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

[N1GTR]

Geez you just cant catch a break with the weather up there can you!!!

Good luck with it at the track - im keen to see how it goes

[Beer Baron]

sounds good mate. yeah fuel system is a tough one. nismo used to make an in-tank baffle system which was awesome. same idea as sump baffles basically. box around the pump with some 1way doors. means you don't need to have anything external, just run the nismo drop in pump which is good enough for 700cc injectors and the in-tank baffles. but these days if you want some kind of anti-surge gear it has to be external. under the car is a good idea. there's a bit of room above the rear diffuser in a 34 for an under boot floor surge tank but the hassle is it still means 2 fuel pumps one of which is either external or inside the surge tank (if it's big enough).

what size injectors are you running? 700cc with a nismo pump might be enough for the GT-RS but it could get marginal. it will definitely need 1000cc if you go to E85.

good buy on the nismo intercooler. they are up there with the best (ARC) for quality and in fact the welding on the nismo one is second to none. they are also designed to give good flow through to the radiator (like arc) so it's a good choice. they are so expensive though it can make my eyes water. I agree with no painting it. they look cool with the nismo logo. they look tough but still a bit subtle.

especially for you where it's hot the balance between intercooler and radiator is very important. I have found the big thick cheap alloy radiators are actually WORSE in normal driving conditions than the nice thing standard ones. the reason is the clutch fan struggles to pull air through the really thick rads at low road speed (or stopped in traffic) so they basically just sit there soaking up engine bay heat. where as the thin standard rad still gets some air moving through it at low speed and when still the clutch fan can still draw air through. on the track it's reversed as there's plenty of airflow and the big radiators come into their own (well the good ones, PWR, koyo, sard, ARC) do.

[GTRNUR]

Thanks for your thoughts Richard. I've decided I dont want to turn the car into some sort of crazy race car. I like it as a streeter, so i'll just keep fuel surge under control by running a full tank. That means a Nismo pump is the best option.

Your right about the intercooler and radiator situation too. Glad to report my cooling system works extremely well. Crusing in traffic yesterday with the aircon blasting at 24 degrees, outside temps were 36 degrees and the engine coolant temp sat on 83, oil on 95. Considering the block is grout filled above the welsh plugs too, im happy with that result. Coolant temps drop below 80 and oil below 90 on the highway when Im able to maintain 80km/h.

The thing that made the largest improvement to the cooling (when stuck in traffic) was that I replaced all the seals around the shroud, so any air that is drawn in via the fan can only come through the radiator. This meant cutting up a lot of little pieces of rubber to fit between the core and sections of the framework of the shroud that are behind the aircon thermo fan, as the shroud doesnt fit the 40mm PWR radiator all that perfectly.

Ive also cut out the bottom of the air slots in the back of the left inner guard lining to allow exhaust from the 19 row earls cooler, but havent done anything to the front of the car to get more airflow to the radiator. A Ztune or Nismo front bar will only improve oil cooling, which is on the cards.

Yes the injectors are SARD 700's. Based on how the tuning is going so far, the injectors will be around 13.5ms at 8000 rpm at 1.5 bar boost, which is right on 90% duty. The compression of this engine is too low to warrant using E85 (<9:1). If I do feel the need to do something extra, it will probably be the addition of a meth/water injection system.

[N1GTR]

FYI 1000's won't work on E85. Go the new ID injectors, it's either 1500 or 1600 or something like that. I'm on the phone now so it's too hard to look it up.

I'm 9:1 CR, 87mm rb30 etc and 1000's were all over by 403rwkw

[GTRNUR]

As luck would have it, the Nismo fuel pump arrived and was installed friday. I didnt have time to perfect the tune as the rain up here has again not let off but managed to get it safe enough to participate in the track day.

The disappointment was in that as it was a practice track day with a lot of new drivers, and there was water over the track in a lot of places we were not able to use the whole track. So the event was instead a motorkarna. Also my video camera stopped working after my first pass on the timed sections. Finally it started pooring down rain before I got to do a 3rd pass, so I gave that a miss. The most impressive spin of the day went to the owner of a 650hp tuned 997 turbo decided to see what would happen when he turned off all the driver aids.

Here's the video of my fist pass. Sorry not even remotely impressive but its better than nothing.

http://www.youtube.com/watch?v=qV_6L6wXVpU

And a few pics are attached.

