theformula

Can somebody tell me the stock size of the blower pulley on these units. I think mine may have been swapped out by Paxton in a checkup. Which would explain my low boost.
Thanks
Ryan

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91 Formula 1LE 1 of 46
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 supercharger, Ford SVO 24#injectors, Crane AFPR,SLP airfoil, ported/polished plenum, March alt. pulley,Crane Gold 1.6rrs,MSD coil,MSD6AL (5400rpm limit),Holley 9mm wires,Ac delco R43ts plugs,custom chip,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,180* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

89GTA5spd

I just emailed you.. but again mine measured 3.5" in diameter on my SN92.

theformula

I'm SUPPOSED to be making 10#s, but I'm only getting 5. I attribute this to the following

A) The original owner,who sent the unit in for a checkup,told them he's getting a bigger engine and needed the blower to turn slower for his shift points (which he did). They in turn put a larger pulley on.

B) My belt isn't tight enough

To tell you the truth I'm not that angry. My car is just about perfectly tuned right now. Any more boost will throw me off .

But..what are you boosting at?
Thanks for the help man

89GTA5spd

I don't know what boost I am at, cause my paxton isn't on yet. But today I was looking through a book my brother gave me (camaro performance 82-92, I think) and it had a picture of an engine out of the car with a paxton on it. How it installs makes a lot more sense to me now. I also realized that the person I bought it from gave me a stock crank pulley and power steering pulley/pump/resivoir.. which would make me believe the person I bought it off's story that he bought it off some kid who crashed his 89 TA, and that it wasn't just pulled off a car when it broke.

This thing looks pretty easy to install (mostly because it doesn't pull oil from the pan or have any kind of oil cooling system.. and uses a seperate belt) I am sure I can do it in a day or less as long as I don't run into any snags.

I can't wait to get it on.. I also can't wait to see what I run with this and a 50 shot (on an otherwise basically stock engine).


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89GTA5spd – Came: Completely Stock w/ 3.42’s, rear disks, dual cats, LB9 305, T5, bad paint & interior. I did: Conical K&N w/cust piping, TPIS Airfoil, Ported Plenum/Runners, TB By-pass, Home Made AFPR, MSD Cap/Rotor, Jet Fan Switch, 180 T-stat, , Flowmaster 3” Cat-back, Eibach 1” Drop, KYB’s, Hotchkis STB, BFG 255 Comp T/A’s, NOS TPI (custom) Kit , Sony CD, Orion Amp, Fosgate 10’s, 1991 GTA interior, new paint. I have but have yet to put on: Alston Bolt on SFC’s, Paxton SN-92. Soon: Mallory Hyfire, Autometer Phantom Elec. FP guage, N20 Guage, Boost Guage, Hobbes Switch, Bottle Blanket. Not So Soon: alum headded L98. Always a work in progress..

89GTA5spd

Oh yeah, forgot to ask.. Where did you put place the vacuum line for the boost guage, did you just pull it from one of the accessories on the plenum (like a T where the cruise control gets it's vacuum)?

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89GTA5spd – Came: Completely Stock w/ 3.42’s, rear disks, dual cats, LB9 305, T5, bad paint & interior. I did: Conical K&N w/cust piping, TPIS Airfoil, Ported Plenum/Runners, TB By-pass, Home Made AFPR, MSD Cap/Rotor, Jet Fan Switch, 180 T-stat, , Flowmaster 3” Cat-back, Eibach 1” Drop, KYB’s, Hotchkis STB, BFG 255 Comp T/A’s, NOS TPI (custom) Kit , Sony CD, Orion Amp, Fosgate 10’s, 1991 GTA interior, new paint. I have but have yet to put on: Alston Bolt on SFC’s, Paxton SN-92. Soon: Mallory Hyfire, Autometer Phantom Elec. FP guage, N20 Guage, Boost Guage, Hobbes Switch, Bottle Blanket. Not So Soon: alum headded L98. Always a work in progress..

Willie

iTrader: (1)

If the blower has never been rebuilt, you have a "standard" impeller. This impeller was only good for ~6 psig boost at compressor redline (38,000 rpm). About three years ago, Paxton decided to install the higher boost impeller on on their rebuilds and new units. This impeller is good for another 3 to 4 psig boost.

Secondly, buy a MitiVac from Carroll Supercharging. It's a hand-held vacuum/pressure pump used to diagnose all sorts of vacuum related problems. It can also be used to test gauge accuracy. I have one and it works great!!

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig): 12.57 @ 111 mph.
Former Paxton (6-psig) & former 50-hp nitrous: 12.04 @ 114 mph.
Current ATI D1SC (Initially 10-psig): Projecting high 11's.
Future ATI D1SC (15-psig): Gotta catch them pesky 26-psig boosted TTA's!!

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

BLOWN85/TA

iTrader: (2)

Hey WIllie
Can you tell the difference by looking in the blower intake as to wether or not the new impeller is in there?

IROCKZ4me

Well, I'm not Willie but I guess I can answer this anyway, LOL

Yes.
The vanes on the original impeller are shaped like an airplane wing, flat on one side and convex on the other. The upgraded impeller is made by machining an original style impeller. The convex side of the vane is left alone but the side that was flat is milled so that it is concave. The vanes are much thinner after milling and you can see the machinig marks left. The original impellers have a smooth cast finish with no machining marks on the vanes.
<hr>
I had my SN92 rebuilt twice. Once many years ago (they put an original style impeller back in), and again this December. I had to pay $100.00 extra to get my impeller upgraded. Otherwise they would have reinstalled the original impeller as it was.

<hr>
There where three sizes of blower pulley and two sizes of crank pulley.

The blower pulley sizes where:
3.00" part #3881904
3.25" part #3881903
3.50" part #3881905

The crank pulley sizes where:
5.75"
6.00"
I don't know the part numbers for those.
<hr>
Mine originally came with the 5.75" crank pulley and the 3.25" blower pulley.

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Tracy /AKA IROCKZ4me
'86 IROC-Z Camaro
"Cogito ergo zoom"

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

My IROC-Z
EFI Performance Club on Yahoo
Club IROC-Z

[This message has been edited by IROCKZ4me (edited April 20, 2001).]