lorie

Does anyone know which pulley size makes how many ponys and boost?

168?
172?
180?

vinnyz

the 180 would make the most but the 175 would be good as well

lorie

I need numbers.

jangy

numbers don't mean all that much, especially peak ones.

From a basic standpoint, the larger the pulley, the more the boost and assuming proper tune, the more the power.

BUT, there is an exponential downside, so again you need to determine what you want.
As you go up in pulley size, it will add "lag" due to the added momentum of the larger pulley. So, you may gain peak horsepower, but it may take some of your power curve away as the car is trying to get the pulley up to speed.
Add to that, the fact that the SC itself creats an inordinate amount of heat and the car's intercooler system is not even close to handling it.
Last thing, all the added boost in the world will not help if your car is designed to reject any pressure over 14psi (which is basically stock pulley at max spin). So, tune becomes critical. You obviously need the A/F ratios, etc. set to compensate for the extra air but you also have to tune against the various TQ managment features in the car.

If you want a quarter mile car, then obviously larger pulley = more power as long as you keep up with tune and cooling.

If you want a street racer, I found 175mm to be max. Larger than that and I hated the lag. Smaller than that and it felt stock.

Keep in mind that we have a number of cars on here running at 500+ HP to the floor. To show comparison, they have all different sizes of pulleys. One of the faster cars around runs the EVOSport pulley and cooling kit and their pulley is a 168mm.

Overall you are talking about roughly 5 psi max that can be added through larger pulley and increased rev limiter.

To add to your question, it also depends on the exhaust side. I lost a good 2 psi when I used the "headers" but that power was regained in the tune PLUS the car lost some of the lag.

Hammer Down

I would buy that with the exception knowing that you have the 168 and are running 11.0@127 when some guys have the 180 and are not runing the same times or speed.

Luke_M

https://mbworld.org/forums/w211-amg/...ize-boost.html

It's only a guide, not set in stone as others have indicated.

I Like Soup

Ah, this is what I was looking for when I posed this question a couple of times but people were more interested in dramatic threads...thanks!

jicl55

I had a 180mm and changed it to a 172mm because of the lag that Jangy was talking about. For quarter mile times, the bigger the better (usually..... with cooling, of course there are exceptions). But for regular driving and reliability, I am much happier with the 172mm. May not be making quite as much power, but runs cooler and there is no lag as compared to the 180 I had on, which annoyed the hell outta me.

Luke_M

What do you guys mean by lag? I would think a bigger pulley would have more grunt from the start and if anything die off as the heat rose.

pearlpower

There is more to it than just pulley size. There is someone one here with a 168mm that is faster than most 180's. It's not the size.............................

prodigymb

who has the EVO 168?

The updated EVO design was a 175.

jicl55

Can't exactly explain the physics of it, but when I had the 180, it would lag at lower rpm, and especially between shifts. It was not a smooth transition from gear to gear when the rpms were really low or even medium throttle/speeds. This is how quite a bit of my driving is done in traffic, etc. At WOT, it was great, but for everyday driveability, I was not so impressed. I changed to the 172mm with the same setup, and this aspect has improved quite a bit.

Luke_M

Hmm, I wonder if that was a tune issue or one that a good tune could fix.

jicl55

It's possible or some other issue who knows, but had the 180 with tune and without tune, it did it. I've talked to a few other people who have had similar observations with larger pulleys. It's hard to pinpoint exactly what may be doing what or the cause of it. But had the stock with 180 tune it didn't do it. Had the stock with stock tune it didn't do it. Had the 172 with stock tune, it didn't do it. Have the 172 with tune now, doesn't do it. I'm not sure if it is the weight perhaps, or larger diameter or what, but I did notice a "lag" with same setup besides the pulley. But Just something I noticed.

pimpjuice

i am interested int his also since a pulley may be my next upgrade. I have a HUGE intercooler and pump just for the SC, this should eliminate the heat issue right? But I am concerned on the Lag...right now I am running evosport headers, 2nd cat delete, upgraded s-tube...I do need a tune, TB and...there is something else but I cant think of it right now. How bad would the lag be? It runs pretty good now street racing wise(we dont have a "track" iin HI).

