Idea for better FMIC plumbing

[sambb]

Ive been toying with different intercooling ideas for the Polo.

1. water to air - use an audi S3 passenger side entry inlet mani (got one coming) and position a water to air core directly between the turbo outlet and the mani eg above where the battery and airbox normally sit. Length of induction piping would be about 1m max. Things to consider are are reservoir positioning (from a heat soak point of view), whether you'd even need a reservoir, and weight of the whole system.

2. air to air top mount- in the same position run an air to air core with a Mazda 3/wrx style scoop feeding it and ducting out to the back edge of the engine bay undertray. Works fine for STi's, it would be a straight shot into the S3 inlet but would be lighter than 1. Could very easily rig up a water spray for it too.

3. air to air FMIC - this is the one that I'm really looking at as a way to run air to air (reliable/light) but with the shortest possible inlet tract (like 1. and 2.)



So looking at third pic you can see that the compressor exit an be brought out and shoot straight to the front of the car. I reckon by looking at my car and the pics of Louis's when it was apart, that if you remove material above the radiator where the CAI normally is (where Louis has the feed for his K&N) that you can continue that pipe straight out the front and then drop it vertically into the top of a FMIC. I don't think there is a more direct way to get into one.


So the type of intercooler that would do this would be an EVO's. First pic are two Evo ones and their aftermarket counterparts in the other 2 pics. But if you take one of these and flip it left to right, the intercooler inlet will sit directly below where we can get the compressor exit to come out above the radiator. That will then put the Evo's IC exit in the perfect position to run existing SEAT/Forge piping up to the factory inlet. The normal SEAT/Forge inlet tract run would be about 4+m I reckon and in comparison this would allow you to run a factory core (or readily available aftermarket), a single pass IC and cut the inlet length by nearly half.

I'm actually intrigued though if an underbonnet air to air could be made to work. With proper ducting and heat insulation/shielding/partitioning it'd be a light, lagless and reliable/simple way of doing things and would have the added bonus of leaving the radiator unobscured which could only help with water temps too.

[sambb]

Bolt on Upgrade Intercooler For 2007+ Mitsubishi Lancer Evolution EVO X | eBay $368 bucks!




I still think the BA/BF Garret IC would be a goodn for up to stage 2 cars. Make the end tank on the right the inlet, get the inlet re welded vertically so it can be fed from above and the left outlet feeds to the stock inlet. For an IC that costs literally 50-100 bucks second hand it'd be worth a try.



or something like this sitting flat above where the stock battery/airbox is in the pic of the red polo above with a butch air scoop feeding it.

[Sydneykid]

Let's see if I can kill off the WRX style (air to air I/C in the engine bay) first, just moving the standard I/C to the front results in a 10 degree C reduction in inlet air temp and an extra 10 kw. That's on the dyno in a temperature controlled room with 2 fans, one for radiator and one for the I/C, simulating driving at 100 kph.

Often the extra net weight f the water to air I/C is offset by the weight of the much larger air to air I/C plus the larger radiator that they often mandate. Net there is commonly not a lot in it. Plus the advantage of the water to air system is the weight is further back in the chassis, mostly within the wheelbase.

An efficient air to air I/C is going to reduce the inlet air temp to around half of the difference between the compressor outlet temp and the ambient air temp ie; 80 degrees compressor outlet temp + 25 degrees ambient = 55 degrees inlet air temp. A really super efficient air to air I/C with spray might get that down to 40 degrees. Compared to an ice water to air I/C that can get below ambient (until the ice melts).

Personally in hillclimb environment I'd pass on an air to air I/C which does next to nothing while queuing and sitting waiting for the green light and water sprays are frowned on. That especially applies to one in the engine bay suffering from heat soak. Water to air has so many advantages and an esky full of ice will last most of the day.


Cheers
Gary

[simon k]

ditto - I hate air scoops...

