2.7 RS running hot

Can anyone help.

I have a stock 2.7RS engine with a 3.2 carrera oil cooler under the front right wing.

On normal day to day use, the engine temperature never really goes above 210 on the temp guage - usually just above 180.

However on trackdays, after about 20 mins, the temperature begins to climb to up to about 240. Thats when I tend to take a rest !

I am aware that the oil cooler is really just dissipating heat as it is not really getting too much air to it under that front wing, but even when I removed the right hand indicator housing, that didn't make any real difference.

Does the problem lie in the engine itself ?


Thanks for any help

Mike Burdon

( Way to go BB2 - you have fans in the UK too !)

Mike-

Have you verified that the front cooler is getting full and proper flow from the thermostat opening properly? Check the temps on the feed and return lines after a hard session. The old thermostats can get gummed up and stop opening all the way. Also, any kinks or squashed points in the lines from debris or a poorly placed lift pad at the tire shop, perhaps?

If the cooler is getting good oil flow, the only thing to do is get better air flow thru it for max. cooling. Just opening up the indicator housing may not be enough. Do you still have your battery boxes installed (I am assuming this is an early car with the dual boxes?) If so, they really block the air to the fender mounted coolers (I love how you English guys call them "wings"!)

I removed my battery boxes and also fabricated ducting from the front bumper to the bottom of the cooler, as well as sealing between the sides of the cooler and the body, in order to force more air flow thru the cooler itself. Does your carrera cooler have a fan?

HTH,
TT

Thanks TT,

I will look at the thermostat again. The oil cooler does'nt have a fan (I'm not sure there is room between the cooler and battery box)

I may look to going to one battery (in the 'inspection hatch' ?) to provide more space to improve air flow. Alternatively, I have an S spoiler. I may cut a large rectangular hole in the spoiler and relocate the cooler to the centre of the spoiler.

Any thoughts.

Mike

(PS what torsion bars, sway bar sizes do you run for track ?)

You could also use larger fan/crank pulleys to spin the fan faster. On my 914-6 I don't run a front cooler but I do use the fast pulleys and I rarely see 210 under heavy load. I think the pulleys are from 75 or 76.

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Originally posted by Mike Burdon
I will look at the thermostat again. The oil cooler does'nt have a fan (I'm not sure there is room between the cooler and battery box)

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You can also put a "puller" fan behind the cooler instead of a "pusher" fan in front of it.

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I may look to going to one battery (in the 'inspection hatch' ?) to provide more space to improve air flow. Alternatively, I have an S spoiler. I may cut a large rectangular hole in the spoiler and relocate the cooler to the centre of the spoiler.

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The removal of the battery box will go a long way to improve the cooling air flow. BTW, we call it the "smuggler's box" over here. :)

I ran my car hard (in the desert @ 100F+ ambient) with a 3.0 in it for several years with just a fender cooler and fan, plus the ducting to prevent the air from dumping around it. It would often push 240F oil temps at the end of a 20 minute session. When I put the 3.4 in it, I had to add a front cooler, too, plumbed in series. I don't think you can fit a cooler the size of the Carrera one in any front spoiler effectively. There is an RX7 cooler which is about the right size for a front cooler and can be adapted fairly easily for less $$$ than a new B&B. You still have to worry about proper flow thru a front cooler as well. If it's too close to the tub without a clear path for the cooling air, it won't be very effective either.

Alternatives, besides increasing the fan speed, as Mr9146 suggests, are using the Elephant Racing lines that Chuck Moreland sells (which are supposed to radiate heat better on the way forward to the cooler and back), and making sure your engine cooling tin is installed correctly, the shrouding is not blocked or fouled by debris, and the block and heads (especially the cooling fins) are clean. It is amazing how much of an insulator the coating of oil and dust that builds up on them can be. Then there are alternatives for cooling the pressure side of the system instead of the scavange side, and also the Cool Collar- but I won't go there... :D

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(PS what torsion bars, sway bar sizes do you run for track ?)

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I am running 21F and 26R T-bars still, about to upgrade them to 22F and 29R.

TT

Many thanks for the help, In the short term I will check the thermostat and clean the cooling fins. In the long term I will remove the battery box(es) to duct more air to the cooler and brakes.

Sorry to keep going on but, given that I have a car that has no electrical extras, will one battery do ?. Can it be routed to the 'smugglers box' easily and will the removal of two such heavy items from forward of the front wheels affect handling.

While I'm down theat end, Do you remove your spare wheel for autocross events/ run with much fuel. What is the effect on handling.


This forum is excellent, the level of knowledge is superb. I just wish some of you lived in the UK

Cheers

Mike

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Originally posted by Mike Burdon
Sorry to keep going on but, given that I have a car that has no electrical extras, will one battery do ?. Can it be routed to the 'smugglers box' easily and will the removal of two such heavy items from forward of the front wheels affect handling.

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Yes, one battery would work fine. Check out the article by my mechanic HERE

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Do you remove your spare wheel for autocross events/ run with much fuel. What is the effect on handling.

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Taking even more weight out of an already light front end does effect handling by reducing front grip somewhat. However, you can adjust for this, by running with your spare and a full tank (if you need to meet minimum weight) or adjusting the suspension (softer front sway bar or lower front tire pressure). Your driving style can make a big difference as well. If the front end doesn't want to turn in well, you can carry your braking a little later and shift weight forward as you initiate the turn.

In some cases, especially with the SWB cars which are usually very loose, less grip in the front can help balance the car and make it easier to trailbrake, etc. You will just have to experiment, because each car's setup can be very different, and I would be hesitant to make any blanket statements without feeling your handling balance first.

Good luck and have fun!

TT