So I have a completely stock engine with a PLM XL heat exchanger and Bosch 010 pump. Is it ok to upgrade to a 83mm pulley with the stock headers? Are better headers necessary for engine reliability? I know the stock headers are very restrictive and I dont know what the implications are of improving the intake without improving the exhaust.

 

Go read my build thread.

 

I read your thread. Thanks for putting that thread together; it was nice seeing the power gains I could expect. However, I didnt see an answer to my question in that thread. I saw a comparison of power with and without headers, but no mention of reliability without headers.

 

you will not get the full potential without the headers, stock boost need headers on these cars, add that extra boost, and heat due to stock manifolds a dialed back tune will keep the car more than ok but kind of blah to drive.

 

I had zero issues running just the 83mm pulley and would have been fine leaving that as is especially with the cooling mods. That said if I were to do it all over, I'd do the headers first and see how that is. It'll help the engine breath more and keep the intake temps down since you're not adding more boost. I should have stopped with the pulley and headers because the 82mm throttlebody was just one giant, expensive headache.

 

But, the throttle body issue is now resolved?? Got it resolved with the Race IQ tune?

 

Yea, so far it's been good, been waiting a little longer before posting about it. It does on paper make less hp than the EC tune before but w/o the hiccup issues so I'll take that and call it a day on power mods.

 

What is different with the tune that resolves the issue?

 

Man, that is the million dollar question. I was not able to get much insight from Tony on what was different. It is a more conservative tune and the dyno operator commented that it felt like the supercharger "came on later" than with the previous tune for whatever that means. There may be a difference in the base map used as well as in the timing/fuel maps but again, that is speculative as I don't have access to the maps used. I do still see STFTs as high as +25 occasionally but I have not had the hiccup nor have I encountered the rough lumpy idle associated afterwards. At idle in park after seeing +25s the STFT return to normal and stay steady. For me, paying for a new tune from RaceIQ and renting dyno time for him to dial it in was worth it for my peace of mind.

 

Thank you for this update on a very long journey not only for you but many others.

 

I did an 83mm and off shelf box tune and have ZERO cooling/IAT issues and the car runs like a raped ape. With pulley mods, highly recommend a belt wrap kit - people will argue it does not do anything, it does (stable and consistent boost all the way to redline without losing pressure). Buy a kit. An 83mm is ~6mm (if I recall correctly, I measured it at ~89mm) different than stock; we aren't talking 77mm or smaller fixed pulley here. You will gain ~1,5-2psi with the 83. I have the exact cooling mods; PLM XL and Bosch 010. No heat issues even after multiple back to back WOT runs. With all the M113K cars, every car is different and responds differently. From feel, to power, to overall delivery.

How many miles are on your car, OP? Is maintenance up to date? If yes and if done correctly with cooling in place, you will not have problems with an 83 and intake temps.

You do not need headers to add an 83mm. Anybody that says that does not have enough experience with these cars. My third 2006, I owned two other 2006 before. I've done all the mods, some left out and won't do again, some same as I did on this one. Having said that, this is not taking away anything from long tubes. This car's bottleneck are 100% the manifolds. From all the E55s I've owned, thousands and thousands of miles with just an upper 83mm and stock manifolds, no issues - and I romp on this daily car a lot.

Your reliability depends on the tune (air/fuel) more than anything else once you add an upper pulley... headers do not 'add' reliability nor take away from it. They simply make it easier to make the power (less boost/boost loss).

Lastly, just because I am in a good mood today - stay away from any and all throttle body upgrades. Some people swear by them and have success (I guess everyone's idea of success is different) but I don't care what anyone else says, they cause headaches and problems left and right. Serious or subtle, if not immediately, eventually.

 

Thanks ArmoE55, I have ~95k miles and the car us up to date on all mainetenance.

 

My thought on pulleys.

-83mm Pulley swap with tune, no other modifications needed BUT a Bosch 010 pump and a bigger heat exchanger definitely recommended.
-77mm Pulley swap with tune, heat exchanger and 010 pump upgrade at minimum. Some shops also recommend larger injectors. Headers, preferably LT help with the back pressure and nice bump in hp.

These are results of just pulley swaps from a well know shop in England.

In order to test the pulley we decided to use the same car and ran it in 3 states of set up;

1) Stock - 423.7bhp / 475lb/ft (500 / 561)
2) 83mm -480.5bhp / 532.66lb/ft (567 / 629)
3) 77mm -509.3bhp / 596.80lb/ft (601 / 704)


1) Stock (OEM supercharger pulley)
2) Euro-charged 83mm supercharger pulley (X pipe fitted in place of secondary cats and resonator removed)
3) As above with 77mm Supercharger pulley


The power and torque figures at the wheels were as follows (flywheel in brackets);
[img]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]



https://forums.mbclub.co.uk/threads/...o-test.189064/

 

This great info. I'm pretty impressed by the numbers. I had a previous post where I ask about how to keep my car as quiet as possible while adding LTH. Looking at those numbers, maybe just adding the 83mm pulley will do.

 

I'd definitely add better headers. The first power mod on my car was mid tube headers with everything else stock. Even with the stock pulley and stock mapping, the car pulled faster from 100-200 by about 0.7s after adding mid tube headers and no pre cats. Those stock manifolds are a bottleneck even on a 100% stock engine. Headers will reduce your boost pressure, because you will improve air flow on the engine. This will put less stress on your intercooler and supercharger and your engine will dissipate the exhaust heat better. You'll also be eliminating the possibility of your pre cats failing and getting sucked into the engine causing a complete engine failure.

If you use the 80mm throttle body (which is in fact a 78mm diameter) there will be no issues. Those throttle bodies came stock on our engines in the SL55 evo, G55 and clk dtm. The M273 82mm ones are problematic though.

Personally I prefer stockish pulleys, which make less torque, which makes the car more driveable in practical use. With 900Nm torque,, most of it will go into wheelspin aka burnt rubber. Also less stress on the gearbox.

In summary, 83mm with stock headers will work, but adding better headers would be advisable.

 

for me too the headers provided way more of a light , part and med pull, because other then testing something or at the track i do not floor my car no need to because its flying by the time i part throttle it and spinning.

 

LTs and cooling should always be the first mods before adding boost.

 

I run an 83mm clutched pulley with stock manifolds still along with RaceIQ stage 2 tune and VRP SECONDARY heat exchanger with Bosch 010 pump that runs whenever key is on due to the ECU tune. I do have a belt wrap kit but I only got it because the TCU tune shifted to fast that the deceleration of the drive pulleys made the supercharger belt chip in shifts. The wrap kit did alleviate the chirp. Very happy with the car but I crave something louder so saving up LTH... most likely MBH headers. This is on a CLS55.

 

Do you have a build thread in the CLS section?