MK4 Supra 2JZ-GTE MS2 all stock EM hardware

Toyota, Lexus.
BaldTurboFreak
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MK4 Supra 2JZ-GTE MS2 all stock EM hardware

Postby BaldTurboFreak » Thu Aug 06, 2009 9:07 pm

94 MK4 Supra Turbo. 76mm borgwarner extended tip, hks header.
I removed a HKS vein pressure converter and uni-chip and installed a MS2, V3 board using a existing T-harness to cut in. (factory wiring stays intact as does pcm)
Keeping the factory PCM in the car keeps all existing functions working correctly, such as cruise control, traction control, dash functions,A/c, etc.

The MS2 has Jean's Sequential modifications and runs the sequntial beta code.
Wasted spark is accoplished using the 5v pullup method, driving the factory toyota ignitor. There are simple PnP's in the proto area. The Cyl's are paired in like throws, 1&6,2&5,3&4.
Semi-sequential injecting is done using the Jbperf.com 4ch board, however I populated the ignition section with To3055's from radioshack to drive the injectors. (after blowing up all kinds of other drivers :lol:) I wanted the Heatsink of the entire lower case cover instead of the dpak fet's.
Driving Low Z injectors with the Jimstim and my powersupply , the case would get slightly warm around 7A's and 92% duty cycle:lol: Speaking of duty cycle, the injectors turn OFF at 85% with the IRF510 Fet's! They stick ON at 92% duty cycle with the TO3055's. A better condition for the pistons sure!

There is a second VR circuit aboard that is built with the exact values perscribed in the megamanual. I havent had to do much to get it to work with the G2 signal .
One positive thing about the 2jz pcm over the other toyota 24/2's is each VR sensor has it's OWN ground. no carryover signal to clean up..
By leaving the factory PCM in place sharing certain sensors such as the Vr inputs, the filter network toyota designed seems to be in place doing it's job. Scoping the inputs for Ne,G1 G2 produced a nice clean sine bilp. 24Vpp at idle speed of 640rpm. A bonus for your MS aspirations.

After chasing a few inductive demons around we are reset free, and ready to street and dynotune. The car made 525observed/548 Std correction on my Dynomite running a myriad of piggybacks and 20psi. It will be interesting to see what MS2 and the sequential code can do for us. 8000 rpm will be one big bonus with a turbo that doesnt do squat until 5K. The previous rev limiter was 6500. :shock:
It's late and I'm tired. I will post a nice "how to squirt your MK4 supra" when a get a moment to sit down (along with pics).

Megasquirt FTW! :yeah!: :yeah!: and Special thanks to Jean for his help + cool daughterboards!

BaldTurboFreak
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Re: MK4 Supra 2JZ-GTE MS2 all stock EM hardware

Postby BaldTurboFreak » Sat Aug 08, 2009 8:07 am

Spent yesterday driving the car 50+ miles around the hills tuning drivability, and eventually some nice 3rd gear pulls. The car is running great other than a few small quirks, some stalls when coming off revs and hunting idle after a boost run. Some of that is the overlap I have on the HKS264's, some of it is the 850cc injectors on a 500cc cyl running semi-batch.(2 injections per 720). Once I get a nice drivability map finished I will enable x-tau and see if I can get the inconsistent transient Afr issue to go away. I'm sure it stems from wall wetting.
Part of this is the legnth of the runner from valveseat to injector, there is alot of wall & divider present to be hosed by the 850's. Compound that by the fact the factory supra has a pump driver that goes from 9v at idle to ~15v WOT under boost. The 30ish psi at idle + the big injector = poor spray pattern. The motor wont idle smooth at 14.7, It likes 13.5 to be misfire free. Im not super happy about that, I think I may bump up the fuel pressure a Bar to 43.5psi low / 58 high to see if the idle quality improves. Im already as low as 1.46mS pw at idle. You cant get much lower than 1.2mS with a lowZ + dropping resistors, so we'll see how far we can go before the problem actually gets worse.

Well going to work on another cold start w/ drive-away cold drivability. Thats a fun one :lol: Then I'll change the oil again, install fresh plugs, re-enable the meth system, and back it onto the dyno! :twisted:

BaldTurboFreak
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Re: MK4 Supra 2JZ-GTE MS2 all stock EM hardware

Postby BaldTurboFreak » Mon Aug 10, 2009 3:16 pm

So the tune is coming along really nice. Im ready to enable wall wetting and try and get rid of the quirky afr's.

Next on my plate is the IAc. The factory one is a 4 wire, but when I look up the diagram, it has 12v coming from the efi relay thru each pole and to the ecm. It's listed as a 255position stepper, but it's sure not wired like the GM units Im familar with.

Also, knock sense is on my plate. I dont like the idea of a high boost car without knock feedback.

BaldTurboFreak
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Re: MK4 Supra 2JZ-GTE MS2 all stock EM hardware

Postby BaldTurboFreak » Fri Aug 21, 2009 6:31 am

The factory IAC is a 5 wire and isnt compatible with the MS2 stepper chip. It would be alot of screwing around to design a circuit to run it, so Im just going to cnc a block to use the GM iac in the toyota postition.
We may end up with a new plenum anyway so I may be able to just wait until the LS1 TB is on there.

Still dailing quirks out of the AFR's. I sometimes get a condition where Im in the exact same load cell, air & coolant temps, but slightly different throttle angles and road speed. The AFR is 17-1 when at low rpm, higer throttle load, low speed. Same cell at a lighter throttle angle, 55+mph is 11.8-1. "huh"? :lol:

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FoundSoul
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Re: MK4 Supra 2JZ-GTE MS2 all stock EM hardware

Postby FoundSoul » Wed Sep 09, 2009 6:01 am

If you can change your throttle angle enough to go from 17:1 to 12.8:1 without leaving a single cell then I think you may need to rescale your table in that region to dedicate a bit more resolution to that area, it seems the engine is breathing very differently. What are the MAP kpa changes between these two throttle positions? Either it's a big change and the resolution is setup too loose in that region, or there are other cells in the region that are interpolating against this one and pulling the PW up/down. Something is going on, you should have no problem dialing this in.


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