D21 Water to air intercooler install

[ChurchurDan]

I thought I would post some pics here as well as in the newbie section of how I fitted my intercooler and radiator. The radiator is a very tight fit as I still have functioning AC and don't want to remove it.

[ChurchurDan]

And all back together.

[tweake]

the ic looks nice and simple
wheres the water pump? looks like its above the radiator. best place for pump is at the bottom.

[Dirtydog]

I chucked my radiator right up the top, cut the middle support peice and welded flat bar over the top to hold radiator in place, and keep it nice and high, also to get as much airflow as possible.

[ChurchurDan]

I dont have a pump on it yet, I am planning on putting it behind the left headlight. Does it really matter where it is? If it gets the water circulating I will be happy.

I put the rad low as it wouldn't fit behind the grill without cutting half the back out and my decorative bull bars protect it nicely.

[tweake]

I dont have a pump on it yet, I am planning on putting it behind the left headlight. Does it really matter where it is? If it gets the water circulating I will be happy.

its important to fit the pump at the lowest point. they flow a lot better than if you fitted it in the engine bay.
pumps are pusher pumps, not suction. think of the pump as been gravity fed.

[IcedJohnno]

What is the I/C and radiator off?

[ChurchurDan]

Early 90's RS legacy

[Dirtydog]

I dont have a pump on it yet, I am planning on putting it behind the left headlight. Does it really matter where it is? If it gets the water circulating I will be happy.

its important to fit the pump at the lowest point. they flow a lot better than if you fitted it in the engine bay.
pumps are pusher pumps, not suction. think of the pump as been gravity fed.

I might have to relocate my pump then, mine is behind the left light, might put it to in behind one of the indicators.

[ChurchurDan]

I dont have a pump on it yet, I am planning on putting it behind the left headlight. Does it really matter where it is? If it gets the water circulating I will be happy.

its important to fit the pump at the lowest point. they flow a lot better than if you fitted it in the engine bay.
pumps are pusher pumps, not suction. think of the pump as been gravity fed.

Would it matter if I use the pump to suck out of the intercooler then pump it through the radiator. That way the supply is above the pump and it is gravity feed.

[tweake]

Would it matter if I use the pump to suck out of the intercooler then pump it through the radiator. That way the supply is above the pump and it is gravity feed.

i would imagen that would work ok, tho probably not quite as good as being on the other side of the radiator.
another downside is its on the hot side. depends on what pump you use, you may overheat the pump.

i wil have to look up some of the discussion on it where they tried different pump locations and recorded the results.

[diogenese]

I'm a sicko that knows too much about early legacys
The legacy cooler runs with a sealed pressurised water system so pump location is not so critical. It's midway between the intercooler and the rad on the legacy in the left front guard. The pump is NOT rated at 100% running on 12v, it has a volt drop resistor and only uses full voltage at high boost controlled by the engine ecu.
The resistor is mounted up by the brake booster on the legacy.

[monstr]

I dont think pump location is that important ,i was running the legacy pump on my set up on the safari ,pump was in the rear (tray back) and radiator in the front ,it worked well ,im now using a large oil cooler as the radiator it works just as good ,

[tweake]

it doesn't make any difference if the system is sealed or not,
most pumps do not suck very well.
i'll have to go dig up some of the threads on the guys testing it.

quite right about those legacy pumps tho. i do recall a magazine (FF&R or hot4's) many many years ago making a boost switch/timer for the pump so it turned on when you go on boost but still pumped for a while after to get rid of the heat.
fairly pointless on a diesel as the pump will be on constantly.
be better off with a heavy duty pump.

one thing to remember here is that on a petrol the IC only deals with a short burst of heat as they are only on boost for a short time.
diesel runs boost almost all the time so is dealing with a large amount of heat.
any 'restriction' in the system will cause heat to build up and you loose performance. so the radiator has to be big enough (most petrol based ones are to small) and pump has to flow very well.

[diogenese]

Any intercooler is better than none at all....

[The Stranger]

it doesn't make any difference if the system is sealed or not,
most pumps do not suck very well.
i'll have to go dig up some of the threads on the guys testing it.

quite right about those legacy pumps tho. i do recall a magazine (FF&R or hot4's) many many years ago making a boost switch/timer for the pump so it turned on when you go on boost but still pumped for a while after to get rid of the heat.
fairly pointless on a diesel as the pump will be on constantly.
be better off with a heavy duty pump.

one thing to remember here is that on a petrol the IC only deals with a short burst of heat as they are only on boost for a short time.
diesel runs boost almost all the time so is dealing with a large amount of heat.
any 'restriction' in the system will cause heat to build up and you loose performance. so the radiator has to be big enough (most petrol based ones are to small) and pump has to flow very well.

My experience is that I wouldn't get too hung up on the pump and radiator.
I have the subi pump and a big custom made radiator.

I know it's cooling the IC well as if I don't use the pump you can burn yourself on the IC, but when the pump is on the IC is barely luke warm.
I have also measured the cooling across the IC with the pump on and off and it makes q reasonable difference - though it was a while back and I don't have the figures at hand now.

There is a big difference in performance and EGT with the IC installed, but there is no discernable performance increase with the pump on or off. Perhaps any gain from the pump running is lost to the alternator?
There is a lowering of EGT with the pump running and for this reason I use the pump when towing, but other than this it stays off.
I would be very ineterested to hear what others have experienced in this regard.

There was a far greater gain in performance, cooling and fuel economy made by focusing on lowering the air intake temperature and at a fraction of the cost of the pump and radiator.