All in all the engine and the car performed extremely well and more importantly, it held together. The track is really tight and the car never achieves full boost anywhere. The entire circuit is driven in 2nd, except for a moment when I tried a change up to 3rd but all that does is un-settle the car into the corner. The engine achieves perhaps 1 bar at the most, as I shifted gears below 5000 rpm. The torque still made it fun enough to get a little sideways. In 2nd gear the engine will achieve full boost somewhere a little below 5000 rpm. The drive home was a lot more fun as in 3rd or 4th is where its really amazing. 1.4 bar boost by 4500 in 3rd or 4th.

So everything is in place to do some dyno sessions now, hope to do that in a week or so when work slackens off again. Have to get a new video camera too.

Edited February 27, 2011 by GTRNUR

[Beer Baron]

nice mate. it sounds great in the vids. makes me miss the old girl. it's many times nicer now than when you got it! it was a very clean car though. definitely one of, if not the, cleanest R34 GTRs I've come across in recent years. with them now 10 years old and most have had multiple owners it's not often I see a really nice one these days. even in japan.

[GTRNUR]

Update time.

I’ve been playing with the cooling system a little lately, changing pulley sizes so as to restore normal pump/fan speed as my harmonic balancer is an under drive size on the alternator/pump drive. Having switched to an RB30 pulley the car sits comfortably on the thermostat temperature when cruising around town in 30+ degree heat, but still creeps up when stuck in traffic. I am considering changing to a slightly smaller 300ZX pulley next.

I have installed an Eboost Street 40, and boost now holds stable to 7000 rpm, which is as high has I've revved it whist under full load so far. So boost control is for the most part sorted, with the exception that the lowest pressure I can get is 1.6 bar. I will be dialing back the pre-load on the actuators this weekend to a 0.6 bar lift off preload (instead of the 1 bar that it is currently at). The actuators are rated at 1.3, so I presume this explains the rather high boost it is achieving.

I have just completed a round trip to Townsville in the car, and put another 700+km on the clock. That puts the clock at 4200 on the new engine now. The car performed flawlessly, except for blowing off an intake hose once while overtaking. I was able to fine tune the economy side of the tune during the drive, and managed about 12.3l/100km. Considering that included stopping for roadwork’s 3 times, driving a range, and some rather liberated use of the right foot when overtaking I am pretty happy with that result. The AFR's at the cruise RPM of 2000-2250 are still only 14.7:1, as I still haven’t hooked up my EGT sensors to my data logger yet. I think as low as 10-11 lt/100km may be achievable when I lean back the mixtures a little more.

As far as the power side of the tune goes, I still have a few dead spots above 3500 rpm when I drop back a gear. Response from idle is ballistic, but when on boost the car is utterly amazing. I'd go into details but I’ll be incriminating myself! Safe to say the drive back from Townsville was a lot of fun

[Weapon]

lol is that where you were going on Wednesday? i was travelling to Cairns on that day and past you at about mid day and was mighty impressed with the driveby

[sucram]

was gonna ask how it was going

Your getting pretty good economy there

You might be able to lean your map a little at cruise and add accel enrichment for a compromise. I found it works better overall, steady throttle for economy but enrichment for torque (hills, passing etc). Power FC is pretty crappy with the hand control, 1k increments are lol microtech technology. Wish I didnt sell my M800

[GTRNUR]

lol is that where you were going on Wednesday? i was travelling to Cairns on that day and past you at about mid day and was mighty impressed with the driveby

I didnt spot you ? Were you in your R33? I only saw 3 other skylines on the drive and none were gtr's.

You might be able to lean your map a little at cruise and add accel enrichment for a compromise. I found it works better overall, steady throttle for economy but enrichment for torque (hills, passing etc). Power FC is pretty crappy with the hand control, 1k increments are lol microtech technology. Wish I didnt sell my M800

Im using a FC Datalogit for tuning and have never actually used the hand controller for anything other than as a gauge. The EGT sensors in each manifold before the turbo's will be able to be logged using the datalogit as well, once I get around to running the wiring through the firewall that is.

I have re-scaled both my RPM scales and load scales to give me more resolution at the cruise RPM (1250-2500 every 250 rpm) and load bands every 500 units in the cruise zone (instead of 1000 unit MAP increments). I also have one extra RPM column placed in the peak torque zone, though I cant actually place that in the perfect RPM point until I run the car on a dyno. For the moment Im just keeping the tune safe but it can certainly go leaner.

[zebra]

Good to see all is still running well!

[N1GTR]

Quite a while with no update - have you turned the boost up now?

