Having had small radiator leaking for the pass 12 months, I’ve decided to get it finally sorted next month before the cold weather sets in. In all honesty, I’m also sick of topping it every week! I orignally thought it was the front rad pipes/jubilees, but I replaced these with Forge ones. I took it apart again the other month due to it still leaking and it does seems to be leaking from the middle of the rad somewhere when hot.
The current radiator is a Pro-Alloy, but I’ve no idea if its a single or triple pass rad - Always assumed the latter (not sure if you can tell by looking).
The other problem i’ve had is that the car runs a bit hot (98-105) when pushing hard on track, so I’d always assumed triple pass would be better, but then there has been some conflicting views on Seloc recently about this…
So do i go for a pro-alloy triple pas rad, or something else??
If yours is an early rad like mine it will only be single pass, I have been told the triple pass makes 4 or 5 degrees difference, mine is coming out this year for that very thing, ring Wayne at proalloy they might be able to repair and convert your rad for you?
If you read the Hofmanns reports on their chargecooler you’d have read the extra resistance offered by the triple pass actually worked less efficiently than a single pass and a big pump. Does the same apply to the engine coolant rad? (admitedly a bit fixed in the pump dept)
Thats kind of what I was thinking, but to be fair I’ve only ever had temp troubles on track at 8k rpm and the coolant flow is pretty good at that sort of engine speed so triple pass would make sense in theory - charge cooler pumps very little in comparison.
As a side note the Bosche PAD pump fitted to my charge cooler is pretty small! After reading that comment by Hoffmans, I’ve been thinking about either upgrading the pump or adding another pump to the circuit (I have a spare one). Need to sort the leaks out first though!
I also thought Randy’s comments were interesting regarding radiators.
You would of thought the mechanical pump on the car will pump shed loads of water at high RPM as they are designed to pump loads at low RPM to keep the car cool when idling.
Would be good to do some testing.
To be fair we have found that on the audi engine you can get cavitation problems with the standard water pump at very high rpm’s The standard car only revs to 6,500rpm and the pump is designed as such. When we start taking them to 8,000rpm you end up with a lot less flow due to these cavitation problems. Hence why we fit electric water pumps.
This wouldn’t apply to the Toyota engine as it is designed to rev to 8,600 rpm or whatever it is, so all should be fine
One other thing to add, is the electric water pump (engine coolant water pump) on my S1, pumps absolutely shed loads of water and I have had a Pro Alloy triple pass rad fitted for years.
I’m getting my charge cooler rad modified to triple pass over the winter along with my normal rad, I hope to get the running temps down a little from this summer
on all of the Pro alloy charge cooler rads I have seen, the inlet and outlet pipes are on the same side, so they are dual pass as standard, and you cant have three passes with the in and out pipes on the same side.
