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Cooling questions
FFMan - 12/8/20 at 04:02 PM

I bought a half complete Haynes roadster with MX5 1.6 engine in it. I intend to use it as a track day car and am looking for some advice on cooling system. It runs and drives but was clearly intended as a road car, but as we intend to drive it quite hard some questions:-

What do you guys do the cooling system :-

reroute - is this a given for sustained high revs ?
remove thermostat ? does this need a blanking plate to ensure proper flow then ?
delete manifold water feed ?

i've Ted in an expansion tank with pressure cap to the top radiator hose, is this ok or do you not bother for racing ?

thanks

coyoteboy - 12/8/20 at 05:11 PM

I never understand the purpose of removing the stat. All it does is slow your warm-up.

FFMan - 12/8/20 at 05:40 PM

quote:
Originally posted by coyoteboy
I never understand the purpose of removing the stat. All it does is slow your warm-up.


but it also allows a lot more flow than an open stat and is one less thing to go wrong.

I race historic ff and no one runs a stat in the old Kent

number-1 - 12/8/20 at 06:21 PM

Personally, i would stick in a Davies Craig electric water pump and LCD controller. It lets you set a minimum temp after you turn the car off and the EWP and fan will run until it hits the preset temp It avoids hot spots. Ive used them on a road legal single seater (stat removed) as i had had huge overheating issues. I fitted just the Davies craig EWP and it solved it straight away. And now my Stylus track car has an EWP and LCD control unit. You can leave the stat in place with this set up. Its worth a google if you've never heard of them.

I would avoid the Evans waterless coolant. I used it before but it tends to hide any issues and will wear the moving water cooling parts out slightly quicker

Good luck

Gord - 12/8/20 at 07:06 PM

I run about 270bhp from my 1.6 MX5 turbo engine in my Haynes Roadster, I use a 55mm core alloy radiator, coolant re-route, just remove the thermostat housing and put a core plug into the gap.
Don't get rid of the thermostat when you look into it you will find that flow needs to be slowed down so it has time to cool in the radiator.
I have an alloy expansion tank, an 8mm hose comes from the top of the radiator to allow hot water to expand into the tank and the cooled water is then returned from the tank to the bottom radiator hose.
The standard Polo radiator that most people use is ok for normal use road but will be very quickly overwhelmed on the track.
I have deleted the water feed to the inlet manifold, removed the air valve and blanked off the inlet manifold, I also have a 12" SPAL radiator fan fitted and lots of bonnet vents to allow the hot air to escape. On the track on a warm day my water temps usually sit around 95c which is really good for a turbo kit car.

FFMan - 12/8/20 at 08:12 PM

quote:
Originally posted by Gord
I run about 270bhp from my 1.6 MX5 turbo engine in my Haynes Roadster, I use a 55mm core alloy radiator, coolant re-route, just remove the thermostat housing and put a core plug into the gap.
Don't get rid of the thermostat when you look into it you will find that flow needs to be slowed down so it has time to cool in the radiator.
I have an alloy expansion tank, an 8mm hose comes from the top of the radiator to allow hot water to expand into the tank and the cooled water is then returned from the tank to the bottom radiator hose.
The standard Polo radiator that most people use is ok for normal use road but will be very quickly overwhelmed on the track.
I have deleted the water feed to the inlet manifold, removed the air valve and blanked off the inlet manifold, I also have a 12" SPAL radiator fan fitted and lots of bonnet vents to allow the hot air to escape. On the track on a warm day my water temps usually sit around 95c which is really good for a turbo kit car.


Thanks that is really helpful. Couple of follow on questions if you don't mind:-

1) what is 270bhp in a roadster like. Have you reinforced the chassis ? Does it wheel spin a lot ?

2) thanks for tip on thermostat, i'll replace my one to keep the flow. I know some people on other cars remove the workings of the stat but keep the fitting so it acts as if its always open anyhow, but with a little extra flow,

3) the water feed to the inlet manifold, where is the return, i couldn't readily find a pipe.

4) what air valve do you mean ?

thanks

Gord - 12/8/20 at 08:32 PM

quote:
Originally posted by FFMan
quote:
Originally posted by Gord
I run about 270bhp from my 1.6 MX5 turbo engine in my Haynes Roadster, I use a 55mm core alloy radiator, coolant re-route, just remove the thermostat housing and put a core plug into the gap.
Don't get rid of the thermostat when you look into it you will find that flow needs to be slowed down so it has time to cool in the radiator.
I have an alloy expansion tank, an 8mm hose comes from the top of the radiator to allow hot water to expand into the tank and the cooled water is then returned from the tank to the bottom radiator hose.
The standard Polo radiator that most people use is ok for normal use road but will be very quickly overwhelmed on the track.
I have deleted the water feed to the inlet manifold, removed the air valve and blanked off the inlet manifold, I also have a 12" SPAL radiator fan fitted and lots of bonnet vents to allow the hot air to escape. On the track on a warm day my water temps usually sit around 95c which is really good for a turbo kit car.


Thanks that is really helpful. Couple of follow on questions if you don't mind:-

1) what is 270bhp in a roadster like. Have you reinforced the chassis ? Does it wheel spin a lot ?

2) thanks for tip on thermostat, i'll replace my one to keep the flow. I know some people on other cars remove the workings of the stat but keep the fitting so it acts as if its always open anyhow, but with a little extra flow,

3) the water feed to the inlet manifold, where is the return, i couldn't readily find a pipe.

