RX7 overheating on track days

Hi RX7 · May 16, 2010, 10:15:55 AM

Having done my second track day yesterday at Japfest (just got through the sound check at 99db) I have a problem with my car overheating after the first lap it rose to 111 end of second 117 then 120 I did try a higher gear to lower the revs and increase the air flow but it didn\'t work and landed up \'nursing\' the car around Castle Coombe yesterday although I still enjoyed camp corner and quarry The car did the same at Odiham and the other RX7 owner said that with his V Mount it never got above 85 so is this the only answer I still wish to keep the air con so can this be the answer because it never overheats on the road i.e. up to 95 then cools.

Laurenzo · May 16, 2010, 11:18:38 AM

Not really David, it will be something silly like sluge in the coolant, one fan not working, thermostat not fully opening. So make sure all those things are ok first, and the airways are free from debris.

The normal coolant system for a fairly stock set up is man enough for a track day.

Hi RX7 · May 16, 2010, 11:38:54 AM

I thought I checked all that and its only recently had a rebuild rad water is clean and blue checked both fans come on. I have thought for a long time that the massive front mounted IC stops any flow of air to the rad which is also behind the A/C rad too

Rex_FTW · May 16, 2010, 11:48:02 AM

The only thing you could try is to improve the ducting.

Otherwise V mount is the only way forward.

Laurenzo · May 16, 2010, 02:54:19 PM

Quote from: David Wiltshire;693732I thought I checked all that and its only recently had a rebuild rad water is clean and blue checked both fans come on. I have thought for a long time that the massive front mounted IC stops any flow of air to the rad which is also behind the A/C rad too

Sorry david I did not realise that you had a fmic, I had a good look at my system the other day and I have to say that now the a/c rad is getting older the fins are not as open now what with corrosion and road dirt. So maybe time to ditch the a/c ?

Hi RX7 · May 16, 2010, 03:34:52 PM

I\'m still of the opinion that the main radiator does not get any air flow I have been toying with the idea of altering the undertray to form a long low scoop that would not effect ground clearance too much but just provide a flow of air where at the moment it seems obvious there\'s not, it may be just the case that a V-Mount will be a cure all having had a look with an inspection mirror the A/C fins are clear and good.

C J R · May 16, 2010, 04:08:15 PM

David,
In comparison, I was round Castle Combe at Japfest, and whilst I didn\'t check my water temp on the first lap, I noted that my air temp was around 50 deg C, due to heat soak waiting to go on track. So I backed off for the first lap to get tyres and brakes warmed and a good air flow thru\' the front mount. Water temp and air temp on the second lap were showing \'normal\' for my car at 80 deg C water and 25 deg C air. Similar temps were shown for the last lap.

This is using a Koyo rad, large front mount and a custom front undertray which is flat without vents. Although my front spoiler/nose has large inlets for the intercooler and oil coolers.

Hope this helps.

Chris

Hi RX7 · May 16, 2010, 05:58:53 PM

I think my first move will be to get an upgraded radiator. I was on the track about 2.30 and I don\'t think the ambient temperature was that much higher than when I saw you on track. When I did the Odiham trackday it was about the same ambient temperature so its definately the car, plus I\'ve read you have to dump the A/C with a V-Mount which is not an acceptable option for me. I know Castle Coombe is known for its very limited run off before hitting something solid but I do like it as a track. I also made a point of not running the engine whilst waiting to go on track because I had this nagging feeling about the car potentially running hot. I have to say this is twice I\'ve recorded 120 in the car and engine wise seems to be fine at the moment, I did of course wait till it had cooled then checked the water level and all was well.

clive · May 16, 2010, 06:17:24 PM

Hi David,

Sorry to hear you couldn\'t get the best out of your car yesterday ,

Don\'t know what mods you have under the bonnet as this will dictate the cooling system, if your stock with stock intercooler, twin turbo\'s etc you can use the Koyo rad as a direct replacement keeping your air con in the same place,

Hope this helps

Hi RX7 · May 16, 2010, 06:30:40 PM

Yes its all fairly stock a very big FMIC (G-Reddy) still twins, water injection and of course the air con rad with a 99 spec front end. Does it make any difference it being a late 97 model 40000+ because I\'ve seen mostly 92-95 models covered.

JBerg · May 16, 2010, 10:34:57 PM

FMIC is generally the culprit to overheating.

Jono FD3 · May 16, 2010, 11:34:13 PM

well, I can tell you now that you can keep your AC with a V-Mount set up! it just meand a little fiddleing! I opted to bin mine due to the system not actualy working, but if you are going to make a custom V-mount using the Greddy cooler & koyo rad (if you opt for one?) then you just have to allow for the AC rad!
I\'ve done my V-Mount and pumped up the power to about 330 running 0.9 bar boost and I struggle to get the coolant up to temp! on the motorway coming up & going back I was sat at a steady 79c and I saw 80c on the way home for about 10 mins! likewise, intake temps didn\'t cross 20c all the way! my set up is using a stock rad & Blitz cooler with stainless water & cooler pipes!

Jono

Hi RX7 · May 17, 2010, 07:49:46 AM

Quote from: Jono FD3;693886well, I can tell you now that you can keep your AC with a V-Mount set up! it just meand a little fiddleing! I opted to bin mine due to the system not actualy working, but if you are going to make a custom V-mount using the Greddy cooler & koyo rad (if you opt for one?) then you just have to allow for the AC rad!
I\'ve done my V-Mount and pumped up the power to about 330 running 0.9 bar boost and I struggle to get the coolant up to temp! on the motorway coming up & going back I was sat at a steady 79c and I saw 80c on the way home for about 10 mins! likewise, intake temps didn\'t cross 20c all the way! my set up is using a stock rad & Blitz cooler with stainless water & cooler pipes!

Jono

I think you have the answer there that I\'m looking for, one of my friends owns a large engineering business so I am sure I can get him to make the V-Mount frame does anyone have any drawings? I have just noticed another post about a radiator issue on this forum and there is a question about the AST is this a potential problem that also needs to be looked at?

clive · May 17, 2010, 09:41:11 AM

Quote from: David Wiltshire;693798Yes its all fairly stock a very big FMIC (G-Reddy) still twins, water injection and of course the air con rad with a 99 spec front end. Does it make any difference it being a late 97 model 40000+ because I\'ve seen mostly 92-95 models covered.

If your on an old stock silted up rad , there\'s your problem,

Greddy front mount should pass more than enough air to feed a koyo rad and keep it all cool, I say this because its your easiest way forward.

Hi RX7 · May 17, 2010, 10:22:41 AM

Does the original radiator have a green painted top? If so then you do have a point although the rad water is a clean as the day it was put in. It would be nice to think that the rad replacement would solve it the only problem is that its only on track when it happens not on the roads and to replicate track speeds on the road would be a tad risky to say the least.