I searched.

Anyone out there running this combo?

I'm on the fence between 15% and 19%. Daily driver. Spirited drives on the weekends. Zero track or AutoX days.

 

Great setup, I ve had MTH for a few weeks now, runs well. But will change to 15% for track. For your needs though, perfect...just dont push the redline

 

A 19% pulley sound like the ultimate. I'm just driving my car on the street and haven't tried autocross or the track yet in 1 1/2 year of ownership. Considering the positive 19% feedback here I should have gone for it. When I decide to go try autocross I'll do the 19% but for everyday driving I like the 15%. Did the 15% pulley 25000 miles ago and have 1500 miles with mth.
I read here that with the 19% the boost realy kicks in at abaout 3000 rpm's.
I do most of my driving at 70 to 75 mph on highway and that is in the 3000 rpm range. I want to keep my fuel consumption low and no driveability funkyness. I'm very pleased with the linear power of the 15% pulley and still get 30 mpg. I would probably find miself over reving the engine with a 19% pulley and prefer the higher redline aspect of the 15% just for the pure joy of reving an engine. Here is what I'm running:
Helix 15% pulley.
Alta intake.
Mth tunning.
Milltek catback.
Kosei k1/falken ziex 512 for a considerable weight reduction.
Perhaps the 19% is the ultimate but the 15% does not feel like a compromise. I'm very pleased with how is turned out, it is much better than stock. That is my humble experience and take, hope it can help you in your decision.

 

What is MTH?

 

lol

its a car chip tuning, do a search in the performance mod drivetrain and you will find all the defenition you will ever need

 

One of the drawbacks of the 19 degree pulley is that it does make the engine much noisier. Maybe that's not a problem, but sometimes I just want the car to let me listen to the HK sound. The other thing you need to check out is who makes the 19 pulley you're interested in. Some problems have occured - mainly spinning the drive belt off the pulley inspite of the tensioner. This was explained to me that the real problem isn't the higher rate of rotation but the actual materials employed to make the pulley. Many of the pulleys are constructed out of aluminum and treaded onto a steel shaft. After time electrolysis sets in and begins corroding the aluminum causing it to get out of round. This could also happen with a 15 degree pulley, but because of the speed of rotation is less likely.

 

Really? Unless you're near redline, it's not spinning the supercharger faster. I don't think it's much louder than the 15% personally.

 

I've never heard of the noise complaint before, but I suppose the SC will make more noise with a reduced pulley because it is working more. Certainly not a problem for me...

Really? Unless you're near redline, it's not spinning the supercharger faster. I don't think it's much louder than the 15% personally.
__________________
Helix 19% pulley, UUC exhaust, Madness intake.
Once you go 19, you won't go back.

The smaller reduction pullies build more boost because they are spinning the SC faster. At least that is what I always thought. Just like the smaller tires on my car need to rotate more to traverse the same distance, so would a smaller pulley. Noise and heat will be by-products, along with the boost. Heat, enough to be an issue... sound, I guess so, but most seem not to mind, and actually like it...

 

I've had this combo running for a couple weeks now. I love my 19% pulley. But I'm a bit disappointed that I've felt no performance difference with the 91 octane MTH map from Franz. The new map did get rid of my cold engine bog/hesitation though (and I never had a yo-yo problem). Power delivery is more progressive... that is, there isn't that "bang" of instant power at about 3500 rpms that makes me grin so big. Without a dyno or nice history of timeslips, I have no way to tell if I'm actualy seeing an increase in overall WHP. So far I like the "feel" of the stock map.

Franz also sent me a 94 octane map. Once I figure out where in Italy I can acquire European 98 octane fuel (same as 94 in the USA), I'll give it a go. If I can't find it, what's everyone's opinion on "Octane Boost"? Worth a try?
Ciao!

 

Randy Webb shared some time ago when experimenting with the 19% that a map would have little to offer, with the exception of a rev limiter.