Project Rb31dett. The Development Of My Open Deck Rb Engine And The Quest For More Torque!

[GTRNUR]

Update.

The re-tune with the water/methanol injection system is nearly finished. I've had a few issues getting the nozzel sizes correct and setting the triggering pressures but now I am past that there is just fine tuning to complete.

I have tried a few variations of the setup but the current implementation is as follows. I have a 5 lt boot mounted tank with 50/50% water methanol mix. I am using a cooling mist 250psi pump in the boot which is triggered by a relay, fired from pressure switch that switches at 15psi.

There is 3 nozzles in the system. I have a 2 x 50cc/min nozzle concealed in the airbox that spray into the air intake stream before each MAF sensor. (maf sensors are not used with my setup, they are there for show only). I also have a 250cc and a 180cc injector in the return hose from the intercooler just before the plenum. The 250cc nozzle and the 2 x 50cc nozzles come on at 15psi.

I am yet to enable it, but will probably enable the additional 180cc injector will come on at 22psi.

The main reason I have gone with a water/meth system is to cool down the air intake temps. It is not uncommon in summer to see air temps in traffic well over 60 degrees. Even 65 degrees on the hottest of days.

The water methanol system is instantly dropping the air temps by at least 20 degrees, possibly more. Its hard to say exactly what it has dropped to as the sensors aren't reacting fast enough. The temp drop alone has resulted in a huge improvement in performance. It is like driving the car at night in winter in 18 degree air temps, when the outside air temp is really 35-36 degrees. The exception is that I am not getting full boost (25psi) till 4500 RPM still. Where as in the cool climate of victoria at SAU nationals a few months ago full boost happened at around 4000 rpm.

The in cylinder cooling effects I have noticed have also been interesting. I have added another 4 degrees of ignition while at 25psi (1.75kg/cm), and the advanced knock values are still below 10. EGT's on average have dropped about 40 degrees when on boost as well. Peaking at 740-760 degrees measured at the dump pipe.

The other interesting effect is that the addition of methanol has allowed me to pull nearly 2ms out of the fuel map at peak load area's of the map, and it is still dipping into the mid 11 AFR's.

I hope to make the time to finish the tune this weekend, and look at getting some dyno time to produce some new numbers next week. My gut feeling is that it is well into the 400kw's despite our tropical air temperatures.

That is all.

[Adriano]

"That is all."

Better not be, this is one of the best threads(apart from wasteland)

Edited January 13, 2012 by Adriano

[GTRNUR]

"That is all."

Better not be, this is one of the best threads(apart from wasteland)

There's plenty more to come. Including version 3 of the engine that currently under development.

[N1GTR]

There's a few of us discussing WMI in the club area, do you have any pics please of the actual installed parts? Trying to get an idea of how bulky this setup is to add

[GTRNUR]

My nozzle placement was simple as I already had the extension in the middle of the intercooler to plenum hose. I just had a couple of 1/8th BSP stainless fittings tigged on there. My spot welded hose clamps are continuing to work well too. 1.75 bar and no leaks or popped pipes. These are 280cc and 300cc nozzles.

I've hidden one of the solenoids under the carbon air deflector in front of the radiator. The supply hose then runs over to the airbox side of the car where I've mounted the second solenoid, external to the box and to the right of the charcoal canister. (shiny... didn't photograph well).

Sorry I don't have any pics of how I've arranged the nozzles inside the air box, but basically ive used a few fittings and a pair of 150cc injectors that aim at the air path.

The boot setup is pretty rough, and temporary. Im going to put the pump under the car once I source a diffuser, which will serve to protect it a little. I'll also put a smaller tank upstream from the pump to prevent sloshing and air bubble issues.

I finished the rough re-tune on the weekend and tried to book some dyno time, but the tune shop I use have their dyno in pieces at the moment. Its going to be a few more weeks till its working again.

[N1GTR]

Thanks very much Ian!

Not very intrusive is it, I was thinking a bigger tank and pump unit but that's quite neat and tidy

[GTRNUR]

Yeah im pretty happy with it too.

The pump runs nearly silent. At least you can't hear it over the engine. It also flows 1500cc/min which is enough for an RB running 1250cc injectors and BP98.

This tank holds about 5 litres and it appears to easily last more than a tank of fuel does.

One other little curious thing I noticed is that the pre-turbo nozzles solved my boost drop off in top end issue. Its possible that the in hot air temps of north qld I was running close to the limit of the GTRS's as it would drop 4-5psi at 7500 from 5000. Not anymore. The increased compressor efficency due to cooler air intake temps have cured that.

There is a thread on the aquamist forum about an R33 GTR with a pair of GT2835's that made more power than the GTRS's were supposed to be able to make as well.

Where is this WMI discussion in the club section you mentioned? I had a look but couldn't find it.

