Elise S2 Heating Matrix

[tonykart]

I live in Hong Kong and have a new S2 111s. Temperatures here from May are around 30+c until October. This means aircon here is usually "tropical strength".

The Elise suffers from 2 problems, 1) crap aircon 2) heating matrix which turns car into furnace. Has here had the heating matrix de-activated? I understand that the pipes leading to the matrix can be disconnected but I also assume this means the car takes much longer to get upto temperature, not a problem here but i guess in the UKs freezing winter conditions this would be a problem.

Reason I ask this is I'm about to have the work done to disconnect this series of piping and at the same time have the remote thermostat and water to oil cooler fitted.

Just seeing if I'm the only one.

btw, the "tub" gets SO hot, you can't even rest your arm on the sill...

[Arno]

Has here had the heating matrix de-activated? I understand that the pipes leading to the matrix can be disconnected but I also assume this means the car takes much longer to get upto temperature

Should not be an issue as long as you bypass the heater and connect it's input hose directly to the output. The heater is part of the coolant bypass circuit, so you can't just plug it.

The longer warmup is only an issue if you fit the remote T-stat at the front of the car, so it always uses the large main coolant circuit to the front while warming up.

If you fit the T-stat in the engine-bay then there's virtually no difference in warmup speed.

Reason I ask this is I'm about to have the work done to disconnect this series of piping and at the same time have the remote thermostat and water to oil cooler fitted.

In that case there are two options.

If the T-stat is fitted in the engine bay then you could disconnect the heater pipes in the engine bay and create a new bypass circuit by running a short hose from the T-stat bypass connection to the heater return connection on the engine.

That way you remove the whole circuit to the heater from the setup.

If you fit the T-stat in the front of the car (close to the radiator) then you can plug the original heater connections and run a bypass hose at the front of the car from the T-stat to the main return radiator hose.

btw, the "tub" gets SO hot, you can't even rest your arm on the sill...

Not really possible to change that as the main coolant pipes run through the sills and these heat up..

That's just the way it's designed..

Bye, Arno.

[tonykart]

Arno, Thanks for the detailed info. Re: the water cooling pipes, is it a big deal to remove them and wrap them in lagging? Also, I'm assuming the heating matrix pipes are giving off a lot more heat than the cooling pipes so that must be the main cause of the tub getting so hot. Once the matrix is disconnected, I'm sure the aircon will function better too.

[Arno]

tonykart said: Arno, Thanks for the detailed info.

Oh one thing.. Installing a remote T-stat in an A/C equipped car may be a little more tricky than in a non-AC car.

The A/C cars have a somewhat different cooling system routing (they have a small electric coolant pump to combat heat soak) than the normal cars.

I'd advise you to get the diagrams for both the normal and A/C cars to see if/what you need to change to install a remote T-stat.

Re: the water cooling pipes, is it a big deal to remove them and wrap them in lagging?

Yes. Very.. Not sure if it's even possible to wrap and re-install them. The pipes are installed inside the chassis when it's made. They can be changed, but it's a big job.

Also, I'm assuming the heating matrix pipes are giving off a lot more heat than the cooling pipes so that must be the main cause of the tub getting so hot.

Actually no. The (thin) pipes for the heater are running along the outside of the aluminium tub under the fiberglass sill covers and contribute little (if any) to the heat in the aluminium chassis.

The main coolant pipes are the culprit here. Once the engine gets up to temperature you get a big stream of hot (80-90-100 degree) water running from the engine through the pipe in the right hand chassis beam to the radiator.

It then returns on the left hand side.

For people like me who drive a LHD car (I'm in europe) this means I don't get hot.. Passengers do (ooh err.. ), but I don't care about those!

Once the matrix is disconnected, I'm sure the aircon will function better too.

It at least cuts down on the heating of the unit itself. It will always struggle though as the intake air is sucked from beneath the radiator and as such is not that cool to start with.

[tonykart]

Thanks for the help Arno. As it happens, the remote thermostat can be fitted with a special made to order part to reroute the heating pipes. Waiting for that part to come in before I can proceed.

Why oh why did'nt Lotus put lagging around the pipe in the first place?

I've also fitted Geary's air horn because I was sick of listening to that sad cow jammed in the front grill of my car...

[DanH]

The Elise heat levels are just screwed. My S2 is a furnace in the summer (all that heat soak you describe), but a freezer in the winter.

Oh well.

[tonykart]

At least I've got my engine temp down. Swapping out the CAT for a CRP, putting in the water to oil cooler, and using radiator relief has helped alot. I'm sure with the remote thermostat and heating matrix work mods, it'll be even better. I've also heard that wrapping the airvents in with some insulation helps make the aircon more useful. We will see...

[tonykart]

OK, I had the work completed yesterday. Here's what they did:

Custom built flex pipe to cutoff the heating matrix pipework.
Fitted the remote 82 deg thermostat.

The result? Car now reports temps from 80-82 constantly even when driven like a SOAB. Power feels much better which must be because the engine temp has come down so much. No more "cooking" in the cabin. AIRCON is now FREEZING.....

oh...almost forgot, it now gets up to operating temp in only a few mins...

All in all, excellent workaround with multiple benefits. If anyone is interested in pics, I'll post some this weekend, just let me know.

>> Edited by tonykart on Thursday 29th May 07:52

[DanH]

What did you do that improved the aircon? Not that it helps me as I don't have it, but still interested.

[tonykart]

I had the heating matrix "turned off". It means the whole aircon unit is no longer getting cooked.