec vs the intended application, given that either way seems to be capable of producing the top end power numbers. In short, it's about the torque delivery. 6 or 7 blade? Interesting analogy from a propeller engineer helped clear the matter for me. More blades = more low rpm throughput, but less efficient at higher shaft rpm. To me, that spells easier/earlier boost rise but slightly hotter boost charge at higher engine rpm. Maybe this response = too brutal delivery? Mafia has expressed a view, but until someone tries the T04S/60mm GT30IW combo we won't know for sure. I believe that there is a place for it depending on the car's intended use. Old tech does not always = wrong spec. Grandad's axe with a keen edge will still remove your foot very effectively. :(

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Very nice Mafia, Hows getting traction like, when rolling it on? I was leaning on the .63 to be more reponsive and better suited to a street RB25 than the .82 option(especially if you like to use the midrange more). although the .82 option would probably help with traction issues.

This is exactly the combo me and dale have been discussing recently. As I will be setting mine up quite similar. Its great to see some results of this setup finally, Thank you :(./

Note * There is the GT3076R in 56T with the .63 your using, and there is the 7 blade GT3076R-WG which is available in the .64 in 52T. more similar to the HKS 3037 ProS in trim size, but the .64 a/r that is available from garret is same a/r of the standard turbo. is this GT3076R-WG with .64 in 52T the other one you were referring to dale?

All this has just made the Headache of my turbo choice even worse :S.

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love your last comment in that post Dale.

As for the igntion timing - I was able to increase full load timing by 12 degrees. THis was past the effective value, and I had to actually take out almost 4 degrees to get the best power gain. There is such thing as lighting the fuel up way too early.

Traction isn't a problem, I just need to get better tyres I think. Third gear is fine, pulls really hard.

Edited by The Mafia

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Damn impressive 12degree's and past mbt.

I think I'll be looking in to water meth after I find where mine maxes out on pump.

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As for the igntion timing - I was able to increase full load timing by 12 degrees. THis was past the effective value, and I had to actually take out almost 4 degrees to get the best power gain. There is such thing as lighting the fuel up way too early.

Well take a bow, Mafia. While the turbocharger selection is obviously superior to your old one, not everyone is after 300rwkW. My maths said this particular GT3076 should support around 275-280 rwkW at slightly higher boost, but 1. My efficiency assumptions were out, and 2. Didn't account for water/meth

What impresses me is the steps taken to get the absolute best from your combination.

Conventional tuning methods would have hampered your outcome probably due to the onset of detonation of some type. Even dangerman4 has had problems combating early knock onset with his bigger turbine GT35. Your control is so efficient the timing was taken past the point of maximum torque WITHOUT knock rearing its head. I've read the actual research papers from the 1940s, and those engineers achieved the same results. Yours is just a modern testimonial to the effectiveness of the system.

I recall you had some fairly significant knock control issues with the previous spec GT30 based high flow, that led to you fitting this water/meth kit. Obviously you developed a tune that sorted that one and eventually got you around 250rwkW. What sort of power gain did you observe through tuning and water/meth at that time? (basically I wouldn't ask you to wind this setup backwards by removing the water/meth).

I will pass a further comment on fuel mapping with your system too. AFR tuning conventions go out the window once you've got a properly engineered WI system in place. Yes, your fuel system is a problem that needs addressing (side issue) but basically you should be aiming to progressively move your full load AFR to 13:1 - similar to tuning a naturally aspirated engine. You are no longer required to pump excess fuel through the chambers to try and cool things down.

Edited by Dale FZ1

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There is the GT3076R in 56T with the .63 your using, and there is the 7 blade GT3076R-WG which is available in the .64 in 52T. more similar to the HKS 3037 ProS in trim size, but the .64 a/r that is available from garret is same a/r of the standard turbo. is this GT3076R-WG with .64 in 52T the other one you were referring to dale?

Here's the range of Garrett CHRA that use a 76mm compressor : 60mm turbine combinations

6 blade

700177-5007; 76mm 56T comp + 60mm 84T turbine

7 blade

700177-5010; 76mm 48T comp + 60mm 84T turbine

700177-5018; 76mm 52T comp + 60mm 84T turbine

700177-5012; 76mm 56T comp + 60mm 84T turbine

700177-5013; 76mm 60T comp + 60mm 84T turbine

Depending on what you wanted, you can get a few different options on housing size/A/R for both sides + internal or external gated turbines. Both internal or external gated housings have A/R roughly of 0.63, 0.82, 1.06 (give or take) but I'd take a punt to say they are very different internally.