I'm waiting on kaanage to get back to me about his SEAT intercooler, but I do like the idea of plumbing it from left to right

the location of the battery is one of the biggest problems when it comes to intercooler piping - move it to the boot and there is a heap more room

[sambb]

H Ha I kind of knew that would be the consensus on top mount air to air but was hoping that it wasnt as bad as that since its so light, short route and simple. I did a lot of searching last night and the air to air underbonnet cores are all quite expensive too.

With water to air, what I'm unsure of is whether you absolutely have to have a header tank. If the core was positioned between the compressor outlet and the passenger side feed inlet, it'd be very high in the system. Surely then the core could have a pressurised cap on it and thats all I'd need. I realise a header tank would gives advantages (ability to add ice too) but in the polo engine bay I cant see where it could sit higher than the rest of the system, and wouldn't it just heat soak? Can anyone steer me towards a formula'y type set of informations that help with sizing the system eg radiator size, ideal water capacity?

Simon if you look at the engine bay of the red polo in that pic above, I reckon you could get the compressor pipe straight out through the front and it wouldn't interfere with anything. Moving the battery to the boot would definitely make things easier though. The cold air intake would have to descend and pick up air from underneath the headlight (where guys bring their single pass IC pipes up through) so that the induction pipe could fit through the CAI pickup above the radiator but that looks about it. The reason I'd still maybe this type of air to air is if I was to change to a bar n plate IC that would be a bit more heatsoak resistant, but then again that would get the weight up close to a water to air system nearly anyway.

Why do water to air IC cores have to cost so damn much?

[simon k]

Simon if you look at the engine bay of the red polo in that pic above, I reckon you could get the compressor pipe straight out through the front and it wouldn't interfere with anything. Moving the battery to the boot would definitely make things easier though. The cold air intake would have to descend and pick up air from underneath the headlight (where guys bring their single pass IC pipes up through) so that the induction pipe could fit through the CAI pickup above the radiator but that looks about it.

yeah, but this pipework seems a bit dumb. I don't like the way the air cleaner is sitting there behind the battery sucking in hot air. There is heaps of room to take that pipe on the right over the top of the radiator and straight down to an intercooler without that turn taking it under the headlight. Piss the battery off and the turbo outlet pipe and air cleaner have all the room in the world.

Why do water to air IC cores have to cost so damn much?

cos they don't make good ones in China yet?

could be worth a crack at one of these

Barrel Intercooler Water To Air Cooler Liquid To Air Intercooler 4" X 10",Water Inlet/outlet 2.25'' - Buy Water Liquid To Air Intercooler,Intercooler,Water Intercooler Product on Alibaba.com

[sambb]

Simon what can be done is take a cold air feed from where that IC pipework goes under the headlight and run that to the airbox or pod partition. The IC pipework I'm proposing runs forward like in the pic but then doesnt turn sideways or down after the first blue silicon pipe - instead it continues forward and punches directly forward and runs beneath the black panel but above the radiator and once its done that drops vertically straight into the top of the IC. Thats a 1.5m run into a single pass compared to about 2.5m to get into a double pass the normal way or the way you can see in the pic where it winds down through the headlight and ends up nearly as long as the SEAT/forge way too.

[simon k]

is there room to get a pipe under the battery where it is now?

[sambb]

Not under but you can squeeze one around the side of it and then down under the headlight. If you get some storm water pipe and a heat gun I'm pretty sure you could get the distortions and bends moulded int the tube to get it to fit.

[Sydneykid]

There are basically 2 types of air to water heat exchangers that I have seen. The tall and wide but thin style, like an air con heat exchanger. Then there is the long but not so high style that are like an oil cooler. The fin area is probably much the same, so which is chosen depends on the area/space is it going to be mounted into. The thin style PWR one on a circuit race car was 460 x 375 x 29 mm which was good for around 400 bhp. I have seen a road/drag car with the header tank under the passengers seat. It had a few litres of water in it (may 5 to 8 ) for road work, but for the drags they filled it with half ice and half water. They just slid the passengers seat back or forward (can't remember which) to access the filler port. The pressure cap was on the heat exchanger which was the short/long/thick style. I've seen them for around $200 on Ebay.


I've seen Chinese barrels for around $150, also on EBay.



The pumps are around $100


There are kits on EBay from time to time for around $450




Cheers
Gary

[sambb]

Gary how does it work having a header tank located lower than the core itself or the heat exchanger (eg on the cars floor)? I always thought the header had to be the highest point in the system. If the header was in the engine bay, is heatsoak likely to be a drama? If the heat exchanger is sized correctly surely a well insulated header would be ok wouldn't it.
The other option for a heat exchanger I was thinking of is a VR6 auxillary radiator positioned where the side mount used to be infront of the drivers side wheel. That would help pull the weight back a bit but would be adding it to the already heavy side of the car too.


For pumps I was going to use two VW 1.8T auxillary coolant pumps (used in my car to circulate coolant around the turbo when the car is switched off) in parrellel as a failsafe.
Do you know if any of the old water to air IC cores from GT4 celicas/RS Legacy were good.

[simon k]

shouldn't matter which point is highest, as long as that's where the filler is. You might need to add an air bleed if there are high points... but not really a drama

[sambb]

But a header tank still has air in it by definition doesnt it so has to be at the top. That makes me think that it has to be in the engine bay a tad higher than the core but I could have that wrong. Seen a few cores where they have the pressure cap on the water jacket itself and no header (all the capacity is in the core and exchanger with no auxillary) but obviously with that system you loose water capacity and the ability to add ice. thinking seriously about this now. One of the things I've been told is that if you want to go E85 then you need rock solid temps. You cant be bunging loads of timing into a car and then have it leave the line at a hillclimb with 80 degree temps but its down near ambient as you cross the line - a recipe for engine death, so if I ever want to do E85 then water to air makes a lot of sense for really stable temps.

[Sydneykid]

Perhaps over thinking it Sam, it doesn't have to be a sealed pressurised system like an engine cooling system. In a long distance circuit race car we use a pressurised I/C system, but for short distance/time event like drags and hillclimbs it's not really necessary.

In the drag car systems the pump takes water from the bottom of the reservoir (ice/water) tank and pumps it directly into the I/C so it always has water in it. From the I/C it then goes to the bottom of the heat exchanger, forcing any air in it out of the top, through the return hose and back into the tank. The cycle continues, the air rises to the top of the tank, the pump picks up water etc. Much like a dry sump oiling system.

If the I/C is,say, the highest point then you could put an air bleed tap there, at say the hose return to the tank. It can be anywhere in the system that is the highest.

Keeping in mind that the "hot" water shouldn't be over 70 degrees (not 100+ like the engine coolant) and even then only in the short hose from the I/C to the heat exchanger. Which should then drop it back close to ambient, so the water in the return hose and the tank should be around ambient temp. Or lower if you use ice/water, until the ice runs out of course. The reason why engine coolant systems are pressurised is to raise the boiling point above 100 degrees. In the long distance race cars the compressor outlet temp often gets over 100 degrees, which could mean the water in the I/C boils, so that's why we use a sealed pressurised system. Unfortunately can't stop after every lap to fill it back up with ice.

Cheers
Gary

[Sydneykid]

Obviously in the race cars we have inlet air temp correction, so if the inlet temp changes the fuel and ignition maps move appropriately. If, say, we have leak in the water to air intercooler system which causes the inlet air temp to rise the ECU moves to the appropriate map to prevent damage. I'd be surprised if your ECU doesn't have that facility, if it does then you need to program it accordingly. If it doesn't then I'd suggest you fit an air temp gauge, in good line of sight. Keeping in mind that you could see inlet air temps from below ambient (with ice/water) to 70 degrees above it (system failure).

Cheers
Gary