after changing my pulley i went and did some wot runs to see what my boost was, im comparing them to previous runs with the stock pulley.

new 3.12 pulley 3rd gear pull
4.1 @ 4605
5.0 @ 5139
6.0 @ 5540
7.1 @ 6027
8.0 @ 6320
9.0 @ 6890

stock 3.33 pulley 4th gear pull
4.1 @ 5234
5.0 @ 5383
6.0 @ 5830
7.1 @ 6410
7.5 @ 6585

 

Very nice... your car is amazing! You going to the Atl 6/31 meet?

 

Interesting. Here are my numbers with the 34-tooth cog pulley:

3500 2.6
4000 3.6
4500 4.5
5000 5.7
5500 6.6
6000 8.0
6500 9.0

--Steve

 

Question: When are your blowers kicking in? So what RPM's are you seeing boost start?

Zimbo I can see you have 2.6PSI @3500, but what are you making at 3K, if anything? Same question for you Tig.

 

mine are [with 3.125 pulley ] 2.6 .3,5000 .....3.2 4,000 ....3.9 4,500 .....4.7 5,000 ...... 5.6 5,500 .....6.5 6000 .......7.5 6,500 and topped out at 7.6 I called Vortech to complain that I think I have a weak blower...they arent going for it . They tried to tell me that running headers and exhuast is cutting down on the boost . I believe it will some....but not 1.5 bl's

 

I'm making about 1.0 psi at 2000 rpms and 2.0 psi at 3000 rpms.

--Steve

 

im not making much if any at all below about 3700 rpms. my recordings on my software shoot almost straight up at that point so that must be where mine kicks it, but i swear i can feel it before that.

 

actually after playing around with the recordings and finding the highest boost, it seems to be 9.1psi @ 6287 in 2nd, damn thats impressive dont ya think? still got another 500 rpms to go. i bet if i had the TS 7100 flash, id be near or over 10, does anybody know if we can post these recordings? also i still cant see anywhere that im making boost down low like you zimbo.

 

here are the pics of my recordings, i couldnt figure out how to copy and paste them, so i took a pic of them,

 

here is a pic of the 9.1psi

 

how the hell do you guys know this???

you cant be looking at the gauges??!?! right??

i would REALLY like to know, for comparison...

help?!?!

-eS

 

Scott,
We could have done a recording with my labtop and the ss software when I was there on Sat, but for your coolant problem.
bay the way..... what did the dealer say?
Timrod

 

A ton of boost isn't any good without flow. I've seen kits drop 2 psi on Vettes when they open up the heads a bunch. However, the big question is, are you making the power? If you still have relatively the same power as someone else with that pulley, then your blower isn't leaking and you're just flowing a metric azz ton of air. If not, then that's bad.

 

Guys... I have a dumb question.... if I change pulleys (either serpentine or cogged), and get my boost to come up earlier, can I still have it capped at 9lbs of boost?

I'm supposedly hitting that already with my set up and what I'm looking for is not peak horsepower, but more area under the curve earlier in my powerband. Does the R4 software let me maintain that 9lb of boost by blowing off the excess or by changing will I have to take the peak gain along with the lower end gains?

My reason for concern is that I was already hitting around 425rwhp and I don't want to push my luck. Now, if I hit that 425 at 5500 rpm instead of 6500rpm, that's fine with me tho!

Thanks in advance for your thoughts.

BTW, it looks like the cogged pulley swap is the more efficient gain between it and the 3.12". Anyone else considering the 2.87" pulley beside me?

 

two more for zimbo...

what's your clearance like on the 34-tooth pulley (pulley to intake pipe doesn't look like there's a lot of room there)?

and what part number is the 34-tooth pulley? I assume a belt change is not required.

 

if you decide to go down a size (from 312) this is the next one on the list....

i plan to pull a ton of timing up top, and add in fuel above 6K...

then we'll see the dyno readings (and i will stay hooked up to the laptop i guess)..

damn, wish i knew more about the r4; i woulda been all over recordation of runs (knew of realtime viewing, but never thought one step ahead!)

so anyway, after talking directly to vortech, and confirming with my tuner (AND dealer), we are gonna try to make more on the low/mid, and retard up top thru ignition (for now)...

id prefer to shift sooner anyway, as the TQ drops a lil above 6200 rpm's.....

guess the 'cat's outta da bag'

 

Okay.. I've decided I will do the 34-tooth pulley AND the 3.12" serpentine pulley... if necessary, I'll pull timing at top end to keep the HP stead at 425 up to redline.

Now, I need to know the part number for the 34-tooth pulley. I don't see it on the Vortech website. They have a 34-tooth in 50mm width, but not in the 35mm width. Anyone know? also, anyone know someplace other than Vortech to get the cogged pulleys? Superchargers online has the serpentine ones, but not the cogged ones (at least on the website).

 

hmm... I'm beginning to wonder if Zimbo is running the 50mm wide 34-tooth pulley...

 

mCdUCK---

I dont know if there's enuf space behind the compressor housing to fit the extra ½ wide cogger......

certainly wouldnt hurt, i guess, as long as it spins okay on the shaft (or would you need a bigger shaft/spacer???)


i remember awhile back, someone told me that .....

 

Sorry I don't know the part number or the size, guys. It's the pulley used on the Corvette kit as I recall. $59.99 for the pulley plus a buck or two for a longer bolt. It does stick out further, but I was able to solve the rubbing problem by using a thinner washer.

--Steve