This is a new possible scenario:

the 178 mm crank setup + new Code3 midsize S/C pulley (good for i think 19.5-20 psi)

Now pretend you try to run a 181 with a slightly larger s/c pulley than this midsize one, and make similar or slightly more boost.....

Now here is where my question comes in.........

from what i have read and heard, the larger crank pulley kits (178, 181, 185) are better for power up top. The code3 supercharger pulley is better for power low down. Thus, it would seem that you can get a little bit of low end and top end by running a stacked setup (please feel free to correct any of my random thinking)....kind of like sequential turbos?....one for down low and one for up top?

Being that 185 > 181 > 178, i would think pulls up top harder than the 181, which pulls harder top end than the 178. Back to those stacked setups, (and assuming my reasoning is all correct), which would be a quicker setup assuming boost is the same or very similar? would there even be a difference? heat differences? i would think they would be about the same.....smaller s/c pulley will get to the 178 quicker than the s/c pulley for the 181, but the 181 will pull back on the other setup b/c it is stronger up top?

please critique my thinking and correct everything that is wrong or that i just completely made up

thanks!

 

by the way, this assumes that A/Fs are optimal, it is tuned for, and fuel is being delivered without a problem...

 

IMO the 178 gives all the mid range you need. My top end came from 3 items, tune, mani's, and ypipe. The bottom end is there and all the car can give with the current gear ratios. The E55 crowd is just getting caught in the bigger pulley more power phase that we had earlier this year. Let's see if any problems arise or solved for that matter. Most don't datalog and just want to get sub 11.5's. They could be running dangerous AFR's and wouldn't know it. All that matters is the word from the tuners adjusting their cars. I met one person with an E55 that was setup and tuned from a major, major company and trusting it was safe after spending the big bucks. The motor blew shortly after. So before anymore mods invest in a datalogger and take it a safe step at a time.

 

Hey jturkel,

Let's assume you're at a load level where the S/C is engaged.

All things being equal (like your note of proper tuning of fuel/timing/etc), the "gear" ratio between the S/C pulley and crank pulley is what's important. So, the performance (rwhp/rwtq) of a 178mm crank w/ mid-sized S/C pulley would be identical to a 181mm crank with slightly larger S/C pulley that kept that ratio the same. The minor footnote to this is that as the crank pulley gets larger, you're overdriving the accessories, which increases parasitic losses (i.e. losing efficiency of getting power to the drive wheels). That said, as you decrease the size of the S/C pulley, you lessen the belt tension, and the surface area of belt contact on the S/C pulley - presumably increasing belt-slippage (i.e. losing efficiency here as well).

My guess (and it's only a guess at this point) is that the 178mm crank pulley, plus the mid-sized S/C pulley, will make roughly the same power as the 185mm crank pullied cars - again, assuming proper tuning and other variables have been addressed. The 178mm car *should* be more efficient as well, due to lower parasitic losses; how much? Dunno. Apples-to-apples, it's also worth mentioning that buying a 178mm pulley kit, AND a mid-sized S/C pulley, would be approximately double the investment of a 185mm pulley kit and leaving the S/C pulley stock. To some, that may make a difference... YMMV.

 

So true, I've noticed this trend as well on the MBW w211 AMG forum. Wasn't aware of the "major, major company" who blew up a M113K - was there a thread discussing it? Can you share any particulars (by PM, if preferred)?

 

the overdriving.....thats why i am thinking about the 178 and midsize....and with regards to running the stacked setup with the 178 and midsize, i have the code3 belt wrap kit which increases the surface area of belt contact and belt tension. i am told it is needed to really run this setup well (from Brandon).

if you make the same boost with method A and method B, but method B uses more overdriving and thus more parasitic loss, wouldn't B also produce more heat?

and yes, it is definitely more expensive.....however, I am told it feels different (and is more of a blast) to drive than with one pulley....which is why i was thinking about the low end vs top end thing. hmm....

 

+1 Evan......would be greatly appreciated if you could share that with me as well

 

if you make the same boost with method A and method B, but method B uses more overdriving and thus more parasitic loss, would B also produce more heat?

 

The 185mm will provide you the most boost at every engine RPM level (the 181mm won't be very far behind) for $850 OTD.

A stacked system using 178mm pulley and Code 3 Pulley with a belt wrap kit will set you back $970 + $649 = $1,619 - - plus what ever the belt wrap kit will cost you. Not to mention the headaches of trying to make it all work.

One way to look at it. - once you bolt on a larger crank pulley (any one of them) you will spin the accessories faster - but not overdrive them until you reach:

Stock @ 6000 RPM
178mm @ 5,160 RPM
181mm @ 4,980 RPM
185mm @ 4,860 RPM

With the AC off - the extra parisitic drag is almost non existant - plus flowing your coolant a bit faster could be a good thing.

Just something to consider...performance gains VS risk.....price VS performance....there has to be some trade off....has to be....

 

and how would parasitic drag be with AC on? I live in Arizona....heat is definitely an issue in my case

 

Quote:

Originally Posted by jturkel

and how would parasitic drag be with AC on? I live in Arizona....heat is definitely an issue in my case

My AC compressor automatically shuts off at WOT, regardless of its HVAC settings.

Another hardware variable to ponder is evosport’s ODPS kit.
It includes upsized alternator and power steering pulleys in an effort to maintain their original rotational speed.