Hope its going well!

I sold the GTRS's, bought dash5's, one super helpful and very knowledgeable friend put them on for me and its all set for the dyno which is booked for about 7 hours time from now. Reason that the swap happened before its planned time was that there is a hillclimb near here that myself and a couple of other tough GTR owners go to often. There's a long middle section in 3rd gear where you cant hold it flat, you have to back off the pedal at about 7000 in 3rd, dab the brakes, then the revs are at about 3500 or so, then full throttle into a slight bend to the right. Where I lean on the throttle after the braking zone those turbos would just choof and choof and choof all the way to the next corner, it was just too frustrating. Out of the next corner there's a 60m straight into a left hander which instead of being able to do in 3rd I have to use 2nd and there's just wheelspin as soon as it gets any meaningful boost. The other GTR there with GTRS's doesnt run the stock gearbox and his goes much better, so I'm not sure how you'll go on the Getrag, but I thought it would be worthwhile posting that info incase it benefits you in some way

EDIT: Also worth noting, this issue didnt exist when it had an Autronic SM4, its on PFC D-Jetro now which I regret.

[GTRNUR]

Yes all is still going well with the engine. A little over 5500k's on the engine now. I have been driving the car every day to and from work, and also to get my groceries!

The only drama ive had was the rubber hose that joins the turbo coolant hard return line to the radiator top hose developed a split next to the hose clamp while I was on a long drive. Fortunatly it happened on a range, and there was a water fall near by that I was able to re-fill the cooling system with. I was able to push the hose on a little further and get home no problems.

I've switched to synthetic oil now and have begun to lean on the tune a bit harder, but have noticed a little oil in the intake. Most likely due to all the factory polution hoses still being in place, and that I am reving past 7000rpm now.

Ive had a catch can on order for 3 weeks now and its yet to arrive so I am now arranging a temporary measure in the meantime. I had hoped it would have arrived earlier this week as I was hoping to book dyno time for today, but no luck.

Response wise the best Ive been able to achieve is full boost by 4000 rpm (in 2nd or higher gears), but it will also hold full boost at 3400 rpm when shifting from 2nd to 3rd. I think that -5's would definatly be a hoot on this engine though. It makes a lot of sense too as the response and torque would come on much earlier in the rev range. For the most part I shift below 4500 rpm anyway and its still plenty quick enough as a street car.

Interesting what you have said about your surge issue and the autronic vs the D-jetro. Was there any differences with the intake? Ive read that deleting the maf sensors alone is supposed to help. Good luck with the re-tune. It will be great to finally see some -5 + RB30 results!

[N1GTR]

Hahaha filling it up from a waterfall? That's priceless

No changes to intake, there were no changes to the entire car other than ecu swap.

The 5's were great on the big rb, full boost very early, better throttle response by far, 3rd gear 40kmh just go full throttle and hold on, as soon as it got to 2500 you are off and by 3000 it's on for young and old. Then out of nowhere it's started a knock, so time to pull apart and inspect. I don't have any dyno print for it which is a shame but I can tell you the RS's feel like caveman technology in comparison. I really didn't expect such a huge difference, but there you have it

[Marko R1]

Hahaha filling it up from a waterfall? That's priceless

No changes to intake, there were no changes to the entire car other than ecu swap.

The 5's were great on the big rb, full boost very early, better throttle response by far, 3rd gear 40kmh just go full throttle and hold on, as soon as it got to 2500 you are off and by 3000 it's on for young and old. Then out of nowhere it's started a knock, so time to pull apart and inspect. I don't have any dyno print for it which is a shame but I can tell you the RS's feel like caveman technology in comparison. I really didn't expect such a huge difference, but there you have it

-5's sound like a good thing on the rb30 stevo - what power did u make in comparison to your -10's with 455rwkw?

[N1GTR]

I had GTRS's not -10's, unknown on exact power, it felt exactly the same as before but the knocking stopped tuning.

I drove it on the old tune the very long way to the dyno, had to tow it home. Not the tuners fault, I'm confident it was the fault of a big over rev from Huntley hillclimb last time I raced it there. Shit happens. Time to have a look inside and see exactly what's going on in there before speculating too much. Would be nice if blocks were see through!

