[thebadger]

Does anyone have a turbocharged 5 running air con with the standard rad? On my last track day my water temp rose to three quarters after about 6 laps of Anglesey coastal circuit. It dropped pretty quick once I backed off a bit. I'm thinking I might just need a new radiator as mine is still original though from the outside it doesn't look too bad; certainly still has all it's fins.

If the standard setup just isn't up to it I was thinking of trying to get hold of a smaller air con radiator from another car, that way the air only has to go through the intercooler to get to the radiotor rather than intercooler, air con rad then radiator. Unless anyone else has some easier tricks?

[Mi5]

Whats worse is that the gauge isn't linear and doesn't start to move until you are well over 100degs.

Ditch the aircon, check you fluid, water pump, I ran 200BHP ok on a standard rad on all but hot days > 200BHP needs an uprated rad IMO.

[Gixer]

Not a tubby but a SC at 13psi here.

AC. IC in front of that then the stock Auto rad.
Only get problems during peak summer months (over 40c), but if i take it steady on the boost i'm fine.

[GaryR]

Similar here,,S'charged 227hp intercooled and ac rad. Never had any issues no matter how hard i drive it on roads but on the track had a temperature rise. Once noticed I just run with the heater on with full fan and burn my tootsies.

If i decide to push the envelope further I think I'll go for evaporative cooling (water spray) of the intercooler which'll have a secondary effect on the rad.

Reducing the size of the air con condensor coil isn't a good move unless its just marginal, effect when ac is running would be higher condensing temperatures compounding your problem with reduced performance of your ac and increased engine load as a result of increased differential against suction / discharge on the compressor.

[Trits]

Standard rad here, and A/C. No cooling issues during last trackday, running 16 psi circa 250+bhp. I left the heater on full.

[MattG]

Mine struggled on the standard rad but it was probably a bit goosed. Since fitting the twin cooler (uprated rad and oil cooler combined) it's been better but the real surprise for me was how much a set of TSIs helped. I only fitted them for cosmetic reasons really as I didn't expect them to do much but they've really helped to keep the temps below 100C on mine. This is all on the road mind, I haven't done a track day yet.

[Mi5]

One observation from the comments above - only those with a standalone ECU are likely to know what their actual coolant temps are. The stock gauge is not linear, and only really shows major overheating issues. On my mk1 the stock guage hadn't moved but the ECU was saying 108C, which is too high IMO.

Just because your rad isn't boiling over doesn't mean you don't have a cooling issue.

[Waitey]

Std rad and no A/C. After 2 hours non stop on the dyno i was still showing fine water temps on the link.

[Trits]

Mi5, on Sep 4 2008, 11:50 AM, said:

One observation from the comments above - only those with a standalone ECU are likely to know what their actual coolant temps are. The stock gauge is not linear, and only really shows major overheating issues. On my mk1 the stock guage hadn't moved but the ECU was saying 108C, which is too high IMO.

Just because your rad isn't boiling over doesn't mean you don't have a cooling issue.

Don't forget EMU has water temp input, fully dataloggable. Can't vouch for the accuracy of the sensor tho.

[steve b]

Mi5, on Sep 4 2008, 11:50 AM, said:

One observation from the comments above - only those with a standalone ECU are likely to know what their actual coolant temps are. The stock gauge is not linear, and only really shows major overheating issues. On my mk1 the stock guage hadn't moved but the ECU was saying 108C, which is too high IMO.

Just because your rad isn't boiling over doesn't mean you don't have a cooling issue.

Absolutely. Mine sits at 92/93 deg off boost, but goes over 97 deg C after only about 2 pulls on boost through the gears and i've no AC, a 37mm Koyo rad and a 13 row oil cooler. I've not had my Display for long and have not been on track with it to see what temps it actually reaches however i'd not be suprised it after 15 minutes solid abuse it hit 110deg C ish.

[Mi5]

Trits, on Sep 4 2008, 12:38 PM, said:

Don't forget EMU has water temp input, fully dataloggable. Can't vouch for the accuracy of the sensor tho.

Indeed, and sharing NTC thermistors will throw the accuracy out a lot! I never got my EMU to log temp sensors properly.

[Trits]

Its also worth mentioning that some of us "non-standaloners" have knock gauges fitted that will generally alert the driver to any overheating issues whilst on boost.
I know from experience that if the engine gets too hot it starts to knock a little. I can vouch for there being no knocking during the last trackday.

[steve b]

Trits, on Sep 4 2008, 01:37 PM, said:

I know from experience that if the engine gets too hot it starts to knock a little. I can vouch for there being no knocking during the last trackday.

When the ECU think's its getting hot surely it pulls timing to prevent knock, so thinking knock = its getting to hot doesn't make sense as the situation shouldn't arise?

[Trits]

steve b, on Sep 4 2008, 01:46 PM, said:

Trits, on Sep 4 2008, 01:37 PM, said:

I know from experience that if the engine gets too hot it starts to knock a little. I can vouch for there being no knocking during the last trackday.

When the ECU think's its getting hot surely it pulls timing to prevent knock, so thinking knock = its getting to hot doesn't make sense as the situation shouldn't arise?

