JDM ECU Considered an upgrade for USDM Alltracs?

I have a JDM Celica GT-Four A imported from Japan that was completely bone stock down to the OEM brake pads and spark plugs when it got here, nothing on the car at the time was aftermarket.

The speedometer has been confirmed (driving beside someone in a brand new Civic SI at 100 KPH, speed’s were the same)

As mentioned I have no problem running 91. Even well spiking to 14-15 PSI due to my exhaust.

We have one station that sells 94, and it’s mixed with ethanol. It’s about a 25 minute drive for me so I run 91 out of convenience. Shell V-Power is the only gas I run but my car loves it. I have ran the 94 for a full tank once(well I was stock) and their was no difference whatsoever, car was pushed hard to confirm.

I have gone well above 180 KPH, the speedo stops at 180 so I’m not sure how fast, but I was well into the 200’s. It pulled hard for a while past 180.

My Fuel cut kicks in at 14-15 PSI.

Are there differences from JDM ecu's from 90-91 and 92-93?

-Towels

Update:


How you guys are running 91 oct on the JDM ecu blows my mind.

When stock, i found 94 just cut it. I could run 92, but 91 and below ran like crap.

According to some sites and posts from other owners, the JDM cars use 95-96 PON oct Stock.

I've since added about 4 psi to my car. And 94 no longer cuts it. At all really

So, ive been experimenting with oct boosters.

Primarily Toluene. Oct PON of 114

In Canada: Toluene can be purchased from Recochem in 1L, 4L, and 20L volumes. Lordco in BC can get recochem products, and they have given me a sweet discount for the stuff.

I can get the 20L pail for ~60$. vs 95$ retail.

Yes thats alot of money, but when compared to the name-brand oct boosters like NOS (20$ for 1L) which dont do much anyway, then its the logical solution. (and how can they: For 1L of NOS to boost the oct an advertised 6 full levels (so 60 points) it would need to have an oct of 170+ (i dont think thats possible), or you would have to add about the same, if not more volume as toluene additive.


According to shell's website. Toluene is the primary Oct additive used in their fuel. Same with Chevron. So its perfectly safe - in moderation.

A few sites reference toluene back to 1980's F1 racing, where they ran 84% toluene fuel so they could boost to 70PSI. the remaining 16% was N-heptane (0 octane). This is how Toluene got the name "Rocketfuel"

ASTM standards allow 25-40% mix of toluene in Canadian gas. So, say the gas is at 30%, that leaves 10% increase of toluene.

But even if you go over that 40%, its still within spec for Europe and asia where shell runs 100 PON Oct.

Also, Toluene is pure hydrocarbon. It doesnt have any metals, or oxygen molecules which can damage emissions parts, or change the AFR.


It is nasty stuff though. Dont get it on the paint, it will be gone before you can wipe it off. Dont inhale it, or get it on your skin

Its used to cut crystal meth too. So when you buy it, point out its going into a car lol.


An RX7 guy on rx7club.com said he left a rubber fuel hose, peice of steel, and a silicone vacumme line in 100% toluene for 1.5 years. the only thing to get damaged was the silicone because toluene is a silicone solvent.


I have noticed no change in gas mileage with toluene added to the tank. The car runs noticably different, in a good way.

The problem with NOS oct booster is its full of so much extra crap you dont need. "Nitromethane" for example.... why? Yes it takes less oxygen to combust than gasoline, but doesnt that change AFR? the NOS booster turned my spark plugs orange. and although it says its 02 sensor safe, i have my doubts.



Anyway, ill keep this thread upto date with any toluene developments i get.

BTW, Recochem Toluene is 100% pure. Thats why its so pricey.

The part number for the 1 gallon cans is 13-274

To treat my tank, I intend to mix ~12L into 60L of fuel. This raises the OCT of 94 PON, to 98 OCT. This is only a 20% mix. Its usually suggested to go no higher than 30%.

Here is a great calculator for mixing race fuel, and determining its price/L

http://ranney.com/mjr/fuel_blend.html


Cheers

Corey

Corey, we're not having any problems running 93 octane with our JDM ECU - running all the way up to 14 psi in cooler weather.
even up to 10-11psi in 102* heat everything was normal as could be :shrug:

iirc most other contries use RON instead of (R+M)/2, so their 96-98 RON is really our 92-93.

If you're having problems with it pulling timing, make sure your distributer is set correctly, It might be a little off causing problems.

Corey, we're not having any problems running 93 octane with our JDM ECU - running all the way up to 14 psi in cooler weather.
even up to 10-11psi in 102* heat everything was normal as could be Shrugs

Click to expand...

I know lol, and its driving me nuts trying to figure out why. The difference is immediately noticeable. If I top up a tank with 10L of Toluene, run it dry, and then fill with straight 94, it will run like crap.

Would you be willing to try higher octane to see if the ECU likes it more? Maybe its simply adapted itself to the lower oct... does the car feel any different vs your old ECU?

iirc most other contries use RON instead of (R+M)/2, so their 96-98 RON is really our 92-93.

Click to expand...

