I finally got a chance to get my car out today and test out the new 17% pulley I installed. It had the factory JCW pulley on it before.

It's definitely making more boost now...it was peaking out around 12.5-13psi of boost with the JCW, and now with the 17% pulley it's closer to 16psi of boost.

Even though it's making more boost now....it really doesn't feel like it's pulling much harder than it did with the JCW pulley when I run it through the gears. I was expecting a big boost in HP and TQ.....but to tell you the truth, it pretty much feels just like it did before.

I guess I would have noticed more if I had a stock S pulley before instead of the JCW pulley?

 

there isnt a huge difference between the stock jcw and the 17%. im not positive but im pretty sure its only around 3.5% or so.

depending on your budget, and what you already have/dont have, i would suggest a cam, header, and tune.

again, it all depends on your goals for the car, but those 3 things would definitely put a significant amount of pep in the pedal.

if you dont plan on adding anymore aftermarket parts, getting a tune is where you will feel the biggest difference in daily driving.

on a sidenote, non engine related... if you havent already done so, i would also suggest springing for some lighter wheels and ditching the runflat tires.

to basically answer your confusion, you are correct that the 17% is for sure a worthwhile upgrade, but coming from a jcw pulley, not a huge increase in power.

depending on your location and what kind of time frame you are working with... if you decide on a tune, i personally went with Jan from RMW and i am very happy with the results. ive put about 5k miles on since the tune and have had no issues.

 

Hmmm, does seem a little strange, a 2.5lb difference in boost should be pretty noticeable, but one thing is to give it a little more time so the ECU had some time to adapt to the extra boost and possible make more use of it. (Don't forget you went from ECU making the best out what you "had" from having to adjust to the new setup)
As far as tuning, the one thing for sure is that if you work out a way to get it done, you'll know for certain that you're getting the most out of what you have.

 

I don't think the JCW pulley is even 11.5% so going to a 17 should be bit more noticeable but your Boost gains sound ok. How smooth / fast does the boost spool up ? What size belt did you use with this swap out.

If you examine the hydraulic belt tensioner's metal strip thru the spring at the top, you should just about see the top edge of a second hole showing and using the equivalent of a NAPA 060532 belt.

Also, 03' JCW kits didn't include JCW fuel injectors unless the "sound kit" was added later on....any idea if your's has them or not. Would be a worthy upgrade to add more fuel when increasing air flow.

The JCW 200 hp kit is what most folks had installed initially.


The JCW 210hp kit comes with additional 380 injectors and JCW Airbox.







The Sound or Upgrade kit for the 200HP JCW equipped R53.





And while some may have installed this air box, it can be purchased separately so not a reliable indicator injectors are present as well.

 

I have the 200hp JCW kit....so it's got the 330cc injectors, not the 380cc injectors. It definitly builds more boost at lower rpms. Yes, I used the 532 belt. I'm getting around 13psi at 3000 rpms, and before I was only getting around 9psi. Everything is working like it's supposed to....but like you said, maybe the ECU needs to adjust. I'm definitely not disappointed with it....I just don't feel a huge gain.

 

DME takes about two tanks or 600 miles I think to re-learn. Or just do it manually using your display. Some instructions here: DME Manual Reset

 

Here are a few graphs a made after doing some data logging. As you can see, I'm definitely getting more boost at all rpms. What I found interesting though is that you can see the motor pulls harder in the mid range, but after a WOT run in 3rd gear....both the jcw pulley and 17% pulley ending up getting to 6000rms in the same amount of time. In other words.....0-60 times for example, would be the same.....but you are going to see more midrange pull from the 17% pulley, then it ends up pulling less that the JCW pulley at the higher rpms.

I guess that's when the hotter IAT's start overcoming the additional boost and start taking power away. You can definitely tell it's got more midrange pull....which for a daily driver car, it what I was wanting.

 

Did you change to a smaller belt? Perhaps there's belt slippage with the smaller pulley. A 3psi increase is something that should be felt; it's not drastic, but is significant.

 

iats def play a big role. i would also check your tensioner assembly.

when i went for my tune, the car was putting out strangely low numbers for the parts that are in it.
we found the belt was slipping (it was brand new) at high rpms, due to the shock style tensioner being worn.

we installed an entire new tensior assembly and then put down an additional 18hp.

if you have the resources to test, make sure that belt isnt slipping. itl rob you blind at top rpm.

 

Yes, I'm running a new 532 belt.

 

Well, I've put around 500 miles on the car since I did the pulley install. I guess the ECU is finally starting to make adjustments, and "learn" the new pulley. It feels like it pulls a lot harder in the mid range than it did when I first took it for a test drive. At first I wasn't all that impressed with the 17% pulley, but now the motor seems like it's really got a lot more grunt

 

This post is full of great info! I had to have my charger rebuilt and while it was out, I had the 15% WMW removed and replaced with an Alta 17%. The car pulls strong but it doesn't seem as snappy in the midrange. Now I know why. Not worried about the belt tension, I used an Alta manual tensioner replacing the flimsy damper. I'll reset my ECU and see what happens. Great info guys.

 

I have a 17% and felt a HUGE difference. But I also have a GP intercooler and did an ATI (which is said to be a 1% overdrive).

 

jealous. i have the same gauge, as well as a 17% and a 2%, along with many other things including w/m injection and a tune. my boost peaks at like 16psi. 18 would be nice.

probably a minor leak somewhere or s/c on its way out.

also, the blue led never comes on when it hits max. could something be wired wrong?

 

I get more boost if I 'no-lift' shift. Plus it was like 20*F that day.

Also the blue light is for peak, when you 'over boost' the gauge numbers and dashes will glow red. Out of the box it's set for 25psi. You can adjust it down if you want to see it glow.

To see blue, just hit the PEAK button and it'll display the highest boost reading.

 

do you remember how to adjust it by any chance?

i have my gauge set so that when i turn the headlights on, the numbers and dashes turn red, and white when the lights are off.

i would like to set that blue peak light though. if you know how itd appreciate it. i think i tossed out the manual.

 

nvm. found it on there website.

 

Ok cool, I was gonna scan the instructions if needed..

 

Did you go from a JCW pulley, or from a Stock S pulley?