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

[N1GTR]

A lot of that makes perfect sense, others on this and other forums have said similar for a long time especially on the UK site

There's a few haltech e11v2's cheap lately since their new one came out, also djetro's seem to be around the 1300 mark. Some as low as 900. Really depends what's included and how realistic the seller is.

Bad news I can't tell you about the exhaust before leaving it won't be done, the saw blade broke

[GTRNUR]

Update.

I bit the bullet and installed the PFC D-jetro on the weekend. Like everyone says they are slower to setup, but once you start to get the low speed area sorted out the rest of the map falls into place quickly. I'm using a single 3 bar map sensor, wired in parallel to both maf sensor inputs instead of having to drill cylinder 2+5 throttles and install additional vacuum connections. Since the engine has stock cams I'm not having sensor fluctuation issues, and the engine produces excelent vacuum at idle and low speeds. -450 at idle when hot @ 950 rpm.

I've completed the low end fuel mapping and a little of light boost tuning. Drivability and throttle response is MUCH better than the L-jetro was, and the transition onto boost is much smoother now. Although the turbo shuffle is still there and you can feel it around 2500 rpm, you can drive through it and it goes away.

I have installed my earls oil cooler and remote filter setup. Street tuning on the weekend has just over 800km on the engine. Oil temps are now within 10 degrees of water all the time now. But temps in general are getting pretty out of control when stuck in traffic (mid 90's). Outside ambient air temp was 41 degrees when driving around at midday on saturday, and I still havent bolted on the under trays and front splitter yet... which I have learned are instrumental in having your radiator NOT re-circulate hot air when your idling along in traffic. In the 80km/h+ zones temps drop to high 70's which is acceptable considering how hot it is outside. Thankfully the air conditioning works really well.

I've just ordered a greddy air seperation tank and cooling panel from high octane, which will go a long way to sorting out the heat issues at low speed. The last compression test had all cylinders within 10psi but Im holding off doing on boost tuning till I have at least 1000k's on the clock. What I have done on boost though is just awesome to experience.

Edited December 6, 2010 by GTRNUR

[GTRNUR]

Update.

900k's on the engine now. All still going well.

Installed the Greddy radiator breather to better extract air from the cooling system, and added a cooling panel. That and having re-installed all the under panels, front lip and splitter have got the temps sitting very nice now.

Still have more work to do on the tune but thats been slow progress as work has been pretty flat out lately. Not far off being able to so some more fun on boost tuning. Already though I can say this. In the lower gears (2+3rd) the engine achieves wastegate boost of 0.8 bar at 4400 rpm. Turbos are making positive manifold pressure of 0.2 bar at around 2200 rpm. Im keeping the knock below 10 across the entire map so its still a very soft tune too.

Here's a few pictures, and the latest video:

http://www.youtube.com/watch?v=xhXiq6evj3k

Cheers,

Ian

[zebra]

Sounds very nice, beefier than a normal mild RB26.

I dont know if its just me, but I can't stand lifter noise on any engine.

I see you are looking for a set of cams though, will you do all the clearances when the new cams go in?

[GTRNUR]

The lifter noise isnt that bad in person. I think its the microphone on the camera. I picks up wind noise when there isnt any wind... You could probably hear me breathing if the car wasnt running.

[zebra]

Ahk fair enough

[StealthX]

Although the turbo shuffle is still there and you can feel it around 2500 rpm, you can drive through it and it goes away.

Can you elaborate on the "turbo shuffle" you're getting?

What is it? a dead spot?

[GTRNUR]

Can you elaborate on the "turbo shuffle" you're getting?

What is it? a dead spot?

Shuffle is when one turbo begins to spool up and flows more air than the other, resulting in the slower turbo slowing down. Then an oscillation sets in as a result of exhaust back pressure and the two turbos switch back and fourth. Its really easy to see when logging with a power fc and watching the MAF sensor voltages. I was seeing at worst around 2V of difference between the two MAF sensors when under light cruise at 2000 rpm, and also if I free revved the engine to 3500 or so the maf sensors would also fluctuate wildly.

As the ecu uses an average of both sensor readings this was playing havic with the tune as the percieved load point isnt actually valid. Look at my previous video with the laptop in the engine bay and watch the cursor. It should go back to the top row on the left after a rev, but instead it drops 1/2 way down the load scale as one maf sensor was reading 0 and the other was about 2v. According to the ecu it was seeing boost at idle, and as a result would over fuel the engine and it would nearly stall out. (The running lean issue I had at the time that would happen moments later was due to throttle body gaskets not sealing properly, and a split hose in the BOV opening vacuum hose which allowed the engine to injest un-metered air)

Using a single MAP sensor instead of MAF solves the ECU side of the issue and allows the tune to be stabilised. The shuffle is still there and you can feel it as an instability in how the car feels when I accelerate by slowly leaning into the throttle from 2000 rpm. It doesnt feel like a dead spot like a lean or overly rich condition does as the engine is still seeing constant boost. The difference is that if you just stand on the throttle hard at 2000 rpm it doesnt shuffle, and acceleration feels much smoother.

At sustained higher revs it disappears completely. The painful part of it though is that the engine drives nicely a good 1000 rpm below where the RB26 did, but that same RPM is right where the shuffling starts. ~2000 rpm.

[9krpm]

Nice build mate

[SimonR32]

At sustained higher revs it disappears completely. The painful part of it though is that the engine drives nicely a good 1000 rpm below where the RB26 did, but that same RPM is right where the shuffling starts. ~2000 rpm.

Ever considered going a single... Instantly get's rid of these problems!

New GTX3076R comes to mind

[Harey]

Yeah agree but it looses the whole factory engine bay appearance thing!

[GTRNUR]

Perserverance with the GTRS's is paying off. That and the now re-scaled RPM scale of the d-jetro that is allowing better tuning resolution for low rpm driving and transition onto boost.. as was done here:

http://www.skylinesaustralia.com/forums/topic/347851-power-fc-scale-tweaking-for-more-resolution/

1200k's on the clock now and what tuning ive done on boost has been a load of fun. So much so that if I am intending on keeping a license i'll have to dyno tune the car's top end.

The cooling system is proving to be a little problematic, though that is typical of this time of the year in Cairns. Even the stock engine struggled in heat like we have been getting. At 10am this morning it was 38 degrees outside with a stupidly high humidity. With the aircon blazing away the engine temps tend to run away a little so I have to keep turning off the air-con. Its fine the moment when the car is doing 80km/h+, but that never happens in city traffic where the average is 30-40. Im contemplating trying a different style of fan and viscus fan clutch to get more low speed airflow through the radiator.

In preparation for the dyno tuning session that will happen next year I did a little shopping today. A big box with Nismo written on it should hopefully arrive just in time for christmas.

That is all.

[N1GTR]

Sorry, 10am and 38 degrees? Time to move!

[GTRNUR]

Sorry, 10am and 38 degrees? Time to move!

Yes the thought had crossed my mind. It been much better the last few days though. Now we are getting cloud and thunderstorms instead. Its just this time of the year we get a few real scorchers of days. The wet season will start soon and that cools things down a lot, and floods everything of course too.

[carbonjunky]

very nice gtr mate i like how youve kept it stock looking

[GTRNUR]

very nice gtr mate i like how youve kept it stock looking

Thanks.

Here's the latest upgrade. I fitted a Nismo intercooler a couple of days ago. Not quite so stock looking anymore, but Im planning on putting a Nismo front bar on the car too with the black grills in place to conceal the intercooler a little.

[N1GTR]

You could spray the intercooler black? Full stealth

My ARC one is all black now

[GTRNUR]

You could spray the intercooler black? Full stealth

My ARC one is all black now

I considered paint, but I also like the look of the z tune's and they use the same front mount which is just visible through the bar mesh. The nismo front bar will do.

[N1GTR]

No updates in a while, is it too hot up there still to be playing with cars?

[GTRNUR]

No updates in a while, is it too hot up there still to be playing with cars?

Too windy and wet actually! We had this catagory 5 cyclone buzz by recently. Fortunatly i'd spent the better half of the last 12 months updating my house roofing, guttering, and removing all the large trees that threatoned the house (and more importantly the garages)! No damage at all other than blocked downpipes from all the debris from neighbours trees.

The latest with the engine is that it going very well. Over 2500K's on it now. I have upgraded the cat to a 3.5" (4" body) high-flow and replaced the 80mm nismo exhaust with a 90mm titanium trust R system. I've also finally put a boost controller on the engine so it maintains 0.8 bar through to redline now (currently 7K). Im pretty sure i'll run out of fuel if I crank any more boost into it though as I'm still only using a standard R34 pump. I havent yet made up my mind on how to proceed fuel system wise. I dont want to have a noisy fuel system that makes the car smell of fuel vapor, so perhaps an under car surge tank will be the go.

The tune is for the most part sorted, though I'll be touching it up a little this week in preporation for the engines first track day. Im not going to be trying to be competetive at this first event for the year. The intention is to go there and make a lot of noise and tire smoke, and have some fun, and of course take some video of the car getting a little sideways. Should be a hoot!