Robgrob

After buying a SC400 this fall, it turned out it had a defective ECU, AFM or some other EFI related issue that was really hard to figure out. Instead of throwing money at the stock system, and in dialogue with the seller that almost ended in returning the vehicle, we split the cost of a megasquirt PNP system for the Supra JZ80 2J engine!

First things first, specs before megasquirting:

92 SC400
2x 2.5" catless exhaust on stock headers
"BFI"
W58 manual transmission


I want to keep the car street friendly, but with some occasional track and drag duty. Ill need some upgrades and I made a quick list:

Electric fan conversion
AC delete
Hurricane headers if they fit LHD cars
Oil cooler
LSD
Bushing upgrade
Supra suspension parts


Enough bull, lets get to the point. I got a PNP ECU from DIY autotune. The ECU was made for the 1 and 2J engines, but it works on the V8 with just some small modifications and a new MSQ (map). The install took about 6 hours in total, Id say 1h was the megasquirt, and the rest was the wideband, new intake and sorting a few details. The stock front O2 sensor was seized in the header, so I had to cut it in half with a large punch and then use a 22mm socket on it.


Stock ECU:


The fun parts:



Stock VS PNP ECU:



New ECU installed - Anyone know what the top right hand ECU is by the way?



The vacuum hose was routed through the passenger side fender well trough the firewall:



Stock there is a solenoid for the fuel pressure regulator. Im not shure is this needs to be removed or not, but it looks cleaner and the solenoid is a potential leak point, so I did.. Here is the stock vac hose connections:



Here the solenoid is disconnected, the FPR has a direct connection to the manifold and the ECU has its own vacuum source:



The only wiring I had to do was done on the "options" connector on the ECU. The options connector offers 23 pins of various outputs, some are programable, others are spark outputs etc. Since the 1UZ has a slightly different wiring then the 6 coil xJZ engine, I had to loop spark output E with output B. This is because the megasquirt has to use output B for coil #2. I also put a wire for wideband O2 sensor input on the connector.



The AFM is no longer needed, so I removed it completely. Engine bay before install:



New 3" pod filter with professional heat shields:



Im planning on cutting a hole and put the filter into the fender well. The cardboard shields will do for now to keep some hot air out.



Software:
I used the 2JZ MSQ file and reworked it. Almost every setting needed to be modified, so it was pretty much like starting from a blank file. I used the VE basemap creator to create a VE table, and that looked quite good. I created a spark table based on previous experience, since I could not find any spark maps for the 1UZ out there. On 100KPA / 15psi (thats WOT on NA, not 15psi boost!) I set 30 degrees from about 4000RPM to redline as a baseline. Hopefully that will keep me from knocking.

The car started on the first try! A few minor settings on the idle IAC had to be adjusted, and then the car idled @ 1000RPM as commanded! Unfortunately, my Innovate LC2 crapped out on me after just 1 minute, and has to be returned to Innovate for repair Hopefully I can find a replacement to use for tuning.



Im happy to share my MSQ with anyone who needs it. More info, tuning updates and so on will follow when I get a new wideband installed. Ill head to the dyno at some point after my new headers have arrived.

t2d2

iTrader: (8)

You can remove the fuel pressure vsv entirely and clean things up even further. I was undecided about taking mine off, by the Lextreme EGR Delete guide said it can go, and I tried it a couple times both ways and couldn't tell any difference, so I finally removed it for good.

Your air intake heat shield is exactly what I was suggesting a few weeks back in a suggestion about cone filters performing worse than the stock air box because of heat soak. I don't know why it's such an either/or issue for everyone. Your setup will work great once sealed up. I would recommend some flexible plastic that can be molded into that shape, finished off with door edge guard or something similar to snug up against the bordering items and bottom of the hood.

Beyond that, I love anything that can remove the fragile MAF from the equation.

Robgrob

The valve will be completely removed, but first things first


About the cone setup, though I havent seen the discussion you are talking about, I tried my setup on the stock ECU running MAFless. With the AFM and stock airbox (BFI) with the AFM disconnected, the car was consitantly about 0.3 seconds slower 0-60 then a straight 3" pipe with a cone filter and heat shields in cardbord. So much for the "BFI".

But Im not starting that discussion in this thread, Im going to put my filter into the inner fender area. The space there is completely heat shielded, and gets a constant fresh air from the front intake. Im placing the filter as high as possible, so the filter should be out of the way from any water that makes it through the intake.

Robgrob

Some minor updates on the progress here. The VE table is slowly developing to a functional table. Car runs smooth as stock, idles great at 14.7 and has good power all over.

VE table:


The table table is what I would call a safe starting point, with a distributor like timing and a conserveative timing at WOT. I expect the engine to handle quite a bit more timing, especially at high RPM where the VE drops very fast. Hopefully a set of headers and completing the exhaust system will flat out the high RPM VE a bit.





The idle control is what I have struggled the most with however. The factory IAC was stubborn, but after f**ing around with the settings for a few days, it now has factory smooth idle in open loop mode. Ill need to work on closed loop, but Im almost there.


Im ordering a set of headers this week, and a pair of flowmaster high flow cats. I will then complete my exhaust and hopefully flat out the VE table. Then Ill need to get to a dyno to do the spark hook test and complete the tuning progress.

Robgrob

Today I wanted to flat out my VE table on the high end. I really dont like the way it feels like hitting a wall at 6000RPM. So I ordered a set of these:




PPE headers with black coating. I then got a pair of high flow cats from magnaflow to bolt on to them.

