30 replies to this topic

[cnrandall]

Has anyone here done any with/without testing with turbo ears. I need to increase my cooling capacity on the Europa as temps are becoming unstable with big power/slicks and trying to fit a set of these is one option to grab more air.

[Decky]

It doesnt take much scientific research to figure out that the turbo ears are going to scoop more fresh air into the engine bay and have a cooling effect. If you need to bring down running temps then look at all the usual stuff, more cores radiator, increasing flow through vents etc. I dont have the turbo engine so cant give any figures for how much they would reduce the temp but Id imagine around 5 or 6 degrees C for double core, another 2 degrees C for the side scoops, and maybe 6 or 8 degrees for a triple core radiator. All guestimates but I would imagine they would be quite accurate.

[mandarinvx]

Are you limited by any rules in the race series regarding bodywork modifications

[cnrandall]

I already have a triple pass radiator etc etc so that bit is well covered. The airflow down the sides of the car is quite dirty but I don't know whether the ears hang out far enough to grab good quality air, hence the desire for some real evidence. No specific regs to cover this in GT Cup...

[Winstar]

Hi chris which temps do you think your having a problem with, charge cooling or engine cooling? or do you think it is just the temps in the engine bay heat soaking everything? Side air will be very dirty as you say, you would be better to try to take the air from higher up may be to the sides of the engine cover. One thing to consider is if you put ears or scoops on where is you air flow going? in the VX it is designed to flow up though the engine bay then out the vents engine cover.

Edited by Winstar, 11 October 2009 - 01:56 PM.

[cheeky_chops]

I already have a triple pass radiator etc etc so that bit is well covered. The airflow down the sides of the car is quite dirty but I don't know whether the ears hang out far enough to grab good quality air, hence the desire for some real evidence. No specific regs to cover this in GT Cup...

try some wool tuft testing to see how unstable the air flow is? Canards at the front and some vents behind/above the front wheel arch to lower the pressure?

I have a thermostat in the inlet pipe now but i drove around with it at the back of the engine bay initially - air temps behind the engine above 50mph were within a few degrees of ambient.

[mandarinvx]

You may well have already done this since the pics on your blog, but how about an F40 style engine cover to ensure the air is being drawn from the engine bay, I'd have though plain holes will cause quite a bit of turbulence

If you have a search on the Badster website there are a few images of a similar setup, as well as a lot more cooling aids (although I think a few are more for the bling effect )

[cnrandall]

Hi chris

which temps do you think your having a problem with, charge cooling or engine cooling? or do you think it is just the temps in the engine bay heat soaking everything?

Side air will be very dirty as you say, you would be better to try to take the air from higher up may be to the sides of the engine cover. One thing to consider is if you put ears or scoops on where is you air flow going? in the VX it is designed to flow up though the engine bay then out the vents engine cover.

The simple answer is all of them! The oil temps are something I've been working on all year and I think the laminova simply isn't up to it and yesterday the oil temp dragged the water temp up. It's very marginal, if I slow down a little then it all comes back to line but you can't race like that. I understand you know a great deal about engine heat transfer so any input from you would be very welcome.

[cnrandall]

I already have a triple pass radiator etc etc so that bit is well covered. The airflow down the sides of the car is quite dirty but I don't know whether the ears hang out far enough to grab good quality air, hence the desire for some real evidence. No specific regs to cover this in GT Cup...

try some wool tuft testing to see how unstable the air flow is?

I had that thought too, would certainly gain some useful info that way.

[Winstar]

Chris, just had a quick look through your race blog and one thing strikes me is that you've moved the exhaust up over the engine but the main outlet for flow through the engine bay is throught the back number plate region into the low pressure are behind the car. The flow through from the side vents will take the easiest route through the engine bay and go round the sides of the engine not cooling the exhaust and the main heat source the turbine housing. IMO you need to get a direct cooling flow from above or inline with the exhaust/turbo then get it to flow down to the back of the car.

[cnrandall]

Chris, just had a quick look through your race blog and one thing strikes me is that you've moved the exhaust up over the engine but the main outlet for flow through the engine bay is throught the back number plate region into the low pressure are behind the car. The flow through from the side vents will take the easiest route through the engine bay and go round the sides of the engine not cooling the exhaust and the main heat source the turbine housing. IMO you need to get a direct cooling flow from above or inline with the exhaust/turbo then get it to flow down to the back of the car.

