Rear mounted radiator - high ambent temp??

[DanielS]

Hi Gang,

I'm in the process of installing a rear mounted radiator to my comp truck.
What are your thoughts on how it will preform on highway in high (50C) ambent temps.

The truck is a boosted, fueled up TD42.

The reason I ask is that I would love to take the truck up north end of the year.

The radiator is going to be a custom 68mm thick, 800x500 dual pass aluiminium job with twin 16" spall fans, including a 115L/Min davis Crage push pump.

Additionally what are your thoughts on a holley fuel fuel push pump for the fuel system??

thanks in advance.

Daniels.

[chimpboy]

That is quite a large radiator, and my guess is that your set up will be more than adequate. I am assuming you're still running the mechanical water pump as well, I am just personally not a fan of the electric ones.

Unfortunately you have to try it to find out for sure!

nfi on the fuel pump sorry.

[its aford not a nissan]

yes , fit a holley red lift pump it does help , and it has lowered egts on mine aswell

[bru21]

rate of cooling is an exponential equation.

The closer the temp your motor runs to the ambient the far worse the cooling.

That said there is still a fairly large temperature differential between the higher temps new motors run at and 50 deg - no different to an older engine with a 90 degree thrmostat and 40 degree temp

[ronno88]

From past experiences with 3 different rear mounted radiators iv found that running a thicker rad can have less cooling effect as the air cant be pushed thru it as easily.
Iv ran a custom alluminium radiator before which was 70-75mm thick and couldnt drive it at all because the fans couldnt pull the air thru it.
I now run a big thinner radiator with the same fans and ewp 115 pump and have no dramas with heating ussues but temp will rise up a bit at along highway.
Its on a cruiser running 350 chev if that helps.
I personaly wouldnt put 1 in if its going to be doing trips in hot weather.

[DanielS]

thanks for info guys,

ronno,
I understand that thicker core will limit air flow, this core is ment to have a less fine count per square inch to help increase air flow, do you think this will help?
I know its not ideal having a rear mounted rad, but i have limitations as to what I can fit in the engine bay.

Bru,
I understand what your saying also, add to this the fact that the 16" spal fans will need to do all the drawing of air. these are ment to be around the 2000 cfm but there is genrally a slight vacum behind a cab if I'm correct?.

Chimboy,
yeah mate it will still have the mechanical pump and just use the DC 115 pump as a push pump when needed.



Daniels

[Mudzuki]

Can you add ducting to divert air into the area like they do for the Australian Safari?

[chimpboy]

Can you add ducting to divert air into the area like they do for the Australian Safari?

I would be interested in what people think of this approach. Personally I think it is completely pointless in an off-road vehicle because once you're in 4L you are going too slow for any roadspeed-generated airflow to help. So your fans need to be fully up to the job on their own anyway. They need to be able to pull in plenty of air but it doesn't need to be from the front of the vehicle.

[ronno88]

I think it would help alot better having less core count per inch as the thick rad that i was running had a very fine core pitch.

[85lux]

we had an xr8 radiator mounted behind the cab of a TB42 turbo'd GQ on gas and it overheated a lot at RD 1 engel and on day drives.
we have since added a duct on top of the roof and we have not had a problem since. the duct did help at low speeds(which was a suprise) as well as high.

[mudmacaca]

Buy putting the duct there you will loose the vacum or low pressure zone at high speeds and at low speeds you will be relying on your thermo fans but with the duct they should be sucking cool air from the roof rather than pre heated air from over the exhaust and engine bay