The exhaust will then be completed with Headers, high flow cats, 2.5" pipes through a large X-pipe and 4 2.5" mufflers to keep the noise down. Im hoping to raise the top end VE enough to make a flat powerband up top. Im keeping my 7000rpm limit for now and then Ill see on the dyno when the exhaust is done if there is any power up there.


Im also looking at the intake. The filter is going through the chassi to a cold location, and Im considering to remove the stock resonator box and replace it with a pipe. The bend is really poor, and way smaller then the rest of the intake tubing stock.

Im considering if the stock intake manifold at the very minimum should be cleaned inside out, and perhaps a mild port match job should be done. When it is off, I can do some minor work removing any cast leftovers in the ports and manifold as well.

alltrac

Thanks for putting this out. Can't wait to read more!

Robgrob

These just arrived today:



TRD JZA80 Supra suspension - 615 (11kg) front and 521 (9.3kg) rear springs. Hopefully it wont brake any bones

Im looking into some bushings to upgrades as well to make the car more stable in high speed cornering.



I did a quick performance check today btw - 0-60mph in 6.1 seconds - Not to bad considering I had massive wheelspin from the 225 winter tires. The car really has a lot more power in high RPM then it did on the stock ECU. It actually pulls fairly strong all the way to 7000RPM, though you feel the power dropping. I did increase the timing in the top 2 coloumns and that really helped. Hopefully my planned mods will flat out the power even more in the top end. I would love to have a flat power curve up to 7000, but Im worried those grandma-cams wont let me.

gerrb

iTrader: (34)

Props to you for getting the MegaSquirt running on your car. The ECU is gaining momentum and more and more people are using it with great results. I see that you are out of the USA and I assume less support. Are you using the auto learn tune of the ECU ?

alltrac

Any improvement in the low RPM range? Those grandma cams shouldn't be holding too much back in that area. I'm debating megasquirt vs a hard wire unichip to beef up the under 4000 RPM performance.

Kris9884

iTrader: (7)

I agree, I'm glad someone is taking it to the next step. My roommate ordered the DIY megasquirt and had to solder everything himself for his Miata. The Auto-Tune was awesome for a great baseline and just needed very minor tweaks on the dyno for a few more HP, Megasquirt is the *****!

Keep up the good work man, Subscribed!!

Robgrob

This is my 4th car on megasquirt, first PNP setup. I dont have any local support unfortunately, but the online support is so good that I have learned everything I needed to intstall and tune all 4 cars myself. I have spent countless hours reading and testing though. And my wife has hated me from time to time, haha. I must admit, the tuning on the first car was terrible, but I learned a lot from it. This was back when megasquirt 1 extra was the "hot" stuff, long before the "auto tune".

On this and my previous build I have used autotune. It has really become a work of art, and the VE tuning on megasquirt is probably faster to tune then any other system. The car went from a barely drivable VE table to a fairly good table in less then 1 hour. That includes making the car idle. I simply bring my PC when I go for a drive, and it tunes it selfe. Amazing stuff.





I cant say 100% for sure, as my stock ECU was probably bad. I have not spent any time at all tuning the low end timing table, but the VE (fuel) table is quite good. On the stock ECU, the low end was absolutely terrible with the AFM connected. Without the AFM the low end was actually quite good on the stock ECU. Id say the low end performance is much the same, but midrange and high end is night and day. I suspect more timing and less fuel in the low end will improve it from stock (AFM less), but probably not by much. Once I get my headers and complete my exhaust I will bring it to a dyno and do a spark hook test in various RPM and load ranges.


The grandma cams looks like they are very good in the low end. They look like they max out just before 6000RPM, but the crap headers and long intake runners may play a role as well. But 1500$ for new cams is not an option at this point.




I cant say anything about the unichp as I have never seen or tried it. However it looks like air flow meter and ECU failures are becoming more common as the cars get older. To me, spending money on eliminating both makes more sense then modifying the stock system.


Here is my current AFR target table. It probably does have a few ponies left on the table,but its a safe start point to tune with.

Boergy

iTrader: (2)

great thread!

please update every day

gerrb

iTrader: (34)

Nice ! My only concern with Megasquirt is support . You have to do a lot of work on your own research. I guess that is why it is marketed by DIYAutoTune. Also their prices have been at par now with the other well known / established ECU makers. Like a PNP for the MKIV is $1599. Kinda loosing their edge on being a cheaper alternative. But no doubt , been hearing some good new about them.

Robgrob

1600$ is almost big name prices. But this is plug and play and still saves a bit of $$$ over AEM, haltech etc. There wont be the same need for support with the PNP system, and if you need it the guys at DIY are very helpful.

I can agree on your support concern with the DIY kits though. When I started I considered it my 2nd education. I spent days and weeks reading, asking questions. But again, the community is great, and the msextra forum answers most of your questions. And it was the only way I could afford to run a big turbo with a proper EFI. I think I spent about 3-400$ back then on a complete kit plus a wideband, compared to my friends who spent 2000$ + on haltechs and then just as much tuning them.

Im sure their tune was better then mine, but that never seemed to stop their overbuilt expensive engines from blowing into bits, where my cheap *** DIY cars could go at it for years! Well, sometimes

Robgrob

Thanks!

Every day, hm, that could become expensive! How about every week?