Gt3076R Antics , Better Late Than Never .

[Dose Pipe Sutututu]

Makes a massive different, you're able to run even leaner without any misfires.. at one stage I had my RB25DET running at 16.5AFR (converted to gasoline scaling) and the car would run great... albeit economy wasn't that great because the leaner you go the less torque is produced.

disco, go flex.. you won't look back. I don't bother with E85 98 maps anymore, just use the compensation tables to add in timing and fuel when the sensor sees E85

[discopotato03]

Overdue update , went back to E70 from P98 last night mainly to get back into Ethanol tuning .

Took about 3 goes and 10 minutes to get acceptable running from my dino juice tune . Still using the Tech Edge to monitor AFRs . Was on the rollers last year after the head refresh and to get P98 maps reasonably close - for road and with ID injectors . Not surprisingly the max power went slightly backwards from the original GTRS/E70 tune but only by 3 kw . I thought the 3076 would do a little better on PULP but I think the Blitz return flow woes had a say here . I have the IC Stao likes on order with a wait time of 6 weeks and should hear back about it soon I hope . Aside from the shorty ID850s also using a 33 GTR Nizmo fuel pump .

A . 

[Dale FZ1]

Throw up the dyno sheet for this setup on 98.

And one for ethanol when you get it on the rollers again.

We understand this thing is not all about the numbers, but it'd be good to see.

[discopotato03]

I don't have the P98 one , I think I had a pic of it ages ago but M.SD card in phone died . Once the IC is in I want an ethanol content sensor and possibly a bypass because I'm not sure they flow that well . Can anyone show how they get around restrictions with these things .

Also depending on how things shape up I may consider a turbo upgrade , EFRs sound nice but some later GT30 based thing like say a gen 2 3071 would at least be an easy swap . No great hurry with this and I'd like to see more results with them .

The existing 90 deg bend off the compressor housing is the old GTRS kit one and it looks terrible , a smooth 2" elbow shouldn't be hard to get . 

Gotta like the smell of ethanol - at the filler and and out the back , not as good as Jamisons but much better than ULP .

A .

[Dale FZ1]

With less than 300rwkW you're not going to strike any restriction problems with an ethanol sensor.

You've identified the air delivery system as being a restriction point, suggest sticking with the cooler ducting and cooler itself.  Maybe the cat also, from memory.

Meanwhile in the absence of a dyno sheet, give us an idea what you actually think of this 52T 3076, the whole point of this thread (I think?).  How does it stack up as a streetable responsive setup?

[Dose Pipe Sutututu]

Come on Adrian, I've got pretty much the same car, a slightly better fuel system than you, same ish motor, same ish turbo (well not anymore) and not once did I have issues with the fuel return.

Stop over thinking it, on idle I can easily get my fuel pressure down to 2 bar and the ethanol sensor is connected on the return line straight out of my FPR. 

Not to mention I've been on the track countless times without a single problem using a pump that probably flows nearly double of yours.

Now if you were running a surge tank with twin pumps on full noise all day then you "might" have an issue with the return being too small.

[discopotato03]

The ethanol sensor is part of a grander scheme with better management , atm I need that IC delivered so the pipework can be sorted . Mine may need to be slightly different because I'm using a Plazmaman rail and the reg is off to front and left of it where the cold side pipes sometimes run .

Also waiting on an aerial unit and fan hub from Kudos . Want a real fan hub which isn't cheap but will out live the car in theory .Back in a sec . 

[Dale FZ1]

On ‎4‎/‎16‎/‎2017 at 8:46 PM, Dale FZ1 said:

 

Meanwhile in the absence of a dyno sheet, give us an idea what you actually think of this 52T 3076, the whole point of this thread (I think?).  How does it stack up as a streetable responsive setup?

Still waiting

Seeing this talk of doing an EFR upgrade, are we to presume that the turbo doesn't hit the desired mark?

Or are you looking at resolving the air ducting systems before committing to a final opinion?

Considering the volume of discussion over some extended time on this oddball 52T 3076, it'd be good form to give us your drive impressions of this unit on an RB25.  Clearly it's an outdated/superceded spec, but some direct commentary helps paint a picture for us all.

[discopotato03]

Well I get side tracked because I have a life to live .

I couldn't get phone to link with this lappy earlier but reg looks like this . And that L shaped elbow . Yes officer than an factory engine and turbo .

The 52T GT3076R . Until everything else is right its hard to give it an honest appraisal . At different times it has felt better and worse mainly because the tuning pre boost has to be right . Last night I was watching lappy WB02 and revs and the dryer didn't offer a real lot of urge under about 3500 revs . This not to say it doesn't add positive manifold pressure lower down but not much of a shove in the butt dyno .

Being again on E70 the part throttle torque is better than 98 PULP and the idle manifold pressure even creeps down slightly lower than on PULP . Problems I'm having is trying to get this engine to return to a consistent idle and no matter how I tune this thing feels like its got a fuel lag as soon as the throttle is opened . I'm using the ID supplied dead time corrections and hoping they're right . I'm double checking everything for vacuum leaks and next replacement is the 21 yr old PCV grommet and hose . Probably pull that IAC housing off again and clean it and the screw adjuster 

Going to be too busy again next week to do anything but hope that intercooler turns up . I need to speak to Insight and organize the flex fuel gear and look further into Emtron .

 

A .

