Quick antifreeze question
Discussion
T0MMY said:
... lives in East Anglia so it should never see less than about -5 deg C as I'll never be driving it to Finland. ...
Unless it's being kept in a heated garage in East Anglia it will see temps lower than -5.http://www.engineeringtoolbox.com/ethylene-glycol-...
I'd go for a 30% mixture; should give over 90% of the heat capacity of water at running temp but with protection down to -16 degC.
wildoliver said:
More to the point your getting good advice from experienced members on here and not listening.
With all due respect I have to disagree.Your experience of running a normally aspirated MX5 trackcar is not really relevant as it is a totally different situation and I am well aware that the standard cooling system can cope as I have done numerous trackdays prior to adding the turbo with no overheating issues. The experience of your friend worries me slightly when you say "particularly"...did it overheat or didn't it? Was that on a track or on the road? Also if he's using the dash temperature gauge and it has moved from the middle even a little bit then he has more serious overheating issues than he realises as the gauge is "desensitised" around the centre and only moves when the coolant gets very hot indeed (likewise, if you are only going on that guage in your n/a cars you may be running hotter than you think). As for not listening, well I've said numerous times the car has no overheating issues in as much as the dash gauge never moves (with the above concern in mind however). I am simply saying having not tested it with the turbo on track it seems eminently sensible to consider the possibility that the cooling system may not cope as it would have to be massively over engineered to do so. The extra power alone is probably adding 50% more heat, then you have the water coming through the turbo itself which obviously runs extremely hot. Combine that with the extra demand of track driving and I wouldn't be surprised if a turbo'd MX5 on track is having to shed literally twice as much heat as an n/a one on the road.
I'm absolutely certain Stevieturbo knows his stuff and I mean no disrespect at all but unless he has actually tried a turbo'd MX5 on track or has figures for both the headspace cooling capacity of the standard cooling system and the amount of extra heat generated with my setup then I'm not really willing to take his word for it as he's only really guessing based on what has worked on totally different cars.
Anyway, it's a moot point as I have booked Bedford for this Saturday so we'll see how the car gets on. Frankly I think the clutch may well be the weakest link and I'll be slightly surprised if I make it through the day without anything breaking at all
If I have no overheating issues at 25% antifreeze I will add more anyway. Edited by T0MMY on Wednesday 9th October 17:08
Well it seams your such a clever person I wonder why you asked the question on here in the first place?
Don't forget BBR was doing MX5 conversions and still do, so your not the only one out there. Is a bigger cooling system part of the BBR conversion kit? (genuine question)
I hope for your sake that your not trying to increase the cooling capacity to mask an underlying problem with your AFR's. Or that track day could end up costing your more than you bargained for.
Don't forget BBR was doing MX5 conversions and still do, so your not the only one out there. Is a bigger cooling system part of the BBR conversion kit? (genuine question)
I hope for your sake that your not trying to increase the cooling capacity to mask an underlying problem with your AFR's. Or that track day could end up costing your more than you bargained for.
No one is trying to deny that your car will need more cooling than a NA car. The point that is being made is if your car was marginal on track (needing the heater on) without the turbo and you are now having concerns about antifreeze mixture then you have bigger concerns than said mixture, this isn't an F1 car where you are calculating every detail down to the nth degree to make weight savings and specing a smaller rad and not running antifreeze would save weight and be acceptable for cooling, this is an mx5 with a turbo strapped to it, the standard cooling system should be acceptable, your upgraded cooling system should be more than acceptable, but if it isn't then don't go looking at the antifreeze mixture because the tiny improvements you can gain there aren't worth the payoff for not running enough antifreeze.
I suggest if it does run hot (and I agree your clutch is more likely to go first as this is the weak point on turbo MX5s not the cooling system) then look at the air ducting side of things as air flow will have a big impact to your overall running temp. Also look to try to get the heat from the turbo out of the engine bay, from my days of playing with supercharged Alfas the killer was always engine bay heat. The more heat you can get away from that turbo the more reliable it will be.
I suggest if it does run hot (and I agree your clutch is more likely to go first as this is the weak point on turbo MX5s not the cooling system) then look at the air ducting side of things as air flow will have a big impact to your overall running temp. Also look to try to get the heat from the turbo out of the engine bay, from my days of playing with supercharged Alfas the killer was always engine bay heat. The more heat you can get away from that turbo the more reliable it will be.
Mikey G said:
Well it seams your such a clever person I wonder why you asked the question on here in the first place?
Don't forget BBR was doing MX5 conversions and still do, so your not the only one out there. Is a bigger cooling system part of the BBR conversion kit? (genuine question)
I hope for your sake that your not trying to increase the cooling capacity to mask an underlying problem with your AFR's. Or that track day could end up costing your more than you bargained for.
Clever enough to not risk my engine on the back of some comments from people I don't know, none of whom have said they actually have any experience of this situation or have offered anything more than opinion. Also, I think you'll find I never asked if I needed more cooling, I asked what protection different concentrations of antifreeze offered. I've already asked about extra cooling on two MX5 forums and everyone running a turbo trackcar has said I need it...in fact that what I've done might not even be enough. I don't know if BBR modified the cooling system but I do know that a) they ran considerably less power and b) that was a kit for road cars not specifically for track cars.Don't forget BBR was doing MX5 conversions and still do, so your not the only one out there. Is a bigger cooling system part of the BBR conversion kit? (genuine question)
I hope for your sake that your not trying to increase the cooling capacity to mask an underlying problem with your AFR's. Or that track day could end up costing your more than you bargained for.
wildoliver said:
No one is trying to deny that your car will need more cooling than a NA car. The point that is being made is if your car was marginal on track (needing the heater on) without the turbo and you are now having concerns about antifreeze mixture then you have bigger concerns than said mixture, this isn't an F1 car where you are calculating every detail down to the nth degree to make weight savings and specing a smaller rad and not running antifreeze would save weight and be acceptable for cooling, this is an mx5 with a turbo strapped to it, the standard cooling system should be acceptable, your upgraded cooling system should be more than acceptable, but if it isn't then don't go looking at the antifreeze mixture because the tiny improvements you can gain there aren't worth the payoff for not running enough antifreeze.
