Miata cooling system thread
#744
Out of curiosity, where is everyone grabbing power for their big SPAL's?
I have one, and it's connected direct to the alternator, but I'm thinking of removing it and wiring the relay direct to the battery because when it kicks on, I fear the voltage drop is affecting things at the ECU momentarily. Would moving it off the alt and onto the battery help this? I find that my VVT would start acting up when my fan draws initially and I can't figure out how to compensate, then it smooths out after the alternator stabilizes.
I have one, and it's connected direct to the alternator, but I'm thinking of removing it and wiring the relay direct to the battery because when it kicks on, I fear the voltage drop is affecting things at the ECU momentarily. Would moving it off the alt and onto the battery help this? I find that my VVT would start acting up when my fan draws initially and I can't figure out how to compensate, then it smooths out after the alternator stabilizes.
#746
Out of curiosity, where is everyone grabbing power for their big SPAL's?
I have one, and it's connected direct to the alternator, but I'm thinking of removing it and wiring the relay direct to the battery because when it kicks on, I fear the voltage drop is affecting things at the ECU momentarily. Would moving it off the alt and onto the battery help this? I find that my VVT would start acting up when my fan draws initially and I can't figure out how to compensate, then it smooths out after the alternator stabilizes.
I have one, and it's connected direct to the alternator, but I'm thinking of removing it and wiring the relay direct to the battery because when it kicks on, I fear the voltage drop is affecting things at the ECU momentarily. Would moving it off the alt and onto the battery help this? I find that my VVT would start acting up when my fan draws initially and I can't figure out how to compensate, then it smooths out after the alternator stabilizes.
I don't think hooking to the battery is going to make any difference, it's not the battery that's maintaining the 14-ish volts.
--Ian
#747
I would love to move it, but mounting it anywhere else will be a huge challenge. Regretting buying the massive 25 row, between the cooler, the AN fittings and hose, it's tough mounting it anywhere but where it is. My buddy who's good at fab work is supposed to check it out and see if he can come up with a better mounting solution / location. My other buddy has a spare ford taurus fan we may try fitting in.
#748
I'm just using the factory fan circuit. It affects the idle because when the fan starts up it sucks a lot of current, so the voltage regulation logic pushes the alternator duty cycle up, which adds a lot more load to the engine. The right solution is to have the computer idle up *before* it kicks on the fan, like it does with AC.
I don't think hooking to the battery is going to make any difference, it's not the battery that's maintaining the 14-ish volts.
--Ian
I don't think hooking to the battery is going to make any difference, it's not the battery that's maintaining the 14-ish volts.
--Ian
I didn't think it'd be as bad as running two fans since it's the only one I have. It's on a dedicated Spal "high output" relay. I just didn't know if it's my alternator acting slow then. Sometimes when starting it just seems to struggle until the alternator makes 14v a couple seconds later.
#749
Retired Mech Design Engr
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From: Seneca, SC
I'm just using the factory fan circuit. It affects the idle because when the fan starts up it sucks a lot of current, so the voltage regulation logic pushes the alternator duty cycle up, which adds a lot more load to the engine. The right solution is to have the computer idle up *before* it kicks on the fan, like it does with AC.
I don't think hooking to the battery is going to make any difference, it's not the battery that's maintaining the 14-ish volts.
--Ian
I don't think hooking to the battery is going to make any difference, it's not the battery that's maintaining the 14-ish volts.
--Ian
Turn Idle Up to ON (red box), and then add settings (blue box).
#750
Looking at the pics, the oil cooler is putting a lot of hot air into the radiator, especially since the oil is usually a lot hotter than the water. More troublesome, the air is likely really hampered trying to penetrate both.
The benefit of a puller fan is that with proper ducting it will pull air from the entire surface of the radiator. This is why oem's often have very large shrouds and only one fan when space allows and use two fans when space is limited. Fans cost money and increase fuel consumption when operating so additional ones are only used when necessary. Some Toyota products have a two speed system to reduce electrical load and increase fuel economy to this end. One good, large fan and a proper shroud that pulls from the entire radiator will be very helpful. The shroud helps avoid reversion of the expelled hot air back through the core and causes the entire radiator to receive air. Being large, like a 16-18in Spal (whatever you can fit), will allow plenty of air flow through the radiator and fan body when the car is in motion with the fan off. If that opening is too small it has the potential of slowing flow from motion.
