R56 Crank pulley Test and Tune

We here at ALTA have done lots and lots of proving of parts over the years. 99% of the time parts do exactly what we want, or they do almost what we want and we modify them to make them work better. Nearly every part we have we have dyno graph for it to back it up. The R56 crank pulley is no exception. Just like our other parts, we have a very good back to back run to show how it works..... or doesn't work......

Our concerns with a crank pulley are that removing the harmonic dampener might cause damage (very rare cases on new engines, but still something to prove) and the fact that some engines produce more engine noise causing the ECU to pull timing. The second concern is easily seen on the dyno with rapid changes to torque. With both of those things said, the ALTA prototype R56 pulley has shown neither to be a concern.

There are calculations for how much HP a lighter crank pulley or flywheel will make based off the diameter, and overall weight removed by the part. With that said on every engine we have seen, we see about 5WHP gained from a lighter crank pulley. But this was the first time we had done a test on our own dyno.

Before we get to the results, its important to mention the difference in weight and construction. The OEM pulley is contrusted of 3 pieces. One is the inner steel par that contains the mounting flange for the crank. This piece is a not so precise stamped piece of steel. The outer part is a machined piece of steel also. The third part of the OEM crank pulley is a rubber band that is molded between the 2 pieces. This is the harmonic dampener part of the crank pulley. It even has the frequency at which its designed to dampen at, written on the band! This is a long standing argument amungst enthusiests about the harmonic damper actually being necessary. Our opinion is time will tell. The R56 crank pulley is ligher than the stock part by about 5 lbs or so.

Like other tests, we ran our 08 R56 at least 5 runs, to show consistency, then as quick as possible swapped the pulley and did 5 more runs. All with the same times between runs and all that other stuff to keep it as consistent as possible. In order to make this as quick as possible we pulled out the fender liner ahead of time and prepared with the tools we needed!



It's a little hard to tell by the graphs, but we eliminated the first and last runs and picked the middle runs to show off the power changes. As you see (or maybe don't see) the power changes are not really there.

Yup, that is right, it didn't do anything! Well if the calculations show it will make HP to the wheels why didn't it on our dyno? This could have to do with the fixed amount of time the dyno runs. Meaning on a roller dyno with no load cell, the lighter pulley would allow the engine to accelerate the drums faster, and it would calculate more HP to the wheels. This is just like when you change the wheels on your car (lighter ones of course), it gets faster and makes more HP to the wheels on roller types of dynos.

We know for a fact the crank pulley will increase throttle response which isn't a measurable thing on the dyno, and definitely something that can be felt by the driver. So while this part didn't make power, we are going to do further testing to ensure the engine and ECU stay happy with the pulley installed. In the next few months you will see our pulley either go up for sale, or an announcement that the part isn't going to be built. But with the time we have on it right now, I can bet you will see it for sale, not in the crapper!

 

Thanks Jeff for that post! People had been asking for a while! Nice to see honest and concise results that people can make an educated decision when the item is available.

The cost of the part VS. a lightened flywheel is certainly going to be enticing, as is the ease of installation vs. the flywheel. Similar improvements in throttle response as well. I noticed it when I got back in the car!

 

Thanks for the honest results guys! It's good to see vendors being upfront about their testing of parts like that.

Hijack--->Now share with us more info on the status of the GT25 kit!!!!

 

Awesome post about a good product testing.

 

I think you had better check the scale you weighed the stock part with!

Also partially as you quoted, rotational weigh decreases need to be measured on an acceleration dyno. You will be able to see what the actual weight redcution translates to in HP based in decrease in acceleration times.

Shawn

 

Thanks guys! More to come!

 

Everything is in motion, but its going to be a while, we need to work out the bugs with some of the newer 08's and Unichips on them. After that is all sorted out, you will see it for sale!

