Which pulley size makes which hp gain?
01-24-2011, 11:48 AM
#76
Wow missed that map!!! Very usefull info.
Working out the optimum size is pretty hard work and as dyno showed from the map and calcs 188mm would be an extreme to provide longevity on the S/C.... but then we are ignoring the efficiency decline as spin rates increase...and 8000rpm seems to be the efficiency peak of the S/C unless I am interpreting the map incorrectly.
It would be interesting to overlay the diff pulley sizes over that map - if you can even see another layer of data on that chart!
If I had to do it again I probably would go for a 175mm... I think what is important is at what engine rpm you hit peak s/c efficiency and that efficiency does not tail off too much at max rpm... whats telling to me is the volumetric efficiency above 11k rpm grows much slower.
It would be very handy to document all this data and be able to view it against different axes...
Working out the optimum size is pretty hard work and as dyno showed from the map and calcs 188mm would be an extreme to provide longevity on the S/C.... but then we are ignoring the efficiency decline as spin rates increase...and 8000rpm seems to be the efficiency peak of the S/C unless I am interpreting the map incorrectly.
It would be interesting to overlay the diff pulley sizes over that map - if you can even see another layer of data on that chart!
If I had to do it again I probably would go for a 175mm... I think what is important is at what engine rpm you hit peak s/c efficiency and that efficiency does not tail off too much at max rpm... whats telling to me is the volumetric efficiency above 11k rpm grows much slower.
It would be very handy to document all this data and be able to view it against different axes...
Also what is wrong with the above equation that concludes a 7000 rpm engine limiter would allow a 175mm pulley, doesn't that mean that slightley smaller would be ideal considering our engine limiter is at 6500rpm?
I guess one factor to help would be to know what rpm the supercharger spins at when engine rpm is X with Y Pulley??? no??
Also this doesnt explain how people are running larger pullies with gains, fine efficiency may decline, but how about the theory of max power out of 175mm pulley???
01-24-2011, 11:52 AM
#77
I would personally not use any pulley that is just a modified factory pulley or a pinned on enlargement.
But to your question, 175mm seems to be the magic number. We've tested larger pulleys and while theoretically it should make more boost, the car does bleed off the excess boost so there is no realized gain. So bigger pulley does NOT mean more power. There may be other downsides to larger pulleys if not addressed, like additional heat buildup, etc.
But to your question, 175mm seems to be the magic number. We've tested larger pulleys and while theoretically it should make more boost, the car does bleed off the excess boost so there is no realized gain. So bigger pulley does NOT mean more power. There may be other downsides to larger pulleys if not addressed, like additional heat buildup, etc.
01-24-2011, 11:55 AM
#78
Not with regard to the issue of boost bleeding. Our Kompressor Cooling Upgrade (KCUP) maintains power that otherwise gets lost when heat soaking is an issue.
Our tests have shown that there is no real value to a 180mm pulley. With a smaller and larger pulley test, we can measure the boost on the dyno with no change in boost or realized power. With regards to controlling boost, you would need to control the actuation of the valve. Again, there may very well be downsides to overboosting the motor.
Our tests have shown that there is no real value to a 180mm pulley. With a smaller and larger pulley test, we can measure the boost on the dyno with no change in boost or realized power. With regards to controlling boost, you would need to control the actuation of the valve. Again, there may very well be downsides to overboosting the motor.
I wonder what the testing was? considering all the 180mm pullies out there.
and I guess this some what answers my question , but would be nice if someone could support it, I would be more than happy to do a smaller pulley instead of a 180mm if there is no benefit, no need for the extra stress on the motor.
01-24-2011, 12:41 PM
#79
MBWorld Fanatic!
I got a 180mm ... BUT a 180mm can be made to work very well too (in fact 190mm's have been made to work), as long as you have the appropiate tune and cooling mods. A 175mm would leave a little more cooling margin and perhaps not bleed off as much boost. Then again if you can get the tune right you can clamp down on the boost bleed off and realise the full 180mm potential.
Have to say my car runs really well now with the 180mm (exhaust repaired over the w/e) but last year PLopes car ran so well in the mile with a 181.x with a 168mm pulley and shelf tune and I suffered (had major exhaust issue), I began wondering again on the pulley story....