[Dale FZ1]

17 hours ago, discopotato03 said:

 

The 52T GT3076R . Until everything else is right its hard to give it an honest appraisal . At different times it has felt better and worse mainly because the tuning pre boost has to be right . Last night I was watching lappy WB02 and revs and the dryer didn't offer a real lot of urge under about 3500 revs . This not to say it doesn't add positive manifold pressure lower down but not much of a shove in the butt dyno .

Problems I'm having is trying to get this engine to return to a consistent idle and no matter how I tune this thing feels like its got a fuel lag as soon as the throttle is opened . I'm using the ID supplied dead time corrections and hoping they're right . I'm double checking everything for vacuum leaks and next replacement is the 21 yr old PCV grommet and hose . Probably pull that IAC housing off again and clean it and the screw adjuster 

I need to speak to Insight and organize the flex fuel gear and look further into Emtron.

 

When I ran the more common 56T 3076, it was very obviously providing urge at 3000.  By 3500 it was really strong, and by 4000 it was all happening.  And all very progressive with no light switch delivery at any point.  General impression is this thing does similar but doesn't really offer the airflow (ie power potential).

Failing gaskets and old components don't help if you're trying to get the thing running right.

Flex fuel sensor is a no-brainer, fairly cheap and makes the whole exercise of using ethanol simple when supplies aren't where you travel.  There is nothing at all deficient about the Link/Vipec ECU for what you're trying to achieve - change of ECU  to Emtron won't help if the approach to tuning isn't right.

Saying it feels like there is a "fuel lag" , along with other comments along the way about pursuing fuel economy makes me think there's a fundamental issue with tuning this thing.  I'd like to see the target AFR table (assuming the actual AFR is pretty close to what is targeted, and the target is rich enough), and think the accel enrich area is the other place to look.

Seems like it's probably too lean as you come into boost, and insufficient enrichment as you come onto throttle.  Too little fuel will do that.

The other issue I would investigate is the WB kit.  Are the readings it delivers accurate?  As in comparable to a known good unit? (if you get it onto a dyno, check it against what the operators shows).  It's not that uncommon, and may be due to ground plane differential.  Tuning with a mistaken belief that your AFR are correct because that's the numbers you're logging can lead you up a blind alley, unless you're reading the signs.

[Lithium]

Sometimes a tuning issue can come down to fuel pressure or some external thing but there is every possibility it's as Dale says, the numbers the ECUs are crunching.  There are bazillions of Links out there on RB25s etc which can rev without hesitations.

[discopotato03]

Well its now richer in the 2500-3500 area and dipping from mid 9s lambda to mid 8s and occasionally down to 7.7 . A bit more positive pressure timing too .

Next is to wind back the accel sensitivity to something more sane like 30 . Just for the record I'm just playing with someone elses PULP mapping by increasing the main fuel multiplier and trying to dial things around that with no rollers . All road stuff . Also Insight said both times they had it that my Tech Edge WB3A2 reads very close to their gear and yes its running the reasonably current LSU 4.9 probe .  

I'd like someone to throw some timing numbers at me for the 100 kpa (atmos pressure) to 200 kpa area . I doubt you could hurt this thing on E70 provided it didn't run stupid lean but I'd like to hear what people typically run at 1-1.3 bar on this or E85 . 

 

 

[Lithium]

Please tell me you mean 0.9 lambda, down to .7x lambda and not 9:1 AFR etc 

[discopotato03]

Yes the Tech Edge reads in Lambda not AFR . Personally I think 0.77 Lambda is ridiculous but I'm not a trained tuner . I think the Tech Edge refuses to read lower than 0.7 and just says RICH . Is there a way to have the ViPec Target AFR read in Lambda ?

Looks like Dale was right with AFRs but the difference feels like more engine torque rather than big increases in turbo excitation in the 2500-3500 area .  

I think the sad truth is than RBs will never have good consumption no matter what you do to them . 

[Lithium]

Depends on which Vipec/Link you have - the G4+ generation allows either. 11.3 is quite a lot on E85, but maybe not so bad on 98

[discopotato03]

AFR Target and timing looks like this . It probably could use a bit more timing at 1 bar but I think this is better sorted on the rollers .

[Lithium]

How did you build your timing map, or where did it come from - and where are your weird mixture spikes?  It's been a while since I've done an RB25 on pump gas but my gut feel is telling me that the timing numbers from 2000 to 4500 at light vacuum are really high, overadvanced timing can result in lean spikes and stumbles at light/transient load.  If you are struggling with accel enrichment in that range I'd consider pulling some timing out around those zones to see if it gets any more sensible.   Bare in mind piston acceleration from TDC (which is very dependant on rpm) have a HUGE amount to do with what timing you run.

On the flip side (and not so much of an issue when in road-tune mode) your timing numbers on boost are pretty soft above 5000rpm.   BTW, if you are who pulled the timing out from 5000rpm... if your intention is to keep it safe then you really shouldn't have bigger numbers below then, especially 4+degrees more! 

Edited April 24, 2017 by Lithium

[Dose Pipe Sutututu]

odd timiing map, surprised motor hasn't gone bang

[Kinkstaah]

Is it? If it's absolute KPA  I have seen worse......:p
Pretty aggressive around 0psi, mind you. But you wouldn't expect it'd be bogging down as the symptom..

[Dose Pipe Sutututu]

If all you have is a hammer, everything looks like a nail