4) what air valve do you mean ?

thanks


1) what is 270bhp in a roadster like. Have you reinforced the chassis ? Does it wheel spin a lot ?
Its good fun, very useable on the track (could easily handle another 50+bhp) mine has semi slicks and Wilwood brakes, once everything is up to temperature it handles brilliant. On the road it can spin a little because the tyres don't fully warm up and you can take people by surprise but with its turn of speed, I have always owned bikes so its no drama. If you wanted to you could spin it up for fun but the tyres are too expensive.

2) thanks for tip on thermostat, i'll replace my one to keep the flow. I know some people on other cars remove the workings of the stat but keep the fitting so it acts as if its always open anyhow, but with a little extra flow,
Some people keep the standard thermostat and drill a small hole in it to allow a small amount of flow, but I haven't bothered.

3) the water feed to the inlet manifold, where is the return, i couldn't readily find a pipe.
The water feed comes from the inlet manifold above the alternator, feeds the air valve on the side of the inlet manifold then returns to the thermostat housing.

4) what air valve do you mean ?
Its a tubular looking thing with 2 water pipes connected to it, on the inlet manifold facing the cam cover.

FFMan - 12/8/20 at 09:02 PM

quote:
Originally posted by Gord
quote:
Originally posted by FFMan
quote:
Originally posted by Gord
I run about 270bhp from my 1.6 MX5 turbo engine in my Haynes Roadster, I use a 55mm core alloy radiator, coolant re-route, just remove the thermostat housing and put a core plug into the gap.
Don't get rid of the thermostat when you look into it you will find that flow needs to be slowed down so it has time to cool in the radiator.
I have an alloy expansion tank, an 8mm hose comes from the top of the radiator to allow hot water to expand into the tank and the cooled water is then returned from the tank to the bottom radiator hose.
The standard Polo radiator that most people use is ok for normal use road but will be very quickly overwhelmed on the track.
I have deleted the water feed to the inlet manifold, removed the air valve and blanked off the inlet manifold, I also have a 12" SPAL radiator fan fitted and lots of bonnet vents to allow the hot air to escape. On the track on a warm day my water temps usually sit around 95c which is really good for a turbo kit car.


Thanks that is really helpful. Couple of follow on questions if you don't mind:-

1) what is 270bhp in a roadster like. Have you reinforced the chassis ? Does it wheel spin a lot ?

2) thanks for tip on thermostat, i'll replace my one to keep the flow. I know some people on other cars remove the workings of the stat but keep the fitting so it acts as if its always open anyhow, but with a little extra flow,

3) the water feed to the inlet manifold, where is the return, i couldn't readily find a pipe.

4) what air valve do you mean ?

thanks


1) what is 270bhp in a roadster like. Have you reinforced the chassis ? Does it wheel spin a lot ?
Its good fun, very useable on the track (could easily handle another 50+bhp) mine has semi slicks and Wilwood brakes, once everything is up to temperature it handles brilliant. On the road it can spin a little because the tyres don't fully warm up and you can take people by surprise but with its turn of speed, I have always owned bikes so its no drama. If you wanted to you could spin it up for fun but the tyres are too expensive.

2) thanks for tip on thermostat, i'll replace my one to keep the flow. I know some people on other cars remove the workings of the stat but keep the fitting so it acts as if its always open anyhow, but with a little extra flow,
Some people keep the standard thermostat and drill a small hole in it to allow a small amount of flow, but I haven't bothered.

3) the water feed to the inlet manifold, where is the return, i couldn't readily find a pipe.
The water feed comes from the inlet manifold above the alternator, feeds the air valve on the side of the inlet manifold then returns to the thermostat housing.

4) what air valve do you mean ?
Its a tubular looking thing with 2 water pipes connected to it, on the inlet manifold facing the cam cover.


I own a ZZR1100 also so am used to the speed, i guess i thought the chassis wouldn't handle it.

What wheels and tyres do you run then. As I run a historic formula ford i was hoping i could use ex-race tyres on the roadster but they are 13in and i've not attempted to fit a 13in weller or similar on the roadster yet. suspect it won't fit which is a shame as i have an endless supply of ex-race tyres from race friends though i think i would then need a tyre machine.

i've just installed 1144 pads as the road car ones had no feel and then locked but i've not tested yet. i know from single seater experience what hard pads are like.

3) yes i see thanks

4) the iscv - yep i understand. i think i'll need to retain the valve to maintain an idle on the standard ecu, i'll remove the heating pipes and cap the feed/return.

will be doing coolant reroute as soon as i get the rest of it settled in a bit more. still work in progress.

snapper - 13/8/20 at 07:53 AM

I agree with Gord and would only add a few cooling tips from my build as cooling is not just about the water system.
I used an earlier opening thermostat on a Pinto 82 degrees some modify an early Mini thermostat that opens at 78 degrees.
Ducting the radiator forces all the air through it stopping air taking the easiest route round it.
Letting the hot air or is very important in a 7 as the under bonnet area is very small, my simple solution was to prop the rear of the bonnet up by 2cm.
Double wrapping the exhaust manifold made a big difference and I also routed cool air to the rear of the alternator, protected other items, wires and pipes with heat wrap material and heat shields.
An oil cooler makes a big difference, always use an oil thermostat.