[Andy@Ross-Tech.com]

I want to thank Helix13 for their outstanding work today, installing the 15% P&D supercharger pulley. As always, Helix did exceptional work, and I was able to get very valuable dyno results and A/F results. I'll post a full writeup tomorrow (with lots of pics and dyno graphs!) but for now let me say this. This pulley is the Dog's Bo11ocks! A very worthwhile performance mod, no doubt the best bang for the buck out there. On the way home, I was spinning my 17"s from a roll, laying patches of rubber while barely trying.

P.S. jlm gets big-time kudos for the excellent design and workmanship of the pulley!

[GordonD]

Quote:

Originally posted by Andy@Ross-Tech.com
On the way home, I was spinning my 17"s from a roll, laying patches of rubber while barely trying.

Tire Rack also wants to thank Helix13 for their great work

[jtucker]

Eagerly awaiting those dyno charts...

[Andy@Ross-Tech.com]

Sorry for the delay, guys. Here are the dyno charts as promised. Here's the big guy - I drove in with 144.1 whp and drove out with 161.7 whp. This is a comparison of stock pulley/stock chip to Helix/P&D Pulley / MTH Chip:



Totally smooth, A/F fine, very rich just like stock. The power increase is noticeable at all RPM. I'll post more later, but for now, off to work.





Looks like the chip is good for a few whp and the pulley is good for at least 10 whp. Torque gains are awesome!

[jtucker]

Nice! So... what kind of $$$ are we talking about here for the pulley and chip? Or, should we just call Helix to find out...

Picking up my MCS today... I need to start pondering goodies like this!

[MiniShuttle]

OK, help for the hotrod newbie. what is a/f?

[jtucker]

Air/Fuel ratio.

[Andy@Ross-Tech.com]

jtucker wrote:

Quote:

Nice! So... what kind of $$$ are we talking about here for the pulley and chip? Or, should we just call Helix to find out...

Picking up my MCS today... I need to start pondering goodies like this!

You'll need to contact Helix for pricing info, but is definitely a cost-effective mod! I'm looking forward to seeing how intake and exhaust increase the gains even more. My plan was (still is?) to keep the MCS in GS, but the power is SOOOOOO much fun, it will be sad to switch back to the stock-sized pulley.

MiniShuttle wrote:

Quote:

OK, help for the hotrod newbie. what is a/f?

See this thread:

http://www.mini2.com/forum/showthrea...threadid=24211

[jlivingood]

Quote:

Originally posted by Andy@Ross-Tech.com
I want to thank Helix13 for their outstanding work today, installing the 15% P&D supercharger pulley.

I stopped by at 7:30pm since I had a hunch these guys were still at work - and they were. I watched the final dyno runs and was impressed with the #s on the dyno. Looking forward to this kit being wrapped up so I can get mine!!

Jason

[Andy@Ross-Tech.com]

Jason,

You missed all the fun. Quick quiz - what's missing in this picture?

[friedduck]

That's easy, chome & neon ;-)

Jeff

[ram_one]

Quote:

Originally posted by Andy@Ross-Tech.com
Jason,

You missed all the fun. Quick quiz - what's missing in this picture?

Half your car?

[TomM]

Intercooler is missing - front bumper is missing - and lots of other tidbits.

[jlm]

like the thread namesake and what it attaches to.

[chiph]

Needs a wash.


On a more serious note... what's the deal with the rise in the A/F mix at the top of the RPM scale? Is that an attempt to roll off the power so you don't bounce hard off the rev limiter?

Chip H.

[jlivingood]

Okay, so since I am not an automotive engineer (systems engineering won't help me this time) I am taking this step by step to make sure I understand it.

I notice at the graphic on "Air Pressure vs. RPM" at http://www.ross-tech.com/Andys-Stuff...oostplot01.gif that there is a pronounced difference between MANIFOLD PRESSURE and UPSTREAM PRESSURE. I am assuming both of those measurements are before the air reaches the supercharger.

So, my question is two-fold.

1. Where specifically is each of these things measured? (I assume this is being pulled from your OBD2 tool by the way.) I know generally but I am curious where the sensors are placed.

2. What do you think explains this difference - the twists and turns the air takes or some issue in the transfer of air out of the airbox?

Thanks!
Jason

PS - Anyone have a link to a MCS engine schematic of any kind? Having trouble finding one for reference sake.

[jlivingood]

So onto a/f ratio. Read your informative post over at http://www.mini2.com/forum/showthrea...threadid=24211 on your wide-band O2 sensor.

It does not look like you are running too lean and your data show that even in stock form there's no worry of running lean. The ECU likes to throw fuel into that motor!

I know that one tuner has noted that running a smaller pulley with no chip would run the motor too rich and risk killing the catalytic convertor. However, your last graph comparing stock pulley / stock chip and smaller pully / stock chip seems to disprove this assertion.

Am I reading that right?

Jason

[Andy@Ross-Tech.com]

Quote:

Originally posted by chiph
Needs a wash.


On a more serious note... what's the deal with the rise in the A/F mix at the top of the RPM scale? Is that an attempt to roll off the power so you don't bounce hard off the rev limiter?

Chip H.

I don't think it has anything to do with the rev limiter since the A/F stops its plummet at around 6k. It may be the fueling limit of the injector/fpr combination. Even so, as noted, it's still very, very rich.

[Andy@Ross-Tech.com]

Quote:

Originally posted by jlivingood
Okay, so since I am not an automotive engineer (systems engineering won't help me this time) I am taking this step by step to make sure I understand it.

I notice at the graphic on "Air Pressure vs. RPM" at http://www.ross-tech.com/Andys-Stuff...oostplot01.gif that there is a pronounced difference between MANIFOLD PRESSURE and UPSTREAM PRESSURE. I am assuming both of those measurements are before the air reaches the supercharger.

So, my question is two-fold.

1. Where specifically is each of these things measured? (I assume this is being pulled from your OBD2 tool by the way.) I know generally but I am curious where the sensors are placed.

2. What do you think explains this difference - the twists and turns the air takes or some issue in the transfer of air out of the airbox?

Thanks!
Jason

PS - Anyone have a link to a MCS engine schematic of any kind? Having trouble finding one for reference sake.

There are two air pressure sensors in the MCS, one is before the supercharger and the other is after it. I logged these values using some prototype BiM-COM software. Remember, this is BMW/MINI specific and has nothing to do with OBD-II.

The one before the charger can be used to see the effects of the air filter and inlet piping. In an ideal world, that pressure would remain constant as airflow through the engine increased. Of course, this isn't the case, since the snorkel, piping, air filter, more piping, throttle body, etc. all lead to pressure drops. There is a great AutoSpeed article on "Negative Boost" that explains alot:

http://www.autospeed.com/A_0629/cms/article.html

[Andy@Ross-Tech.com]

Quote:

Originally posted by jlivingood
So onto a/f ratio. Read your informative post over at http://www.mini2.com/forum/showthrea...threadid=24211 on your wide-band O2 sensor.

It does not look like you are running too lean and your data show that even in stock form there's no worry of running lean. The ECU likes to throw fuel into that motor!

I know that one tuner has noted that running a smaller pulley with no chip would run the motor too rich and risk killing the catalytic convertor. However, your last graph comparing stock pulley / stock chip and smaller pully / stock chip seems to disprove this assertion.

Am I reading that right?

Jason

I'm not sure where the rumor about running rich came from. If anything, I was concerned about running too lean, but as you can see, that definitely isn't the case. The MCS is one of the richest-running stock engines I have ever seen, so the cat must be robust enough to take it. We all know how quickly our exhaust tips get blackened, even in completely stock cars.