Do any of you have frequent overheating problems?
 

I, of course, plan to turbo my miata in the future (I think it will come after a roll bar in the course of modifying my car). I was speaking with a PCA guy today who was mentioning that all of the turbo miatas he had seen had serious overheating issues- mind you, he is at the track all the time, so was probably encountering cars being run at their limit.

I looked through the DIY FAQ and didn't see anything mentioned about overheating problems or needing upgraded cooling. It seems like most people on here run the Godspeed radiator. Aside from this change, are there any other necessary augmentations to the cooling system for a mostly street driven turbo car running an intercooled 10-12psi?

thanks in advance for feeding the noob.

https://www.miataturbo.net/forum/sea...earchid=378027
a lot of people run the coolant reroute that keeps hot coolant from flowing back into the motor.

I've faced overheating issues ever since I bought my Miata; even before it was turbo but; my statement has a couple of caveats:

1) I live in a tropical climate (90* weather and high humidity basically all year round).

2) I faced issues with my car's timing ever since a local shop installed the new timing belt and water pump.

Now, having said that I must say that my car is running fine now and for the first time in many months I don't have overheating issues. BTW, my car has been turboed for the last 4 months.

Even though I'm not facing overheating issues I did order the new Qmax system offered by 949 Racing because it is a proven fact that "some" and not all Miatas tend to overheat. According to those knowledgeable in that regard, that is mostly due to the fact that the Miata engine is the same one Mazda originally used for the Mazda 323 (transversal engine) and I've read that when it was mounted on the Miata (longitudinally) Mazda did not change the routing on the coolant to work in the correct manner. I should also mention that you can buy Begi's coolant reroute kit also for much less money.

I too bought an aluminum radiator (a PWR one in my case) and the fan shroud offered by FCM. My advise to you would be to do the coolant reroute first and forget about the radiator and fans; in the end, you'll be much better off if you ask me and it will cost you much less.

Just in case, here's a better explanation: http://users.pandora.be/miata/. When you get to his page, just click on coolant reroute and read his explanations. His are much better than mine!

Hope this helps.

Regards,

Rafa

wes65, when I click on the link you posted, I get a "no results found" message from vBulletin :dunno:

ive been turbo since early January. no over heating as of yet
i have a front mount blocking the mouth of the car too

however, i don't beat on the car too often
once in a while ill get on it for a few seconds,
sometimes quickly going through 2nd, 3rd and 4th,
and then i cruise. so i don't beat on it too often

I seem to recall Paul starting a thread on the subject. Do a search for all of Paul's threads or just search: "coolant reroute", you'll get plenty of info.

I cracked the plastic end tanks on my stock radiator very quickly. But I have owned an all metal automatic radiator and the godspeed since then and have not really had any problems with either.

My car has only overheated (and only very slightly) on a 105+ degree day at Buttonwillow with 280 degree oil temps (stock fans, 2" aluminum radiator). Now with a big oil cooler, I don't expect it to overheat no matter what the temperature is. 14psi, 220whp.

I had sever overheating problems that couldn't be solved by the simple fixes like shrouding, water wetter, changing thermostats, or higher ratios of water:antifreeze AND swapping in a 37mm Koyo (Goodwin). Finally solved when putting in 2x12" SPAL fans (more flow than FM's spal fan combo according to specs). They move ALOT of air through the rad! Haven't had a problem since, and we get 36-40*C+ weather up here. Canada isn't just for Eskimos! I also did a coolant re-route when I rebuilt my engine, just for safe measure, similar to Bob Bundy and Frank Devocht.

Overheating usually occurs in two different circumstances - at speed or in traffic/stopped. And they're addressed differently. Bigger/powerful fans can fix the traffic stuff, but won't help overheating at speed.

Since you're referencing track, then you'll want to focus on the air flow through radiator. That means making sure all the air entering the mouth is forced through the rad. This is a achieved by sealing up the mouth (frontal area) and by ensuring an easy exit on the other side (why you see hood extractors- which also vent underhood heat at a stop like a chimney). Next move would be a larger capacity radiator and then an oil cooler.

