Dropped by Helix Minisports today for some upgrades and a Dyno run. Thought I'd share it with y'all.



Baseline = Intake, Exhaust, 15% pulley, NO ECU
Test Run = Intake, Rogue Exhaust w/res, no inserts, 19% pulley, NO ECU.

Pulls like a freight train from 3,000 RPM. Check out the low end torque! Only 19hp diff. (:

Thanks Eric, fun day.
"The customer feels the difference."



Lots of stuff....saving up for better driver!

 

Why does the numerical results say peak HP with 19% pulley at 6750, when it looks like the one graph only goes up to about 6250? Also, those graphs look way smoothed, but I know that's how Mustang dyno's do their thing.

Very cool that you got almost 20HP out of the deal, wow!

 

Wow! I expected the top end with the 19% to start dropping, but it goes up all the way to redline!

How far is the supercharger being pushed over its redline with this mod?

 

19%.... seems to be calling my name :smile:

Peace,
D

 

>>
>>Baseline = Intake, Exhaust, 15% pulley, NO ECU
>>Test Run = Intake, Rogue Exhaust w/res, no inserts, 19% pulley, NO ECU.

Can you elaborate on the differences in the exhaust configuration? What do you mean by inserts?

 

>>Wow! I expected the top end with the 19% to start dropping, but it goes up all the way to redline!
>>
>>How far is the supercharger being pushed over its redline with this mod?
>>

I was surprised about the shape of the high end HP curve as well. Not only is the low end torque curve unexpectedly high but the typical peak and falloff of the HP curve not there. The torque is very noticable. I'm not really interested in the last 750 rpm unless I go to the strip. I will mentally drop my red line to about 6,250 RPM.

Reports from racers is that the supercharger survives very well even with long term running at or above is stated redline. I am a bit more worried about the water pump but don't expect to test its limits.

The baseline is one of Eric's typical runs with an intake, exhaust and 15% pulley. I don't know which brands he was running. My intake is a cheap generic brand and is nothing special. The hp and torque differences in the exhaust curves are not reported to be very significant especially in light of the differences we are talking about here.

My Rogue has inserts to quiet it down. Really don't know if these were stock or fabricated. Anyway, they are restrictive and were not installed for the run.

 

If your're interested, I posted some info on the supercharger pulley differences on the Webb Motorsports Forum

Basically, with a 19% pulley, the supercharger is spinning as fast at 6950RPM (stock redline) as a 15% pulley is at 7200RPM

Have fun,
Ryan

 

Holy crap! Note to self, 19% pulley ASAP.

 

must have been the Rogue.

 

Maybe it was a secret pea-shooter mod?

 

Hmmm... must rethink upgrade strategy...

15% for now, with an upgrade in the future. Sounds good to me!

 

Although I'd love to see the dyno of a MCS with 15% pulley and then 19% pulley right afterwards, 170HP at the wheels is pretty much what one would normally expect from the intake, exhaust and 15% pulley as that would equal the low 190's at the crank. So I CANNOT believe that going from a 15-19% pulley gave you 19HP!!! And more importantly - ANOTHER 15LBS of TORQUE - the same increase as stock pulley to 15% pulley?!!! Something's not totally accurate there - it just can't be. But I'm sure it really is noticeable and it really is tempting. Especially since I've been waiting for the GIAC chip for months and each month that goes by is really wasted since I put several 1000 miles on each month. I'm going to Helix sometime in the next two weeks for Eric to check and tighten up my new exhaust. This is going to be hard to resist!

 

>>
>>The baseline is one of Eric's typical runs with an intake, exhaust and 15% pulley. I don't know which brands he was running. My intake is a cheap generic brand and is nothing special. The hp and torque differences in the exhaust curves are not reported to be very significant especially in light of the differences we are talking about here.


Ahh, so these runs were actually made by two different cars then? Even so, the 19% pulley now has my attention.


