Intercooler thoughts

[Madone]

I am at stage 2 with the stock IC and obviously considering upgrading. However I have been logging the intake temp to get an idea of what is going on as things stand. Try as I might I can't seem to get the temp anywhere near the 50deg mark where the timing gets cut back by the ECU. The most I have seen is 48 after sitting in traffic for ages on a hot day, as soon as I started moving, even at 30mph, the temp dropped back to mid 20's when the ambient was 18 or so. Once is sped up a bit it dropped further.

I can see why this sort of thing would be a nightmare on a dyno, heat soak would be bad. But in real world driving I cannot drive the car hard enough for long enough to get the temps up. It's so fast I would either be in the verge or in the police station before getting a sustained high temps. I know some people use their cars at the track but the standard IC seems to be ok on the road. I would consider upgrading it, but the temps don't increase to the point where it's costing power.

It would obviously cook on a dyno but that's not real word scenario. What are people's thoughts ?

[Dan_FR]

50 degrees?  Thought the ecu pulled back at a lower temp than that. High 30's? What software?

Lower temperature = denser air. More to power than just the ignition timing, also CF's will be higher meaning less actual ignition advance. Intercooler flow & (lack of) pressure drop are also vitally important.

I noticed a big difference upon fitting mine at stage 2, and I went with the cheap China THS copy.

[Madone]

From airtech

Standard intercooler & Stock ECU Map – Intake temperature of 34 degrees @ 205.3bhp ‘this is completely acceptable and not bad for a stock car’.
Standard intercooler & Stage 1 Remap – Intake Temperature of 49 degrees! @ 237.1bhp ’49 degrees is the absolute limit before ECU starts retarding timing to keep the engine safe, which means you will start to lose power.
Airtec 2.0 TFSI intercooler upgrade & Stage 1 Remap – Intake Temperature of 31 degrees @ 249.5bhp ‘ Temp drop of 18 degrees & 12.8bhp Gain, compared to standard VAG intercooler!

[duncatr]

I really need to log my car to give some feedback on this.

I'm running the standard intercooler on my mk2 Leon Cupra R (Same as the newerS3 with plastic end tanks)
Car is running APR map and making 360/360 on a dyno proven to be pretty acurate (so its not funny dyno figures)
CDL engine with APR HPFP, EVOMS intake, usual uprated clutch etc. And I'm actually still running the oe exhaust.

It certainly doesn't seem to pull too much timing so would appear to be pretty efficient.
Might be a good cheap upgrade. I know pleanty people that have used the S3 intercooler at good power although most seem to go for the alloy end tanks

[Madone]

I really need to log my car to give some feedback on this.

I'm running the standard intercooler on my mk2 Leon Cupra R (Same as the newerS3 with plastic end tanks)
Car is running APR map and making 360/360 on a dyno proven to be pretty acurate (so its not funny dyno figures)
CDL engine with APR HPFP, EVOMS intake, usual uprated clutch etc. And I'm actually still running the oe exhaust.

It certainly doesn't seem to pull too much timing so would appear to be pretty efficient.
Might be a good cheap upgrade. I know pleanty people that have used the S3 intercooler at good power although most seem to go for the alloy end tanks

It would def be really interesting to see what temps you get. I am really struggling with the reason to upgrade the IC when the temps indicate (in normal road use) it's just not needed. The irony is it seems the most important place to have a updated IC is on the dyno then after that you can't load he engine in the same way, repeated 4th gear pulls to the red line aren't something British roads and speed limits lend themselves too !

[duncatr]

road logging is where I would take my data.
I dont drive the car on the dyno - I drive it on the road.
A dyno will never simulate the airflow going through the front of the car past the intercooler.
2 fans and an open bonnet is not real life.

I'm not saying that a Peron wouldn't be better than the oe but like you I always have to justify my costs before spending out on an upgrade.
So if its not adding any safety to the engine and no signals that there would be significant gains then I probably wont bother. Not while there are other areas of the car I could spend the cash to see significant improvements - brakes and suspension for a start :)

[xjay1337]

I fitted a THS/Darkside Intercooler to mine.
Inlet temp recovery rate increased dramatically. Cruising temps 4-5 degree below previous, even lower than ambient at times
Proven gain in holding power at high RPMs on the same dyno in the same car. (peak power exactly the same).

It's more than just temperature, it's pressure drop across the core. Lot of people don't necessarily realise that.
for most people then a THS/Ebay intercooler is more than enough. If you are running 400+bhp and massive turbos then you need to worry about pressure drop etc and a peron would be a good choice here.

