I'm upgrading my ECM to the 86-89 165 and want to use the ARAP bin as a base. My current fan setup is the single fan. I noticed that most people who use the ARAP have the dual fan setup. Will the ARAP bin or any 350 based bin cause me to have any problems becuase I am not using the dual fan setup? Is it worth switching to or do I even have to? If it is how hard is it?

Some people say the single fan is better while others feel the dual fan puts less strain on the charging system. I'd rather keep what I have so I don't have to change too many things.

James

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1985 Z-28 305 TPI
221,000+ mi., Original Eng.

 

Whether or not you go with dual fans depends on several factors: 1) where do you live, and 2) do you overheat in the summer. Both of those are heat related.

I would say that the bin your chip is based on really is not a consideration. It is, however, common to lower your fan turn-on temp in whatever bin you use just for that reason.

Details for converting to dual fan: http://www.metzcon.com/racing/dualfans.htm

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Mike Metzler (Desert86Roc)[*] Webmaster: SpeedWorldMotorplex.com[*] Click Here For 86 IROC 305 TPI (406 build in progress) Page

ET's @ 1250 ft[*] 14.28 @ 95.461 mph (uncorrected, NOS, no headers)[*] 15.365 @ 86.785 mph (uncorrected, headers, no NOS)

 

After reading the material it appears that dual fan and the primary fan uses the same wiring and the secondary fan is run with a relay to the AC pressure switch. Just what I was looking for.

I'm just looking for the gotcha's in the ARAP and 165 upgrade. I don't think anybody has a list that states what to look out for. Like the AC pressure problem, the high timing numbers, VSS disable (for mech. speedo)? etc.

James

 

On my 86, the only things I actually had to correct was to disable the VATS of the 89 code (ARAP bin), and since the ARAP was a 350 chip, I had to lower my fuel injector flow rate to 19#. But while I was at it, I lowered my fan turn on temps. 86-89 vehicles have a VSS, it is just located behind the speedo on cable driven models, instead of on the trans for electric speedo models.

 

You should be fine with the ARAP bin in your car with a single fan. The xtra fan IS NOT controlled by the ecm, just the AC pressure switch, and a high-temp coolant switch, which is set ridiculously high, like 238F. I used to have both fans running to cool my motor, and it really worked, but probably not necessary. I was told that it would put extra load on my cars' electrical system. So I just modified the chip to turn on fan 1 at 185/off at 179. I control the second fan by a Hayden thermal switch located in the radiator. This should only kick in if the primary cannot cool the motor, or when the AC is on.

As for the tricks using this ARAP bin, nothing really special, except what Desert86 said. You may have to reverse the logic for the fan request input. I had to change mine to "normally open". If you are using TC, then no problem. Maybe you could use some numbers from an 88 or 89 305TPI bin, just to get you started. It is a fun process playing with the bins, just go slow with the changes, before you figure out if they work or not. I am on my 3rd chip, with many more to go!!!
Enjoy

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Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!

 

...I am now planning to upgrade the ECM and get everything working right with the current 305 before putting the 350 in. I'll lookup the bin for an 89 305/auto and use that in the 165 w/ my 305.

I can't sem to find a 165 ECM at a self-service salvage yard. I keep reviewing the upgrade diagrams so I can feel more confident about the re-pinning and such.


James