[tweake]

I know it's cooling the IC well as if I don't use the pump you can burn yourself on the IC, but when the pump is on the IC is barely luke warm.

it should be stone cold.

i don't know your setup but running with no pump is very risky. would only take a short length of time to boil the IC and depending on what cap is fitted either boil it dry or possibly split it the ic.

performance wise it depends a lot on the engine and setup.
what engine do you have and what boost is it running?

[The Stranger]

I know it's cooling the IC well as if I don't use the pump you can burn yourself on the IC, but when the pump is on the IC is barely luke warm.

it should be stone cold.

i don't know your setup but running with no pump is very risky. would only take a short length of time to boil the IC and depending on what cap is fitted either boil it dry or possibly split it the ic.

performance wise it depends a lot on the engine and setup.
what engine do you have and what boost is it running?

I assume that it doesn't boil the water in the IC as there is no water loss.
I suggest that this would be for 2 or 3 reasons.
1) the IC is in a pretty good cold air stream when the vehicle is moving.
2) the radiator is quite large and the system was designed such that convection should move the water anyway.
3) Perhaps also the fact that I have set a target maximum EGT of 700c also helps to prevent excessive heat build up. It only reaches 700 when towing (and thus using the pump anyway) - and it's water injected too which lowers EGT significantly - unless I run meths in the water injection that is.

It's a TD27 running max 18PSI.

[tweake]

egts have absolutely no bearing on how hot the water in the IC will get.
however the WI will make a massive difference to IC temps if its pre IC.

you must be getting a fair bit of convection circulating the water. cruise at 5-10 psi and 18 psi up hill would boil straight water for sure and be near the limit for glycol mix.

either way not running the pump doesn't make sense to me. loose any performance/economy gain and risk failure just to save some wear on the pump.

[The Stranger]

egts have absolutely no bearing on how hot the water in the IC will get.
however the WI will make a massive difference to IC temps if its pre IC.

you must be getting a fair bit of convection circulating the water. cruise at 5-10 psi and 18 psi up hill would boil straight water for sure and be near the limit for glycol mix.

either way not running the pump doesn't make sense to me. loose any performance/economy gain and risk failure just to save some wear on the pump.

EGT certainly impacts the cooling system.
The engine will overheat if EGT is sustained above 700 for long periods - it won't overheat the engine cooling system even when towing with a heavy load if EGT is kept at or below 700. In the same way the EGT has a direct impact on the heat going into the turbo, so it's hard to imagine that it does not impact the heat coming out. But I haven't attempted to measure this aspect specifically.

WI is post intercooler.

As noted, there is no discernable performance or economy gain from running the pump in my set up at least. I'd like to imagine that there is because I spent money on it - and perhaps there is on a dyno - but sure as hell can't detect one on the road and even at times such as going up scenic drive when it's on high boost for long periods there is no loss of water or other apparent damage. Next time I get around to it I will measure the temperature, but I'd be surprised if it exceeds 80c in the IC - as I say, hot enough to burn, but not at all life threatening (to the IC system). So there is no point running the pump around town or on the highway. And even if I did lose all the water it really wouldn't matter much at all.

For the record, this is the IC that I am using
http://www.trademe.co.nz/motors/car-parts-accessories/performance/turbos/auction-599721519.htm As I say, it's a large lump of ali stuck in pretty good air flow anyway.

[tweake]

egts have absolutely no bearing on how hot the water in the IC will get.

EGT certainly impacts the cooling system.

read what i wrote

i would be very surprised if the wasn't a performance gain. i know plenty that fit intercoolers and gain performance tho i don't know with your engine.

if you ever get a chance put some probes in the intake tubes before and after the IC. see what the temps are and how well the IC works with pump on and off.

a lot of the guys are chasing every bit of cooling they can, especially with water/air IC as they always perform worse than air/air (on road).
hence why things like pump locations are critical.

[lax2wlg]

This is an interesting discussion and looks like a lot of work too.

I am planning an intercooler. I am no expert on this but for some reason I like the concept of a simple, properly installed top mount air to air & simple fan

With only moderate fuel and boost, would this water to air setup offer any real world advantage?

It looks like something more performance oriented

[tweake]

performance wise big front mount IC rules.

top mounts tend to become interheaters at low speeds as hot under bonnet air gets blown up through the vent, unless your running a fan. the radiator and IC airflows can compete against each other a bit. generally not as good performances as a front mount.

water air while not as good as air-air on road, does beat them when the going gets slow. very good for slow hard working engines where you have minimal air flow.

turbo diesels love intercooling.

[Dirtydog]

Front mount intercoolers vs Water to air intercoolers can be a very interesting topic,

For example, with a front mount intercooler, depending on how it is setup you gain alot of area that has to be compressed by the turbo (cant find the right word for it)

However, with a water to air setup, you have the same amount of area (roughly) as a top mount, aswell as cooling the water and therefore the air from a source well away from heatsoak.

big disadvantage, not so much with 4x4's, but with performance cars is that you are then carrying around the extra water (weight)

The other good thing about water to air intercoolers, is that you can run an ice box or equivalent in the boot of the car without adding more piping.

[The Stranger]

read what i wrote

i would be very surprised if the wasn't a performance gain. i know plenty that fit intercoolers and gain performance tho i don't know with your engine.

a lot of the guys are chasing every bit of cooling they can, especially with water/air IC as they always perform worse than air/air (on road).
hence why things like pump locations are critical.

Oh, I read what you wrote just fine thanks - but it really doesn't explain the result I am getting. The water doesn't boil (despite you writing that) and the pump makes no discernable difference (despite you writing that too).

For the record - and reading what you wrote - the intercooler makes a huge difference to performance, filling the system with water makes a big difference to performance, the pump none (detectable) - despite cooling the IC significantly.