Jump to content
  • Welcome to SAU Community

    Welcome to SAU Community, like most online communities you must register to view or post in our community, but don't worry this is a simple free process that requires minimal information for you to signup. Be apart of SAU Community by signing in or creating an account.

    • Start new topics and reply to others
    • Subscribe to topics and forums to get email updates
    • Get your own profile page, build reputation and make new friends
    • Send personal messages to other members.
    • See fewer ads!

    Consider joining our newsletter for the latest content updates

    Click here to register


The Mafia

My 300rwkw Adventures

Recommended Posts

Hey Mafia, 300rwkw sounds very nice!!

Ive got a Bosch 044 intank in my 95 S1.5 R33, yes they are noisy, they whine but only really noticeable when idling or your out of the car. . .

The 044 is intank and was reccomended to me and installed by Hyperdrive Motor Sport (WA), the difference between the 040/044 is in the pickup style and outlets + terminals.

basically the R33 tank does not have a flat bottom and the 040 has a mesh bottom inlet whereas the 044 has a thread so you can attach the standard sock and get the correct pickup height. which means you can use the whole tank as with an 040 you MAY get surge issues at a low tank lvl,

if you rubber mount it it should quieten it down a lot i reckon!!

good luck

Share this post


Link to post
Share on other sites
Course, but I find Skyline's are engineered in such a way, rarely do we have to :P 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)

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!

Piston engined hot-rodders usually go for cubic capacity for bulk power and/or jungle juice race fuels to make their engines produce the sorts of specific power outputs (kW/litre) that the rotor motors do on a regular basis. I'm not going to pooh-pooh them - they are great bits of gear but not necessarily my cup of tea. So yeah, they've got the tricks a bit more sorted.

I believe the two compression types are termed adiabatic and isothermal. The first conforms to the normal gas laws in which P1V1/T1 = P2V2/T2, where the second does not. Isothermal allows for compression without temperature rise, and is evidently where the efficiency comes from when spraying pre-compressor. I do not have a strong science background, so the understanding here is only of the layman's type.

I think there's room for different methods of actuation, pumping and metering of water. The key to making it work is correct metering, matched to the fuel mass being drawn into the combustion chambers. Anything else boils down to budget and length of penis arguments.

And yes, there are plenty of reports of WI equipped engines having zero carbon deposits when pulled down after many hard miles.

What Mafia has shown is that he has a system that allows for maximum efficiency of a given combination. He has been able to use a smaller turbine A/R that (with actual back-to-back comparison) gave a streetable spool-up, allowed the compressor to give pretty much maximum effort, and the turbine has not effectively choked the top end or been allowed to prevent optimal ignition timing from being used.

AND he can do it SAFELY using an AFR that should lead to detonation via conventional tuning but allow for reduced specific fuel consumption while doing it. Sounds like this setup offers pretty much all anyone would want, and there are lessons to be learned.

Long live WI? You bet.

Edited by Dale FZ1

Share this post


Link to post
Share on other sites

Very interesting read.

Just a few questions,

what size tyres do you run? What diff gears? Would like to know rpm rather than speed.

Your car is manual right?

Do you plan on taking it to the drag strip? It would be interesting to see what trap speed you end up with. I would estimate 123mph with a weight of 1450kg including driver.

Congrats on tuning it yourself as well. I do the same on my car and it is great to see other people doing the same.

Share this post


Link to post
Share on other sites

Aren't you worried about the water washing the oil off the bores and causing excess wear and tear? Especially pushing a stock bottom end to 300rwkw.

Share this post


Link to post
Share on other sites
Aren't you worried about the water washing the oil off the bores and causing excess wear and tear? Especially pushing a stock bottom end to 300rwkw.

Water doesn't wash oil off, running rich mixtures causes washdown

Share this post


Link to post
Share on other sites

Hey mafia, wondering if you could recommend any changes to this combo to suit an rb30, only hoping to make the same power, or a little less, but without the WI(its a friends car and he doesn't have the $$$)How much do you think the WI gained you in KW?

Share this post


Link to post
Share on other sites
I'd really like to see the two manifold pressures compared to see if the EMP is significantly higher than IMP .

If I told you how to make more torque and power potential everywhere without buying another turbo would you be interested ? If so what sort of budget would you have to achieve it ? If it ment possibly throwing away the water/alcohol system and having better fuel consumption would that be significant ?

Adrian

Definitely a good point re: measuring exhaust manifold pressure. That would answer most questions, and no doubt pose a few more of their own.