I suggest if it does run hot (and I agree your clutch is more likely to go first as this is the weak point on turbo MX5s not the cooling system) then look at the air ducting side of things as air flow will have a big impact to your overall running temp. Also look to try to get the heat from the turbo out of the engine bay, from my days of playing with supercharged Alfas the killer was always engine bay heat. The more heat you can get away from that turbo the more reliable it will be.
Thanks, some good points although I do have to ask, when you say my upgraded cooling sytem should be more than acceptable is that based on some knowledge of this situation? I agree that the difference the antifreeze makes isn't that great but just thought I may as well do as much as I can. I suggest if it does run hot (and I agree your clutch is more likely to go first as this is the weak point on turbo MX5s not the cooling system) then look at the air ducting side of things as air flow will have a big impact to your overall running temp. Also look to try to get the heat from the turbo out of the engine bay, from my days of playing with supercharged Alfas the killer was always engine bay heat. The more heat you can get away from that turbo the more reliable it will be.
As for air ducting, I am indeed worried about engine bay temperatures but I don't really want to start hacking holes in my bonnet. From diagrams I've seen of airflow over the front of an MX5 you really only get low pressure about half way up so you'd need to cut a hole. Lifting the rear of the bonnet or taking off a headlight will pressurise the engine bay and bugger up the airflow through the radiator completely. Not sure what other free and easy mods I could do unless I could improve the undertray or seal the front of the engine bay better.
Ultimately, by plumbing in water cooling for the turbo I've shifted that heat issue a little bit from the turbo to the cooling system I guess.
Edited by T0MMY on Wednesday 9th October 18:34
The turbo cooling jacket will not contribute a meaningful heat flux to the cooling system whilst the engine is running. This is because the CHRA water jacket is of a small total area an mean flow velocity in it is tiny. It's really there for shut down heat soak, where the high specific heat of the "bulk" water in the jacket is used to help moderate peak CHRA bearing temps. When running, in fact, more heat is rejected to the oil system than the water system via the turbo!
Ok, that's interesting. Perhaps explains why HKS say water cooling the turbo is not necessary (I didn't want to chance that so hooked up the water cooling). I was indeed worried about heat soak with the engine off so I've tried to promote thermal siphoning with the positioning of the pipe work but as it's a top mount I was a bit stuck for space with the angles of the fittings I had.
wildoliver said:
On another point if you have the water cooling set up it's well worth looking at getting an electric pump to run after the engine switches off to pull the heat out of the turbo.
Most VAG's have them fitted and i'm pretty sure they run all the time and are also timed to run for a certain period after the engine has been shut off. May be the best way to get a decent flow of water through the turbo? I suppose it depends on how good its plumbed in in the first place.wildoliver said:
On another point if you have the water cooling set up it's well worth looking at getting an electric pump to run after the engine switches off to pull the heat out of the turbo.
I think as this is no longer a daily driver I don't need to worry so much about that as I can do cool down laps. I only do open pit lane days so don't need to worry about wasting track time!I think I've done all I'm going to do cooling wise now, so we'll see how it goes on saturday. I will be utterly astonished if the clutch survives the day but didn't see the point in assuming it won't take it without actually trying it first. I'll try to go a bit easy on it anyway. Beinteresting to see how the brakes go too...they were excellent when the car was standard but I'll be hitting the braking zones a lot faster now and the pads are a little thin now so there'll be a lot of heat going into the fluid.
Edited by T0MMY on Thursday 10th October 17:33
Why do I get the feeling that the default position on this forum is that any new poster is an idiot
The clutch is not iffy, it's fine on the road, I just hadn't tried it on track with the turbo. No point in assuming it won't take it and shelling out for a better one if the standard one is fine. And when I said the pads were thin I (obviously) didn't mean they didn't have enough meat left to do a trackday, they just aren't very thick so will transmit more heat to the fluid. I obviously would not do a trackday knowing the pads will not survive the day!
Anyway, I did the trackday today and the car survived. The clutch was mostly ok but I got a bit of slip at the end of longer runs so I think I'll get an upgraded one as I don't want to have to nurse it. Cooling wise the car was fine and the brakes were ok too despite the thin pads. The exhaust baffles didn't fair so well and I have a power steering leak too. Also the gearbox was a bit of a pig when it got hot but might just need an oil change.
Might stick up a video if anyone is interested. Seems a lightly turboed MX5 is a bit of a giant killer
The clutch is not iffy, it's fine on the road, I just hadn't tried it on track with the turbo. No point in assuming it won't take it and shelling out for a better one if the standard one is fine. And when I said the pads were thin I (obviously) didn't mean they didn't have enough meat left to do a trackday, they just aren't very thick so will transmit more heat to the fluid. I obviously would not do a trackday knowing the pads will not survive the day!
Anyway, I did the trackday today and the car survived. The clutch was mostly ok but I got a bit of slip at the end of longer runs so I think I'll get an upgraded one as I don't want to have to nurse it. Cooling wise the car was fine and the brakes were ok too despite the thin pads. The exhaust baffles didn't fair so well and I have a power steering leak too. Also the gearbox was a bit of a pig when it got hot but might just need an oil change.
Might stick up a video if anyone is interested. Seems a lightly turboed MX5 is a bit of a giant killer
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff