Intercooler question to experts

[Ramee]

This is a new thing I got the know while reading about A45 AMG which has a water cooled intercooler. It is not a air to air intercooler like we have but air to water intercooler. I heard it helps to reduce turbo lag and boost drop through intercooler and more efficient. Does any one know this is true and has any one done something smiler as a conversion to normal car.?

[Lucas_R]

Its a completely different intercooler setup - the old Toyota Celica GT4's used to use water to air intercoolers too.

Reduced turbo lag and boost drop comes from a much shorter network of pipes (normally the water to air intercoolers are located quite close to the turbo), whereas traditional air to air intercoolers have a much longer network of pipes as the intercooler is located at the front of the car.

[brad]

Early Subaru Legacy turbo had water/air intercooler.

77tsi Polo has water/air intercooler too.

IIRC, the Legacy had a separate radiator & water pump for the "turbo water".

The Polo uses the same cooling water as the engine / transmiision / oil cooler (not sure how many heat exchangers they've got in the system but you get the concept?).
I think it's under the heatshield


The Subaru version was very efficient & relatively compact.
I'm not so sure about the efficiency of the 77tsi version as I assume it's running at about 95c all the time because it's cooling the engine as well?

If you google images "water air intercooler" you will see plenty of examples

[guile]

does anyone know if water (water only) injection would have a similar effect. i'm thinking about installing it on the s3 but don't want to run meth and change the timing as it sounds a bit dangerous...

[Ramee]

Yes. Thanks, I get some idea about it. I think polo 77tsi has so small engine and a intercooler so cooling through already available radiator and pump for engine cooling may be cost efficient?

But for bigger engine may need a separate water pump + radiator + new water air intercooler. Anyway this should bring more better efficiency because A45 using it with 29 PSI boost. But conversion of a standard type intercooler system to a watercool type may be prohibitively expensive.

[brad]

does anyone know if water (water only) injection would have a similar effect. i'm thinking about installing it on the s3 but don't want to run meth and change the timing as it sounds a bit dangerous...

I've run water only (serco or sparco??) injection back in the 80s on a falcon & a capri - both Naturally aspirated. On the Falcon it was brilliant. I could run big timing & the fuel economy on a trip was amazing - 40mpg! On the Capri it didn't seem to do a thing but the Capri was always a disapointment so maybe that's to be expected.

I'm not quite sure what you mean by "the same thing" but water only injection will cool the incoming charge & clean the intake, cylinders & (a little bit) exhaust. It will also slow the flame front & help control detonation & help if your fuel is a bit stale.

If I could get a decent plug'n play kit at a good price I'd do it tomorrow.

[brad]

Yes. Thanks, I get some idea about it. I think polo 77tsi has so small engine and a intercooler so cooling through already available radiator and pump for engine cooling may be cost efficient?

But for bigger engine may need a separate water pump + radiator + new water air intercooler. Anyway this should bring more better efficiency because A45 using it with 29 PSI boost. But conversion of a standard type intercooler system to a watercool type may be prohibitively expensive.

77tsi would be cost, packaging & weight.

I don't a water/air intercooler would be OTT expensive but it would require a lot of thought for possibly not a lot of gain. It's not a new thing.

[h100vw]

77tsi would be cost, packaging & weight.

I don't a water/air intercooler would be OTT expensive but it would require a lot of thought for possibly not a lot of gain. It's not a new thing.

I can't see coolant being able to remove any heat from the intake air. It's going to be over 80 degrees easily!

Water to air has a separate water system.

Gavin

[Mysticality]

Also reduced lag because the water/air IC is smaller than an air/air IC

[Guy_H]

It's all about the ability to exchange heat - you can have good & bad in both systems. You can heatsoak an air / air version, but they recover well. If you heatsoak a water / air then they take a long time to recover.

best Water / Air version i had was on my Cayman S Turbo. It used a big heat exchanger, massive water pump & had 38 litres coolant capacity. That sucker could really control intake temps.

On our APR Supercharger kits for the RS4 / S5 / RS%, they are all running W/A for packaging purposes - ultimately it's up to coolant capacity & the exchanger cores & radiator on how well they work. The S5 is better than the RS4 as you can fit way more coolant in the system.

[zei20t]

Lotus were using water-to-air intercoolers for a long time in Esprit models. I think they stopped with the V8.

Anyway, the only down side of that system was the pump. The rest was fantastic, probably why they use them in high-end model.