BMW M5 Forum and M6 Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Hello everyone. Please forgive me for asking if this question has been answered before. Which pulley and why would you recommend? Evo Sport or RPI? Thank you in advance for your responses
 

·
Registered
Joined
·
221 Posts
i just purchased TMS seems liek they all look and weigh the same also same material ....
 

·
Registered
Joined
·
966 Posts
I just installed evosport pulley and did before and after dyno. Saw almost no gains and that is supposed to be one of the highest rated, lightest, and best pulleys. I would say save your money. I'm gonna post a dyno in my thread soon.
 

·
Company Representative of RPI Power
Joined
·
3,394 Posts
So that people are not mislead, here is the correct info on dyno testing products that change drivetrain weight and or drag:

http://www.m5board.com/vbulletin/e60-m5-e61-m5-touring-discussion/173108-pulley-choice.html

Just a reminder: as mentioned many times in this forum, eddy current braked dynos will not show power differences with drivetain weight/drag changes. This includes Mustang dynos and DynoDynamics dynos. Only inertial dynos measure that.

Lemme take a quick guess as to what kind of dyno that was measured on...
<!-- google_ad_section_end -->


Loss of drivetrain weight doesn't really add power. Your engine is putting out the same amount as before. This is what an eddy current braked dyno is measuring.

However, when you lose drivetrain weight (or more precisely, drag), your car will accelerate more quickly. An inertial braked dyno is measuring this accelerative force (you're basically turning a big heavy drum).

So does a pulley add power? No, not really. However, does it change your rate of acceleration in the same way adding power does? Yes, definitely.

Lighter wheels/tires have the same issue/effect. They allow you to accelerate faster, but do not add to your engine horsepower.

Your dyno operator should have explained that to you, and he did a disservice to you by not. Dynos are GREAT tools, but they're only that: tools. How they're used and how the information is presented to you really determines what you, as a customer, gets out of it.

I hope this helps!
<!-- google_ad_section_end -->
 
1 - 5 of 5 Posts
Top