Custom tune and any pulley 168-180 will work reliably - thats been shown over and over. I suppose there is a sweet spot somewhere and gut feel says its at 175mm. I have no real science to back it up. Also as you go higher the more crucial cooling becomes and the more likely the power will fade over long runs...
Another thing to keep in mind is bigger pulleys give bigger torque low down perhaps triggering load limits and breaking traction more easily, smaller ones may allow you to get power down more reliably....
Dyno's email pertty much explains how to calc the s/c speed given the S/C pulley diameter and the crank pulley diameter. 13500rpm is operational peak of the s/c, most efficient area 8k-11k ... if you can max out at peak power with s/c rpm under 12k I think thats pretty much ideal... and that pulley size is 179mm!! aka ASP
So
12000 at 6500 168 (no sweat)
12500 at 6500 175 (safe, and some margin)
12860 at 6500 180 (still safe, but not much margin)
13320 at 6500 186.5 (right on the operational limit)
At power peak assuming its arnd 6100
11260 at 6100 168 (no sweat), and better efficiency (40kw)
11750 at 6100 175 (nice, margin available) (43kw)
12000 at 6100 179 (seems ideal really) (45kw)
12500 at 6100 186.5 (heading for trouble if u keep hitting limiter I would say) (48kw)
So there is a ~5kw (~7hp) parasitic loss going from a 168 to a 180mm... not too bad....
You can do the same exersize using your power peak... so to me ideal is propably in 170-180 range - brings me back to the 175mm.
Again my 2c....
Have to say my car runs really well now with the 180mm (exhaust repaired over the w/e) but last year PLopes car ran so well in the mile with a 181.x with a 168mm pulley and shelf tune and I suffered (had major exhaust issue), I began wondering again on the pulley story....
Custom tune and any pulley 168-180 will work reliably - thats been shown over and over. I suppose there is a sweet spot somewhere and gut feel says its at 175mm. I have no real science to back it up. Also as you go higher the more crucial cooling becomes and the more likely the power will fade over long runs...
Another thing to keep in mind is bigger pulleys give bigger torque low down perhaps triggering load limits and breaking traction more easily, smaller ones may allow you to get power down more reliably....
Dyno's email pertty much explains how to calc the s/c speed given the S/C pulley diameter and the crank pulley diameter. 13500rpm is operational peak of the s/c, most efficient area 8k-11k ... if you can max out at peak power with s/c rpm under 12k I think thats pretty much ideal... and that pulley size is 179mm!! aka ASP
So
12000 at 6500 168 (no sweat)
12500 at 6500 175 (safe, and some margin)
12860 at 6500 180 (still safe, but not much margin)
13320 at 6500 186.5 (right on the operational limit)
At power peak assuming its arnd 6100
11260 at 6100 168 (no sweat), and better efficiency (40kw)
11750 at 6100 175 (nice, margin available) (43kw)
12000 at 6100 179 (seems ideal really) (45kw)
12500 at 6100 186.5 (heading for trouble if u keep hitting limiter I would say) (48kw)
So there is a ~5kw (~7hp) parasitic loss going from a 168 to a 180mm... not too bad....
You can do the same exersize using your power peak... so to me ideal is propably in 170-180 range - brings me back to the 175mm.
Again my 2c....
Last edited by stevebez; 01-24-2011 at 12:43 PM.
01-24-2011, 01:27 PM
#81
I got a 180mm ... BUT a 180mm can be made to work very well too (in fact 190mm's have been made to work), as long as you have the appropiate tune and cooling mods. A 175mm would leave a little more cooling margin and perhaps not bleed off as much boost. Then again if you can get the tune right you can clamp down on the boost bleed off and realise the full 180mm potential.
Have to say my car runs really well now with the 180mm (exhaust repaired over the w/e) but last year PLopes car ran so well in the mile with a 181.x with a 168mm pulley and shelf tune and I suffered (had major exhaust issue), I began wondering again on the pulley story....
Custom tune and any pulley 168-180 will work reliably - thats been shown over and over. I suppose there is a sweet spot somewhere and gut feel says its at 175mm. I have no real science to back it up. Also as you go higher the more crucial cooling becomes and the more likely the power will fade over long runs...
Another thing to keep in mind is bigger pulleys give bigger torque low down perhaps triggering load limits and breaking traction more easily, smaller ones may allow you to get power down more reliably....
