rainman10

Hey...

I have just bought a 94 FM2 turbo miata and with finally driving it in 100 degree temps outside (it was raining for a month and temps were in the 90s), i am having overheating issues. Was hitting 205 yesterday at 70mph cruising on the highway. I drove the car from Tennessee to Tulsa a month ago without any overheating issues or any other issues. Car runs great other than this issue so far. I am leaving in 2 days for a 1500 mile round trip to Santa Fe on vacation and need the car to make the trip to the desert without overheating, or i miss my family vacation this year!

Setup is FM2 with intercooler, Megasquirt, Koyo Rad, bigger injectors.

Read this forum and called Flyin Miata, and the consensus for getting engine temps down is the following:

1) PUT ON THE UNDERTRAY! It came without an undertray. I just got the plastic OEM undertray and my local turbo mechanic said that it will have to be modified due to the intercooler (?) getting in the way. Cant remember what he mentioned caused the undertray to need to be modified. What do we need to do to get this to work?

2) Change to 70/30 coolant mix along with bottle of water wetter

3) Add the coolant reroute (just ordered the FM coolant reroute). I read about some mods or issues needing to be done in order to install the coolant reroute properly (drilling holes in the thermostat for example?, tight fit around X for example?). What do we need to do in order to install the FM coolant reroute properly? How many hours to install the coolant reroute?

4) Add custom ducting in the nose to direct airflow into the rad. I am contacting the moderator on this list that lives in Dallas (Hustler) to see if he can help me install this custom ducting properly. In the meantime, what exact threads are there that show and detail exactly what kind of ducting to do? Would prefer to wait on the ducting until i learn more about it, and just do the above stuff for now. Is that the right decision?

*** With the above said, i am figuring that just adding the undertray, coolant reroute and 70/30 (with water wetter) coolant mix will get me plenty ok to take the trip to Santa Fe in a few days.

What do yall think, i am right?

Long term though (especially since i want to take the car to the track once a month or so), i need to get the car really setup to not overheat, even at the track on a hot Texas or Oklahoma day!

I am figuring that i need to get the above basics done, then get with yall and Hustler, etc and finish anything else that needs doing in order to not overheat even at the track...

Thanks!
Randy

Savington

iTrader: (31)

I'm figuring JUST the OEM undertray and 70/30 coolant mix will get you across the desert without an issue. Stock cars overheat without that undertray. It's an absolutely critical component, and it's an excellent litmus test for the overall quality of a car. No undertray in place means the builder wasn't well-versed in Miatas.

Yes, the sides do need to be trimmed to clear the pipes - it's not hard for a competent mechanic to figure out and it can be done with a razor blade.

Our rental track car did 2 double-driver days at Laguna this past weekend with nothing more than our massive triple-pass radiator (3.25" at the endtank) and a factory undertray in place. No reroute, no cooling fans (planning to add a small one for hot pit idle time), no ducting beyond that undertray. Never saw any overheating at all.

Braineack

iTrader: (62)

when is 205*F overheating?

pdexta

iTrader: (17)

^ Whew, that makes me feel better. My stock '99 thermostat seems to start opening right around 195 and usually sits right around 200.

hustler

iTrader: (6)

I just talked to this guy on the phone and he's cool just ignorant to turbo Miata reality because he's been talking to the SM guys about cooling who have the rule-book perspective.

Hustler's Rx:
2-cups of coolant, fill with distilled water
deal with the crappy reroute, replace with hard-pipes later
restrict the heater hose feed to reduce mixing hot water with cool water at the water pump
duct later
yes, 220whp will be too much for your first track event.

flipt86

iTrader: (4)

FYI, I had the stock undertray on intially after the install, it just became cracked due to a misplaced cone on the auto-x course and I did not replace it before selling... Trimming to fit around the intercooler is no big issue, pretty self explanitory.

rainman10

Hustler said that you shut the engine down at 215, so its higher than i thought...

Randy

rainman10

Hey Will! This is Will's car...

I went with Hustler's advice , fluid changed to just 2 cups of coolant/rest distilled water with a bottle of water wetter, and the coolant reroute and undertray is going on tomorrow...

I am planning on visiting Hustler when i am back in Dallas to see his ducting, etc... Thanks Hustler!

Randy

Braineack

iTrader: (62)

but 207* is when the fans kick on. so it's possible temps would have gone back down on their own is all im sayin'

hustler

iTrader: (6)

That's not what I said...when you shut the car down after running it hard, the engine will warm the water and it may go slightly higher.

rainman10

“There are known knowns. There are things we know that we know. There are known unknowns. That is to say, there are things that we now know we don’t know. But there are also unknown unknowns. There are things we do not know we don’t know.”-Rumsfeld

Ah, the wisdom of our dear leaders...

Randy

jim_rocketmow

Belive or not, but we have had these overheatig issues also in normaly cold Finland. This summer ambient temps have been around 25-30celsius and in track coolant temps have been too hot. I found garage vary lip useful for keeping temps down. Seems like it scoops air into radiator over IC. I have begi S1 and 55mm ebay radiator without undertray, 30/70 + waterwetter. Yes, I will put undertray back "later".