Sounds like you have something waiting out in left-field there. Keep the 3076 turbo, ditch the W-M Injection, run even leaner mixtures, and get even more efficient mass-air throughput? Sounds interesting. I hope it can be achieved through economic means? Wacky fuels? Fabricated manifolding? Exotic or aggressive engine internals? One of Dr Dowker's Energy Polarisers (remember those??) Time to stop teasing >_<

cheers

Edited by Dale FZ1

Share this post


Link to post
Share on other sites

All this and your not running with splitfires??? I didn't see them mentioned. Does the WMI cooling help to stop the spark from blowing out?

I would have thought splitfires would be a must.

Bl00dy good result though.

Share this post


Link to post
Share on other sites

If you've got more timing up your sleeve then I would be playing with exhaust cam timing to bring the turbo on even sooner and then try to get the timing back in the top end so you end up with the same power but even better response. Or you could just increase the compression - have found that this usually helps if you have an unreactive chamber - as you have.

Dont know about bending rods, as has been said - they are only short little f**kers. But I would definately be monitoring exhaust gas temps will leaning out the mixtures.

I'm attemping a WI install at the moment with an xede - semi closed loop ie feedback from a EGT sensor to determine final water injection amount.

Share this post


Link to post
Share on other sites

Rob, use maths to help your water nozzle sizing for max flow, then tune the system to get the optimal flow curve up to maximum.

Calculate the progressive fuel flow through the rpm range via injector duty cycle against injector flow. Your water:fuel ratio is done as a mass (not volume) calculation, similar to air:fuel. Use specific gravity of each to convert to volumes that your WI nozzle(s) be rated with.

Then it's a case of playing a bit to get the ramp rate to match the fuel. Not simple, but not exceedingly difficult either.

And WI is unlikely to affect your EGT to any significant extent - it's about controlling combustion chamber temps rather than the temperature of combustion.

Share this post


Link to post
Share on other sites

well, I pulled the fuel pump and its a genuine Walboro 255lph pump.

Any reason why it would be leaning right at the top? I maxxed the injectors and it made no difference.

I thoguth a 255lph pump would be heaps for 300rwkw?

Surely I don't need a Bosch 044?

Share this post


Link to post
Share on other sites

mafia there are a few good threads on the actual flow rates of walbro's when they are pushed on turbo cars.

the rating of 255L doesn't take into consideration fuel rail pressure plus whatever boost levels you are running. additionally they are rated with 13ish volts so if you are using the standard wiring your pump will be seeing 11 or so volts. you are most likely to be getting a fair bit less than 255L.

Share this post


Link to post
Share on other sites

About controlling combustion chamber temps not combustion temps ? I must be missing something here .

David Visard did some interesting write ups on water and water/methanol injection . He mentioned that Spearco used to do a sort of programmable type system that only fed the fluid in when the engine was likely to detonate . I have to wonder what distribution between the cylinders would be like even with a fine misting system , multi point would be best but more complex to apply . I think there would be a chance to actually lose some power by injecting water if it wasn't doing anything ie no detonation . Before I go any further if possible its best to find out why your engine is detonating because as I'll show you may find some power lurking behind whatever was causing it .

Only because Dale can't sleep at night : Drum Roll ....................

Twin scroll turbine housings and properly designed pulse divided equal length exhaust manifolds .

Make a pot of coffee because this'll take some time .

I'll start with the exhaust manifold because they get discussed a lot but the people who make or obtain them swear by them .

The reason behind having all the runner lengths the same is that the time it takes the slug of exhaust gas to reach the turbo needs to be the same in the engines sequential order ie 153624 . If you have a manifold with different lengths the short ones take less time for the gas slugs to travel between the exhaust valves and the turbo and vise versa with the longer ones . The best situation is when they are evenly divided so you get a sharp pressure/velocity rise at the turbo followed by a pressure drop then the next cylinders event etc etc . The aim is not to have them overlap when avoidable because a cylinder blowing down into an area of higher than avoidable pressure will lose some of its velocity attempting to overpower the raised pressure in its path . A non divided manifold is not very efficient because it does a good job of tyring to pressurise every other exhaust port . The turbo (turbine) much prefers to have slugs of gas rather than a constant feed so to speak to benefit from the highest pressure/velocity just as the exhaust valves first crack open . With a divided exhaust manifold on an in line six the exhaust ports are grouped together 123 and 456 , with the firing order being 153624 the exhausting cylinders alternate between the front and rear groups in theory timing the gas slugs evenly to the turbos mounting flange . When you have a divided or twin scrol turbine housing you are separating the two groups all the way to the turbine nozzle - actually there are two nozzles . So we get the high pressure/velocity gas slugs evenly time feeding pulses as widely but evenly divided as possible doing the expansion thing into and through the turbine blades . You don't tend to get a cross feed occuring between the parallel nozzles because the exhaust gas finds it difficult to flow backwards through the turbine blades .