Dyno's email pertty much explains how to calc the s/c speed given the S/C pulley diameter and the crank pulley diameter. 13500rpm is operational peak of the s/c, most efficient area 8k-11k ... if you can max out at peak power with s/c rpm under 12k I think thats pretty much ideal... and that pulley size is 179mm!! aka ASP
So
12000 at 6500 168 (no sweat)
12500 at 6500 175 (safe, and some margin)
12860 at 6500 180 (still safe, but not much margin)
13320 at 6500 186.5 (right on the operational limit)
At power peak assuming its arnd 6100
11260 at 6100 168 (no sweat), and better efficiency (40kw)
11750 at 6100 175 (nice, margin available) (43kw)
12000 at 6100 179 (seems ideal really) (45kw)
12500 at 6100 186.5 (heading for trouble if u keep hitting limiter I would say) (48kw)
So there is a ~5kw (~7hp) parasitic loss going from a 168 to a 180mm... not too bad....
You can do the same exersize using your power peak... so to me ideal is propably in 170-180 range - brings me back to the 175mm.
Again my 2c....
Have to say my car runs really well now with the 180mm (exhaust repaired over the w/e) but last year PLopes car ran so well in the mile with a 181.x with a 168mm pulley and shelf tune and I suffered (had major exhaust issue), I began wondering again on the pulley story....
Custom tune and any pulley 168-180 will work reliably - thats been shown over and over. I suppose there is a sweet spot somewhere and gut feel says its at 175mm. I have no real science to back it up. Also as you go higher the more crucial cooling becomes and the more likely the power will fade over long runs...
Another thing to keep in mind is bigger pulleys give bigger torque low down perhaps triggering load limits and breaking traction more easily, smaller ones may allow you to get power down more reliably....
Dyno's email pertty much explains how to calc the s/c speed given the S/C pulley diameter and the crank pulley diameter. 13500rpm is operational peak of the s/c, most efficient area 8k-11k ... if you can max out at peak power with s/c rpm under 12k I think thats pretty much ideal... and that pulley size is 179mm!! aka ASP
So
12000 at 6500 168 (no sweat)
12500 at 6500 175 (safe, and some margin)
12860 at 6500 180 (still safe, but not much margin)
13320 at 6500 186.5 (right on the operational limit)
At power peak assuming its arnd 6100
11260 at 6100 168 (no sweat), and better efficiency (40kw)
11750 at 6100 175 (nice, margin available) (43kw)
12000 at 6100 179 (seems ideal really) (45kw)
12500 at 6100 186.5 (heading for trouble if u keep hitting limiter I would say) (48kw)
So there is a ~5kw (~7hp) parasitic loss going from a 168 to a 180mm... not too bad....
You can do the same exersize using your power peak... so to me ideal is propably in 170-180 range - brings me back to the 175mm.
Again my 2c....
I am going to stretch just a bit and go for Evosports new pulley the 178mm or end to end 180mm depends how you measure.
It seems they are most reliable, it is amazing that they have never had pulley failures, at least that im aware of, from all the thing of ive looked up.
01-24-2011, 01:32 PM
#82
01-24-2011, 01:47 PM
#83
MBWorld Fanatic!
168 renntech
172 asp/euro
175 vrp
178/175 evotech measures 175 from the inside
180 asp/euro
450 shipped but you would need a new bolt from the dealer(about 20)and maybe a new belt.The stock one might fit but not 100% sure.
01-24-2011, 02:06 PM
#84
Its a gen 4 vrp and I also have a water pump pulley to go with it.I was playing with boost and at one point had 5 pulleys
168 renntech
172 asp/euro
175 vrp
178/175 evotech measures 175 from the inside
180 asp/euro
450 shipped but you would need a new bolt from the dealer(about 20)and maybe a new belt.The stock one might fit but not 100% sure.
168 renntech
172 asp/euro
175 vrp
178/175 evotech measures 175 from the inside
180 asp/euro
450 shipped but you would need a new bolt from the dealer(about 20)and maybe a new belt.The stock one might fit but not 100% sure.
Thats a great deal!! I myself am sort of fixed on the idea of a Evosport Pulley because of the impecable track record (never heard a bad thing)
But I may reconsider, in the mean time ill ask around and try and push it for you, good luck and thanks for getting back to me so quickly,
by the way, whats on your car now?? how was the evosport?
