Fan Temperature Switch? - ZR-1 Net Registry Forums

90ZRJR1 · 07-04-2010

I could use some help guys! Is the electric fan controled by an external switch or is it controlled by the computer? I have a 1990, totally stock, and I would like to have kick on a little sooner. It seems like it kicks on around 240 degrees or so. What can I do? Thanks Jimfahne

gbmidyear66 · 07-05-2010

Change the PROM in your ECU to have them come on earlier. Marc Haibeck offers a PROM upgrade that is a good choiuce

Paul Workman · 07-05-2010

As mentioned, Marc Haibeck's calibration upgrade for the 90 ZR-1 includes better heat control by way of operating the fans to both come on at 205* and turn off at 200*. I can tell ya it makes a world of difference - not just the fan operation, but the entire calibration package really improves overall drivability (IMO).

P.

tomtom72 · 07-05-2010

Not to sound like a shill for one of our beloved ZR-1 Tuners.....

....but, I agree with Paul's statement 100%.

I've had my Z for 5 yrs and this year I finally broke down and bought one of Marc's reprogrammed PROMS. Man what a difference! On the face of it the price does seem steep. After all your car is not on a dyno and the program is not written for Your car while it is data recording on the dyno....but I can not describe how pleased I am with Marc's off the shelf PROM.

You can wire up a manual switch to turn on the secondary fan when the temps start to rise, or you can just turn on the A/C to get the secondary fan to help pull heat out. I did this for 4 yrs because I was too stupid and cheap to realize that Marc's program is a total package, not just fan call in temp changes.

My best advice is just call up Marc and mail order the PROM. The install is easy as it is a piggy-back that plugs into the existing PROM below the cylinder ident slots on the factory PROM. The only thing you need to do is remove the OEM cover from the OEM PROM and plug in Marc's PROM starting below the first 13 pin holes, slip it back into the ECM and push the PROM back into it's slot and you're done!

Sorry if I sound like a cheerleader, but this was the best $$ I spent on my Z in the five years of ownership!

Tom

90ZRJR1 · 07-05-2010

Thanks for the info guys.Looks like I'll give Haibeck a call for an upgrade! Keep it revved up, Jim

1990 Blk/Grey #115

Hammer · 07-05-2010

I ahve Marc's prom also. Read up on what his prom will do for the operation of the car. Can't go wrong. The car will drive much better with his calibration.

Keep your old Prom in the static wrap your new comes in for later, selling the car or emissions.

Let us know what you think once you've swapped them and driven it.

07-05-2010	#2
gbmidyear66 Join Date: Feb 2008 Location: Vancouver, BC Posts: 252	Re: Fan Temperature Switch? Change the PROM in your ECU to have them come on earlier. Marc Haibeck offers a PROM upgrade that is a good choiuce __________________ [SIGPIC][/SIGPIC] __________________ 1990 Corvette ZR-1 #2824 4.10's, Custom PROM, Flowmaster, Top End Port NCRS BC Chapter

07-05-2010	#3
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Controlled by the ECM... As mentioned, Marc Haibeck's calibration upgrade for the 90 ZR-1 includes better heat control by way of operating the fans to both come on at 205* and turn off at 200. I can tell ya it makes a world of difference - not just the fan operation, but the entire calibration package really improves overall drivability (IMO). P. __________________ Good carz, good food, good friendz = the best of timez!* 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry Last edited by Paul Workman; 07-05-2010 at 07:31 AM.

07-05-2010	#4
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Fan Temperature Switch? Not to sound like a shill for one of our beloved ZR-1 Tuners.........but, I agree with Paul's statement 100%. I've had my Z for 5 yrs and this year I finally broke down and bought one of Marc's reprogrammed PROMS. Man what a difference! On the face of it the price does seem steep. After all your car is not on a dyno and the program is not written for Your car while it is data recording on the dyno....but I can not describe how pleased I am with Marc's off the shelf PROM. You can wire up a manual switch to turn on the secondary fan when the temps start to rise, or you can just turn on the A/C to get the secondary fan to help pull heat out. I did this for 4 yrs because I was too stupid and cheap to realize that Marc's program is a total package, not just fan call in temp changes. My best advice is just call up Marc and mail order the PROM. The install is easy as it is a piggy-back that plugs into the existing PROM below the cylinder ident slots on the factory PROM. The only thing you need to do is remove the OEM cover from the OEM PROM and plug in Marc's PROM starting below the first 13 pin holes, slip it back into the ECM and push the PROM back into it's slot and you're done! Sorry if I sound like a cheerleader, but this was the best $$ I spent on my Z in the five years of ownership! Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

07-05-2010	#5
90ZRJR1 Join Date: Oct 2009 Location: Barnegat NJ Posts: 6	Re: Fan Temperature Switch? Thanks for the info guys.Looks like I'll give Haibeck a call for an upgrade! Keep it revved up, Jim 1990 Blk/Grey #115

07-05-2010	#6
Hammer Join Date: Apr 2006 Location: Ideho Posts: 2,653	Re: Fan Temperature Switch? I ahve Marc's prom also. Read up on what his prom will do for the operation of the car. Can't go wrong. The car will drive much better with his calibration. Keep your old Prom in the static wrap your new comes in for later, selling the car or emissions. Let us know what you think once you've swapped them and driven it. __________________ [I][FONT=Comic Sans MS]John Boyd[/FONT][/I] [I][FONT=Comic Sans MS][SIZE=1]Ideho[/SIZE][/FONT][/I] [FONT=Comic Sans MS][SIZE=1][I]2015 ZL1 [/I][I]Camaro #1121 BLACK/BLACK 6 SPD (540 RWHP)[/I][/SIZE][/FONT] [I][FONT=Comic Sans MS][SIZE=1]1991 ZR-1 #458 [COLOR=red]RED/[/COLOR][COLOR=black]BLACK 72[/COLOR]k miles ([B][COLOR=red]SOLD[/COLOR][/B]) 1991 ZR-1 #473 [COLOR=red]RED/[/COLOR][COLOR=black]BLACK [/COLOR]37k miles ([B][COLOR=red]SOLD[/COLOR][/B])[/SIZE][/FONT][/I]

07-04-2010	#1
90ZRJR1 Join Date: Oct 2009 Location: Barnegat NJ Posts: 6	Fan Temperature Switch? I could use some help guys! Is the electric fan controled by an external switch or is it controlled by the computer? I have a 1990, totally stock, and I would like to have kick on a little sooner. It seems like it kicks on around 240 degrees or so. What can I do? Thanks Jimfahne