[TiTAN]

it's in the private Nsw members area.

we were discussing wmi setups vs e85 power potential.

[GTRNUR]

it's in the private Nsw members area.

we were discussing wmi setups vs e85 power potential.

That explains why I can't find it...

I figure if WMI should be considered regardless of fuel. A small plain water system (post turbo) on an E85 tuned car would buy that safety margin that you lose due to E85 detonation sounding different, and it would also allow you to run leaner safely. Instead of using the methanol/alcohol approach to tuning where you just drown the detonation in fuel.

My finalised rough tune has my EGT's peaking at 810 degrees at the dump pipe. This is with 19 degrees of ignition at peak torque advancing to 25 degrees at 7500 rpm, with 1.75-1.8 kg/cm boost and 12:1 AFR's. Knock values are still below 10 as well. Im nearly tempted to re-tune to lower octane fuel to see how it goes, and save a few $$$ on fill ups.

The map has more than 2ms of fuel pulled out of it in top end compared to a straight BP89 tune, which means the 700cc injectors have the headroom to run 2kg/cm boost and max out everything again. This is something I might try after the version 3 engine is running, as this motor was never meant to make more that 700 crank hp.

[N1GTR]

Yeah sorry mate it's in the NSW club area. Forgot to mention the nsw part haha

If you could get the standard boot trim to fit around the tank it would be a very subtle install! Overall I like how you've done it!

[GTRNUR]

Yeah sorry mate it's in the NSW club area. Forgot to mention the nsw part haha

If you could get the standard boot trim to fit around the tank it would be a very subtle install! Overall I like how you've done it!

The boot trim would still fit behind teh tank and pump, but I'd have to make some holes in it.

Everything is mounted off factory holes or bolts at the moment, no holes drilled anywhere. The supply hose goes through the factory drain grommit. No sence in making it perminent until its 100% sorted out I figure.

[TiTAN]

my car was just tuned with my WMI setup and as the tuner approached 400kw he started running into ignition problems.

have you noticed with your setup any high rpm ignition breakdown? or has your ignition system been upgraded?

(currently running yellow jackets with 0.8mm gapped BCPR7ES plugs and wasted spark in mine)

[GTRNUR]

I did initially as my fuel map combined with the WMI had the AFR's dipping into the 9's at around 5000 RPM. Once I came to terms with just how much more lean it could run safely, and pulled out a heap of fuel from the base map it all came good.

Im using standard 6 heat range NGK iridiums gapped with 0.8mm gaps, and stock coil packs. Works perfectly.

[TheGotoGuy]

i have played with water/meth a fair bit, your airbox mounted nozzles (pre boost) are spraying water/meth that is taking up valueable oxygen space in the intake charge as it is getting compressed (remember water molecules are still basically a liquid although somewhat atomised and gas compresses easier than liquid so the water molecules will take precedence in the compressed chargeand air will be left out) , in order to get that winter spool all year round you should start your pre throttlebody spray as you are at 15psi and do not activate the pre turbo nozzles until 2psi or so before peak boost. the pre turbo nozzles actually let the water close up the clearance between the comp wheel and the cover thereby increasing its efficiency. this is the reason why it holds boost longer, if you found the ceiling for boost that your turbo could produce the water would increase that by a couple of psi as well, basically there is less room for air to escabe back out the cover between the comp wheel and comp cover. by using so much water low in the spool area you are decreasing exhaust temps before full boost is achieved, turbines turn heat energy into kinetic energy. keep the heat energy as high as reliably possible during spool then push more water/meth in as it ramps onto boost to control exh temps. flow a small amount of water/meth in as it is building boost as you want the anti det properties of the water to allow more ignition advance in this spool up zone. BTW, with the right amount of water/meth you can run AFR in mid 12s safely, this also frees up some injector headroom if you want to wind up the boost some more.

Once you start pushing large volumes of water/meth you may need to close plug gaps down to .6 to get a clean spark around peak torque as water/meth and timing increases midrange torque more than peak power.

Edited January 24, 2012 by TheGotoGuy

[GTRNUR]

Thanks for your thoughts and I follow what you are saying.

Regarding tuning, and appropriate AFR's there are two schools of thought I have come across. Your approach is one in that saying a 12.5:1 afr is safe. I would agree with that if I had individual nozzles in each intake runner, I could consider leaning it out further as I could be sure the combustion temps for each cylinder would be closer matched.

But as I am injecting post intercooler in the intake pipe I cannot be 100% sure WMI is evenly distributed all the time. It will be close, but not perfect. I am also only able to monitor EGT's in each manifold before the turbine, and not at each cylinder port.