Since the pics in the blog I've changed the setup around the turbo and manifold considerably. It's all boxed in with nimbus now with trunking from the side vents to underneath then a chimney out the top and that pump loads of hot air out making a big difference to engine bay temps. I've also made a big vent in the engine cover. The ECU measures pressure in the engine bay and there is actually a depression their currently so if I opened up some more vents into the engine bay there should be airflow straight away.

[techieboy]

Do you have NACA ducts in the middle undertray? Not sure whether more of them are a possibility or if that would have any adverse effect on the aerodynamics underneath the car.

[cnrandall]

Do you have NACA ducts in the middle undertray? Not sure whether more of them are a possibility or if that would have any adverse effect on the aerodynamics underneath the car.

No, they mess up the airflow to the diffuser. I think my current plan is to use the laminova to cool the gearbox, then fit a decent size air/oil cooler on top of the rear subframe and feed it by turning the quarter glass windows into duct like a F355. What do you recon?

[techieboy]

My next suggestion was going to be something on the buttresses but I'd forgotten all about the Europa's quarterlights. Sounds like a good possibility to me.

[alanoo]

Isn't that basically a low pressure vs high pressure air cooling the engine bay debate ? If so, I guess the answer is simple but you need to know for sure what overheats In theory low pressure is much better if you can transfer all the critical components heat in the front using liquid coolers (laminovas are fine for this, but the bigger ones are expensive) If you don't have NACA ducts, you should do something to force air on the engine sump (with low pressure in the bay, you most likely have no air cooling here), I was quite surprised when I saw how these very simple and cheap design worked on the stock setup, I remember it was about a 10°C difference on oil and much slower to pass 130°C

Edited by alanoo, 11 October 2009 - 03:46 PM.

[Winstar]

The simple answer is all of them! The oil temps are something I've been working on all year and I think the laminova simply isn't up to it and yesterday the oil temp dragged the water temp up. It's very marginal, if I slow down a little then it all comes back to line but you can't race like that. I understand you know a great deal about engine heat transfer so any input from you would be very welcome.

The way i see it is that the main problem is that the oil system isn't up to coping with the increase in revs and heat generated by the big boost turbo. which as your using laminovas is then over loading the engine cooling system which is probably at it's limit anyway due to the pre-rad for the CC system. The first thing i'd look at is changing (or adding) the oil cooling to oil-air and loosing as much heat as possible through this, Lotus did this with the v8 esprit as they couldn't fit a bigger rad so it looses 50bhp worth of heat out of twin oil coolers. Also how much can you cut the heat getting into the oil can you reduce the flow to the turbo as it's a ball bearing it shouldn't need much flow or can you delete the piston cooling jets?

What is also a concern is that your inlet temps where suffering as these should be some what isolated from the other cooling loop. The only thing I can think here is that either the pre-rad isn't big enough, which in turn won't help the engine cooling loop, or there is serious heat soak into the CC and header tank. Are these lagged? to stop engine bay heat soak?

If you want any more specific help like heat rejection calculation then drop me a PM, one of my roles at Lotus Powertrain was in vehical thermal management systems.

Since the pics in the blog I've changed the setup around the turbo and manifold considerably. It's all boxed in with nimbus now with trunking from the side vents to underneath then a chimney out the top and that pump loads of hot air out making a big difference to engine bay temps. I've also made a big vent in the engine cover. The ECU measures pressure in the engine bay and there is actually a depression their currently so if I opened up some more vents into the engine bay there should be airflow straight away.

ah ok

[cnrandall]

That's massively helpful and thankfully along the same line as I was thinking. Will drop you a U2U shortly....

[cheeky_chops]

i guess your CC rad and water rad are piggy backed ? I have tried a manual switch for the 2 spal fans on my PA rad (if you have same setup), it made no noticeable difference on track to either the inlet or coolant temps (tested on fast and slow a circuit). It does however cool the engine significantly on slow cool down lap and parking up - abit late when your racing! What oil temps are you reaching?

[Winstar]

i guess your CC rad and water rad are piggy backed ?

I have tried a manual switch for the 2 spal fans on my PA rad (if you have same setup), it made no noticeable difference on track to either the inlet or coolant temps (tested on fast and slow a circuit). It does however cool the engine significantly on slow cool down lap and parking up - abit late when your racing!

What oil temps are you reaching?

I would expect it doesn't run any fans at all, they will just be a restriction to the flow when racing.

[cnrandall]

Currently I have one rad but I'm planning to remove that now, along with the mesh grill above the rad outlet.