redc36

Hey guys

anyone running a stock size FSP? whats your opinion? I am just looking for a better response and not looking for more power.
Actually, with headers my boost should drop as well so less heat so maybe adding a FSP might be ok ?

hayseed

iTrader: (2)

read this and search is your friend
https://mbworld.org/forums/w211-amg/...tersheild.html

GinDistiller

Love my FSP! Just make sure your IC pump is in good shape and don't worry about cooling. Tony (RaceIQ) said his tune runs the pump constantly when up to temp, I certainly haven't seen any issues. IATs are higher than ambient but not much, I never logged before and I'd guess they aren't drastically different.

I'd have a better report but it's Seattle, cold and wet, and I won't find traction until late April!

redc36

thank you for the link. I seen that post but that member is using 83mm FSP which generates about 10-12 degrees of additional heat (i am assuming F degrees not Celsius).

I am looking at stock 90mm FSP option. I dont mind staying with stock boost but would love a better response and knowing that i eliminated pulley failure point as well as the whole shims issue where I might not be getting a full boost. I might be wrong about shims / boost so please correct me if i am wrong.

i guess my question would be AT IDLE would 90mm generate less heat than 83mm?

GinDistiller

I would think at idle there would be no (or negligable) difference in 83 vs 90 FSP. The supercharger is engaged and not building boost, boost levels are the main difference between the two at full tilt, so 1-2 psi at WOT can only be a fractional amount at 600 rpm...

But it will inevitably create more heat than clutched at idle since a clutched pulley is disengaged.

Honestly, a few degrees more at idle doesn't worry me as I don't worry about leaving the garage if it's 85 degrees out versus 72 degrees, and the car responds SO much better with the FSP. Plus the failure rate of clutched pulleys...

BC928

I don't think modern cars have clutched pulleys, and some say that Mercedes dropped the K because of the smoothness that they could not fully acquire because of the on-off supercharger.

So FSP is good, and does require extra cooling to overcome the additional heat it seems to product over clutched. You can have high intake temps and still bring them down before that air gets to the combustion chamber. Two variables - how you can reduce the temp for the physical combustion chamber entry - as well as how you can reduce temp for the sensor so the ECU KNOWS its lower.

drothgeb

A twin scroll supercharge compresses between the blades as it rotates regardless of downstream is compressed or not. You will get heat. Mine spins a bit faster with a 72mm fixed but I have hit >140 letting the car idle for 20 minutes with my sleeping daughter waiting for my wife to get out of the grocery store (before I added a second pump and went with a DTK heat exchanger)

redc36

so what you are saying is that at idle it doesnt matter if FSP is 72mm or 90mm it will build heat since supercharger is engaged and can get to 140 degrees regardless due to its design. only decoupling can help at idle and nothing to do with the size of FSP.

so how much cooling needs to be added in order to keep stock temps at idle with FSP (pulley size doesnt play role here it seems). PLM v2? PLM + 2nd cooler?

GinDistiller

That's what I'm thinking. I don't think there are many folks running the stock size FSP yet, let alone logging idle temps, so you may be the guinea pig. That said, these cars need better cooling regardless, so maybe log your stats now then pull the trigger on the pulley and a larger HE and see how the numbers look after. Pulley install is much easier with the core support off too.

One other thing to note: not everyone gets it but I'm one that has some increased supercharger gear noise at idle with the FSP. It's kind of annoying, I don't really hear it in the car with the windows up but the first time I pulled into the garage my wife gave me a funny look thinking something was wrong with the engine...just beware.

BC928