silver beast

I have read and searched the threads for info on the stock heat exchanger and its location that is supposedly between the radiator and the a/c evaporator in the SL's. I cannot find one picture/drawing or proof of any kind that it even exists. I have looked for it on my car as well as the shop and they are telling me it doesn’t exist. They say the radiator is the heat exchanger for the S/C...is this true? If this is true then that explains why we get heat soaked so easy. I have seen the drawings for the e55 that has a separate H/E in front of the radiator and vendors that sell a larger add-on separate H/E that is to go in line with the stock unit. But what about us SL guys… Does anyone know the real answer?

cal1

I believe there is no separate HE on the stocker. Here is a photo of my SL with a Renntech HE installed in front of the stock radiator.

jmf003

Been meaning to come back to this thread but time sort of slipped away.

My 2003 has a intercooler heat exchanger separate from the radiator as described in this page from the MB Service DVD. Other model years may have different arrangements, of course.

Hope that helps.

iAMGod

So did you run it in series? If so did you notice any difference with the supplemental Renntech HE, I ask as I have one arriving soon.

silver beast

Thanks, JMF003... for the pics.

Yes all SL's have that very large HE and I had ordered the Renntech one but cancelled it after seperating the cooling loops with the small PS fluid tank, rewiring the pump to run full time with the key on and setting the fan to come on 10c sooner.

This made a HUGE difference as the full power is there all the time now and no heat soak.

iAMGod

funny i just did the same - however i still have my HE ordered - I wonder if will be useful to run it in series? can anyone comment on this?

busaboy

Does anyone have a diagram(s) showing all the heat exchangers on the SL55? Engine coolant and oil, power steering, transmission, SC coolant..etc Is there any difference between years?

busaboy

x

cal1

iAMGod

I don't know if the RT HE was run in series or not. I know it shares engine coolant with the rest of cooling system. The dumb a$$ mod shop that did the work forgot to tighten some hose clamps on the HE. I got a low coolant light and was lucky to get pulled over quick and shut down. Damn near every once of coolant leaked out since that HE is mounted so low in the front.

I noticed an awesome difference, but the HE was part of my first mod that included what RT calls extra large pulley plus tune plus pump. My engine temp runs 3 or 4 c cooler at cruise and I notice the temp drop fast after a rise from stop and go traffic.

I had an EC guy that no longer works with them look at the RT HE and comment that it is small compared to theirs. I don't think he realized it is "V" shaped and just might have as much surface area or even more than the EC HE.

iAMGod

Damn that is lucky - no doubt you wont use them again! I wouldnt care if the Ren was smaller I would always choose Ren or Kleeman over any other product.

Ok well i guess it must be run in series if they didn't remove your factory HE - If you have not split your cooling i would highly recommend this and then have your pump set to run with ignition - you will notice major difference!

cal1

That is for certain. The first thing the tool did was slide the pulley on too far and cut the front crank seal and then claim he didn't. Later fed me some drivel about front crank seals get brittle and leak all the time. I could go on and on about the botched install.

The old girl (80,000 miles) can still pull a high 11 on street tires in the quarter and take on well the majority of people that want to try her, but I just wonder if the extra cooling the engine gets out the HE is a good thing. Wouldn't that drop off a bit if I split the cooling?

iAMGod

Damn really not worth using these cheap installers!

Of course it will! Yes I realized the pressure may drop off which is why I was considering upgrading the CM30 to CM90 -just not sure whether anyone else has tried this and can comment on it. Heat from my 178 was just killing my power so doing anything that might help keep the IAT's down.

cal1

That is for certain. I make the decision to spend the extra jack to go with what I still think is the gold standard in mods for MBs; Renntech, only to get hosed by a local installer that says he can do it. He did have all the right crap. He had F-cars, P cars and a Lambo in his shop when he convinced me he was legit. Little old Indianapolis doesn't have a single competent shop that can install mods properly and the dealer is one of those that says it would have been stock if it made since. One big positive for the dealer though, is they fixed all the F-ups the installer did. Too bad they didn't do the mods for me in the first place.

sl55per

I came across this old post you provided info on regarding a heat exchanger for the SL55. I purchased a PLM heat exchanger and a new Bosch 010 pump but I have come to find out that the H/E does not bolt right up to the SL55 like it does the E55.

Your post said you returned your Renntech unit because the stock H/E was big enough on the SL. I am putting in my new Bosch 010 pump regardless but if I can help it it sounds like I don't need this second H/E per-say. Your post said you went stock, wired the pump to always be on with the key, and to turn the fan on 10 degrees early. Did you get a new T-stat or was that part of a tune?

I am planning on a EU supercharger pulley and a ECU tune but do not have any pressing desires to increase HP past those mods. Can I get buy with the stock H/E with the new Bosch 010 pump and supercharger pulley with tune?

JohnH

Here is a picture of my SL55 with the additional heat Exchanger fitted. Also fitted Bosch 010 at the same time.

cal1

To a certain extent, the need for an additional HE is going to be based on your driving habits. The existing system will keep your intake air temps low enough in normal driving and likely handle a quick blast or two on the throttle. For instance a quick shot from nearly zero to freeway speed at or close to WOT. IATs will have risen during that run, but they begin to cool back down if you are not on the gas again. If you find yourself doing back to back hard pulls, I suspect your IATs will go high enough to shutdown the SC. You will know it when it happens, by the big loss of power. Once the IATs have dropped, the ECU will bring the SC back online for you.

I personally think an additional HE is a must for these cars because the SC design is prone to heat soak anyway. Once you increase boost they become even more prone and as your IATs rise, you lose the benefit of some of the extra boost anyway.