Put in my B6 ECU

[Safety Guy]

So far nothing spectacular, but it is an automatic.

I think I feel a bit more ooomph.

I'm going on a trip soon and the really important part will be the fuel economy. I want better than the 25.5 mpg I was averaging. My best was 27.5 mpg. I want over 30 average! About 35 highway would be nice.

Man, getting my B3 ECU out was a nightmare, but I did it. And the B6 ECU went in a lot smoother!

I'm getting a timing light on Thursday and I'll check timing.

Karl

[Safety Guy]

I just got back from my trip to Miami University (about a 250 mile round trip from Columbus) with my new B6 ECU. Seems I could tell a bit difference on the freeway over 65 mph.

Luxstiva cruised very nicely on the highway.

My gas mileage for the trip was 33.2 mpg, a significant improvement (from the B3 ECU after the engine swap) of from 24.5 to 27 mpg. IIRC, I got around 33 mpg with my old B3 engine when I went to Ohiostiva II, with speeds mostly just under 65 mph.

I did go slower on the way back, and there was about 20 miles of city-like driving in there. Plus about another 20 of 35 to 55 mph country road driving.

I'm pretty pleased now.

Karl

[packrat427]

:thumbright:
Fantastic Karl

[Silv3rBull3t]

Yeah I noticed a big difference in highway cruising power with the correct ECU and I noticed a big bump in MPG... Glad your trip went well!! -Kyle

[Safety Guy]

I forgot to figure for my larger tires!

I'm running 165/70-13s instead of those little 12s. I'm a half-inch taller.

I used the Miata tire calculator http://www.miata.net/garage/tirecalc.html and refigured my mileage. It's a 4.7 percent difference.

My new figure is 34.8 mpg!

I was also doing about 2 to 3 mph faster than what I thought at highway speeds. Not bad mpg for speeds of over 65 (on the way there).

Until I put in an Aspire ATX I'll have to factor in the tire size differences.

Karl

[festivaWES]

where did you get the ecm from??? Is it the 2 plug style i can't seem to find one at the junkyards for the life of me. I need B6 323 5 spped ecm

[Safety Guy]

'90 on 323 ECMs should be the same 2 plug style for both MTX and ATX applications.

A guy has a 323 ECM and harness for sale in the for sale forum. You might give him a yell and ask if it's a 2 plug and out of the later model 323.

If you have the older ('87 to '89) 323 engine, it could be either 2 or 3 plug, I think. Better make sure.

I'm using a 2 plug out of a '91 323 for my '94 B6 engine.

Karl

[festivaWES]

my engine i have is 87-89 323. All ecu's that i have looked at are 3 plug from 87-94...

i saw a 3 plug festie the other day too in the junkyard, but it was on a carbed model i think

[Safety Guy]

My second tank of gas was in town going to and from work, etc. I kinda drove a bit...fun.

Got 28 mpg even. That's 1/2 mpg better than my best mileage on the old ECU and probably represents close to the worst mileage I should get.

Now I need to "re-dyno" and then put in the new Bosch ignition stuff. And check timing. I just bought a light for that.

I should probably check plugs and clean any fouling off, too. I would think running so rich the past 3 to 4 months might foul the plugs?

Karl