Has anyone done a head to head comp on diff pulley sizes and or brands. I havent beenable to find anything here. I thin a lot of people would be intersted. As well as maybe a ecu head to head. mc2 should maybe look at this.
any info appreciated

 

An ECU head-to-head would be nice. However, a Pulley head-to-head would be worthless in my opinion. They are all the same diameters and basically the same design. I don't think one is any better than the other. Just pick your favorite brand, as many people say.

 

it's left as an "excursize for the student" to find it.....

But it's out there.

Matt

 

Try here for starters.

 

My experience with a 17% s/c reduction pulley (on an otherwise stock MCSa) seems to track to Andy's chart - I definitely have more boost (as expressed in my seat-of-the-pants dyno) at lower rpms (~3,000) than with the stock s/c pulley at higher rpms (~5,000 - 6,000). Where previously I would have to run up to 5,500 - 6,000 rpm to get the car to really move, 4,000 rpm gets the job done. This might be one explanation for an increase in the gas mileage (after the initial period of exploration of the new-found power is completed) - you are spending less time in the higher-rpm ranges with the s/c reduction pulley on....

 

now for a aggressive street driving, never going to the track, what are the down sides of a 19% pulley and what else is need at the same time, ie:plugs,ecu, injectors

andy's chart is great thanks copi

 

Um, there are no downsides to the 19% pulley other than the heat issue with the belt which doesn't allow you to track because of the continuous time spent in the upper RPM range (4000-redline). Colder Plugs are definitely recommended with the 19% Pulley even more so than with the 15% and 17%. The ECU and Injectors are NOT necessary. Yes you will get even more power and be able to really use the 19%er to its full potential but it's NOT necessary. If you have the money however, go for it, I would've if I had the funds, that's the only reason not to IMO.

 

i have read here that the 19% spins the supercharger out of its efficency range. there has to be some down sides to it if jcws didnt use it and ost of the big tunners dont recommend more then a 16%.

I am just very confused, seems there are so many differant opinons and few facts. it would be a nice artical for mc2, pulley tests each size with what else needs to be done to be safe. ie: plugs injectors. DOc try this one next after the ecu stuff. I leanered a lot from your ecu articles.

 

wow don't bogart that joint man pass it to the left hand side.

 

the nail on the head as it were.

 

JCW doesn't use it because the 14.?? % pulley is a more moderate upgrade. For daily street driving your fine. I live in Florida, with hot temps in the summer and I didn't have any problems with my 19% pulley. There have been zero reports about something happening DIRECTLY related to a 19% pulley. People talk shyt about the TC kits too, and nothings gone wrong with one of those either. Basically, people will praise one MOD that the majority like and talk shyt about the not-so-common MODS.

 

nothing big has gone wrong with the TC kits yet. but wait till someone turns the boost up that one time. nothing has gone wrong with the 19% because all it does is moves when the boost kicks in lower into the rpm range. if you go up to redline it hampers performance by spinning the supercharger too fast and heating up the air too much. thats why most tuners go with nothing bigger than a 15 or 16%, much better for the track where you are spending time at redline

 

TC kits have been out for a LONG time. And several people have turned up the boost, running anywhere from 350whp to nearly 600whp. As far as turning up the boost with TC kits, so long as you do it properly (uprating pistons as they can't handle high boost) and get the right injectors you won't have any problems and that's been proven. Oh and, when running really high boost and going for high HP numbers, race gas is usually necessary. You're wrong about the 19% pulley, it also creates more boost at redline, although you see higher IAT's there is still a power increase at redline over the 15%,16%, and 17%. The reason the 19% is not used for the track is because when in the upper RPM range for extended periods of time, as on the track, the heat on the pulley becomes too much for the belt to handle and it will snap.

 

ohh. that is what i meant to say about the tc kits. i was talking more about the person with a stock car turning the boost up to much. and i didnt know that about the 19 pulley.

 

Yeah I get what you mean about the base TC kit on an otherwise stock car (internally) and raising the boost. But then, that engine failure would be a result of negligance and improper engine build. Not as a result of the TC kit itself. There are TC kits meant for higher boost, stage 2 and above that include uprated pistons and the necessary injectors. For example the SPI kit, the one that FBT sells, has a stage 2 kit that is good for almost 300whp as it sits.

 

What are you trying to compare? MCS used for:
Track
Autocross
Drag racing
Street driving
Mixed driving
Driving school

For many of these you can only rely on lap time or run time and ease of use.