 

I don't know if it is possible but with an item such as a lighter flywheel or pulley doesn't it allow the engine to rev faster. So a better measurement would be time to rev level

In effect, if it takes x amount of time to move from 2000 - 5000 RPM stock under a load then with the lighter pulley it takes y for the same.

Also while the swap of a single pulley does not really show on dyno as a HP increase is it not part of a holistic approach where multiple small gains add to a larger gain. For example while a pulley alone shows little gain, and possibly a flywheel alone show little gain the combination will show a more significant gain. This being one of the rare instances where mods build on each other.

 

[quote=gnatster;2337793]Also while the swap of a single pulley does not really show on dyno as a HP increase [quote]

I beg to differ! Dyno Jets show gains just fine big gains and small gains depending on engine size, mods and NA or forced induction.

Shawn

 

Exactly! We thought about doing a rev test, but we knew that guys would ask about the HP they make. And since our dyno didn't show too much difference we left it at that and continued on with the long term testing. At this point it is something we are going to make, as long as things go well over the next month or 3.

 

A small HP gain is very hard to show on the types of dynos we have access to. Slight anomalies between runs mask the results.

It would take an engine dyno in a closed cell to create accurate reproducible results

 

Yeah if Jeff and I can come up with a reasonable testing methodology for the rev speed, then we will certainly do that and publish the results. I can say from moving the car around in the lot, you can tell the difference.

 

Does Alta pulley fits to R56 cooper non s???

Any benefit???

Thank u..

 

We have not checked that yet. Hope to VERY soon!

Thanks for asking!

 

Yup its the exact same part, and it should make the exact same changes to engine responsiveness. I would say that if we dynoed it back to back, it would show the same results as we saw on the turbo car.

 

Thank u very much...

When will the pulley release ???

I would like to put it to my cooper non s R56...

 

Jeff should poke the GO button today. That would make it 2-4 weeks.

Thanks again!

EDIT: Jeff mentioned we need to do a bit more time on road testing, prior to machining. So lets add another month to that estimate. MY bad!

 

all i want in life is to rev faster!!!!!!!! even without a hp increase, the decrease in rotational mass is a nice concept. i hope all goes well and we see this part forsale very soon. im a bit annoyed that over a year into the r56 model line, the market still is pretty slim pickins for hp &tq upgrades. however Alta seems to be doing their part to contribute so thanks guys.

 

Thanks matt! Let me know if I can ever help further!

 

Will u have an oversize pulley like the old model???

 

Not likely as that would only increase drag and speed up accessories. Not a great plan for building power on a turbo car. On the S/C car then it built more boost.

Thanks again for asking!

 

Doesn't matter if it's a "no load" inertial dyno or a unit like the dynopak. If there is a delta RPM/ delta t measurement rotational mass changes will show up. Think about it as partitioning the work.... A certain amount of the work goes into changing the speed of the parts over the given time. The rest is dealt with by the dyno. If you do a change where it takes less of the work to do the same change of speed of the parts over time, the dyno has to deal with "extra" work making out of the cars driveline.

What would be nice to see as well is the 5 runs for each state in separate graphs. That would give us some idea about the basica repeatability of the measurement and the measurement resolution.

What I'm guessing is the power change is small, and it's smaller than the measurement repeatability, so it's hard to resolve....

Matt

ps, all the debate about dampener vs non-dampener will have to be repeated again.... This is a different block/crank combo and we have little insight into the designers intent. On the Tritec, that wasn't the case. I guess cars are like fasion.... They repeat in cycles!

 

waiting!!

 

I have several hundred miles on the pulley. When Jeff says enough is enough, we will go poke the button on the CNC machines.

Sorry for the delay!

 

Ok, fine, its good to go!

Even though it may only have 1000 miles on the car, things are going great, nothing is going wrong no CEL's for misfires or anything. While it may take 5 years of solid use to figure out if the pulley is 100% ok, we feel that its just fine. The engine runs just as smooth and makes it a bit snappier, its time to poke the button! Expect parts to show up in a few weeks!