Miata cooling system thread
#481
Hood is vented, car overheats at part throttle over the course of 5 laps or so of no more than 10 psi too. It also now overheats under light load on the freeway. This led me to believe it was the head gasket. Head ckecked out and gasket was replaced as well as wp, thermostat, etc. Freeway overheating was resolved slightly but it still ran around at 200 after a few highway pulls which it never did before. I've pressure tested the coolant system and didn't see a drop in pressure from 20 psi over 20 minutes.
#485
SADFab Destructive Testing Engineer
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The only thing I can think of would be the intercooler is more dense and not allowing as much air through as the old unit did.
Otherwise sounds like something wrong in the engine.
Otherwise sounds like something wrong in the engine.
#489
Before yanking out the motor I would put a high pressure radiator cap, tap into one of the coolant barb fittings for the oil cooler lines on the back of the head and presurize the system to make sure it is holding the correct pressure per the cap you have on the radiator, if not start looking for the place where the pressure is escping like cap, loose hoses heater core etc. the system does not reach your cap rated temp the water will boil on the cylinder jackets and head and the engine will overheat.
#492
Cpt. Slow
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He should probably mention the new sand paper finish on Pistons 1&2, and the ~dozen or so pit marks on #4. That's my suspicion. Anything but a smooth surface generates a lot of heat, so says the theory. It does run warm at cruise. Shouldn't hit over 180 just cruising around in 68 degree weather, it's sitting around 195-200. Hit steady boost and it sky rockets.
#493
I'm running the FAB9 IC on the Silver car. That intercooler mounts really far forward, it's a really good air blocker. I'm not overheating on the highway, even with AC on. It does run warm though, around 215-220. When I drop the top and turn the AC off, it's 195. I have to baby it when I take it to the track, and I'm only around 200HP give or take. Then again, I'm in N. TX (along with Gary from TDR), not Oregon.
Guess I wasn't much help, but everything else you did helps cooling except for the intercooler. I'm wondering if that was the difference?
Guess I wasn't much help, but everything else you did helps cooling except for the intercooler. I'm wondering if that was the difference?
#495
Could that really be the cause? My old intercooler was much taller and wider basically covered the entire surface of the radiator, but it was mounted much further back than the fab 9 unit. I'm just at a huge loss ar this point. I'm considering pulling the IC off and running a straight pipe with 2 couplers to bridge the gap to do some testing. Would really suck if this IC was the issue considering I gave up a larger free unit for this piece.
#500
One other thing I'll mention is that I'm running the "Stage 1" FAB9 IC. It still leaves a bit of a gap between the top and the plastic bumper support to flow some air to the condenser/radiator/oil cooler that doesn't have to go through the core. If you're running their "Stage 2," I honestly have no idea how you would have any cooling beyond really low intake temps.
I've seen posts from Braineack talking about switching from a dense bar/plate IC to a cheaper tube type IC to get better radiator performance. Sixshooter, another hot climate guy (FL), has posts about trimming away the plastic bumper support to promote air flow over an IC into the radiator. Assuming your "tube" experiment finds a smoking gun, then these are both options for you.
I've seen posts from Braineack talking about switching from a dense bar/plate IC to a cheaper tube type IC to get better radiator performance. Sixshooter, another hot climate guy (FL), has posts about trimming away the plastic bumper support to promote air flow over an IC into the radiator. Assuming your "tube" experiment finds a smoking gun, then these are both options for you.