The second approach to WMI tuning (which I use), is to tune the engine first for peak power with the normal fuel. Monitor EGT's at their peak. My engine was consistently 800 degrees at the dump and 840-850 at the collectors at 7500 with 1.6-1.7 bar boost. Total fuel delivery was around 3.9-4lt/minute. Then when adding WMI, the injector nozzle sizes need to be 20% of the total fuel delivered, and the distribution of the nozzles is 25% pre turbo and 75% pre throttle body. 800cc in my case. I am spraying 900cc though for a little more safety.

With this done and a base fuel map re-scaled to achieve 11.5:1, ignition is added until knock levels are similar to before. Then fuel is further removed until EGT's at the end of the run match the result of the standard fuel tune.

This approach optimises ignition by advance using the benefit of the octane boost WMI adds, yet keeps EGT's where they need to be to make the turbo's work at their best.

While a better performance result might be able to be had by spraying pre-turbo at lower boost levels, my concerns for tuning are not entirely performance focused. I am driving the car daily as a work/company car, and below 15psi boost its still awesome to drive. Spraying later means I use less WM mix overall. The engine doesn't need an octane boost to control detonation at low boost levels as it is an 8.2:1 cr engine with stock cams.

Also, spraying later when air velocities are higher at the turbo intakes means that for any given amount of WMI sprayed into the intake, evaporation/vaporisation is more efficent. This equals less turbine impeller erosion.

So while what I have might not be the most efficent for overall perforamnce, my general needs are met.

[TheGotoGuy]

While a better performance result might be able to be had by spraying pre-turbo at lower boost levels, my concerns for tuning are not entirely performance focused. I am driving the car daily as a work/company car, and below 15psi boost its still awesome to drive. Spraying later means I use less WM mix overall. The engine doesn't need an octane boost to control detonation at low boost levels as it is an 8.2:1 cr engine with stock cams.

this is what i am saying, keep your post intercooler spray at 15psi and change your pre turbo nozzles to 24psi or whatever 2-3psi below full boost is, that way when your turbo efficiency is starting to drop off the pre turbo water/meth is regaining some efficiency lost to heat and it isnt exceeding the 25% fuelling lower down the powerband resulting in some lost midrange torque and spool rpm, and also using less of your water/meth mix for daily duties. i suspect 350cc is more than 25% of total fuel flow at 15psi and 4500rpm where it starts spraying with the onset of boost, as the revs rise the meth ratio will correct itself but remember water/meth is fixed flow and efi isn't so your meth-fuel ratio changes as revs change unless of course you are using a variable flow controller on your meth pump and matching it to injector duty cycle. what might be correct 25% ratio at 7000rpm on 1.6bar may be closer to 35-40% at 15psi and 5000rpm on a fixed flow meth system, this robs fuel from combustion and replaces it with steam which doesnt burn too well.

anyway, look forward to seeing some further experimentation, this thread is a good read.

[r32_psi]

I dont post much but I'd just like to say WOW!!!

Just finished reading the whole thread & this has to be the best project/build thread I've read so far, nice work.

[GTRNUR]

Thanks mate.

I should have some more results and video footage soon. I have been able to book some after hours dyno tuning time for Thursday, 2 weeks. With any luck it should be cool enough so I can reach my original power goals.

[GTRNUR]

Well I got my dates wrong and my dyno time happened today instead.

We went back to basics with the tune and dropped the boost to 0.8 kg/cm (boost controller off), did a few baseline runs and started to tweak the cam gear timing. Fiddling with the intake cam got 15kw more in front of the curve as it ramped up onto boost. Maximum power achieved with 0.8 kg/cm was 255kw atw with rich afr's in the mid 11's. It was 33 degrees and 78% humidity. Intake air temps were 44 degrees(MFD), so I think that power level was reasonable for 10lb.

Moving onto high boost tuning is where the issues started. First we had glitches getting the boost control stable. On the first attempt it spiked to 2kg/cm. But didn't knock, lean out or even miss fire. Knock values were still sub 10's all the way to 32lb.

With some tweaking of the avcr boost, was stabilised at 1.5kg/cm and we tried some power runs. Some minor adjustment of the exhaust cam bought boost on even quicker (1.5ish @ 4000 rpm), but we then started to have issues with the ignition breaking down at 4500. That bought the tune session to an end for the moment. I have a week to make some corrections, change plugs, check base timing and change the water/meth nozzle sizes a little. WIth any luck I'll be ready for more tuning next thursday night.

I had a HD camera setup recording for nearly 2 hours (or until the battery went flat). I'll be uploading soon.

[GTRNUR]

Finally managed to get the video to upload after the 3rd attempt. Not the most exciting video by a long shot, but at least there was some progress and some nice sounds recorded. Seeing how easily the car climbed up on the front rollers on the high boost attempt was good too. It felt really strong in the car.

http://www.youtube.com/watch?v=rYJfbfGg17E

The dyno platform really needs a lighting upgrade too. I didn't get a dyno print out as we didn't really make any inspirational numbers. It is breaking the 200kw milestone at about 3900 rpm now though.