The Tuning Talk Thread - Forced Induction EFI & JZ Tuning.

[JZA70 R]

phil unless the tune on the 30r was a bit average too, i would say its unfair to compare the two at this stage. its obvious your current tune still needs some work, and i wouldnt be surprised if the 35r's low end power was significantly improved once you fix that massive hole at 100kph. not only that but the 35r is going to make another big hit of power once you lean the top end out as imo its too conservative.

from the comparisons i can see you're losing almost 70kw @ 4250 which would be very noticable. get the tuner to fix that hole up when the turbo comes on song and i think you will be surprised at the new results.

[1JZ-Rolla]

Dude, you're missing the point, the power difference at <4500rpm is not nearly as relevant to the tune (AFRs or ignition advance) in that area of the map, its rather the turbo's ability [or inability] to make the same amount of boost at those revs, i.e: boost threshold is vastly different between the two turbos.

notwithstanding this, as you can very obviously see, the transition point as it builds boost (i.e: less than the target 19psi) is too rich, but I can almost guarantee that a leaner mixture at this point is unlikely to pick up even half of what you seem to be expecting.

not only that but the 35r is going to make another big hit of power once you lean the top end out as imo its too conservative.

did you read my original post? At best i'd be happy if it held its 306kw past 6000rpm, but a "big hit of power" is very optimistic. Its very unlikely that further tuning alone is going to yield results that outweigh the flow limitations of the current setup.

That said, it will of course it will get further attention with the tune.

BTW: don't entirely trust the AFR readout from the dyno, I have a sidepipe that exits flush through the bodywork, so the wideband sensor was mounted in a compromised position on a tripod next to the car. The results from my incar wideband (with sensor permanently mounted after the dump pipe) read quite differently.

[JZA70 R]

not missing the point, i understand the two turbos perform differently, and also understand that is partially why you are now lacking power where the the 30r was producing... however, (if im reading the graph correctly) your afr's are (compared to how i tune) three whole points richer than what it could be, and there is significant power to be gained there. What i was trying to say is you could alleviate some of that power loss by correcting the tune at that point. if the afr's are not to be trusted then forget what i said. and who knows what timing is implemented at that point too. timing is just as important and as effective as fuel.

moral of the story is, its not just your turbo that dictates when and how boost comes on, your tune plays a major role in that too.

as for my comment on peak power, imo i would estimate there could be 20kw or more by maintaining 12:0 to redline instead of tapering off to 11:0. again depending on what timing is input, further gains could be had. Everyone's opinion on "safe tuning" is different

[1JZ-Rolla]

Hey Todd, I remember ages ago we chatted about introducing more timing/reducing fuel past the point of peak torque, how much did you end up with in your final tune? I know our setups are quite different (can imagine that the twin turbo setup possibly doesn't allow as much advance near its peak flow) but with 98PULP I was surprised that mine would wear as much as 23 degrees @ 20psi, though it made no more power than at 19 degrees, so that's where its stayed to leave a margin.

Cheers
Phil

BTW: any progress on getting a spray painter to take your car for a reasonable price?

[JZA70 R]

it was just timing, no need to touch fuel... so between 14' and 16' at 18 to 20psi @ 7200, however if you remember I experimented with an additional 4' over the entire map momentarily on a dyno to confirm my timing was concervative (safe)...

you can see the timing increase in my map below.



the final load row on this map is circa 20psi,

have found a renown painter in perth, very expensive but you get what you pay for. car is booked in for a spray in feburary/march...

Cheers

[1JZ-Rolla]

Awesome, looking forward to seeing the result of the spray job, i'll be jealous as hell


[edit] BTW: do you really run as lean as 13:1 at around 6psi boost?

[JZA70 R]

more like 13.4:1

here are my target AFR's...