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Where there is some area for discussion is in the actual compressor spec vs the intended application, given that either way seems to be capable of producing the top end power numbers. In short, it's about the torque delivery. 6 or 7 blade? Interesting analogy from a propeller engineer helped clear the matter for me. More blades = more low rpm throughput, but less efficient at higher shaft rpm. To me, that spells easier/earlier boost rise but slightly hotter boost charge at higher engine rpm. Maybe this response = too brutal delivery? Mafia has expressed a view, but until someone tries the T04S/60mm GT30IW combo we won't know for sure. I believe that there is a place for it depending on the car's intended use. Old tech does not always = wrong spec. Grandad's axe with a keen edge will still remove your foot very effectively. :teehee:

I think you've hit the nail on the head with that analysis.

My T300s (T04s 52t (i think) t3 .63 rear) will make 1.4 bar by 3200 in the higher gears on the street, so response wise it really does make the current generation turbos look poor. Remember this is a plain bearing turbo too.

Where it loses to the newer turbos is up top at higher boost where the timing has to come out of it to prevent detonation. If anyone can be stuffed looking at the rb25 dyno thread i have graphed 7,14, 18 and 20psi runs from memory. 14 made peak power of 274rwkw, 20 only made 288. you can really see the thing is running out of puff up top. This is on pump 98 too btw.

While it's probably not a true comparison to mafia's setup as i have cams, manifold and ex gate, thats probably off set by the use of water/meth somewhat.

I honestly think his turbo has more to give, even in .63 form, particularly as he has such effective detonation control so can add more boost (if the engine can take it).

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well to be honest, after adding the water methanol in on the original turbo (220rwkw) and then going to 250rwkw, the car went spastic in power. No gear was safe, boost came on hard, but it ran out of puff due to the ex housing being a ground out RB25 housing, and the 2.5inch outlet on the first 300mm of the dump pipe.

After putting the GT3037 on, its a .63 housing now, and 3inch straight off the back of the turbo, holy shit, no more back pressure, and obviously much more scavenging as Dale has said in a previous post. The detonation was gone, allowing me to ramp it up again. Then I hit the detonation wall at about 270rwkw I'd guess, then the WMI kit allowed me to blow 300rwkw, 700nm of torque, and make timing NOT the limiting factor.

The limiting Factor now is the air delivery and exit. If you increase one (boost) you increase the other (exit) and I think at 20psi+ the 0.63 rear might just start to show its limits, as you can see the power is dropping off slightly at the end of the plot.

But shit, 300rwkw? Garrett engineers said the 0.63 rear would only do 400hp at the ENGINE which is about 250rwkw, Mnaybe they are just being careful? The internal gate is a little tricky though. The Gizzmo has a fair whack of trouble hanging onto it.

I'd really love to see what this Log style manifold can do too. maybe its the thing thats nearing its peak, not the rear housing?

But someone correct me - am I getting more flow from these devices (manifold and housing) because the WMI is cooling the combustion down that much?

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The ones that spoke to me said that the compressor/housing combination (map confirms it) maxes ~ 53-54 lbs air at around 2.75 PR or 25 pounds of boost (PSIG) . I'm conservative and work on 10Hp per pound of air (mass not boost) but a lot of people say 11 . So I guess you could say that turbocharger compressor wise is capable of supporting 530-540 Hp conservatively or 580-590 not so conservatively . Down round 60% adiabatic efficiency increasing the rotating assemply revs doesn't pump significantly any more air (mass not boost) .

That GT30 .63 A/R turbine housing will to a degree give the turbo the lowest boost threshold (of the 3 available) but as the boost climbs so does the turbine inlet or backpressure . It will run out of gas flow capacity on the exhaust side before the compressor side .

The water/methanol injection is very obviously working for you to supress detonation but what it can't do is control exhaust manifold pressure (EMP) . BTW By IMP I meant inlet manifold pressure . You've proved that you can supress detonation to the degree that advancing it past the point of BMT (best mean torque) no longer makes anything worthwhile .

As I said in the past I would have tried to use the 52 compressor trim version of that turbo because it may have enabled you to get away with the next size up or .82 A/R turbine housing . Its still capable of moving 50 lbs air by mass but takes a little less turbine energy to excite it .

