Rb Engine Track Work Temp.

[GTR_JOEY]

Where the HICAS solenoids used to be!! If you haven't pulled all that out....do so.

oh its getting done dont worry, thats shits coming out with the engine when i do the sump along with other things

good suggestion though

[KiwiRS4T]

Here's some purpose made fuel coolers: http://www.summitracing.com/search/part-type/fuel-coolers

or you could just use an aftermarket trans fluid cooler from Supercheap etc.

[JustinP]

Are we talking gaining a few kW's by running a fuel cooler, or something more significant?

[GTSBoy]

A few kW, and also avoiding teh fuel getting hot enought to flash to vapour in the suction side of pumps. Which tends to result in a sudden stoppage.

[kitto]

A few kW, and also avoiding teh fuel getting hot enought to flash to vapour in the suction side of pumps. Which tends to result in a sudden stoppage.

This. When fuel gets hot it causes a vapour lock in the fuel system. Pressure pump starves - car runs like shit, stalls and possibly leans out under load.

Fuel cooler is also good to help prevent knocking.

[GTR_JOEY]

Here's some purpose made fuel coolers: http://www.summitrac...pe/fuel-coolers

or you could just use an aftermarket trans fluid cooler from Supercheap etc.

Cheers Bob

ive seen a few examples of fuel coolers now where there is on a couple of rows of tubbing, Is this all that is required?

i would have thought that it would need something with a few more rows.

i do like that design though as it "looks" like it has a very solid build and would resist damage from stones/rocks etc

This

http://www.summitrac...80125/overview/

I dont exactly know how it works, im guessing this is very similar to what you have

[Risking]

This is where and how I usually do undercar cores.

These are hollinger and rear diff coolers but could be used as fuel coolers as well.

Simple duct that limits the chances or rock damage, Dont ever put a cooler behind a wheel obviously.

Those coolers have probably seen more of a beating than any GTR ive ever seen and they havent really taken any massive rock strikes, they do accumulate debris from the circuit and require constant cleaning out with an air blower to keep tire rubber and dust out of the cores.

[GTR_JOEY]

Looks good Brad, have you mesasured the temperature drop before and after with this set up... i know its oil not fuel, (just for a rough idea)

are those pics off an R32 GTR?

[kitto]

This

http://www.summitrac...80125/overview/

I dont exactly know how it works, im guessing this is very similar to what you have

This requires liquid CO2 to cool the fuel. Not an ideal fuel cooler for most. This is suited to drag racing more so i think.

[Risking]

Looks good Brad, have you mesasured the temperature drop before and after with this set up... i know its oil not fuel, (just for a rough idea)

are those pics off an R32 GTR?

Those are on an R32 GTR yes.

Pretty much every car we build that is going on E85 gets a setup similar to that. Doing one on an R34 GTR today I'm a similar way.

Oil temps are usually around 75deh for those coolers but they require switched pumps to circulate to the coolers. Pumps are on at 75 and off at 60. Hollingers recommended oil temp.

The fuel systems I've done that have actually had temp sensors put in them show a consistency more than a temp drop. Usually surge tank temperature is around 45degress

[kitto]

So back to radiators.

PWR do a 42mm and a 55mm radiator to suit Skylines.

The 42mm is designed to work with the factory clutch fan and shroud. The 55mm will only work with a thermo fan. They recommend a thermo fan on one side of the radiator with no shrouding. They supply brackets to do this. The 55mm rad they do is designed for track use only more or less.

I think the idea of having no shroud and a single fan is to try and promote maximum air flow while the vehicle is in motion. The fan is to help cooling at low speeds/idle.

Is this theory correct?

My question, whats the ideal way to go?

[GTR_JOEY]

Are you hell bent on buying a PWR one?

I just installed my racepace triple core in my 32 today, went in sweet and it retaines the factory shroud.

From what I've been told by people in the know I don't see a reason to have a radiator so big that it can't retain the factory shroud and fan. Getting a thermo is just going backwards in any case.