Subscribed to this one!!!

skratch77

can you describe the lag a little better?with a bigger pulley the car is making more boost sooner,this is not like a turbo that has to spool up.

the only thing I notice with the 180 is it engages hard when it kicks in and that might be my clutch.

Roseylv

Some of you guys started to scare me. I have a 180mm on order and I had temporarily changed my order to a 170mm. After sleeping on it, I came to a realization that if I don't like the feel and performance of the bigger pulley, I can always switch without incurring that big of cost.

vinnyz

ya but i have more mods than most of the others .. i focused on cooling before i even modded my car .. there was a time when system wasn't bleed that my iat's went high on me but since then its stays pretty cool ..

lorie

What are your cooling mods?

jicl55

Sorry, can't really describe it better than I have, but it feels like, at least initially and not at WOT, it did take longer to "spool up."

Thought you already had a pulley? Anyway, don't mean to scare anyone, but offer my thoughts and opinions from my own personal observations and experiences that I did not consider or know about when I initially bought a pulley and maybe would have looked into a bit more, that's all.

Many people have run 180s or larger pulleys on Mercedes and other supercharged engines without problems for many miles and years, but there are drawbacks that I have experienced that I think people either do not consider or don't post about (it's all about numbers and trap speed for most). Plus, almost no car is "exactly" the same, so it is hard comparing apples to oranges. And you can't go back in time and undue what you did and see if you had the same observations/results, so it is really hard to say "this is due to this" etc. A lot of modding seems to be by trial and error.

Other things to consider: remember, this is your harmonic dampener, a very crucial piece of the car. I don't think or know anybody has really looked into how the dampening capabilities change (or by how much or if they do at all) with a larger, heavier pulley. The stock dampener is meant to absorb vibrations at certain harmonic frequencies. Does this and by how much does the variation in pulley size, increasd hp/tq, etc. effect this and is it still within acceptable, reasonable limits?

Further, the larger the pulley, the faster the other pulleys will spin. I do not believe the other stock parts are able to handle this as well, thus seem to fail sooner and need to be replaced (or upgraded) more frequently. Something else I have experienced.

My recommendation is if you want a 180 (or larger) go for it (but at least get cooling). You'll probably kick yourself in the butt later if you don't. But I'm just trying to make others aware of things that they may not have thought about or expected based on my experiences of modding.

jangy

The "lag" being talked about is from the rotational mass of the pulley itself when it is winding up to or down from speed.

We all know that the MB motors are slow to react when you punch it, but the larger pulley adds just enough more to make me not like it in the long run.

Lets be clear, I do not believe that you are compromising by going smaller. It is all about having the car in its sweet spot under the conditions you use. I fully believe that a car with better cooling and a 168 (original EVOSport) will outrun a similar car with so - so (i.e. using a CM30) cooling and large pulley. Heat is HUGE.

Last thing, keep in mind that taking backside pressure away will help compensate for the heat by reducing the pressure but there is an efficiency point that you would need to find............that is why they call them tuned exhaust...

Roseylv

Nope! I had a VRP setup on my E55 But I recently switched over to a CLS and am starting fresh. I have a Eurocharged 180 on order.

and I'm finalizing some research on cooling as I type

jicl55

Definitely get a larger/aux HE, PTE thermo and the -10C mod, at the least, and put it on before the pulley. There is a lot of discussion on water/intercooler pumps, so plenty to read there.

bassn_07

Nice write up Jangy.

This lag you guys talk about is either non existent or I just don't notice it in my car. I could break my tires loose up 65 mph or more on a cool night. I honestly believe that with a good tune most of these issues could be resolved.

skratch77

I cant notice any lag what so ever either,the only thing I feel is the s/c kicking in.its instant power everywhere in the power band.

here is my dyno from stock to 180 pulley