A friend of mine tracked his AVO turbo'd 95 Miata for ~4 years on a regular basis. In the end he sealed up the frontal opening, used a larger radiator and ran an extractor hood. But on the hottest days in SE would start to see high temps near the end of a 20 minute session. He didn't run an oil temp gauge, but I suspect the oil temps were quite high at the point the coolant was. And that's why I think a BIG oil cooler is a good idea for track events in the summer. Increasing the oil capacity will show a benefit to all systems.

Not all coolant reroutes remove the heater core return from the pump. Some of us like quick heat in the winter and removing that feed has shown minor overall temp drops- only important to those need a few degrees drop. I think the reroute is more important to achieve a balanced cooling of the engine - the majority of coolant was originally designed to exit at the rear of the head. I think it's a good idea regardless of over heating or not.

Any data on how much of a cooling improvement is seen with the reroutes?

From my limited understanding of coolant systems, and my expert skills in following pictures, it seems that all the reroute does is increase flow out of the head and back to the radiator by bypassing some fluid around the heatercore. I think this increased flow is probably marginal, as the whole system has to be bigger for it to make a difference.

I think the biggest difference, comes from the fact that coolant doesnt have to pass under the manifold through a pipe cooked by the manifold and through the waterneck and internal galley at the head.

My guess maybe 5 - 10 degrees.

Would you mind sharing where did you buy those Spal fans and their fcm specs?

Thanks

Rafa

I've never seen a turbo miata make it through a session without overheating. I'm very worried about this, and its making my penis shrivel up inside my body.

and pics of the shroud.

Shrouds and fans aren't gonna help on track. IMO - you want hood extraction, big rad, coolant reroute, big oil cooler, and good air routing through the heat exchangers.

i run my miata at the track and i have been dealing with cooling problems for 3 years. I overheat in 15 min sessions. and im only running 200hp. I have a dual core rad and paralleled stock fans that are pretty much sealed, and i raised the hood, but im going to drop it back down and put in a hood extractor.. suggestions? im,not sure if i want something along the lines of FM's or if i want the DIY solution like M2...

When I first turboed my car I had overheating problems only when sitting in traffic. However I live in South Florida with 95*+ weather everyday of the summer. I put in a godspeed radiator with 2 ebay 10" fans, water wetter and a 80/20 water/coolant mixture. I dont over heat anymore but I think I need either bigger or stronger fans, because when they come on they stay on for a long time.
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I don't really have any overheating issues. I have a brass radiator, and big oilcooler, no A/C. Last weekend it got a little hot on track when the waterpump belt decided to detonate but the big oil cooler kept temps in check for the rest of lap.

I had overheating at speeds <~100 km/h and also at stops. Fans seemed to be the only thing that fixed both.

I found www.jaycorptech.com to be the least expensive. Model #30102038 (spal #VA01-AP6-36A). They are spec'd at 1630 cfm each.

The SPAL fans that FM uses are apparently made for FM by SPAL. I don't remember what the exact numbers are, but when I asked the guys at FM what the size and "specs" their fans were, they were less than 3260 cfm. The FM website says "these fans flowed 1975 CFM and 1610 CFM when mounted to a Miata radiator despite being rated for less", so I'm going out on a limb to say that the fans I bought from jaytechcorp will flow more than "spec" as well (?). Since the cost of the jaytechcorp fans were $250 vs FM's $428, it was a no-brainer. Even for arguments sake, if FM's flow at 3585 and mine flow at 3260 (~10% more), I couldn't justify the extra $$$.

I originally shrouded the mouth and the back of the rad, but I'm not sold on the benefits of a flat shroud on the rad. Seems to me a flat shroud would just block off the air flow that would hit the areas not covered by the fans, but not necessarily "force" more air through the areas the fans cover, if that makes sense. The only way I can see a shroud working is if it is tapered away from the rad, kind of like a funnel, and the fan at the narrow end of the funnel. I think for most of us, there wouldn't be room to do that.

Fans do help at speed. I once killed a fan relay washing the engine, and the car would overheat doing 60 mph in 90*F weather.