Bought a 72mm pulley
 

So I bought a 72mm on ebay it's a DTK clutched and received it. I am on stock pulley but I just put a bid on a PLM XL heat exchanger with cm30 johnson pump. Can my car run comfortable with just that cooling mod?
Is 72mm too aggressive will it risk damaging my engine? I do daily drive the car but like speed as we all do, I want it to at least be reliable. I have the pulley already just need to know what belt to buy.

Definitely do cooling prior or in conjunction with scp. What about tuning?

Mind i I asking what you paid for 72 scp?

250 lol, got a good deal as guy had it laying around. I will be doing cooling mod with the pulley

Good price! You got a tune already for that smaller pulley?

Car's in the body shop getting repaired as bumper and hood got damaged. Once it's out it will be done!
Currently hydrodipped my interior center trim blue carbon fiber. Looks cool

post some photos or hydrodip interior, please, I almost did a CF interior wrap but didn’t think it flows with the E W211

https://postimg.cc/67jcxkxr

It's by no means the greatest, I don't think it looks like real carbon fiber but I like it better than stock. First time doing it

looks good, you’re doing all the wood trimming like that? Can you post pictures when they’re installed in car?

I will gladly post pictures when it's installed but what I am worried about is if it doesn't really look the greatest. If I install the the center pieces and it doesn't look good I will just not continue it and wrap the interior or something. My interior is black/blue which is why I went that route

I’m not an expert on these platforms by any means, but I’ll throw in my 2 cents anyway. 72 is a pretty aggressive size but with a stock crank pulley I think you should be okay. For cooling, I’m not sure. I think you should be good for daily driving, but after a couple WOT’s it will probably start pulling timing. If you ever want to go with a bigger crank pulley, there was a chart on here that listed boost pressure with different combinations of upper/lower pulley sizes and their corresponding “safety” levels so to speak. I would consult that if you ever are going to go with a different crank pulley because 72 is pretty small. Good luck, and if cooling becomes an issue I would probably go balls to the wall and go with a killer chiller or meth injection just so you won’t have to worry about it again.

You'll need bigger injectors and long tube headers for that size pulley. You also need a tune for ANY power adder. Those DTK pulleys are known for their bearings to go once they get to the smaller sizes like 72mm and smaller. I don’t recommend that pulley at all for daily driving. You’ll be faster with a PLM XL heat exhaust, a new Bosch 010 water pump, stock pulley and a good tune vs adding a 72mm pulley on top of this.

I had a 74mm fixed pulley made for my SL55 with all the other non-internal mods one can do (stage 2 EC kit), stock SC, only shorty headers, KC and tank, stock fuel system, Pierburg 50 IC pump. I had seen information that that is the smallest size pulley before boost no longer improves, just heat increases. In any event Tony Lawshee sent me a tune and I am very pleased with the result. I live too far from the drag strip to get 1/4 mile times however I do have a V-box which I use to time 100-200 kph which I then compare to that interval in road tests of other cars. It is a low 11sec maybe high 10 sec car based on those comparisons. I have an AFR gauge which showed 11.8:1, no leaner. I can't see the need to do more as the $'s needed to go quicker are exponential and unless drag racing is your sport, not needed.

As an aside I also have an in cabin temp read out of the water in my tank which receives it direct from the KC. I highly recommend that guage for KC users as you quickly see the heat loads and recovery of that water temp. The water is always still under ambient temp after those 100-200 pulls and gets down to 15 deg C below ambient while cruising, so much much colder than any heat exchanger provide which is probably 5 deg C above ambient best. I have the 'drag valve' which when full on to the KC I get another 5 deg colder. The hotter the ambient temp the bigger the temp drop I see. IMO a KC is a no brainer. Sorry this last paragraph is a thread hi-jack.

My car had a 72mm on it when I got it. I had no idea it was considered so aggressive. Hmmmm.

If you don't have upgraded cooling it is aggressive or if you are a Mercedes owner. A better pump and intercooler you're good to go. I ran a 74mm without a tune for months. If you're at higher altitude it's just getting you to what someone at sea level has with a 83mm. I don't think I ever saw something about a dtk pulley failing? Mb you could link a thread, I'm not a slave to the forum.

My friend that's local to me had a 70mm pulley from him and the bearing failed. He had it for less than a year with a couple thousand miles. It's mostly discussed in the Facebook AMG groups. You can find multiple reviews in there. I don't know if there are many threads on it on MBWorld. The FB groups are a lot more active now unfortunately.

Here's one guy with a 74mm pulley with a failed bearing: https://mbworld.org/forums/w211-amg/...ed-pulley.html

thanks for the quick response, I'm mostly on MySpace so that explains it. Good info, i wonder if that's due to cheap bearing or not right one in that size for the application.

Had one sitting in my parts department.
The bearing is a 6809z it's a shielded bearing so it can keep things of sorts out, but it also allows all the grease out when it's spinning 15000 Rpms. There is 4 of these bearings in there with a spacer in the middle because 5 wouldn't fit but there was space to spare.

HI,
What model belt did you buy for the 72mm pulley? If you have the brand and model, it would be greatly helpful as I just got a 72mm pulley also.
Thanks,
Ajai

I bought my car with 138k miles and a 72mm clutched pulley with headers and basic cooling mods.

I've beat on it every day for 5 years and I'm close to 193k miles now. It's totally fine.

Speak to the durability of these motors. BTW, do you know or can you check what size belt you have around the pulley? If you can provide brand and model, that would be great.
Cheers

gates k080530
this is with an ultimate PD belt wrap kit as well.

The best belt should be the Gates RPM series

More pics here: https://mbworld.org/forums/c219/8443...ml#post8653485

https://lh3.googleusercontent.com/pw...-no?authuser=0

https://lh3.googleusercontent.com/pw...-no?authuser=0

Do you have injectors or tb or just 72mm pulley, header, and cooling?

@blowupmye55 fast forward few years and what was your experience with the 72mm clutched pulley? How were the reliability, durability, bearing or other failures, etc?

My first experience was a 77mm pulley from DTK, the bearings failed, twice. Then I bought a 74mm pulley, bearings failed and then a 72mm pulley, the bearings failed much faster, I replaced them with better quality SKF bearings but they lasted only a year. I'm now thinking of going with a fixed pulley after installing an interchiller. The grease in the pulleys just can't seem to stay in place.