If the vehicle is in motion there would be plenty of air passing through the radiator

If you are not in motion or at low speeds, then yes you defiantly need a fan going to draw air through the radiator. A mechanical fan does a better job at this then a thermo. Also having the shroud will be advantageouse in directing air where u want it..

At the end of the day the mechanical fan and shroud will kick a thermos ass if your barely or not moving.. And if you are moving it doesn't matter so much

[arrydjay]

For the guys who are running their cars up to 100 ° or more I'd be making sure you have a way to monitor knock levels.

Not all tuners account for temps this high and you could be knocking when approaching these temps.

I know it's not the most accurate gauge but using the knock sensor on my pfc, and first few laps at around 80° knock levels about 10-20. Temp usually gets up to 85-90° knock is around 20-35 but if it's a hot day and the temps get to 95° knock levels start to get to 50-70 and I will have to do a cool down lap or two.

[Risking]

Thermo fans are not a step backwards. They are an alternative to a clutch fan. If set up properly and understood they will work as well as a clutch fan.

A lot of fans supplied out there are meant to be push fans. Problems occur when people try to use them as pull fans and don't reverse the blades, or the motors polarity.

Problems also occur when the fans body isn't mounted flush to the radiator core. The fan will draw air from around the fan body instead of through the core if there is a gap between the core and body.

A lot of people also try to use cheap fans of poor blade design and or recycle things like falcon fans that can't be mounted properly to the radiator.

If I'm using fans it's spal or nothing, PWR will supply you brackets to mount a spal can flush on the radiator core and it will be a pull type fan suited to the mounting location.

I do agree that the massivly thick radiators out there aren't nessiary. You want something that's side flow and at least a twin pass preferably triple pass.

Like I wrote about fuel coolers, the longer the fluid if kept inside the radiator the more heat it can potentially disperse.

[GTSBoy]

Like I wrote about fuel coolers, the longer the fluid if kept inside the radiator the more heat it can potentially disperse.

Ah, but that's where logic gets in the way of a good story. If you have a choice of two cores with the same frontal area, but one is a single pass and the other is a (say) double pass, the coolant will spend the same total time in the core. In the single pass it will travel slowly (velocity) through a shorter flow path, and in the double pass it will flow faster (velocity) through a longer path. But the time remains the same (give or take a few % here or there for things like uneven tube counts).

The time remains the exact same. So it is not "the amount of time" that the fluid remains in a core that determines the amount of heat it can shed. The faster velocity through fewer tubes causes the convective heat transfer coefficient to increase (think of it as the turbulence level increasing, although that is not the full reason). That means that you will move more heat between fluid and wall provided you can take it away on the air side of the core, which is not usually a problem - although given the discussion here about fan types and ducting etc, obviously we do run up against those limtis as well. The price you pay for the higher velocity is more pressure drop, but in a cooling system we probably don't worry too much about that. Pressure drop is an issue if comparing single pass intercoolers with double pass ones, or the old Supra type where they had a higher number of shorter tubes flowing vertically. Pressure drop in intercoolers is obviously an important factor, on top of thermal efficiency.

[gtr jet]

Well you learn something new everyday.

Very informative.

[kitto]

Im not hell bent on a PWR no. But as far as i know they are one of only few if not the only place to get a direct fit to siit an R31.

Im pretty sure an R33 unit will fit but it sits lower and needs new brackets made up. The brackets are easy but the sitting lower part is a concern.

If i do end up with a thermo fan it will be a spal only.

Does anyone know of other very good rads to suit an R31? Obviously a cross flow twin or triple pass would be a good option. Im fairly sure the PWR units are vertical single pass.

[DVS JEZ]

Arrydjay- did u check what ur airtemps may have been getting up too?

[SimonR32]

My ECT sits at about 82 driving normally and went up to around 90 after some laps at the track.

Just received a Sard 68deg thermo from Japan, hopefully will sit just over 70 in normal driving and around 80-85 when thrashing

[gtr jet]

Would that mean that my car has a low temp thermostat as it sits on 72 degrees on cruise.