Thanks take care and talk to you soon
01-24-2011, 02:12 PM
#85
MBWorld Fanatic!
I dont run an evosport,I use an evotech pulley from germany.Its a moddified stock pulley with oem damper and basically a MB pulley that has an outer ring installed over it.
renntech,kleemann,barbus,evotech,asp all use this same setup.
eurocharged,vrp and evosport make a new pulley from the ground up and dont use a modded stock pulley.
renntech,kleemann,barbus,evotech,asp all use this same setup.
eurocharged,vrp and evosport make a new pulley from the ground up and dont use a modded stock pulley.
01-24-2011, 02:39 PM
#86
I dont run an evosport,I use an evotech pulley from germany.Its a moddified stock pulley with oem damper and basically a MB pulley that has an outer ring installed over it.
renntech,kleemann,barbus,evotech,asp all use this same setup.
eurocharged,vrp and evosport make a new pulley from the ground up and dont use a modded stock pulley.
renntech,kleemann,barbus,evotech,asp all use this same setup.
eurocharged,vrp and evosport make a new pulley from the ground up and dont use a modded stock pulley.
Is there any reason you havent tried the Evosport, it seems you have tried every other ppossible option....lol
Doesn't ASP make Eurocharged pullies??
I think brabus is now doing it like Evosport
see below...
This thinking is really flawed IMHO. We have seen so many crank pulley's fail that are this design.
A few problems:
1. The factory dampened pulley fails on stock cars. As the years have gone past and cars are getting higher mileage, we are seeing more and more failures on BONE STOCK cars of the pulley. They crack and they also work out of the "grove". Here is an example of a pulley that did both:
This pulley WILL fail. It may fail at 40K miles or it may fail at 150K+, but it will fail.
2. The "pinned" design is flawed. By that design, I mean that someone takes a factory dampened pulled, machines off the groves and slides on an alum ring and uses 4-6 "set-screws" to bond the outer alum ring to the inner ring. The amount of torque that goes through this pulley is immense. A few set-screws will not hold it together for a long time. Again, some may last longer than others, but it will fail.
3. Same design as above, but welded not pinned. This is better than pins, but it adds a lot of weight to the outside outer edge of the pulley. The failures we have seen with this are of balancing and of damaging the crank due to the extra mass added to the outer edge of the rotating assembly.
We have been doing crank pulley's for Mercedes for about 9 years. We have gone through more research time than many of these companies who now sell pulleys have even been in business. There is a method to our madness.
Our pulley is a clean sheet design with a lifetime damper (ok, we have had one fail in 9 years). Take a look at ours and compare to the stock or the other competitors:
To my knowledge at this point only evosport and Brabus do it this way. In fact, Brabus changed their design to one similar to ours after we released this design. While some may think evosport is the "new kid" on the block, I think we can agree that Brabus is the pinnacle in terms of long term reputation for a MBZ tuner. So if they also do it the way we do, there just might be something to it, don't you think!?
Thanks
brad
This thinking is really flawed IMHO. We have seen so many crank pulley's fail that are this design.
A few problems:
1. The factory dampened pulley fails on stock cars. As the years have gone past and cars are getting higher mileage, we are seeing more and more failures on BONE STOCK cars of the pulley. They crack and they also work out of the "grove". Here is an example of a pulley that did both:
This pulley WILL fail. It may fail at 40K miles or it may fail at 150K+, but it will fail.
2. The "pinned" design is flawed. By that design, I mean that someone takes a factory dampened pulled, machines off the groves and slides on an alum ring and uses 4-6 "set-screws" to bond the outer alum ring to the inner ring. The amount of torque that goes through this pulley is immense. A few set-screws will not hold it together for a long time. Again, some may last longer than others, but it will fail.
3. Same design as above, but welded not pinned. This is better than pins, but it adds a lot of weight to the outside outer edge of the pulley. The failures we have seen with this are of balancing and of damaging the crank due to the extra mass added to the outer edge of the rotating assembly.
We have been doing crank pulley's for Mercedes for about 9 years. We have gone through more research time than many of these companies who now sell pulleys have even been in business. There is a method to our madness.
