Not one person is telling him to blow up his engine.

The engine has sub factory compression/leakdown numbers. Big deal. It runs and runs well. It makes good power. He drove it many many miles with no water loss and no oil contamination. How does that point to a head gasket? Not that it can't be a head gasket but it's pretty unlikely.

The car runs perfectly fine under a certain speed and outside air temperature. Above a certain point it begins to overheat. How does that point to the head, compression or leakdown? It might, but I'll bet beer and food on it.

You HAVE to get airflow through the stack (IC, condenser and radiator). There are many ways to do it. It just has to be done.

-seal up air leakage
-ducting
-higher airflow (through or around the) intercooler (both probably reduce IC efficiency)
-vent the hood
-V mount (properly done)
-remove condenser (when I've done this in the past the increase in radiator cooling capacity seemed to be very large)
-separate airflow paths to the IC and radiator, favoring the radiator.

Yeah, there is somethign wrong with the head or the head gasket.


He should be able to run without ducting on the street...I did and my intercooler is much larger than his. For the track though, he must have the ducting.

You've neglected to realize the countless number of TDR cars that run the same intercooler, with an AC, and run without overheating throughout the summer even with crummy ducting.

There are also lots of racecars that run stacked heat exchangers successfully...like JC Minnet, Sierra Sierra, and AMS.

Please reread the leak down numbers
 

Please reread the leak down numbers and the compression test numbers. The engine damaged! If the issue was a blown head gasket the leak down test would have pumped coolant out of the radiator but, as the OP says instead air escaped through the intake and exhaust valves as reported by BEGi.

The tests are tools for troubleshooting and should not be ignored. It is also the only valid test info we have in this situation. I would be surprised at this point if once these issues are resolved that the OP does not need to re-tune.

Please reread the leak down numbers
 

Please reread the leak down numbers and the compression test numbers. The engine damaged! If the issue was a blown head gasket the leak down test would have pumped coolant out of the radiator but, as the OP says instead air escaped through the intake and exhaust valves as reported by BEGi.

The tests are tools for troubleshooting and should not be ignored. It is also the only valid test info we have in this situation. I would be surprised at this point if once these issues are resolved that the OP does not need to re-tune.

Yes, the head in that video was leaking. Installed on a car there would be coolant loss or contamination.

There is some additional information that there are some oddities with the intercooler. I don't know for a fact if it is a TDR intercooler or not.

Yes, many cars run the same setup. There are so many other factors involved.

I recently worked on a 2001 with a coldside. Compression: 25, 0, 0, 10. Leakdown: worthless. You could hear air in the exhaust and intake. Turns out 15/16 valves were not seating - thanks to a "pro" engine builder. Most of the valves were still open at zero lift thanks to complete neglect of the shims. The car ran a little rough but was DD and still ran a 14.6@93mph in that condition. It was running in Miller Cycle mode.

That's why his numbers don't bug me. I didn't say they were good.

I have yet to see a car with a bad head/headgasket that only overheats at high speed with the A/C on and only in high outside air temps. Every bad headgasket/head that I've personally come across has had issues under a wide range of condtions - usually running was a bad enough condition.

There is something going on with the car. It will be fixed. The information doesn't point to the head/gasket causing the problem. No, it's not perfect. I get that.

I am local to the OP and will probably be doing some hands on at some point.

The intercooler is most likely a TDR knockoff. It came from a company called BRP which was out in South Carolina. From what I was told they have since closed down. The intercooler setup looks like a TDR but I can assure you from the receipts that it came from BRP. Corky opened up the intercooler and told me it looked like a bunch of straws stuck together; he could see right out the other end. I've never seen the inside of an intercooler so I don't know what to compare that to (edit: nevermind... http://www.sdsefi.com/techcooler.htm)

Here's an old post from them... http://forum.miata.net/vb/showthread.php?t=135691 Seems like their website address was taken over by a clothing company.

If the shop the car's currently at can't tell you what's wrong with it, get it out of there and find someone that knows what they are doing.

BRP was a supercharger company. I have one of the their setups. To the best of my knowledge they never made an intercooler. They did sell other manufacturer's products to increase their range. The FM superchargers from a couple of years ago were BRP products.

Ah cool, that's good to know, thanks.

I think its become more obvious that something is really wrong and the head needs to come off at the least. At that time, clean and replace consumables in the cooling system. Also, next time it overheats, put a laser-thermometer on the top of the radiator and see if the water temp really is that high. My GF's jeep likes to indicate 220 @ 190*.

If you want to send the head out for work there is a guy in Dallas who with a pheneomenal history of good customer service and extremely reliable FI track Miatas...luckily he's affordable too. John Day Machine gets a lot of love on all cars we see at the track around here.

Did we ever establish that with the belly pan the car still overheats?

I killed a head gasket once that caused over-heating.

Good tip with the IR thermometer. We'll get some good data when the car comes back.

The airflow path has been 95% sealed, belly pan and air scooper on.

Do you have dimensions on that intercooler or a build thread? I wanted to do an otr setup but didn't think it was possible with a/c.

Well, actually.... BRP did make an in-house IC solution to compete with the TDR at one point. It was a similar over the pipe solution. I believe it was around the time the turbo kit was out as well.

They did also re-sell TDR though, so it's possible, the receipt says BRP, but it's a TDR.

The issue with the BRP IC, I think the core was not as good as the TDR core. If you check on m.net, I believe there were several posts from Bill (who used to work at BRP at one point). IIRC it was less efficient, and had more boost loss than the TDR.

That said, I also have a BRP kit, one of the first M1 1.8 hotside kits out there....

Dave,

The TDR fits as an over the rad, with AC. You need to move brackets and bend some stuff to fit the core, but it fits.

Dave,

Well I saw it was a tdr but I don't have a grand to drop on an intercooler, was going to look for an eBay one of close/similar dimensions.

Corky called me today saying he's fixed it and if I'm able to get it to overheat then we'll melt the car down (jokingly). He moved the front swaybar towards the rear half of an inch in order to space the fans, radiator, and AC condenser apart. He uncapped the front coolant port (was capped from the M-Tuned Reroute), put a restrictor in and T-junctioned that into the hose coming off the back of the head going back to the radiator. It'll work for daily driving but I'll probably still have to duct it for the track. I'm just happy I can have it back. They've had the Miata for 6 weeks now.

good, you're on the right track. I don't know what spacing the heat exchangers does if its already ducted...but hopefully it works.

If it fucks up again, pull ths sc and run na. Track time is way more important than power. Did you ever get any slicks? I might have some for sale...call me.

Thanks fellas. Hopefully I won't have to yank the SC. No, I haven't gotten slicks yet. I first need to get a set of 15x9 6UL's to put the track tires on. Once I get it back I'll be finishing the roll bar installation, changing out all of the fluids (engine, tranny, diff, brake), and install new brake pads. I'll see if I can take it out to the track on the tires it has now to see how the heating issue is out there.