I stuck a StealthRammed 355 in an '89 IROC a few days ago, and I'm working on getting all the bugs ironed out of her. I pulled the '165 in favor of a '7730, repinned and rewired the harness to match, and she runs and drives (although a lot of tuning will be needed.) My question is this: the IROC has dual fans stock, and I want them both under the ECM's control. The $8D code has secondary fan settings, but what pin on the ECM is the output driver for fan2? Is that part of the code even functional? None of the wiring diagrams I have show a secondary fan control circuit which makes me wonder. Any help would be great, and I'm starting with an AXYC bin if it makes a difference.

 

I could be wrong but I think the 730 only controls one fan and the other fan would have to be controled by a temp. switch. I think you could just split the singnal to two relays and control both fans that way.

 

This have been up before, do a search and you will find the info.

/N.

 

Primary cooling fan control is on E8
Secondary cooling fan control is on F8
Secondary cooling control works just fine in all $8d variants I've tried it on,
including AUJP and AXXC. Running AXXC and 9C1 Caprice fans on my 454
with no troubles.

 

Great info. Thanks Scott.

 

Yes, you can either "jump" or you can "swap" pin D12 to F8. Do some research on it. I made a post a couple of years ago on the advantages of making Fan2 the primary and Fan1 the Secondary by making the Fan2 temp setting in the eprom lower than the Fan1 Temp setting. This is espeically useful when you A/C comes on (which uses Fan1) on a hot day.

 

I like that idea Grim...my setup is a little different though. I don't just run the two fans independently, I have the "primary fan" set up to run both fans in series, which turns them at a little over half speed. This way they run quieter, and I get even airflow across the whole radiator instead of just one side. "Secondary fan" kicks them both up to full speed by changing it to a parallel circuit, and the A/C switch is set to run just the pass. side fan at normal speed (if pri. and sec. are not requested.) When the A/C is running the pass. side fan, and the ECM commands the primary on, it'll run them both at full speed.

Just something different that I wanted to try. Feedback is welcome, both good and bad.

 

Jaxon / TheGreatJ (I remember ya!) -

Would you be willing to explain or draw out a dummy's circuit on how you wired the fans to do that? I'd be quite interested in trying to duplicate that set up on my 91 Formula if you're willing to share the info....

 

Sounds like a good idea running the fans that way. I have mine wired like Glenn was saying and it works great.

I swapped out the factory dual fans as well. For a shrouded LS1 setup. Should help the car stay nice and cool under extreme conditions.

 

It's nice to be remembered Vern...it's really not that hard to wire up, it just takes 3 relays instead of 2. FWIW it mimics the stock setup on a '98 or so dual-fan Stratus.

Explaining it without a diagram is kinda tough...the primary relay stays like stock, the #2 and #3 relays are the funky part. Both of them are operated by the secondary fan request in parallel with the A/C switch. The #2 relay should have the common contact connected to the ground wire for the primary fan. The NO contact on #2 goes to ground, and the NC contact ties to the NC contact on the #3 relay. The NO contact on #3 goes to the fan fuse, and the common contact on #3 goes to the power side of the secondary fan. The ground side of the secondary fan is grounded.

Anybody get that? I can try to put together a diagram but my art skills are pretty limited.

Mike...how hard was that fan swap? I could use shrouded fans in mine (for those hot Alabama summers) I just haven't had time to try to implement it. This car has only been running for about 2 weeks.

 

The diagram actually turned out pretty good. Here ya go.

 

It was really easy.. And looks close to factory. The hardest part is cutting the upper shroud to hold them in. The motors have the same pigtail connectors so they plug right in. Its almost a bolt in swap, the lower tray holds the bottum of the shroud.

Supposedly they turn a little faster then the L98 setup. The LS1 setup is a little better design then the LT1 imo. And it looks like they upgraded the motors as well.

This is what the LS1 setup looks like on a LS1 radiator.
And few pics of them on the car, sorry not very good.