I figgured I'd ask so I dont miss anything. My 91Z has a L98 with a Vortech S-Trim supercharger. The cooling system is completely stock, and the car regularly runs @ 200 degrees on the freeway. In traffic (or during idle) it regularly runs at 220 degrees. After long periods of idle (bad traffic) during hot days (90 degrees) it hits 230-235 degrees. I've noticed its killing the viscosity in my oil (15w50 mobil 1 red cap syn) so I've been changing more often that 3000 miles. I'm planning to redo the entire cooling system while the engine is out of the car. For some reason I feel the car is unreliable with the current cooling system. Is there anything you guys can think of, other than the normal cooling mods, that might help cool down a F/I setup? Here is what I have planned:

Aftermarket Aluminum Radiator
Aftermarket Fans (2)
Aftermarket Fan Switch

Car already has a Cowl Hood

The only thing I left out is an Intercooler. I plan to do that (ATI Twin Setup) a little later when my drivetrain can handle more boost (aka power). In the meantime, do you think those mods will cool my car down enough? The goal is to run @ 180 degrees. I live in a hot climate (Hawaii) where the temp is always between 70 degrees (night) and 90 degrees (day). This is adaily driven car, and traffic here sucks some times. Thanks!!!

 

220 is normal, you shouldnt have any problems

 

My goal is to run 180 on the freeway and 200 in traffic. I guess I should have worded it better, right now it runs 200 on the freeway and 220+ in traffic. Highest its ever gone is 240 degrees, and that was right before my water pump blew. Everything I've read (Kingtal0n's buildup and others) sudgests the best operating temp for a blown setup is between 170 and 180. Around 220 should be the max, in traffic, with the A/C on. Is that unrealistic? When I move to the 749 ECM in the future and up the boost I am expecting around 650hp. I want to plan for the future, hence the goal of 180 degrees. Let me know if this is unrealistic. Thanks for the info!!

Shawn

 

I would recommend, if you don't already have it, an oil cooler, if you have the stock one, I would recommend an aftermarket one, it won't help your coolant temps, per say, but it will help your oil viscosity

 

Hey good idea Dave! Thanks! Combined with the new cooling stuff, an oil cooler will make my engine very happy.

 

i am running a stock cooling setup on my 91 formula 350 tpi, i just added a 180 stat and it stays in the middle line between the beginning and 220 on the temp guage, and in taffic it moves alittle towards 220 but then i start to move again, i always have that manual switch for the passengers fan so i can turn it on anytime and i am still using the stock fan switch so i use the drivers side as more of a backup now..

 

i'd second the 180° thermostat idea. my new engine ran around 200° on the highway and 225° in town, which is all right in the winter, but kills the a/c and things in the summer. the new thermostat took it down about 20-30° on average (on the highway, it should have taken it down the 15° difference from 180-195, but i think the 195 was defective anyway). you could even go to 160°, but you'd really be better off burning a new PROM for the ECM if you do that, depending on climate you could get stuck running open-loop a lot, which hurts performance and emissions.

 

I'll actually be burning custom EPROM's for the 749 ECM. Do you know what kind of mods I can do to my cooling system with a modified chip? Didnt think about it. Thanks!!

 

well, i haven't done it, but from what i recall you can change the temps the fans come on at, and i believe there's some variability in the 'warmed up' temperature when it goes into closed loop mode. there's a whole PROM board on here, i'd search and read there though.