Out of time but if you really want to uncork the hot side you now have to address the turbine inlet pressure and reversion issue otherwise volumetric efficiency and reversion will become the impass even if detonation is not .

Later tonigh or tomorrow , A .

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You're also getting a fair wack more power as you've increased your compression ratio, whilst keeping things cool.

Water won't compress. Just remember that... :teehee:

Depending on what your bottom end is like, you might be putting ALOT of stress on your rods.

Edit: Also, if you've tuned ignition timing to maximum torque, go and take around 5 degrees out, across the lot. You WILL not pass emmisions etc like that. You'll have extremely high NOx counts.

Torque VS Ign Timing is a fair bit like a parabola. Right up the top 5 degrees either side is only a very minimal change in torque, but NOx VS Timing it's a HUGE change.

Edited by MBS206

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you are correct but only to some extent - Water may not compress, but there is bugger all in the combustion chamber the make a difference to the compression ratio.

I am using a 225ml\min Nozzle, so every second there is 3.75ml of water going in. Then divide that by 6, = 0.625ml second going in to each cylinder.

Thats hardly enough water to cause any problems or cause any Comp ratio increase.

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My T300s (T04s 52t (i think) t3 .63 rear) will make 1.4 bar by 3200 in the higher gears on the street, so response wise it really does make the current generation turbos look poor. Remember this is a plain bearing turbo too.

Where it loses to the newer turbos is up top at higher boost where the timing has to come out of it to prevent detonation. If anyone can be stuffed looking at the rb25 dyno thread i have graphed 7,14, 18 and 20psi runs from memory. 14 made peak power of 274rwkw, 20 only made 288. you can really see the thing is running out of puff up top. This is on pump 98 too btw.

While it's probably not a true comparison to mafia's setup as i have cams, manifold and ex gate, thats probably off set by the use of water/meth somewhat.

I honestly think his turbo has more to give, even in .63 form, particularly as he has such effective detonation control so can add more boost (if the engine can take it).

I looked long and hard at your results, and over time they helped me to understand what this 6 bladed internally gated 3076 would do on a RB25. Running a free floating (external gate) type housing is probably going to give higher overall turbine efficiency, and the better flow of an external gate should eliminate the slight boost creep Mafia is showing. I'd say it might run away slightly if he tried for 20psi.

Power-wise, my maths say he is pushing around 54lb/min of air @ 2.40 PR, allowing for pressure drops through the inlet tract. That puts it at the extreme right edge of the compressor flow map. To get more power requires more mass air flow in an efficient range, and running extra boost would (if my calculations are right) push the plotted flow requirements upwards and further to the right. He would get a little more, but consistent with the law of diminishing returns as the inlet air becomes progressively hotter and less oxygen-rich. Without changing engine internals or manifolding, I'd say maybe (at best) another 10rwkW @ 20psi will pull it up.

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You're also getting a fair wack more power as you've increased your compression ratio, whilst keeping things cool.

Water won't compress. Just remember that... :whistling:

Depending on what your bottom end is like, you might be putting ALOT of stress on your rods.

Edit: Also, if you've tuned ignition timing to maximum torque, go and take around 5 degrees out, across the lot. You WILL not pass emmisions etc like that. You'll have extremely high NOx counts.

Torque VS Ign Timing is a fair bit like a parabola. Right up the top 5 degrees either side is only a very minimal change in torque, but NOx VS Timing it's a HUGE change.

Quite a valid point about the NOx emissions, but ATM the main point of the discussion is about full load timing. Don't want to get off-track, but I'd say emissions testing will be within a fairly tightly defined range away from full load.

Most importantly, a properly engineered (and tuned) water injection system will have the water introduced as an ultra fine mist that turns to vapour (gas) prior to and partly during the compression event. Steam is as compressible as any other gas. The key to tuning a water injection system is to understand what is happening (and needed), and progress slowly. Same as mapping fuel and ignition. The most commonly reported occurrence from running too much water is that the combustion event is overly inhibited, and power lost rather than rods bent.

It would be a different situation altogether if the nozzle stopped making a mist though. Like Mafia said, use the right gear to get the right results.

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you are correct but only to some extent - Water may not compress, but there is bugger all in the combustion chamber the make a difference to the compression ratio.

I am using a 225ml\min Nozzle, so every second there is 3.75ml of water going in. Then divide that by 6, = 0.625ml second going in to each cylinder.