[duncatr]

Yes I'm aware that there is more to it. Recovery rates are more for track and quarter mile in my opinion and rr data is not 100% valid as you dont see the real airflow through the intercooler as you will on the road. Even the airflow is not representational as you normally have 1 or 2 fans and an open bonnet on the RR.

On the road this is not the case. Like I say, road data is where its at for me. Even when mapping big power cars on the RR its best to final check and log on the road as thats where the car is run.

Size is not everything either, far from it in fact. Its the overall design. Bar & plate v tube and fin. end tand design and material. pressure drop through and accross the intercooler. Inlet and outlet position and size. Location and flow through for the cooling air. Even the piping to and from it. Lots and lots to look at, all depends how far you want to go. For a road car under 400BHP I've yet to be convinced that the oe S3 cant cope. Again, not saying there are not benefits to be had, just that I cant justify the expense for these. And thats from someone that spend over £20k modifying an Impreza LOL. Perhaps I'm just getting old and sensible :(

I'm no expert, thats just my opinion based on previous experience (Mostly in the subaru world) and what I have seen to date.

[Madone]

I fitted a THS/Darkside Intercooler to mine.
Inlet temp recovery rate increased dramatically. Cruising temps 4-5 degree below previous, even lower than ambient at times
Proven gain in holding power at high RPMs on the same dyno in the same car. (peak power exactly the same).

It's more than just temperature, it's pressure drop across the core. Lot of people don't necessarily realise that.
for most people then a THS/Ebay intercooler is more than enough. If you are running 400+bhp and massive turbos then you need to worry about pressure drop etc and a peron would be a good choice here.

For sure I agree that there is more too it than just temps, but temps are the thing that (in theory) will reduce power as the ecu knocks bag timing. I could as you say gain something from better flowing end tanks etc, but for the moment I am just thinking about not loosing power, rather than gaining more. Fitting a bigger IC will create a larger air chamber the compressed air needs to fill before it reaches the engine, so surely there are some downsides to just fitting the biggest you can ?, filling a bigger void with compressed air must produce more lag or reduced responsiveness ?, it might be small but it must be there ?.

The moment I see my temps rise to anywhere near 50 I would buy a new cooler, but so far, try as I might I can't get them up ! Haha. The increased air flow I get from driving faster pushes more air through, so seems to balance out and stay cool. I have no doubt in the rollers it would heat soak and be too hot to tune properly. But I wonder how many updates IC's would be fitted or even recommended if all tuning was done on the road and not in a workshop with two fans blowing warm recirculated air at the grill.   

As you say, if you are chasing 400+ then you need flow for peak numbers, but just looking at inlet temps on the road it seems to be another story

[pudding]

Yes I'm aware that there is more to it. Recovery rates are more for track and quarter mile in my opinion and rr data is not 100% valid as you dont see the real airflow through the intercooler as you will on the road. Even the airflow is not representational as you normally have 1 or 2 fans and an open bonnet on the RR.

On the road this is not the case. Like I say, road data is where its at for me. Even when mapping big power cars on the RR its best to final check and log on the road as thats where the car is run.

Size is not everything either, far from it in fact. Its the overall design. Bar & plate v tube and fin. end tand design and material. pressure drop through and accross the intercooler. Inlet and outlet position and size. Location and flow through for the cooling air. Even the piping to and from it. Lots and lots to look at, all depends how far you want to go. For a road car under 400BHP I've yet to be convinced that the oe S3 cant cope. Again, not saying there are not benefits to be had, just that I cant justify the expense for these. And thats from someone that spend over £20k modifying an Impreza LOL. Perhaps I'm just getting old and sensible :(

I'm no expert, thats just my opinion based on previous experience (Mostly in the subaru world) and what I have seen to date.

I'm of a similar opinion tbh.  The standard item is 'satisfactory' for most scenarios, given VW will have tested it Dubai, which can hit 50 deg C ambient!  But the standard item is designed to shift the heat of standard boost.  Whacking the boost up generates a lot more heat and sometimes the standard item can heat soak too quickly.

Aftermarket ones aren't always great either though.  I've seen some comedy IATs during dyno tests over the years, the worst being a MK4 Golf 1.8T with an 'uprated' side mount with ally end tanks and a 30% bigger core.   Said MK4 had the boost turned up to the max and IATs on that hit 70 (yes 70!) deg C by the top of the 3rd gear on the first run!  Completely useless.

What I don't really like about the standard setup is the a/c condenser being in front of the IC, but I suppose they had to put it there for packaging reasons, and to make the MK5's poor A/C performance as good as it can possibly be, but I also agree the S3 part is plenty good enough for the K04 turbo.  I just can't justify £350 + all the faff of fitting it for a core that's only a little bigger than standard.  I'm confident I wouldn't see night / day differences in IATs after all that!