spec my electric water pump please
Discussion
Hi all, we have a small issue with our race car .. in line 6 cylinder 3.6 engine making just shy of 400hp at 7800rpm
When the car is on track things are fine with the cooling, holds 85deg (thermostat temp) but if the driver comes into the pits the coolant boils straight away..
We'd like to add an electric pump in series with the mechanical pump .. but what flow rating do y'all think we will need to support 400hp on a hot day on track and not be a hindrance to the existing mechanical pump?
Removing the mechanical pump at this stage isn't an option, it's chain driven inside the front timing cover and the same chain also drives the oil pump.
this is the car on track, sadly doing a rare misbehaving session chucking its coolant out after being cooked in the pits earlier in the day.
https://www.youtube.com/watch?v=mYZNK7v4Odc
When the car is on track things are fine with the cooling, holds 85deg (thermostat temp) but if the driver comes into the pits the coolant boils straight away..
We'd like to add an electric pump in series with the mechanical pump .. but what flow rating do y'all think we will need to support 400hp on a hot day on track and not be a hindrance to the existing mechanical pump?
Removing the mechanical pump at this stage isn't an option, it's chain driven inside the front timing cover and the same chain also drives the oil pump.
this is the car on track, sadly doing a rare misbehaving session chucking its coolant out after being cooked in the pits earlier in the day.
https://www.youtube.com/watch?v=mYZNK7v4Odc
We already run a large cooling fan , but could fit another one.
The way the temperature goes sky high on coming to a standstill can be partially reduced by keeping the engine revs high, but that only works for a short time .. what we've read into that is that the water pump flow at low rpm isn't sufficient, and keeping the revs higher aids flow and keeps things under control in the short term, but the very action of keeping the revs high introduces yet more heat which is then counter-productive.
Our thinking is that if we can keep the engine revs low in the pits, but still have high total coolant flow , then that would be the best scenario.
Plus extra fans and larger rads and more coolant adds weight and we're already a bit lardy compared to the fast boys in the series!!
The way the temperature goes sky high on coming to a standstill can be partially reduced by keeping the engine revs high, but that only works for a short time .. what we've read into that is that the water pump flow at low rpm isn't sufficient, and keeping the revs higher aids flow and keeps things under control in the short term, but the very action of keeping the revs high introduces yet more heat which is then counter-productive.
Our thinking is that if we can keep the engine revs low in the pits, but still have high total coolant flow , then that would be the best scenario.
Plus extra fans and larger rads and more coolant adds weight and we're already a bit lardy compared to the fast boys in the series!!
Evans coolant would probably sort it .. Im reluctant to use it because one guy in the race series already cooked his engine (partial seizure) the very next race after switching to it from water .. but i do agree it would likely sort this particular issue.
I am going to go with an electric pump anyway as it will help for next year when we go for 9000rpm .. I expect the std water pump may well cavitate at those revs. Thanks for the suggestion
I am going to go with an electric pump anyway as it will help for next year when we go for 9000rpm .. I expect the std water pump may well cavitate at those revs. Thanks for the suggestion
Returning to this thread rather embarassingly to say i've ordered a DC pump 
Sadly though it hadn't turned up by the time the car was finished (11pm last night ..) and the car is now back with the customer who probably got home after midnight ..
The pump was ordered through demon tweeks so at least if it does leak I can send it back .. then if it leaks again I can get my money back and go for the Stewart pumps mentioned earlier which look better?
Anyway, the deed is done now for better or worse .. when the pump does arrive though I will have to fit it at the circuit before the fist race, not the best way to test a new item.
We certainly need something though .. ran the car up on the dyno for a couple of power runs late last night and the temperature was fine running on the dyno .. back at tickover though the temps soared quickly once again ..
Thanks for all suggestions .. will let you know in a few weeks how we got on.
Sadly though it hadn't turned up by the time the car was finished (11pm last night ..) and the car is now back with the customer who probably got home after midnight ..
The pump was ordered through demon tweeks so at least if it does leak I can send it back .. then if it leaks again I can get my money back and go for the Stewart pumps mentioned earlier which look better?
Anyway, the deed is done now for better or worse .. when the pump does arrive though I will have to fit it at the circuit before the fist race, not the best way to test a new item.
We certainly need something though .. ran the car up on the dyno for a couple of power runs late last night and the temperature was fine running on the dyno .. back at tickover though the temps soared quickly once again ..
Thanks for all suggestions .. will let you know in a few weeks how we got on.
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