Our pulley is a clean sheet design with a lifetime damper (ok, we have had one fail in 9 years). Take a look at ours and compare to the stock or the other competitors:
To my knowledge at this point only evosport and Brabus do it this way. In fact, Brabus changed their design to one similar to ours after we released this design. While some may think evosport is the "new kid" on the block, I think we can agree that Brabus is the pinnacle in terms of long term reputation for a MBZ tuner. So if they also do it the way we do, there just might be something to it, don't you think!?
Thanks
brad
01-24-2011, 02:50 PM
#87
MBWorld Fanatic!
That picture that evosport posted is NOT from an e55k pulley.ASP has 2 pulleys,a true asp that is a modded stock pulley and one that is made to eurocharged specs thats not using a stock pulley to start with.
For what its worth,Iv asked evosport many times to show me a failed modded e55 pulley and have yet to see one,at least of the newer gens that are out there.
They have made claims that all modded pulleys will fail and basically **** talked about every vender selling a modded pulley to make there design look better and scare people out of buying another brand.
That picture isnt even a e55 pulley.
Iv been there and I want to help you out,it looks like you just want a fun car and want it safe and not wanting to break any records ect.My advice is,if you dont get my pulley to call Cory at kleemann usa and get there stage 1 kit.
It is by far your best option for quality and reliability.
stage 1 is a kleemann 168 pulley and there perfect tune.You will love the car and it will 100% solid and safe.
For what its worth,Iv asked evosport many times to show me a failed modded e55 pulley and have yet to see one,at least of the newer gens that are out there.
They have made claims that all modded pulleys will fail and basically **** talked about every vender selling a modded pulley to make there design look better and scare people out of buying another brand.
That picture isnt even a e55 pulley.
Iv been there and I want to help you out,it looks like you just want a fun car and want it safe and not wanting to break any records ect.My advice is,if you dont get my pulley to call Cory at kleemann usa and get there stage 1 kit.
It is by far your best option for quality and reliability.
stage 1 is a kleemann 168 pulley and there perfect tune.You will love the car and it will 100% solid and safe.
Last edited by skratch77; 01-24-2011 at 02:55 PM.
01-24-2011, 03:10 PM
#88
That picture that evosport posted is NOT from an e55k pulley.ASP has 2 pulleys,a true asp that is a modded stock pulley and one that is made to eurocharged specs thats not using a stock pulley to start with.
For what its worth,Iv asked evosport many times to show me a failed modded e55 pulley and have yet to see one,at least of the newer gens that are out there.
They have made claims that all modded pulleys will fail and basically **** talked about every vender selling a modded pulley to make there design look better and scare people out of buying another brand.
That picture isnt even a e55 pulley.
Iv been there and I want to help you out,it looks like you just want a fun car and want it safe and not wanting to break any records ect.My advice is,if you dont get my pulley to call Cory at kleemann usa and get there stage 1 kit.
It is by far your best option for quality and reliability.
stage 1 is a kleemann 168 pulley and there perfect tune.You will love the car and it will 100% solid and safe.
For what its worth,Iv asked evosport many times to show me a failed modded e55 pulley and have yet to see one,at least of the newer gens that are out there.
They have made claims that all modded pulleys will fail and basically **** talked about every vender selling a modded pulley to make there design look better and scare people out of buying another brand.
That picture isnt even a e55 pulley.
Iv been there and I want to help you out,it looks like you just want a fun car and want it safe and not wanting to break any records ect.My advice is,if you dont get my pulley to call Cory at kleemann usa and get there stage 1 kit.
It is by far your best option for quality and reliability.
stage 1 is a kleemann 168 pulley and there perfect tune.You will love the car and it will 100% solid and safe.
01-25-2011, 02:52 AM
#89
MBWorld Fanatic!
01-25-2011, 04:56 AM
#90
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you cant go wrong with ASP 180. i measred its weight and other brands that are moddifed.
although ASP use stock pulley and replace the outring i think the holes that were there is to reduce its weight. it wieghs less by 0.6kg = 1.32 lb.
i don't know how much does stock pulley weighs. but i think someone can do this if he has them.
although ASP use stock pulley and replace the outring i think the holes that were there is to reduce its weight. it wieghs less by 0.6kg = 1.32 lb.
i don't know how much does stock pulley weighs. but i think someone can do this if he has them.
Last edited by Ali_E55; 01-25-2011 at 04:58 AM.
