Overheating problem solved...I think

[Newbie]

:D

I've always run very hot, 250 water and 230 oil. After trying about everything I could think of, I swapped ECU's with a fellow 2nd gen driver. Holy Crap, what a difference!

I could tell on the pit lane as I went out for qualifying. The engine came to life at around 5K and pulled until 9. Plus, the water temp was down to 190 and oil at a comfortable 210-215 for the entire time. I ended up putting it on the front row, outside pole for by best effort of the year so far.

My computer is marked #326, and so was the one I borrowed. Both have been modified to remove the rev limiter. I have an extra marked #327, but I think that is for an automatic transmission, and It probably still has the rev limiter.

Can anybody tell me what ECU's will fit the '87 harness? What is the best way to get one with the rev limiter removed. Is the 86-88 harness compatible with the 89-91 ECU? I have an S-5 engine. I need to make one more race this year (Oct 21st).

Steve

By the way, does this ECU/Temperature/power relationship make sense? I've heard that the ECU controls the timing curve and maybe it was not advancing/retarding the timing properly causing super high EGT's and loss of power.

[bldn10]

"Is the 86-88 harness compatible with the 89-91 ECU?"

NO. And don't even think of trying to mate S5 ECU connectors w/ an S4 harness. Been there done that. :wacko:

[Scooter]

So the new ECU you put in there has a 326 number on it?

And that's the good stuff? Or is there some other modification that's been done to that ECU you borrowed?

Some RX-7s seem to run hot and some don't. I wonder if it's the ECU?

My ECU is whatever came with the car. And it runs hot. How do I get one like you borrowed?

thanks!

[C. Ludwig]

The 326 ECU is an 86-87 model year part. The 327 is an 88 part. There is no real difference. About the same time Mazda made a switch from saturated injectors to peak and hold. I'd suspect the programming has to do with that which is really of no consequence to your temp issue.

As Bill said the S4 ECUs most definetly do not interchange with the S5 stuff.

FWIW...

84-85 GSL-SE N304 18 880A
86-87 NA N326 18 880, N3Y6 18 880
87 Turbo N332 18 880
88 NA N327 18 880
88 Turbo N333 18 880
88 Convertible N338 18 880
89 NA California N350 18 880
89 NA Fed. N351 18 880
89 Conv. CA N352 18 880
89 Conv. Fed. N353 18 880
89 Turbo N370 18 880

[Eagle7]

...from saturated injectors to peak and hold....
[/b]
Huh? I need another lesson. I know about low and high impedance, but .... what's this? Seems like the more I learn the less I know.

[C. Ludwig]

Same thing only different. Saturated are high impedance and peak and hold are low impedance. Peak and hold is a better injector. They snap open and closed more quickly providing more consistent control.

And I got it backwards. The switch was from low to high impedance. Correct? I always get that part confused.

[aryton]

You guys need to talk to Keith Golden.Hes the guy in the back of Sortscar magazine that eliminates rev limiters from stock ecu's.He claims,and others have backed him up,that there are different compuers even though they carry the same N326 or N327.It has to do with the smaller numbers below the number you are referencing.I have notes somwhere on the topic in case i ever built a 2nd gen.Keith has spent many hours on the dyno to find some computers make as much as 4-5 additional HP over those that would otherwise apear to be the same computer.Hope you post your findings.