There are some important things to understand about divided and undivided turbine housings of the same family and A/R size . If you had for example a .82 A/R divided housing its really more like two .41 A/R housings in a common casting . This is why you need to increase the A/R ratio with divided housings compared to non divided ones because while yes the combined area is similar the same sized engine cylinders have to flow through them and .41 A/R is a bit restrictive .

So ideally the gas slug leaps from the cylinder out of the port and through the split manifold into an area of lowish pressure not losing to much velocity and barrels into the turbine blades via the divided nozzle . The divided housing was say 1.20 A/R giving ~ .60 A/R so again not a lot of velocity robbing restriction in the separated passage .

Wastegating needs to be done properly ie separate gas flow paths from the manifold or turbine housing all the way to the wastegate valve other wise you lose the pulse effect at the turbine .

The properely designed divided system achieves pretty much what twin parallel turbos do , two separated groups of three cylinders pulsing into separate nozzles but this time with one turbine and one compressor . Twin GT28's obviously have their own integral wastegates but the same thing can be achieved with two vent paths and integral flat valves in one turbine housing . Toyota did this with one version of their CT20 turbo on some GT4's , Mazda did it I think on an RX7 Rotary and more recently Subaru have it on some Rexes and Legacy's (JDM USDM Liberty) . I've got some pics of IHI's (MHI) VF36/37/38 and for emissions clean cars they make pretty good torque . Current JDM Legacy GT makes 430 Nm at 2400 rpm from a 2 Litre 4 .

The people that get this system right and tune the engine properly tend to REALLY pull up the bottom end torque and generally make more torque and power everywhere - right throughout the range . They do this with much lower exhaust manifold pressure and EGT and the engine suffers a lot less of a thermal thrashing when worked hard .

At the moment firms in the US like Full Race Motorsport and ATP Turbo can sell you a real GT3071R or GT3076R with a T3 flanged divided housing and FRM (see above) is doing some for the GT3582R AKA GT3540R . Last time I spoke to Brett Lloyd I asked him if Garrett was going to make divided turbine housings for the GT30 and 35 turbine based GT BB turbos and he said no , the high temp resistant iron is difficult to cast reliably so none in the near future . Their loss I reckon because the aftermarket is already modifying workable generally Diesel divided housings and the results speak for themselves . Who would have thought a twin scroll GT3071R could help crank 400 ft/lbs out of an SR20 at 4500 rpm with porting better cams and injectors etc . I think its entirely possible to make an RB25 feel a lot better than they normally do without lifting the engine out of the car . I still think porting and mild cams help a lot but how close to a mild RB30DET can we get the RB25 ?

Night all .

Share this post


Link to post
Share on other sites

I thought that noise in my ears was tinnitus, not drums rolling. :laughing-smiley-014:

If I can clarify my understanding about temps, and the dynamics of what I was trying to explain, then I will.

Rider: this is what I have deduced, but am happy to be put straight by anyone with a better grasp of what happens.

Detonation is brought on by a range of different factors including combustion chamber design, fuel characteristics, excessive heat within the combustion chamber, excessive heat in the intake charge, incorrect spark plug spec, dynamic factors in operation such as backpressure, etc. Control measures are introduced either in the basic engineering of the engine or its support systems, in conservative fuel/ignition strategies, or as an add-on eg. WI, or add-in eg. higher octane fuel to obtain reliable performance.

In a reliable combustion event, the fuel load is burned in a consistent, repeatable manner – not an explosion. Because of that, the peak temperature is consistent and repeatable. In a knock event, the combustion is not consistent or repeatable, and may not even originate from the spark plug. It is an explosion of sorts, and the temps and pressures within the chamber peak beyond the capacity of the engine components. Longer term failure looms large…

Where WI helps (my understanding now), is in keeping the combustion chamber AS A WHOLE (not just the intake charge) cool. Water has a very high ability to absorb heat. It is this feature that makes the combustion event occur smoothly, avoiding the staccato rapid-fire type burn that happens when knock occurs. Hot spots within the burning mixture are in essence tamed down, and peak temps and pressures are avoided. As importantly though, there is heat removed from the piston crown, combustion chamber, and whatever is exposed to the combustion event. Less heat is retained in the environment where the next combustion event will happen in 2 more revs of the crankshaft.

The average fuel load in a given inlet charge for a correctly tuned WI equipped engine should be lower (leaner), for a higher specific output. So I see the exhaust temps as otherwise likely to rise – BUT the water has controlled/contained the rate of combustion. So the cooling effect of the water probably has little net effect on gas temps.