P09 - 10800 - 0.0 psi - .00 kg - 14.4
P10 - 12000 - 2.3 psi - .16 kg - 14.1
P11 - 13200 - 4.1 psi - .29 kg - 13.8
P12 - 14400 - 5.7 psi - .40 kg - 13.5
P13 - 15600 - 6.8 psi - .48 kg - 13.2
P14 - 16800 - 9.1 psi - .64 kg - 12.9
P15 - 18000 - 10.8 psi - .76 kg - 12.6
P16 - 19200 - 12.5 psi - .88 kg - 12.3
P17 - 20400 - 14.2 psi - 1.00 kg - 12.0
P18 - 21600 - 15.8 psi - 1.11 kg - 12.0
P19 - 22800 - 17.6 psi - 1.24 kg - 12.0
P20 - 24000 - 19.3 psi - 1.36 kg - 12.0

[1JZ-Rolla]

Fark, i'd be worried about the situation where you'd be climbing a constant gradient hill for an extended period in that range, with cylinder temps rising.

Probably never going to hurt it when only transitioning through that point (eg: WOT), but a bit risky otherwise.

Obvoiusly its worked for your setup so far though

[OnAll-FOUR]

What are your target AFRs by comparison Phil?

[1JZ-Rolla]

Whatever the engine needs, and is happy with

As a guide though, I won't tune mine in particular with leaner than 12.5-13.0:1 at zero manifold vacuum, and taper that off to a flat 12.0:1 by 4psi, and maybe 11.7:1 around peak torque.

My car spends plenty of time under constant load though at the circuit etc, so I won't push for marginal power increases over a safety margin (within reason).

[JZA70 R]

Fark, i'd be worried about the situation where you'd be climbing a constant gradient hill for an extended period in that range, with cylinder temps rising.

I think that right there is why too many tuners are being too conservative on tunes these days and hence why a lot of peoples tunes perform poorly. Too much theory, too much what if's and too many excuses to keep it safe.

Its would have been a $500 lesson learnt if I made a big mistake, but that never happened. Yes i pushed the limits and maybe am a bit unorthodox with the way i tune, but there is no doubt the car was amazing to drive. Impressed a lot of people and performed extremely well. I would, and will do it all again with my 2J.

[JP]

do any of you guys use EGT to tune with also? I've been looking around for a 6 probe amplifier to wire in to my ECU for logging/tuning purposes.

[mr1jz]

A Pyro kit JP?
Yes they are awesome and yes i have used them. Provide great feedback for cylinder temps.
I think i will just use an EGT probe in the dump to begin with to see how things are going.

JZA70R=Most tuners are also under the pump from customers. They want maximum HP with the best fuel consumption with a motor that will last for as long as they do. People don't realise the extra stress added to performance engines and expect too much. My tuning practices are close to 1JZ-Rolla's to begin with to set a base and then change to suit what the engine likes/dislikes.
I have tried lean outs with no gains and vice versa with running rich. You have to find what each type of engine likes.

Cheers, Brendan.

[1JZ-Rolla]

I think that right there is why too many tuners are being too conservative on tunes these days and hence why a lot of peoples tunes perform poorly. Too much theory, too much what if's and too many excuses to keep it safe.
.

I'd happily test the limits on my own vehicle in this respect (leaning off the mixtures under load) with the use of an EGT to analyse results. But as you say, if $500 is your only downside (plus labour time) then that's probably cheaper than an EGT setup.

Agreed for sure there are some less than impressive tuners out there, however Indeed most are under the pump from customers to produce an acceptable result in a "reasonable" [unreasonable?] timeframe. Think of the time you've spent on your tune........ then analysing the results, and retuning again. 10 hours? 20 hours? 30 hours? more? Now imagine a workshop doing the same thing, and then handing the customer a bill for it. I reckon 80% of performance car "enthusiasts" would throw the invoice back in their face and ask WTF? Unfortunately this is because there is an expectation that a full tune can be conducted in a matter of half a day, and only cost $600 or less. That's a harsh market to cater for.

You took the right step in opting to take the task of tuning on board for yourself Todd, and reaped good results, with the right equipment. For that you should be commended The best move to make if you're not happy with the tuners out there is to vote with your feet But understand that there are limitations (expectations) that the "professionals" have to work with.

Cheers

[gwilmarlio]

well this is my fuel map so far with a few hours of road tuning
was a mess to start with