Is the bottom of the bumper mouth sealed to the underside of the IC and the radiator currently? If so, if the ducting beneath the IC could be lowered and the black plastic could be notched or cut back to allow some of the air to go beneath the IC and then back up to the lower portion of the radiator it could increase the air it receives. The radiator needs to have primacy over the IC for fresh air. I did this to mine since mine is sealed from the bottom of the bumper and not the bottom of the bumper mouth. I'll try to get a pic uploaded of what I did.
The benefit of a puller fan is that with proper ducting it will pull air from the entire surface of the radiator. This is why oem's often have very large shrouds and only one fan when space allows and use two fans when space is limited. Fans cost money and increase fuel consumption when operating so additional ones are only used when necessary. Some Toyota products have a two speed system to reduce electrical load and increase fuel economy to this end. One good, large fan and a proper shroud that pulls from the entire radiator will be very helpful. The shroud helps avoid reversion of the expelled hot air back through the core and causes the entire radiator to receive air. Being large, like a 16-18in Spal (whatever you can fit), will allow plenty of air flow through the radiator and fan body when the car is in motion with the fan off. If that opening is too small it has the potential of slowing flow from motion.
Is the bottom of the bumper mouth sealed to the underside of the IC and the radiator currently? If so, if the ducting beneath the IC could be lowered and the black plastic could be notched or cut back to allow some of the air to go beneath the IC and then back up to the lower portion of the radiator it could increase the air it receives. The radiator needs to have primacy over the IC for fresh air. I did this to mine since mine is sealed from the bottom of the bumper and not the bottom of the bumper mouth. I'll try to get a pic uploaded of what I did.
#751
I notched back the black plastic at the bottom so the air could go beneath the intercooler and under to the radiator. My intercooler bottom sits a little lower than yours, too.
I also rolled the metal lip on the bottom of the cross member upward to allow additional 3/8 or 1/2 inch of opening between the top of the intercooler and the crossbar. I'm pretty sure I did it at the top of the bar as well, but mostly to accommodate the oil cooler I added. Not elegant in my case but every little bit helps. I'm more worried with inexpensive DIY functionality than style points. Be sure to plug the all of the gaps between the black bumper support and the bumper cover. There are many of them in the stock configuration.
How I did it, by Victor Frankenstein:
I also rolled the metal lip on the bottom of the cross member upward to allow additional 3/8 or 1/2 inch of opening between the top of the intercooler and the crossbar. I'm pretty sure I did it at the top of the bar as well, but mostly to accommodate the oil cooler I added. Not elegant in my case but every little bit helps. I'm more worried with inexpensive DIY functionality than style points. Be sure to plug the all of the gaps between the black bumper support and the bumper cover. There are many of them in the stock configuration.
How I did it, by Victor Frankenstein:
Last edited by sixshooter; 05-09-2017 at 09:48 AM.
#754
~250-260whp on track. I occasionally hit the button to flip over to high boost ~300whp for catching and passing certain high horse cars that want to run away in the straights and not give room to pass in the corners but then flip back to low boost once I am comfortably past them. Most recent virtual dyno (thanks Ryan for crunching the numbers) was 327/308 but no way could I hold those levels on the track without breaking everything and overheating everything. It's been tough enough to get it to handle ~250 consistently.
Edit: The larger oil cooler has been upgraded in size since the last track day so hopefully it will be able to tolerate higher ambient temps with things turned up. This one is 3in wider and 3 rows taller.
#759
Well I'm happy to say my upgrades to my cooling system made a big difference. I managed to get a spacer in my upper hose with a sensor for my VEI temp gauge before my track day. I have a reroute so I can assume it's not accurate until the thermostat opens on the back of the head but freeway temps stays right around 188 and track temp with about 8psi of boost is just under 200 until I come in. I usually short shift and take it easy for the last 1/4 of the lap after I see the checkered flag but as I go through the paddock temps get to 208 and when I park as high as 215. I leave the car running with the large Spal fan going until it switches off around 204.
I noticed the VEI gauge was running 8-10 degrees hotter than my megasquirt which reads off the stock sensor at the back of the head. I never saw the MS trip the CEL light this time so I'm running below its initial alarm setting.
Next is an oil cooler and a gauge to measure those temps. The oil looked a lot fresher after this track day then last time which I take as a sign I'm not cooking the oil anymore.
I noticed the VEI gauge was running 8-10 degrees hotter than my megasquirt which reads off the stock sensor at the back of the head. I never saw the MS trip the CEL light this time so I'm running below its initial alarm setting.
Next is an oil cooler and a gauge to measure those temps. The oil looked a lot fresher after this track day then last time which I take as a sign I'm not cooking the oil anymore.