Edit; When I drove it there it was at 24 psi, first dyno run was ebc off to makesure it's all good. That did 320 and a curve to die for. I can probably get a print of that, but it's a waste of time as the curve would be very different with another 10/11 psi added and the tune modified to suit of course. Also this engine has done about 9000k's, all hard k's, shame there's no datalogger on it for rpm - I'd love to know exactly how high it went at Huntley but I can tell you it was into stupid number territory which it was never built for. Anyway, enough of my story it's Ians thread

[GTRNUR]

I had GTRS's not -10's, unknown on exact power, it felt exactly the same as before but the knocking stopped tuning.

I drove it on the old tune the very long way to the dyno, had to tow it home. Not the tuners fault, I'm confident it was the fault of a big over rev from Huntley hillclimb last time I raced it there. Shit happens. Time to have a look inside and see exactly what's going on in there before speculating too much. Would be nice if blocks were see through!

Edit; When I drove it there it was at 24 psi, first dyno run was ebc off to makesure it's all good. That did 320 and a curve to die for. I can probably get a print of that, but it's a waste of time as the curve would be very different with another 10/11 psi added and the tune modified to suit of course. Also this engine has done about 9000k's, all hard k's, shame there's no datalogger on it for rpm - I'd love to know exactly how high it went at Huntley but I can tell you it was into stupid number territory

It would be interesting to overlay the torque curves for the GTRS's vs -5's. Like you said, similar feel so the numbers must be very close. But down low obviously better, and up high possible less. With your hill climbs it will be fun though, not having it drop off boost in the corners, the evo's will have to watch out.

Sorry to hear about the knock too. I'd hate to hear something like that... and experience that sinking feeling that quickly is mirrored to your bank account balance.

On another note, my catch can finally arrived friday so with any luck dyno time for me will be later this week.

[Ryan1200]

Hahaha filling it up from a waterfall? That's priceless

No changes to intake, there were no changes to the entire car other than ecu swap.

The 5's were great on the big rb, full boost very early, better throttle response by far, 3rd gear 40kmh just go full throttle and hold on, as soon as it got to 2500 you are off and by 3000 it's on for young and old. Then out of nowhere it's started a knock, so time to pull apart and inspect. I don't have any dyno print for it which is a shame but I can tell you the RS's feel like caveman technology in comparison. I really didn't expect such a huge difference, but there you have it

With the -5's making a crap load more power at 2500-4000 region your GTRS tune might not have had enough fuel in those areas and caused a problem.. I hope its a simple fix mate...

With all the surge issues with 71mm front wheel and the fact iv got exhaust back pressure problems with the standard hks 2530 i doubt an even bigger compressor wheel is really beneficial...

Hope your dyno session goes smoothly Ian everyones dying to see some numbers. Good luck

[Marko R1]

With the -5's making a crap load more power at 2500-4000 region your GTRS tune might not have had enough fuel in those areas and caused a problem.. I hope its a simple fix mate...

With all the surge issues with 71mm front wheel and the fact iv got exhaust back pressure problems with the standard hks 2530 i doubt an even bigger compressor wheel is really beneficial...

Hope your dyno session goes smoothly Ian everyones dying to see some numbers. Good luck

surely u wouldnt just fit the -5s & run it on the same tune as the gtrs's?

[Ryan1200]

The 5's were great on the big rb, full boost very early, better throttle response by far, 3rd gear 40kmh just go full throttle and hold on, as soon as it got to 2500 you are off and by 3000 it's on for young and old. Then out of nowhere it's started a knock, so time to pull apart and inspect. I don't have any dyno print for it which is a shame but I can tell you the RS's feel like caveman technology in comparison. I really didn't expect such a huge difference, but there you have it

I had GTRS's not -10's, unknown on exact power, it felt exactly the same as before but the knocking stopped tuning.

I drove it on the old tune the very long way to the dyno, had to tow it home. Not the tuners fault, I'm confident it was the fault of a big over rev from Huntley hillclimb last time I raced it there. Shit happens. Time to have a look inside and see exactly what's going on in there before speculating too much. Would be nice if blocks were see through!

Edit; When I drove it there it was at 24 psi, first dyno run was ebc off to makesure it's all good. That did 320 and a curve to die for. I can probably get a print of that, but it's a waste of time as the curve would be very different with another 10/11 psi added and the tune modified to suit of course. Also this engine has done about 9000k's, all hard k's, shame there's no datalogger on it for rpm - I'd love to know exactly how high it went at Huntley but I can tell you it was into stupid number territory which it was never built for. Anyway, enough of my story it's Ians thread

surely u wouldnt just fit the -5s & run it on the same tune as the gtrs's?