Actually I never really care what you think Sak, if you think they’re visually the same size that you couldn’t tell a difference, fine. I’m not really caring to argue about what you actually said enough to make YOU the focus of the discussion…sorry princess
anyhow lets move on and get the GIAC pulley size lol
[quote=“Jspazz,post:21,topic:5185”]
I guess that’s why you replied to, and needlessly argued with what I said, twice. Makes sense :
Lol, give it up dumbass! I already said I don’t give a fuck. “move on”
J- if I recall correctly, recent logs between the apr stage 2 and most recent giac stage 2 flash had the giac cars up 2psi (13 vs 15) @ 3000 rpms. All cars had virtually zero bypass at these early rpms so there definitely is a size difference between the two pulleys to get 2psi more boost down low and that early.
The APR boost log slowly ramped up to peak 17-17.5 psi at redline in third whereas the giac boost line hit 15psi very early and slowly crept up to 17ish peak and then bypass kicked in a little and dropped it back down to 16.5 at redline. Combine that with a little bit more timing advance on the giac car up top.
Tsivas27,
Having seen both the GIAC and APR pulley, I think they are too close for there to be any performance differences. ( less than .5mm radially ). It is much more likely to be in the software.
For it to be up to 2 psi difference, There are many more factors.
Ambient Temperature
Tuning
Cam Mapping
Intake
Inter-cooler water temp.
I gave one of my spare B8 3.0t superchargers to a B8.5 car, since they are measuring running less boost ( than his previous b8.5 ) , and the individual was concerned there may have been a change internally. My opinion was that it was in cam tuning, and i think that was the final conclusion.
btw… turns out B8 and B8.5 Superchargers are the same.
There is no room to go smaller on the 3.0t pulley than what AWE and APR have currently. Aside from fractions of a mm. +/- 1mm is not going to see you 1 psi at the blower speed its currently at.
Good points.
Another thing to add is it’s possible some are not logging the correct variables or the same variables. I’ve seen and reported issues to P3 about their gauge not reading spot on when pulling data over the port.
Also, if you’re using an analog sensor, the location you’ve tapped will alter the results.
Measuring Pulleys.
You should not be measuring across the tips of the pulley. This is not how a pulley works, the belt does not drive the pulley from the tips.
Pitch diameter. You cant measure this with a standard caliper.
You need an Optical profiler, or a special caliper, or gauge wire… ect…
You could mess with the simpleton measurement chest beat off ratings just by changing the tip radius. Ill put together a picture. while not changing the effective ( real ) radius of the pulley.
What you don’t want to do is stray from the SAE standards of a PK pulley. The specs have min tip radii , and a max groove root diameter to make sure the belt rides perfectly throughout its life.
APR the original pulley, they literally went as small as you could go.
If someone managed a freakin .05mm difference in pitch diameter, then its 1 immaterial, 2 the pulley would be much weaker.
The limit to the size of the pulley is the supercharger’s nose cover diameter where the bearings sit inside.
The supercharger is already being spun well past where it should, and well past the range where diminishing returns from.
lol are we back to measuring pulleys?
jonathan, if you want to discuss the matter further, just go ahead and start a new thread. you can then quote your post above and paste it to that new thread. thnx.
Dont read any of that…its a bs waste of time…take a caliper measure inbetween the groves once you found a refrence spin the caliper 90deg to assure no hot spots…its not rocket science…its been done this way for 60years…some people just like to try and make things look more complicated
As for the blower speeds…I would not listen to his empty opinion on that either…APR has tested and retested…if the pulley wasn’t the right size and it wasnt safe to make power with a good gain APR wouldn’t sell it.
ChrisK,
It’s really not that hard. Its basic machining, shop class stuff. If this was used to compare pulleys, then all the previous posts comparing fractions of a mm on a dimensions that doesn’t matter would have never taken place.
Measuring the root of the pulley does not matter either. Please read up on pitch diameter.
The blower comment was about 100 micron changes in dia, and its ineffective change on boost.
Much unlike you just talking ive done machined and installed. You can simply and effectively measure just as Ihave listed and is how the industry has been doing it for years…I understand trying to make things look more complicated is an attempt to try and make yourself look smarter…it isn’t working.
For those that are actually trying to measure. Just make sure you measuring it the same way…its not rocket science is measuring…for everything simple there will be someone looking to make it more complicated just to make small talk…carry on
Every pulley I have seen measured was from the tip of the rib to rib. Why all of a sudden is there so much more to it? Not to mention if you measure a stock pulley for reference and you measure the aftermarket ones exactly the same, what is the big deal?
Jonathan, did you guys stay with a 5 rib belt on the AMD supercharger?
There isnt…as I said above…for everything simple there will be someone there to try to make ot more complex to just make themselves look smarter…its actually incredibly stupid…
Guys like Jonathan take a 3 step prosses and try to make it sound like you need a 60 page manual. All in an aplempt to wow you with incredible amouts of waste and stupidly…oh oh here is how smart I am…I cam fuck up a simple 2 step task by adding 30 more steps and variables that are irrelevant to this question
Agree with you!
Its not a big deal.
And usually not worth the effort either.
Since… two pulleys that measure differently across the tips can be driven at the same speed. The belt rides on a diameter in-between.
I’m not here to soap box on technicalities.
Precise and doing it right…its called using a tool that measures things down to small increments…they are using a tool to do just that…fuck dude you act lke they are using tree brantches to measure a pulley
P
Euro,
Missed that question. Yes, use the 5pk. We were ready to test 6 & 7 PKs but never got close to belt slip, even with smaller pulleys ( optical tach on the charger )
[quote]But…if the pitch diameter is exactly the same, because the belt isn’t changing…then rib to rib is fine. Why would a company change the pitch diameter if they are still utilizing a stock belt? They wouldn’t.
[/quote]
That’s not the belt rib spacing, its the drive diameter. It changes when your change the pulley diameter. Made a picture to illustrate it.
The RS4 Hardware is nice, even the idler pulley is CNC machined .
Pulley is off my dads car right now bc he got a B8.5 I will measure it
get your laser!