My new toy does get very hot in the engine bay department. I believe this is a common problem.

I have looked at possible solutions.

I have seen in the GTM owners club tech manual that one solution is to fit a scoop to the underside of the car to divert air up into the engine bay. Can any one tell me how well this works and some idea of the arrangement of the scoop.

Another suggestion was to insulate the exhaust with asbestos. Obviously this is not available these days. Is there an alternative and how much effect does it have on engine bay temp?

Has any one tried fitting a fan or two in or near the top engine cover vent?

Thanks


Richard

You can wrap your exhaust with material available from ebay etc and it will keep it cooler.

This is my solution-





It's a 12v bulkhead extraction fan for a boat and has a capacity of 275cfm If I get stuck in traffic I just switch it on for a bit to keep things cool but it's a little bit heavy on the battery though...
Also, I find that once the radiator fan kicks in it takes for ever before it stops again and I have also fitted an override switch to it in case the thermo one in the radiator fails. Paranoid? Moi?

I have seen that type of fan on ebay for about £20. is that the 3" or 4" fan you have there? I was thinking of a way to duct fresh air into the bay with one or the extract the bay air out of the top vent. Does your fan do this or act to stir up the air inside the bay. I also note that your engine bay is open to the boot. Is that standard on your car or has it been cut away?

Did you wrap your exhaust box or jut the pipework? I can find pipework wrap but am not sure what to wrap the box with.

I looked at your outer photos of the car. It is usefull to see it in bits. I have an oil leak some where around the diff on mine. The previous owner had the engine out and put a higher final drive ratio in it. I think he didn't get a good deal on the diff housing. Do you think I can get these out and fit new gaskets with just the rear boot section removed or do I have to drop out the engine?

One thing that I found was that the rear boot also gets very hot - I left my torque wrench in there one day and the plastic case buckled with the heat! I solved this by putting a thin sheet of stainless steel between the boot floor and the silencer, spaced away from the fibreglass to give a gap of a few mm.

I've wrapped now the exhaust, but won't know how well this has worked until I get it back on the road.

Raymond - what did you use to paint the inside of your boot? It looks very neat - mines a mess.

That's the 4" fan and I tried to duct cold air in to it but couldn't without cutting a visible part of the boot panel. I could take it from the floor but that would just draw in hot exhaust air. The 'lid' on top of the boot lid is different from the MK2 and when the fan is going air is drawn in the right hand side and the back while hot air is blown out the left hand side and the front. Hot air is also blown out underneath the engine. The fan is set so that air is blown round to the front of the engine as much as possible but it really would be better if it had a cold air intake so a wee bit more development is necessary and I think that, done properly, the 3" fan would probably be fine and also easier to duct air to. The cut away boot is how the MK1 was made and it's not ideal because there's no way of sealing it on the engine side so everything gets covered in dust, or worse . I've been thinking about boxing it in but it's not really a problem unless I decide to do some Continental touring
I haven't wrapped the exhaust although I have done it very effectively on a previous car. I have the GTM stainless system and there is a heat shield on it which you can just make out here



When building the car I also thought that the boot floor might get very hot so I lined the underside with this (rather expensive) heat reflective material and between that and the heat shield it only gets warm now, just enough to keep your chips from getting cold...



The paint in the boot is Plasti Dip brush on which is water based and a pleasure to use. Two coats are needed but it dries quickly so it's not a nuisance. It chips fairly easily but it's easy to touch up. Hope this helps.

Thanks for the information Raymond.

I have the Stainless exhaust too and it has the same heat shield.

I found some flat ducting in Tool Station 225x25mm. I am toying with fixing a 90 deg bend to the rear of the floor pan and use the ram air effect to get some fresh air in the engine bay.

That looks like it's worth a go. The biggest issue is likely to be ground clearance which is only 5" and a bit. Winter fun

Thanks, Raymond. I'll get some Plasti Dip as both front and rear boot looks a mess on my Rossa. Regards, Peter

I found a cheap solution to the hot boot floor problem. I was working on a project where they were stripping out some corridor doors - they had half height stainless steel door protection, ie a sheet about 3' square and I managed to scrounge one. It was exactly the right width for under the Rossa floor, so I only had to cut it to length - which was easier said than done, but worth the effort.

Call me a cheapskate, but it worked!!

Finding your own solutions to problems using available material is half the fun! (And the cheaper the better )

I was more worried about it over heating ! I was going to cover with ali duct tape.

I think the ground clearance should not be and issue as the duct will be close to the wheels.

I have also been toying with getting a sheet of steel bent up in to a top hat section about 40mm deep and as wide as posible to screw to the floor pan with some kind of scoop at the back to push the air into the bay.

The biggest problem is the lack of space. Both of ductwork and the passage of air.

I will post some photos if I do find a worthwhile solution. I may prototype one with that plastic sheet that they use for house for sale boards.