Long way of saying that for the engine tuned without WI but to its optimum (without knock) should exhibit similar exhaust temps and probably slightly higher mechanical component temps than an engine equipped with WI but tuned to its particular optimum. This part is not my theory – the 1942 tests by NACA confirmed it by empirical testing.

Grandad's axe was sharpened up long ago. We just happen to be dealing with a slightly newer axe with a keen edge.

FWIW, I would be very impressed with some data logging of EGT both pre and post WI setup and tuning.

cheers

Edited by Dale FZ1

Share this post


Link to post
Share on other sites

Adrian I think you're onto a good thing with the split pulsed housing and manifold idea. Like WI - nothing new though. Remember the AIT / Normalair Garrett Falcon XE? They were onto that idea and using it in the mid 80s to some good effect.

The theory is good; if well applied, it will work. Our friends in the US are not doing anything new, just doing something that works, and doing it well.

That's what so impresses me about engineering - you can take some completely different approaches to getting eerily similar end results. Again though, without side by side testing it would be hard to know which would be "better" overall. Would the potential increase in turbine efficiency and resultant combustion chamber scavenging outweigh the proven ability to get maximum ignition tuning with Mafia's spec?

Maybe we could get some ballpark costing comparisons of the parts alone (not labour or tuning time) to see where the RB25 hot rodder's $$$ are going? Given that most of us are on limited budgets, I think that's a very important part of the equation.

Just as importantly, is there any option outside of Garrett product that has the same features and quality you like?

Share this post


Link to post
Share on other sites
If I told you how to make more torque and power potential everywhere without buying another turbo would you be interested ? If so what sort of budget would you have to achieve it ? If it ment possibly throwing away the water/alcohol system and having better fuel consumption would that be significant ?

I wondered what you were leading up to.... :domokun:

Nice write up!

Share this post


Link to post
Share on other sites
I thought that noise in my ears was tinnitus, not drums rolling. :laughing-smiley-014:

If I can clarify my understanding about temps, and the dynamics of what I was trying to explain, then I will.

Rider: this is what I have deduced, but am happy to be put straight by anyone with a better grasp of what happens.

Detonation is brought on by a range of different factors including combustion chamber design, fuel characteristics, excessive heat within the combustion chamber, excessive heat in the intake charge, incorrect spark plug spec, dynamic factors in operation such as backpressure, etc. Control measures are introduced either in the basic engineering of the engine or its support systems, in conservative fuel/ignition strategies, or as an add-on eg. WI, or add-in eg. higher octane fuel to obtain reliable performance.

In a reliable combustion event, the fuel load is burned in a consistent, repeatable manner – not an explosion. Because of that, the peak temperature is consistent and repeatable. In a knock event, the combustion is not consistent or repeatable, and may not even originate from the spark plug. It is an explosion of sorts, and the temps and pressures within the chamber peak beyond the capacity of the engine components. Longer term failure looms large…

Where WI helps (my understanding now), is in keeping the combustion chamber AS A WHOLE (not just the intake charge) cool. Water has a very high ability to absorb heat. It is this feature that makes the combustion event occur smoothly, avoiding the staccato rapid-fire type burn that happens when knock occurs. Hot spots within the burning mixture are in essence tamed down, and peak temps and pressures are avoided. As importantly though, there is heat removed from the piston crown, combustion chamber, and whatever is exposed to the combustion event. Less heat is retained in the environment where the next combustion event will happen in 2 more revs of the crankshaft.

The average fuel load in a given inlet charge for a correctly tuned WI equipped engine should be lower (leaner), for a higher specific output. So I see the exhaust temps as otherwise likely to rise – BUT the water has controlled/contained the rate of combustion. So the cooling effect of the water probably has little net effect on gas temps.

Long way of saying that for the engine tuned without WI but to its optimum (without knock) should exhibit similar exhaust temps and probably slightly higher mechanical component temps than an engine equipped with WI but tuned to its particular optimum. This part is not my theory – the 1942 tests by NACA confirmed it by empirical testing.

Grandad's axe was sharpened up long ago. We just happen to be dealing with a slightly newer axe with a keen edge.

FWIW, I would be very impressed with some data logging of EGT both pre and post WI setup and tuning.

cheers

Same as yourself Dale, only my current understanding till corrected.

