mattski

Hi,

I have a 94 WRX with the angled intercooler, I was wondering if there are any performance gains to be had from using one of the later, straight intercoolers?

Also, are there any differences between the more recent intercoolers, i.e. STi5 and UK?

Would the intercooler be a straight swap or are there other differences to take into consideration, assuming it is a worthwhile change?

ta,
Matt

GavinP

Matt,

The later intercooler won't fit without a lot of messing around - it certainly isn't a bolt-on job.

I would recommend putting a thermostat in the pipe to the inlet manifold to monitor temperatures first. You want to leave this in place for at least a couple of weeks to see how different driving conditions affect the charge air temp. Maplin sell them for around a tenner.

You can experiment with an IC water spray and/or three 120mm fans mounted on the underside of the existing intercooler.

The RS Legacy chargecooler will bolt on but you need a water pump, radiator, reservoir, hoses etc - the cost mounts up. My setup has cost me about £600 in total.

I know MRT make an upgraded top mount IC but it is not cheap. I also understand that Forge Motorsport are making an uprated top mount for the later models but I haven't seen a published price.

Several companies make front-mounted ICs which are even more expensive but will be more efficient in lowering the temperature (although lag will allegedly increase marginally).

Good luck - it is a can of worms you have just opened......

Thanks

Gavin

mattski

thanks Gavin...

The thermostat sounds interesting, did you fit another guage to monitor it or something?

And the fans, where do they go? Would it be worth getting some PC cooling-type fans blasting air into the intercooler or have I gone straight to improbability drive land?

I think the water spray may be worth looking at, although is it warranted at the sort of performance level my WRX has?

ta,
Matt

GavinP

Matt,

The thermostat I used was an indoor/outdoor car LCD thermometer from

Sam Elassar

hi gavin.

how did you fit the probe in the pipe to the inlet ? do you have any pictures of this ?

i have got water spray installed but i am not very sure if it is making any difference or not. and the idea of being able to meassure the temp is ideal.

so are you gettig lower charge temperature now with the new set up ? are you running more boost because of that or is it just for safety.

scoobymania have developed their own top mounted intercooler which is £700-800 if i remember correctly. looks the same as the more expensive MRT one they used to sell .

GavinP

Sam,

I fitted the probe into the hose between the intercooler and throttlebody.

The wire comes out one end and the jubilee clip keeps everything in place.

It is not a permanent fixture and I don't intend keeping it there after testing.

With the current setup, the intake temperature peaks at 45 degrees C and stays between 25 -40 normally. The intake temp does not rise anywhere near as quickly as it did with the original IC in slow-moving traffic.

I am not running any extra boost but the car definitely seems keener. I haven't put the car on a dyno yet to get figures.

Thanks

Gavin

Sam Elassar

did the waterspray make any difference at all? and is your new set up reducing the charge temp at high boost as well as in slow moving traffic ?

i think i will be doing some testing my self.i have the halfords heavy duty water pump just now but i might get the one from MRT which is a very powerful pump that is used for their rally cars only if i can see any poitive signs from water spray!!. i know that doing it properly by means of sti nozzels and tank and so on you are talking few hundred pounds but in theory it should work, however so far it does not seem to make any thing at all.

any one out hear that has done any testing with the water spray in the UK?

sam

GavinP

The new setup has a much higher heat-sinking ability so when you boot the car, the temperature rises very slowly .

Unfortunately, the water also takes longer to cool down.....

When driving normally (i.e. using high boost occassionally) it works very well - I think that on a track it would be much less effective.

With the slanted air/air, I was seeing upto 60 degrees C but that was in "summer" so it's not a straight comparison.

I'm sure a water spray would help but the water pressure needs to be fairly high and the spray produced VERY fine.

Thanks

Gavin

Spatch

Chaps,

You have been talking about water spray injection and the fact that some of you have even fitted your own with bits from B&Q etc.

It sounds interesting and I may have a go myself but I was just wondering, does the spray run all the time or is there any control (flowrate, pressure etc) required. After all I would have thought that the amount of water required at full boost is somewhat more than that required at idle.

Also, where do you do the injecting, before or after intercooler, and how do you actually get the spray nozzles into the inlet system.

Ta
Spatch

Sam Elassar

sorry to disappoint you spatch. it is water spray not water injection we are talking about. I am spraying water onto the intercooler, however it is not effective as it sounds due to the lack of testing I think more than anything else. don't they also run it in rallying ?

I have been told that the P1 uses a bigger intercooler than the standard ? also the new Subaru has got a bigger one so I wonder if we will be able to get it to fit our cars !!!!hmmmm. my car will definitely benefit from a bigger intercooler I think ( could be wrong ) but I am basing my opinion on the fact that I get more knock on the track in the summer unless I wind the ignition down.

Bob Rawle

Water spray is not water injection.
I have a few facts and figs, my MY96 Sti 2 (angled intercooler) was hitting nearly 70deg C air temp at the exit of the intercooler as it entered the throtle body. Not good but I do run just a touch more boost than normal. I also had water spray as factory fit but only manually operated. Now water spray triggers at 0.75 bar and cycles on for 3 secs and off for 1 sec (get just as much cooling from evap) repeating for as long as the boost is above 0.6 bar. Temeperatures now rarely exceed mid to high 40's even on the track. I fitted a temp 12 litre plastic tank to see what the effect would be as I was using alot of water with this setup. Found that the 12 litres would do approx 20 laps of Castle Combe. I use the same pump and nozzles (Sti) that you fitted Sam and can factually state that temps are reduced significantly. I use a high speed temperature meter (2000 counts/sec) and a K type thermocuople just slipped in under the flex pipe that joins throttle body to intercooler.
Be careful using the maplin items, the probes can become detached and they are a bit large to have disapearing into the engine. They do measure the temperature ok though.

P1 intercooler is same as STi 5

[This message has been edited by Bob Rawle (edited 26 November 2000).]