GTR Forum banner
41 - 45 of 45 Posts

·
Registered
Joined
·
48 Posts
Discussion Starter · #41 ·
That’s a good selection of pictures. Thanks.
i might have the exit funnel sprayed black.

From looking at the pictures they could have done away with the exit funnel. And just added a fan to draw the air through the rad and blow it out around the exhaust exit and rear grill, the fan could switch on with the pump.

duel pass radiator will force the hot water from the bottom to the top and back to the bottom. Hot water rises so it does the first half itself.
It’s more expensive to produce and more difficult to bleed the air out. Could be the reason.
 

·
Vendor
Joined
·
4,754 Posts
I did have a little read up and some advised a change of water pump with a twin pass system.
I suppose it depends also on how good the cores are being used.
 

·
Premium Member
Joined
·
92 Posts
Yep the latest Litchfield dual core rad has a bleed screw at the top now, the one I have didn’t and it took a while to bleed the air out. The core is split by a divider in the end tanks, it needs a transfer pipe fitted as the outlet location is now the bottom, not the top, and a hole cutting in the plastic bulkhead, but it’s not difficult. The spare hole at the top where the pipe used to come out is conveniently located for the bleed screw.

The coolant is exposed to two passes across the core, but also another perceived change is the increase in coolant pressure, which should help. I have back to backed their dual core and the single core aluminium radiator on track, both were an improvement on the OEM rad, but the dual pass yielded a small improvement over the single core. I think back to backing two full aluminium rads was worthwhile as a lot of OEM rads on a car with any amount of mileage, might well have the fins bent or blocked with leaves and debris, so anything would be an improvement. I also ran a coolant system pressure sensor to check for any issues with the pump, and there were none. What we saw was what you’d expect, a linear increase in coolant pressure throughout the rev range. You can see coolant pressure overlay on the onboard videos I posted in the build thread. AMS use a dual core radiator too.

I can’t comment on the idea of using a fan on the trans cooler, theoretically where the outlet is placed is a strong area of negative pressure, so the airflow would be stronger than any fan could produce, but without putting it in a wind tunnel it’s all guesswork. Fans work great at low speed but once the airflow is faster than the fan itself, they’re actually obstructing flow. That’s why I believe the radiator fans turn off above a certain road speed.
 

·
Registered
Joined
·
48 Posts
Discussion Starter · #44 ·
Has anyone tried these.
 

·
Premium Member
Joined
·
92 Posts
Not the Import Racing Ones, no. I tried some other ones which look similar, but without the deep rubber extensions on them, and they did the sum total of absolutely nothing. Like literally nothing. Calipers got just as hot, fluid boiled in 4 laps (Castrol SRF), discs got to over 800c. I am not paying € 750 for a clip on bit of carbon with no data, so I will never know I guess... That said, it's very easy to modify the ones I have with rubber extensions held on with anchor nuts, so I probably will.

When my car comes back from Litchfield (hopefully in 10 days), I have an air pressure sensor ready to plug straight onto the inside of these 'scoops', to measure if it is actually positive air pressure there.

If it is, and they do actually hang far enough into the air flow to deflect some of it (two big 'if's), then it may help reduce the temperature of the calipers and prevent fluid boil. What it won't do though is significantly lower the temperature of the discs themselves... The only real way to do that is to duct air into the centre of the disc, which is very hard without a bespoke upright designed to channel air around the driveshaft and bearing journal. NISMO make one for their GT3 race car, I believe it costs over £10k a side and has different geometry anyway...

I have tried to do it on my car using custom dust shields that incorporate a 3" hose boss, but the next big problem is where to duct air in from. There is no space in the front bumper with oil coolers and radiators in the way. When I tried running a hose off the back of the splitter (connected to ducts in the front of it) the hose is easily ripped off when you ride kerbs, plus it's only a 2" hose anyway.

Some people say "If they do nothing, then why do Nissan and Porsche fit them?" Fair point, they must do something, but you will never see a fully ducted brake cooling system on a road car unless it's been fitted after market, as it would never pass type approval with that kind of gubbins hanging in a vulnerable position under the car, ready to get ripped off the first time you drive over a piece of debris.

This is my big gripe with this kind of stuff. If it works so well, how hard is it to make up a YouTube video showing peak brake temps with and without, before handing over hard earned cash? Or one might suggest, if you're charging over €700 it might even have been worthwhile fitting IR temp sensors so you can overlay real time brake disc temps... Just sayin'...
 
41 - 45 of 45 Posts
Top