Knock, I believe is a lot like the “flash point” of a material, and is solely heat related. The higher the mean temperature of the turbulent combustion mix, the higher the chance of an uncontrolled, unregulated ignition, from either a hot source like a incorrect spark plug, hot exhaust valve, carbon deposit etc. The fact its unregulated in itself mean shite, the real issue is that the spark plug is STILL going fire as well… So it’s the resultant collision of the two pressure differential fronts that causes the massive spike. Proper knock events cause quiet severe spiking in cylinder pressures, nothing like the almost linear rise that adding more fuel brings ( through boost, better efficiency etc) This is why, im a big believer that as long as a motor doesn’t det, you can take a particular combo a LONG way. You better believe the BIG power stock motors you see around have very good tuning, and never det. Its why I believe, all things being equal, Mafia’s motor will live for ever in this state, and will not bend a rod. ( slong as that lecky water pump never dies)

Det being an “explosion” is an interesting term. What’s classed as an “explosion” any way. When is a super rapid burn (and resultant increase in pressure from expansion) an explosion?

I would think its purely a pressure difference over an area or time .. hrmm.

Where I would disagree with the “water is purely a cooling agent” blurb, is when its injected pre turbo. In this case, its agreed compression is occurring at almost isothermal levels, that is, with out temp increase. As the state change is occurring here (fine droplets turning into gas) in the compressor covers its self… how could that steam move into the combustion chamber and THEN cool components down? True, it could be overall the air moving past the inlet valve is cooler then without WI, but… its something I cant get my head around.

The state change, the occurrence that’s actually absorbing heat, is occurring a long way out from the combustion chamber…

What I believe is going on, is that the fuel/water/air charge is proving harder to det due to the distance the water puts the fuel molecules apart. The definition of chain reaction, is just that, a reaction in a 3 dimensional pattern. The water stops a super hot point from pre igniting the mixture. Proof? Proof is that most proper 30% WI setups require hardcore CDI to even have a chance of igniting the mixtures in a controller fashion.

As for WI being an “add on” as Dale and Disco have mentioned, its like saying a correctly shaped head design (that tries to prevent hot spots) being a tacked on design consideration!

Disco talks like WI is there to cure a det issue only, and that really, something like split pulse m.fold should net better over results. I would like to think one could use ALL of these things in an effort to make power, as they are all effecting very different parts of the combustion or fuel -> torque process.

Me thinks, you spend all this cash on good components, to help you rev, move air and make power.. but for fear of detonation, you strengthen components to crazy levels (copper head gaskets?!?) and then retard ignition and over fuel up top to stop it from exploding…

People use’d to turbo carby OR EFI a rotary.. not both for a while, thinking EFI comparable to forced induction…. Now look at things. What im saying, is why cant you do EVERYTHING you know to make power, turbo’s EFI, tricky cams, split pulse m.fold, good fuel, silly CAI’s.. and then in the end, use water to allow one to wait till that slug almost goes TDC until you fire the spark plug in a mixture bordering on NA ratio worthy

I'm not shy to admit, this thread is giving me a automotive Tech hard on, keep the intelligent thoughts coming!

- M

Edited by GeeTR

Share this post


Link to post
Share on other sites

LOL , I didn't claim it was any new form of rocket science but there are some important difference nowdays . From a mechanical perspective the turbos are more modern and so can be specced to respond better than the older ones . Some of these GT UHP turbines can be made to handle quite high flow rates and provided thats what the engine wants its a win for turbine power and the pressure balance across the engine itself .

I'll quote Corky again for the umpteenth time , "Turbine inlet pressure is an evil and should be delt with accordingly" .

When you do you throw away a large number of the things that gang up and promote detonation . They WILL restrict power development even when detonation is no longer the limiting factor . This is why I used to harp about measuring EMP and IMP because when EMP is significantly higher its trying to tell you that the exhaust side flow restrictions are getting out of hand .

Cheers .

Share this post


Link to post
Share on other sites
LOL , I didn't claim it was any new form of rocket science but there are some important difference nowdays . From a mechanical perspective the turbos are more modern and so can be specced to respond better than the older ones .

Sorry man, I didn't mean not to acknowledged what you wrote. It explained, in a very clear manor how split pulse design work, and helped immensely in an understanding. How you explain modern designs are far more superior, makes me really think, anything else would be a waste of time... like a carby suck through setup :D

I didn't know other OS AM companies are working on split designs of current popular turbine sections!!??!! ... i need to look around before picking up a non split GT35

Legend

Edited by GeeTR

Share this post


Link to post
Share on other sites

One other thing to throw in the fire is the Variable Vane exhaust housing which garrett said they couldnt make to suit petrol, giving the lowest possible exhaust backpressure necessary to maintain boost, whilst giving the best possible response. There's the reason why im not upgrading my dinosaur HKS T45S yet, i thing the next few years of turbo technology will blow us away compared to the "old" wastegated turbos.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




×
×
  • Create New...