Ryephile,

"Basically, with a 19% pulley, the supercharger is spinning as fast at 6950RPM (stock redline) as a 15% pulley is at 7200RPM"

I'd sacrifice 250 RPM for even half the reported torque gains of the 19% pulley!

 

I think eric has dynoed many, many pullied coopers which come in around 170hp, +/- a few hp. mine came in at 168.

 

I just peeked over at Randy's forum on this topic (note to everyone: we have enough forums already!!!), and I must admit, I absolutely DO NOT get it at all.

Look, what's wrong with going 19% reduction. Yes you probably should get a new belt, so that the tensioner is OK, but big deal. Yes, you now have the potential to overspint the SC, but if you're already on the ECU re-program tip, why not just set redline at 6500 or 6000...or even LOWER? Why wouldn't a 25% reduction pulley be awesome, if you could make it fit and you adjusted the redline accordingly?

Assuming that we adjust maximum engine speed in the process, what's the big deal? How would that be detrimental to the water pump or the SC or the gearbox or ANYTHING. We're not looking for max HP here (or at least I'M not). In this case, I'm just wanting to drastically alter my boost curve (is there such a thing?). I want to boost the boost at a lower engine speed. My biggest problem with the MINI 's engine is its lack of low end torque. My car takes off slowly. If I spin the SC faster at lower engine speed, then I get the SAME torque/HP that I would at 5000 RPM that I would get with a normal engine at 7000 RPM.

So explain to me how getting identical HP numbers would be detrimental to my car in any way! I just want the HP SOONER!!!

 

>>Ahh, so these runs were actually made by two different cars then? >>

Yea, sorry. Had a bunch of things to do that day and if we did a baseline we wouldn't have had time to do the final.

Eric has done so many runs with 15% pulley, intake and exhaust (the blue plate special) that he just went in and grabbed one. The range is pretty narrow according to him.

 

What version of Stock Mini software are you running? 34? 35? 36?

 

Chi -

That's my feeling too but the 19% satisfies both the drag racers and the track/autoX guys.

There's always that turn where you are bogging in second and a shift to 1st will just cost you time and spin the tires. This should help a lot!

There is enough torque that you can almost go up another gear (up one for the 15%, up 2 for the 19%). 12.5 lbs of boost at 3,500 rpm....that's why. Yea, higher cylinder pressures and more torque and hp will eventually take their toll on various components but it should not break anything quickly. But isn't that what its for?

I expect much more frequent belt changes. My shorter belt installed with the 15% had stretched significantly in about 4,000 miles and lots of events.

I think that we are nearing the limit for pulley reductions with the current designs. You have to have some metal to bolt through. We are getting close. Also the belt contact patch can only get so small until it slips.

Let's see...a one piece steel press fit 30% reduction with matching custom lightened toothed belt auxiliary pulleys and dampener. That should do a number on our head gaskets.

 

This 19% talk is CRAZY! I love it!

 

>>What version of Stock Mini software are you running? 34? 35? 36?

Doug - My car has never been to the dealer as I have heard they will flash you whether you want it or not. I am running what was installed on an 8-02 mfg date car. Sorry, don't know the number. Just a hint of stumble.

 

This may have been the case at one time. But with all of the stumble problems, dealers now, I believe, don't touch your ECU unless there is a problem. My MCS (28k miles) has been to the dealer 4 times I believe and they haven't touched my ECU.

 

mechanically, from a a drive point of view, 2*% is about as small as you can go. (I did make a few 22% pulleys) as the diameter gets so small. Problem is the belt has to wrap such a tight radius it will suffer from excess flexing sooner or later. Second problem is that the groove minor diameter is about 3/8" smaller than the pulley OD and that minor diameter has to clear any fasteners. I suppose we could make single piece press-on and get down to 30%...

Remember last winter when htere were a few worries about the pullied cars blowing a gasket in the hot summer...file that one with the water pump cavitation, blet wear, detonation fears.