Limits of FMII with stock cooling
 

Did some searching and couldn't find what I was looking for because maybe it's a common sense question.

But anyway, what are the limits of the FMII kit on stock cooling bits? My '92 I picked up in January has all the updated FMII pieces but with the LINK and is only tuned to a safe 6 psi as it was previously only driven in the city. Now I brought it out of the city where I can use the power, 6 psi is fun but I need more!

So to clarify, the question is is it safe to be running 12 psi on the FMII kit on a stock engine, stock cooling system for long term? I know the stock FM spec for the kit is 12 psi but I wanna know if people who have been running it for awhile have felt any long-term effects. I plan on doing the BEGi coolant reroute soon but just not yet.

Thanks,
Ray

No way to answer this question definitively because each and every 23 year old car is unique.

If your stock setup is as new then if you're not on the track you should be fine with stock bits. But chances are, your stock bits are NOT like new.

If street driven only, probably ok. Like Turbofan said, we don't really know the condition of your stock bits. Original radiator or automatic trans version OEM replacement? We don't know your location either. Could be Canada or Texas?

Make sure your ducting is as good as it can possibly be, this includes the belly pan.

Install an aftermarket water temp gauge and monitor it closely.

If it's really the original radiator, I'd replace it on general principles. Plastic end tanks lasting 23 years is a miracle.

The main stress to the cooling system from the turbo, on the street, doesn't come from the extra power (you can't use it hard enough to do that on the street without getting thrown in jail), but from the fact that the intercooler is blocking airflow to the radiator. Mine (with FM aluminum radiator, but stock coolant routing) would overheat with the AC on in 110F+ temps just cruising down the freeway.

--Ian

I'm running essentially the same kit w/ stock radiator and routing. I've seen temps of 233, briefly, on moderate days (~75F, installed last fall so it hasn't see summer temps yet.) I only have stock radiator ducting/splashpan. Would not recommend.

I'm in the process of ducting and getting an aluminum rad this weekend.

I'd recommend swapping in a good ol ebay aluminum radiator. I had my ???year old brown stock radiator and it handled the Virginia spring time decently with 6-7 psi. Then I moved south to NC and the summer heat gave me a good bit of lifter tick on startup after a drive where I got on it at all. I didn't feel comfortable pushing it after examining datalogs. I could tell the system was happier when I put in the ebay rad and no more ticking either even at 11 psi.

Its all about dat confidence. You don't want to be worrying about whether your shit can handle all the boosty fun. Or worse, dumping extra-hot coolant all over the road for your rear tires to lap up.

are you even overheating?

My plan is to do the reroute and keep the stock rad for as long as I can. I autocross semi-frequently and do track days rarely. Just got the car so I'm still feeling things out. Also live in Upstate NY at the moment, will be moving down to Mississippi next year.

I think I might retune it to 12psi and just stay out of high boost until I get my cooling mods done. From what it sounds like, everything stock should be okay temporarily. Water temp gauge is great idea, didn't think of that.

Thanks guys.

There is a really simple way to tell if your cooling system is inadequate: If you are overheating.

There's no hidden magic. You can hit high boost (provided you have the supporting mods to do so, like a good tune, etc) as long as your coolant temps are staying low. You can have a radiator the size of a suburban or none at all (theoretically) as long as your coolant temps are within range.

You should get Megasquirt. 12 psi is such an arbitrary thing. It's not as though the first time you hit 12 psi your car will overheat. Get a real EMS solution then worry about cooling if it becomes an issue.

Right. The thing is it's next to impossible to tell from the stock non-linear temperature gauge. Aftermarket will solve that problem.

The LINK seems to do the job for now. I haven't really played around with the tuning side of the car yet so I haven't seem it's inadequacy yet.

I don't have huge power goals, ~240hp is fine with me so if the LINK can do that effectively then I don't see the need to go to MS or Hydra.

Do you have a wideband in the car?

I have an autometer oil temp short sweep electric gauge that will work just fine for coolant temps as well. Autometer sells a heater hose adapter for the sending unit for something like $30 which I intend to buy soon. Looks like a pretty easy PNP solution.

Yep, I have an AEM non-gauge type wideband. Have a Flyin' Miata AFR/EGT dual gauge hooked up to it.

I'll have to look into that. Will have to figure out where this gauge will go too... I already have two gauges on my a pillar.

Can't you log your coolant temps? I don't know anything about link ECU's. The last link that I gave a shit about was Lancelot Link, and that was only because he stole my girlfriend Mata Hairi.