Thats hardly enough water to cause any problems or cause any Comp ratio increase.

Oh, that is only a minor amount, as at 3000RPM only 0.025ml is entering each cylinder. I didn't think the amount of water would be so small.

Here's a question that just came into my head. What sort of fail safe do you have incase the water/meth runs out? Like activate an alarm, or alter a fuel map through an input?

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I cant believe it! A WI discussion on SAU!

I didn't think the amount of water would be so small

WI amounts are usually discussed as a % of the fuel amount. Iv seen anywhere from 10-40% water/fuel ratio ( I think 40% was used on the well known WWII bombers)

I've of late, have had some friends who have had some serious power outputs on water. An extend ported 13B, T04S 340rwkw's on 22psi and a bridge ported 13B w/ T45 and 430rwkw on 19psi. These setups are injected pre turbo, so there are no electric pumps to fail. Having the misted air move through the turbine itself means compression occurs with very little associated heat and effectively changes the volumetric efficiency of the turbine ... i hear.

Kits are made locally here in CBR, and have had not a single WI engine failure in close to a decade.

With more water, less fuel, i would think Mafia hasnt seen the end of this turbo combo :thumbsup:

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It's not only the rotor-heads who look at alternatives. :thumbsup:

Introducing the water pre-compressor is getting very tricky, and beyond my area of knowledge. There's some different laws of physics at play once you do that, and all indicators are that it works even more efficiently. There are also some tales (whether originating amongst old wives or not, I don't know) about that suggests the water will abrade the compressor over time.

Mafia will continue to reap the rewards for his efforts every time he drives the thing I would say; and hopefully for a long time.

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well, for some reason I liked the bottom end pull the 7 blade compressor. I doubt the 7 blades would have made too much of a difference up to, maybe 20rwkw less, but the power is there, and even 280rwkw isnot much different to 300rwkw.

The 6 blade is definately not a big of a deal compared to the 7blade everyone is going on about.

Nice thread dude, enjoying all the WMI info as well - starting to make me think :thumbsup:

Do you think the initial spool is completely to do with the compressor design, considering how much the restriction of the RB25 turbine housing has been referred to - maybe the "tight" nozzle of the RB25 turbine housing is a lot more of the reason for your much lower power figure, and also better response than the shift from 52trim 7 blade to 56trim 6 blade? Obviously the 6 blade is going to have greater pumping efficiency, but shouldn't it have a bit less inertia as well?

Just questions - not debating one way or the other :thumbsup:

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It's not only the rotor-heads who look at alternatives. :P

Introducing the water pre-compressor is getting very tricky, and beyond my area of knowledge. There's some different laws of physics at play once you do that, and all indicators are that it works even more efficiently. There are also some tales (whether originating amongst old wives or not, I don't know) about that suggests the water will abrade the compressor over time.

Mafia will continue to reap the rewards for his efforts every time he drives the thing I would say; and hopefully for a long time.

Course, but I find Skyline's are engineered in such a way, rarely do we have to ;) Often you'll find the buzzNuts, are FORCED to use alternatives to keep those things in high states of tune ;) Bloody Rota's

Correct, the term evades me ATM, if i get some time, might dig up old posts from AusRotary, US RX7, and Mustang forums.

Maybe not more "efficient", as you don't get the complete state change from mist to vapor occurring in the combustion chamber, but the added compressor flow and safety, of not needing a electric pump, off sets this. (Theres a huge amount of information out there, one must just look)

Not a wives tale, people have seen pitting of the compressor wheel... but on setups that consist of the fore mentioned, "Washed bottle and a garden sprayer nozzle"

The examples i gave above use proper stainless, adjustable flow rate, misters, that use boost pressure in one side, and a water feed in the other. The water hits a metal cone at speed and gets atomized by the surrounding boost pressure, 8µm is the desired water droplet size (80's F1 teams somehow managed to decrease the size of the droplet by surrounding it in a skin of race fuel)

Iv heard about many pre turbo setups run for 6 years with no wheel damage. People will have undoubtedly heard how the steaming effect almost nullifies seal / bore wear, and prevents carbon deposits, which themselves can glow red and cause detonation.

Long live WI!

Michael

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well, I just checked my fuel pump voltage and its getting 14.2 volts. So its maxing out. Never thought it would, so looks like I'll be purchasing a Boche 040 tomorrow. That should do the trick.

Then its back to the dyno....

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