JHM Over sized Crank Pulley

B8 S4
#21

:-\

#22

I thought I already knew lol maybe not.

#23

k0rn

#24

;D That wasn’t nice Jake…


http://i1012.photobucket.com/albums/af247/concordslim/image.jpg2_zps4zrgs5oc.jpg

Oh and the cars getting up there mileage wise :o. I’ve been testing these parts for 20k miles…

http://i1012.photobucket.com/albums/af247/concordslim/image.jpg1_zpsswgylcsu.jpg

#25

All I said was a band… :wink:

I see what you did there!

#26

I’ll update my first post also, but took measurements today prior to install…

Stock crank size is 6.385 inches or for the Canadians it’s 16.2179 CM… The oversized JHM is 7.00 inches or 17.78 CM…

#27

So if my grade 7 math is in tact, circumference is around 50.9 cm stock and 55.8 JHM, so a 9.6% increase. So 7000 RPMs becomes 7672 RPMs in effect.

What are the ratios on the stock and stage 2 SC pulleys?

#28

haha nice one

#29

[quote=“sakimano,post:27,topic:7932”]
Saki, Here you go… Courtesy of Mike from Chipwerks… lol

STOCK - 2.490 or 6.3246 cm
Unitronic - 2.296 or 5.83184 cm
APR - 2.273 or 5.77342 cm
Revo - 2.270 or 5.7658 cm
AWE - 2.266 or 5.75564 cm
CTS - 2.245 or 5.7023 cm

#30

primetime can you double check the stocker. the measurement i have is 6.225 which makes sense as the stock ratio is 2.5:1. The stage 2 rations are 2.75:1

Mike

#31

I’m only asking because someone on this site measured the AWE pulley at 57.15 and it is actually 57.55. Thanks, mike

#32

Mike, Yes, I can check again… We measured the JHM crank pulley lower portion as it was before the stock one was taken off the car, I doubt JHM changed the size? My brother used calipers and checked several times but I’ll have him check the true stocker, he’s been a tool and die maker for nearly 30 years so I doubt he got it wrong but I’ll check…

Spazz, I think you measured these I just can’t find the email as I’m in the office now… What did you get again?

#33

Based on these numbers, the JHM pulley is basically a replacement for an APR or AWE pulley. In other words it will push the blower just as much as the small supercharger pulleys.

Interesting development.

Running both in tandem might be a bit much for the blower RPMs wise, but I’m not sure as we haven’t seen anything formal from Eaton. If you buy an APR tune, and go ‘stage 2’ you have to also buy their pulley or they won’t give you their stage 2 tune. Same with GIAC and the AWE pulley I believe. JHM is an APR dealer, but again, this doesn’t help anything as you still need to pay APR $550, even if you already paid JHM $500.

So what good is the JHM overdrive crank pulley without a tune?

They’re working on a JHM 3.0T tune is what. No doubt about it now.

#34

Saki, Correct they’re all around 9.5% change… IMO which is based on data and conversations with folks, including people at Eaton, spinning the blower at the RPM’s the dual pulley’s will in short bursts, IE drag racing isn’t going to kill it. Yes, it will probably shorten it’s life but as I’ve said numerous times this is a toy to me. If I daily drove this car I don’t think I would do it. The key for me will be how the tune performs and if APR is willing to adjust anything if I get bypass. If not my brother will take the pulley off and machine it down by x% and reanodize it so that it doesn’t bypass boost and with an additional benefit of not spinning the blower as fast.

Not sure on JHM’s motivation as you’re much closer to them than anyone I know… I’ve offered them and I believe I said to CV I’m always willing to be a tester… Of course they’re in CA but CV is close… Either way with their results on the 4.2 cars it would be nice to see them produce a tune.

#35

Oh and + karma to Mike for being a good sport on my ribbing… Other than him pushing chipwerks I like what he brings to the forums… I personally would like to see him post over here more…

#36

Right on and thanks for taking the time to double check the measurements. I can update the blower rpm thread then. I’d like to get the max rpm and max iat data from Eaton for their 1320 and 1740 but can’t find it, just the performance map

Mike

#37

JHM seem to have ziploc mouths on this project so I’ve heard only what we’ve discussed in this thread

are we firm on the RPMs for the stock blower? If we jack up RPMs with 9.5% each pulley, there’s a compounding effect there. The 9.5% of the second pulley is +9.5% of 109.5…i.e. 119.9 and not 119. Yes?

If stock is around 2.5 x engine RPMs at 7000 = 17,500…one aftermarket pulley means around 19,160 RPMs, and two pulleys means 21,000 RPMs

Stage 2, at 7000 rpms, you’re hitting around 19,000 RPMs. For perspective, that’s where you’d be on stage 2+ at about 6400 RPMs. I don’t imagine most people move from 6400-7000 RPMs too regularly in daily driving, so as you say, short bursts are all the blower would see, and not very often. I hit 8200 in my RS4 every day, but maybe for 2 or 3 gears out of the few hundred gears I go through in a day.

have I got that right?

Here’s the compressor map…no mention of 21,000 lol.

http://www.eaton.com/ecm/groups/public/@pub/@eaton/@per/documents/content/ct_127898.gif

#38

I emailed you the radius oops - 89.4 and 81.7. That should have read 178.8 vs 163.4 (mm, like ze Germans use). Top of the ribs.

But I had to do 2 measurements for each on small calipers (all I had at home) using my perfectly flat ex-lab bench and a perfectly square metal calibration block. I am pretty consistent though, so I believe the 9.5% is right.

#39

Oh, I never measured the stocker- just the difference on the JHM pulley.

#40

Pretty sure they say 18000 and 150C max blower exit temperature as per their design.