Yep. I think the convention is to take about 4 points off from RON to get our PON. I think the consensus here, and definately on gt4oc.com is that the cars run stock on 96 PON. So about 100 RON. Thats why im sure the 94 ive been using thus far is no longer doing the job at 12 PSI, 4PSI over stock.

If you're having problems with it pulling timing, make sure your distributer is set correctly, It might be a little off causing problems.

Click to expand...

I've considered that. I checked my timing a few weeks ago before messing with toluene. It was at 11*. I retarded it to 9-9.5* ish.



Anyone have a USDM ECU i can buy? Its not worth the 20hp lol.

It sounds like you have something else wrong too, I would focus on that instead of changing the ECU.

Any idea if you have carbon buildup on your pistons?

I ran a reprogrammed JDM MR2 ECU for several years on 93, and have been doing the same with an RC ECU for about 4 months.
Neither has any significant issues, even in the middle of the summer [was 92* today and high humidity]. Anywhere from 12 - 18 PSI. I haven't experienced [heard] noticeable knock, and the car has ran smoothly. Either ECU definitely feels better than the US one.

However, some days [hot ones] the ECU definitely feels like it's massively retarding timing [still feels better than the USDM one], and for a bit after some hard pulls the car won't be as responsive, most likely due to knock response.
Resetting the ECU back to base maps [removing the ECU fuse] clears everything up, and the initial drive feels good, but as soon as I get on it I can feel some of the power slowly draining.

A higher octane than 93 RON+MON/2 definitely brings more power to the table.
I have a friend with a RC swapped 6th gen, race gas in his car makes a very noticeable difference. I haven't tried that yet [will soon], but even adding supposedly good quality octane boosters [NOS and some Dale Earnhart 4 pack] makes a seat of the pants difference in mine.

I recently rebuilt the head. while in there, I cleaned all carbon off the combustion chambers, valves, and pistons.

I still want to try a new coil, but it sure appears to be a knock response problem. this toluene clears the problem right up.

:shrug:

hey guys i am about to do this also, i purchased a jdm engine and it came with an ecu but i just plugged it into my usdm ecu. Now I have a MAP ecu it does not do timing tho (mapecu2 does this) I was looking to gain this timing advance and octane rating also because I have put in 540cc injectors and I am now running 100% e85. Which by itself seems to have given me 10-15 hp on the butt dyno.
Anyone have any experience with this? I hear e85 is upwards of 100 octane so I assume this mod would suit me nicely?
Wideband going in at the same time, laptop realtime programmable for the ecu.
Solenoid adjustable EBC installed already (only getting 10 lb not sure if its because my mid-pipe cat is clogged or if the turbo is wanting to poop out... spiked to 15 psi ONCE when i first installed it, now its peaking at 11 holds steady around 9 wtf??)
I have also had problems with the car not accelerating smooth at part throttle I hope this swap helps me the way it helped the other dude.
Ill let you guys know.

oh its a 91 ST185 BTW

Well I got all the pannels off yesterday and plugged the ECU in only to find no go! After a bit of research I find out its a 93 JDM ecu, apparently I got a 93 motor tranny and ecu. Sooo after looking at a few diagrams and a page that showed all the pin-outs of each part number It took me a little under an hour to re-pin/re-wire the ecu. The timing on the distributer was all the way forward, this combined with the more aggressive timing on the jdm ecu caused timing to be pulled at anything over 2psi boost. I clocked it all the way back and it seems fine now.... although I am having problems with idle its only doing 600, do i need to put the timing forward some or is this another issue? Also another weird thing, ive only gotten there twice but when i hit about 6750 i get what seems to be fuel cut???? I hear these dont cut till 15 or 16 anyways, im only hitting 11 because i think my exhaust is clogged. I also have an HKS FCD installed that worked fine with my jdm ecu... whats up with that?? well anyways ide say 5-10 gained on butt dyno... also cruise and partial throttle are MUCH smoother, loving this aspect!

Another benefit not talked about, is the fact that the JDM ECU has no wiring for EGR. So no codes will be thrown if you remove the EGR system. You will not have the "higher EGT" problem, after removing the EGR with a JDM ECU.

You guys should just use water injection if you are going to run a jdm ecu. Heck of a lot cheaper than race gas or additives. There's a lot of discussion about JDM ecus on mr2oc.

Also if you are interested in e85, check mr2oc and esp. supraforums.

J.

Guys, can a 92-93 JDM ECU run fine on a 90 USDM car/motor/wiring harness?

^ yes, you'll just have to move a few pins to plug the 92-93 ECU into a 90-91 harness.

darthripley":2qi22s57 said:

^ yes, you'll just have to move a few pins to plug the 92-93 ECU into a 90-91 harness.

Click to expand...

uggg
really? That sucks. how many pins is it?

there are a few pins that are different there's a diagram in this thread where you can compare:

http://alltrac.net/phpBB2/viewtopic.php ... cu+diagram

i'm sure there's a better thread dealing with repin-ing & i know Nitroalltrac has done it too.

UPDATE:

I take it back, the only reason my car needed more than 94 octane on the JDM ecu had nothing to do with the ECU.

My AFM was in fact damaged, and a replacement has completely fixed the issue as far as i can tell from the 15 minute test drive i took.

So, just as everyone else has attested - JDM ecu really only needs ~94 oct.