skratch77

I recently hit the dyno in summer weather and only made 500 when 2 months before I was in the 530-540s depending on temp and gas and had me thinking for the longest time wtf is up with the car.

I totally forgot I was trying different size belts to get rid of the S/C harsh engagement and I dynod the car with a 52in belt and I just installed my 6 rib(yes 6 rib)k61295 belt thats like a 51in and the car is seeing almost 1.2-1.5 more psi than before.

I was also trying to figure out how I went from almost 600rtw to 520-530 so If you guys are running a 178 the k61295 is a super tight fit and will take some man power to get it on the car,it will not fit a 180 and you will get more boost if you are coming from a 51.5 belt.

That was my biggest secret on making easy free power and just wanted to let you bros know.

Dont come crying if this belt blows your bearings on you blower,you need to come up with a way to get some tention off the belt...hint jam something inbetween the coolant line.

I will try to hit the dyno soon and I have no doubt the car is back to where it was since second gear now feel like first again

and for you 180 owners there is a slight chance a k81298 belt might fit with some force,we need asp to machine a smaller pulley for the tentioner to fit these smaller belts.

cij911

I am not sure I am following your title & thread, but I think what you are saying is that by using a smaller belt you are not getting slip and therefore making more boost and power....

Do you log boost, if so would you send me a boost plot so I could see what you are running ? TIA

tbal

So smaller the belt the better for making maximum boost on a certain pulley?

skratch77

not only was I slipping I think the smaller belt will spin the sc faster and make more boost,try it out I know its not in my head its hot out today and the car feels alot stronger.

A shorter belt will end up spinning the sc pulley faster too,if my math is right it should

I am seeing 12.5-13psi now and I barely say over 11 with longer belt

tbal

On my 168 i use the stock belt... barely fits wonder if it helps lol

skratch77

thats the best combo to use as most people bump up the next belt with the 168 but the stocker will fit.

I am in love with the car again its got so much grunt again and the wine of the blower is WAY better

Koru_Kinshi

AMG E Power

not to high jack the thread but tbal how long have u ran that kleemann pulley and headers for ? i have a kleemann dealer right down the road from me and im gonna go with that pulley being i think its the safest. its 3000 installed sound fair ?

TopGun32

what brand of belts do you use?

I have Gates belt, and seems only my harsh engagement only comes on when I feed slowly the throttle input.. but its not too bad. In C mode, is almost non existant.

I'm planning to get a S/C pulley, I will need to come up with the right belt for that application..

justinwrock

Makes me curious - I am running a Napa belt that is a little longer than OEM/dealer. Am I loosing power with that little bit longer belt?

urbamworm

When you say 178mm or 180mm pulley are you talking about the actual measurement of the belt surface where the ribs are or the outer diameter of the pulley?

And also, I thought you said you had cams in your car and think there was something else different when you did 540whp or whatever it was?

ghettoroadster

and for the folks on stockers, is there an even tighter/smaller belt?

skratch77

I was at 556 with cams and race but the car had a ****ty idle and was not running as smooth and was a pita to sell the car in its state.

My last dyno at 530whp was with a a gallon of 104 mixed with 5 galons 93 and this same shorter 6 rib belt.

I forgot that i tried like 3 or 4 different sizes to try to get the car to engage smoother and the belt was really long and made the car not build as much boost.

For the guy thats not sure its a well known fact that the shorter the belt the more boost you will make,you arechanging the speed the belt will run threw a shorter ratio.

And my pulley is a true 178 from evotech not sure how the asp 180s are but if they are true 180s the 6k1295 belt will not clear as my 178 is at the limit.it took 10 min to get it on with a set of pliers pulling it over sc pulley

BBBSS

Belt size can help take away slip but will in no way at all spin the blower faster unless it was slipping that much before.

Your engines main bearing (particularly the front one) will wear out notably faster as well as wearing out tensioner bearings and the blower bearings faster by running crazy tension.

A good belt wrap kit to get the belt to contact the pulleys as much as possible along with whichever belt slips the least is the proper cure for belt slip.


I know with the procharger guys Reichard Racing made a pulley with lil notches in the pulley ribs and that helped with belt slip. Not sure if anyone building pulleys on the blower side (only one place making these I believe?) has looked into this but it may help here as well.

adianaty

+1 this is exactly right. The belt tightness will only help with slippage which is why there is more boost. A good check of this would be plotting the before the belt and after runs and seeing the boost through the range. If the delta is greater at higher rpm's then its belt slip.

Tech-Tune

Affirmative, your previous belt must have been too loose.

GT-ER

This is absolutely NOT correct in absolutely ALL ways. Assuming belt slippage is not in the equation, you can have a 2ft drive pulley with a 3ft long belt driving another 1ft pulley and your ratio will be 1:2. If you keep your same pulleys and add a 700ft belt instead of the 3ft one then your ratio will continue to be 1:2.

You need to study up on your pulley knowledge.

Here, have fun with this calculator:
http://www.csgnetwork.com/pulleybeltcalc.html

Notice how no matter how long you put the belt length, the input and output rpms don't change. Only the spacing on the pulleys and the belt wrap change.