When on the track, at autocross or any with any performance driving event it is the skill of the driver that makes the most difference. So you'd need the same driver do several runs in the same MCS with the only difference being the pulley size. You'd have to correct for outside temperature and tire temperature, etc.

Just because you have different sized pulleys in different MINIs you cannot easily tell if that will make any difference at all with how the car performs.

Indeed there can be times when a skilled driver in a stock MCS will out perform a less skilled driver in a modded MINI.

From watching many stock and modded MINIs at the track, autocross, and at driving school the presence of a reduction pulley or it's exact size isn't that important and generally doesn't make that much difference.

The exception would be in the hands of a very skilled driver any reduction pulley upgrade from 15% to 19% would give a little more torque and HP that could be measured on a drag strip or at the track provided there are no other limiting factors on the MINI being tested. Same with various ECU upgrades.

An example-
A stock MCS with only 15% pulley upgrade vs one with only 19% pulley upgrade will have only slightly more torque and HP and on the street should function about the same. The more mods you add the more you can begin to take advantage of the 19% pulley but without the added mods you have a more muted benefit.

By the way, a 19% pulley upgrade alone is fine for street use, belt wear varies with using high RPMs when driving. If you drive normally you will be fine.

So what does this all mean. Generally the pulley or ECU upgrade you choose is up to you and how you want to use your MINI. Unless you are drag racing or doing lots of track work on a big track it won't make that much difference what you add.

Your driving skill will likely be your biggest limiting factor followed by your wheels and tires. The ECU upgrade should be matched/tuned to the pulley upgrade you have for the most benefit. The 19% pulley also does best with ECU for 19%, larger fuel injectors, colder spark plugs and smaller pulley belt. However that setup is better suited for the track or drag strip than for street use or autocross. If you use it for street use you can find that your mpgs are less for your trouble.

 

All of these questions were answered a long time ago... in a forum not unlike this one.

The systematic test of pulley sizes was one of Webb's original undertaking back in 03. After talking with the guys who make the Eaton, Randy obtained the efficiency charts of the M45, and started testing sizes to try and match the pulley reduction to the correct RPM for the blower. I believe he started with a 10%, guessed 12% to be the sweet spot, and traveled all the way to 19% in search of that magical %.

Well, he found it on the 15%. He tested the pulleys both on the dyno(paying strict attention to IAT in order to get repeatable results) and also at the track(RIP second Creek ). What he found was once you get towards 17% and up, the power would drop off up top. Why? Since the M45 was out of its own efficiency range, the temps being spit out of the blower were high enough to cause the ECU to start dumping fuel in order to keep the cylinders cool. In turn, not making any more power than lower % pulleys.

And as most people know... Not only did the belts break one after another(due to the heat and the major angle the belt was being asked to turn through), when using the 19% after a couple laps, the oil temp sensor started to jump. What he found out was that the water pump(which is directly attached to the back of the blower) would start to cavitate, and stop the flow of coolant through the engine at those upper RPMs. In turn, the oil cooler, which is cooled by the flow of water, would then not transfer its heat. This is a bad thing...

Would anyone like a picture of an M45 whose rotors have machined into each other?

So to add to the debate, why would you want a pulley that will not allow you to use the full RPM range?

-Brian

 

I would like a picture, think it would look cool

 

Well, if you are not going to be tracking your car and want more low end grunt, a larger than 15% pulley may make more sense. Even when I am driving spiritedly, I don't see much beyond 5,000 rpm. (5,000 rpm in the curvies will have me over the side of the road going down a ravine....) With a 17% pulley, I am finding a sweet spot around 3,000 to 4,000 rpm that matches quite well to the roads in my neck of the woods. With a CAI and cat-back, the 17% pulley is my E-ticket ride (and for a whole lot less than a JCW kit). I could have similar levels of fun with a 15% pulley; I just can have more fun with the 17%....

 

My boost STOCK is 8 lbs.. till I really rpm and then it is 10 PSI!! my friend has a Altra 15% blower and 2% crank.. and his boost is 12 psi moderate and 15 under hard accel!! %%% duh.. the results are 10 PSI to 15 PSI... cool??
Oh yeah, with Thumper Head he is at 200+ wheel hp with his pulleys and stock intercooler!! cool ??

Just me.........................................

Thumper

 

Cool!