77mm S/C Pulley on M113K's - Thoughts and Experiences Please!

[whereami]

HI All

Well it looks like I just can't bring myself to part with my old wagon. I am therefore thinking about a s/c pulley change from my current 84mm one down to a 77mm. I know there are quite a few of you now out there running the smaller pulley, so I am after some genuine feedback and any negative experiences with one fitted. Also what mods have you needed.

Any info much appreciated

Hi Simon,
I am the guy who bought Jules' CLS. It now has 103,000 miles on it and still runs as strong as ever. The only performance additions I have added are a tcu and a larger heat exchanger. I went with a DTK HE, mainly for the facility to split the cooling with it, since it has a pressure cap fitted. It's not the prettiest item, but that is reflected in the price, and it functions well. I have not tested the car on a rolling road, but the feel is a subtle but detectable improvement. I describe it as feeling like the cool 3am air at any time of day, I'm sure you will know what I mean.
For perspective I ran a S211 E55 for 5 years, completely standard before the CLS55.
The 77mm pulley and tune is awesome, and other than normal maintenance items that happen with a car of this age, the only problem has been a prodigious appetite for rear tyres!
I hope this is helpful, please let me know if you have any further questions.
ps Hi Jules

 

[Cyclone1]

Hi Simon,
I am the guy who bought Jules' CLS. It now has 103,000 miles on it and still runs as strong as ever. The only performance additions I have added are a tcu and a larger heat exchanger. I went with a DTK HE, mainly for the facility to split the cooling with it, since it has a pressure cap fitted. It's not the prettiest item, but that is reflected in the price, and it functions well. I have not tested the car on a rolling road, but the feel is a subtle but detectable improvement. I describe it as feeling like the cool 3am air at any time of day, I'm sure you will know what I mean.
For perspective I ran a S211 E55 for 5 years, completely standard before the CLS55.
The 77mm pulley and tune is awesome, and other than normal maintenance items that happen with a car of this age, the only problem has been a prodigious appetite for rear tyres!
I hope this is helpful, please let me know if you have any further questions.
ps Hi Jules

Hi Mark,
Hope you are well and so great to hear the Car is still as stunning as ever. I know you don’t post often, but if you get the chance then please post a pic of the car, whilst I still have many saved from my ownership, it’s still great to see a newer one. The colour, wheels and stance really made it look stunning.

Jules

 

[Kooky1976]

Out of interest what are the real-time differences between going from OEM to 77mm plus map? Say for example on the 1/4 mile? Mine is pretty standard short of a Johnson pump and was 501bhp/515Ib/ft at the crank. Is it really that different? I kept thinking about it but was until recently having significant traction issues with Pzero Rossos but having switched to Uniroyals I can finally get the power down consistently.

 

[BuckharryAMG]

Hello everyone, I do believe I’m a little late on this discussion but would love a bit of advice. I’m also thinking of going with a 77mm pulley on my CLS55 but I’m not sure if that’s safe to do with a standard Heat Exchanger. Are there any risks running a 77mm on a the standard HE?

 

[AMGeed]

Hello everyone, I do believe I’m a little late on this discussion but would love a bit of advice. I’m also thinking of going with a 77mm pulley on my CLS55 but I’m not sure if that’s safe to do with a standard Heat Exchanger. Are there any risks running a 77mm on a the standard HE?

Welcome to the forum

Did you read Post# 2 in this thread? The poster, Cyclone1 did extensive tests with both 83mm and 77mm pulleys without extra cooling.
As long as you fit a clutched pulley and not a fixed pulley, the worst that can happen if the heat rises too high, the ecu will cut the boost until temperatures drop sufficiently. Make sure your IC pump is performing 100% (can be checked with Star using live data) and consider an ice tank if you don't want to fit a bigger heat exchanger.

One member here (merc85) fitted the bigger heat exchanger with success. Have a search for his thread to see what was involved.

 

[ChrisHampshire]

If it's a clutched pulley, there's probably little risk as the ECU should be able to shut down the s/c if the intake temps get too high. Although there's little risk, if your intake temps are too high, you'll suffer from not having a s/c some of the time!

The same cannot be said for a fixed pulley though....

Either way, I'd connect an OBD reader which can monitor intake air temps and then check that it's staying below, say, 45-50C even after some 'pulls'

 

[Lenny63]

I bought the DTK600 kit earlier this year for mine (77mm clutched, large heat exchanger, belt wrap kit, gearbox TCU **I've fitted this already, a noticable and pleasing difference** and all this will be tied up with a remote re map.
Due to moving house and not having any tinkering space now I haven't yet fitted the kit but once spring comes I can't wait to get it all bolted on
My advice would be fit larger heat exchanger if considering the 77mm