But it does arise since the factory ecu doesn't know the car is FI'd, by virtue of the piggyback. Therefore the ecu doesn't pull enough timing to prevent knocking, as you say at the higher temperatures the engine probably wouldn't knock if it weren't running boost - but the OP is asking about boosted cars running north of 200 bhp.
Also consider that the early 5s didn't have any form of knock input to the ecu, unfortunately. Back when my water pump failed, I didn't even know I had a problem until the engine began to knock (inaudible). Also, its often been said that the number 2 reason why cylinder 4 suffers greater knock and tends to pop first is because it runs slightly hotter than the other cylinders, due to the heat transfer profile inside the head/block. Hence, even if the ecu did somehow pull timing to prevent knock in cylinders 1 - 3 when in boost, it most likely wouldn't do for cylinder 4.


EDIT: Just remembered, actually I was using the EMU water temp timing adjustment before doing the trackday, so yes in my case you are right more temperature = up to an extra 2 degrees timing retard, which is what I programmed it to pull, iirc. Its driven by the water temp input, but I don't have any reason to believe the temperaure is reading wrong. But, pulling an extra 2 degrees is designed for daily running and won't stop knock if the engine starts to overheat.
MI5 had other problems with his EMU, including hot start issues so I'm guessing its possible there could be a link. Water temp seems okay to me, but I can't get the air intake temp sensor to work right tho...

[greg_D]

I am running 240 odd with standard rad and no AC.

Assuming from the comments above i assume i am pushing my luck!!!

I have seen twin coolers which are great from a packaging point of view, but surely you would be better off with a normal full size alloy rad and a seperate oil cooler rather than the smaller rad you get with a twincooler?

Am i correct about that?

Greg

[steve b]

Trits, on Sep 4 2008, 02:53 PM, said:

EDIT: Just remembered, actually I was using the EMU water temp timing adjustment before doing the trackday, so yes in my case you are right more temperature = up to an extra 2 degrees timing retard, which is what I programmed it to pull, iirc. Its driven by the water temp input, but I don't have any reason to believe the temperaure is reading wrong.

Thats along the lines i'm thinking, my ECU for example has maps for pulling or adding timing or fueling dependant on temperature from engine core or AIT. As an aside it also drops rev limit and introduces a soft cut followed 300rpm later with hard cut + "cooling off" period at whatever AIT or Engine core temps I set it at.

[thebadger]

GaryR, on Sep 4 2008, 08:30 AM, said:

Reducing the size of the air con condensor coil isn't a good move unless its just marginal, effect when ac is running would be higher condensing temperatures compounding your problem with reduced performance of your ac and increased engine load as a result of increased differential against suction / discharge on the compressor.

I'm not planning on running air con when pushing the car hard on track, I only really use it for demisting. I was hoping to reduce the obstruction in front of the radiator a little. Think I might take the nose cone off at some point to have a look if I can move things around a bit to improve air flow.

[jimbob]

there's not a great deal of space to jiggle things about up front, and you're limited by the alloy A/C pipework, and the aircon radiator is pretty big too.

se how you get on with the Aircon in place, if you get constant problems then consider removing the aircon system, as you say it's only used for demisting anyway I'm sure it won't be missed too much.

[MattG]

greg_D, on Sep 4 2008, 04:05 PM, said:

I am running 240 odd with standard rad and no AC.

Assuming from the comments above i assume i am pushing my luck!!!

I have seen twin coolers which are great from a packaging point of view, but surely you would be better off with a normal full size alloy rad and a seperate oil cooler rather than the smaller rad you get with a twincooler?

Am i correct about that?

Greg

It's hard to say whether or not you're pushing your luck, some cars seem to run hot with boost and some don't. There doesn't even seem to be a common denominator like air con or a standard rad. I'd say the first thing to do is get a decent water temp gauge and then go from there.

With regards to the Twin Cooler I guess there could be a disadvantage due to the fact the rad is slightly smaller rad compared to most uprated ones (still much bigger than stock though). There's also the possibility of heat transfer between the two coolers although my oil and water temps rarely match so I don't think that's a real concern. It's all academic anyway as FM stopped making the twincoolers some time ago.

[greg_D]

MattG, on Sep 5 2008, 09:22 AM, said:

greg_D, on Sep 4 2008, 04:05 PM, said:

I am running 240 odd with standard rad and no AC.

Assuming from the comments above i assume i am pushing my luck!!!

I have seen twin coolers which are great from a packaging point of view, but surely you would be better off with a normal full size alloy rad and a seperate oil cooler rather than the smaller rad you get with a twincooler?

Am i correct about that?

Greg

It's hard to say whether or not you're pushing your luck, some cars seem to run hot with boost and some don't. There doesn't even seem to be a common denominator like air con or a standard rad. I'd say the first thing to do is get a decent water temp gauge and then go from there.

With regards to the Twin Cooler I guess there could be a disadvantage due to the fact the rad is slightly smaller rad compared to most uprated ones (still much bigger than stock though). There's also the possibility of heat transfer between the two coolers although my oil and water temps rarely match so I don't think that's a real concern. It's all academic anyway as FM stopped making the twincoolers some time ago.

that's interesting, phil still has them listed on his site, is he just out of date then. As for a temp sensor, where is the best place to site it, i have seen a lot on the top rad hose which is dodgy if you have a leak as the temp will go down rather than up.

Greg