HomeDashboardFAQSearchRiviera Questions & AnswersWrite-Ups IndexRegisterRelated LinksMemberlistLog in
Share | 
 

 FAQ: Smaller SC pulley? What Size?

View previous topic View next topic Go down 
Go to page : 1, 2, 3 ... 11, 12, 13  Next
AuthorMessage
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18310
Merit : 239

PostSubject: FAQ: Smaller SC pulley? What Size?   Mon Jan 15, 2007 7:53 pm

Smaller SC pulleys spin the blower faster for more boost; this enables the engine to make more power (in the form of low-end torque). Be careful, though. If you go too small right away, the engine will knock, which will rob power and can even do harm to your pistons under certain conditions.

The diameter of the OEM SC pulley is 3.8". It only takes a small drop in pulley size to make a noticeable power increase. Just 0.1" diameter decrease will yield about 1 PSI increase in boost, which is enough to feel in your seat from increased torque.

For Series II SC (L67) engines, aftermarket SC pulleys are available in diameters ranging from 3.6" down to around 2". Start larger and work your way down. 3.6" pulleys can be used with little or no issues on a stock Series II SC Riv, giving up to ~10 HP increase. A 3.5" pulley may give ~15-20 HP and is probably fine if you run cooler plugs and t-stat, but scanning is a good idea. Racing with a 3.5" SC pulley, or running a 3.4" size on the stock engine is not a good idea unless you scan and tune the PCM with a tuner or AFC device.

Average boost numbers on the stock 3.8" SC pulley will max around 6-8 PSI, depending on the car, other mods, and conditions. With the 3.4", you'll see around 9-11 PSI. This extra air charge can add ~25-30 HP to your engine's output, a very noticeable gain in low-end torque. You'll feel the extra pull when launching the car, and on shifts. With this mod, wheel traction can become an issue.

SC pulleys can be had for as low as $80 in the case of the press-on variety, but a modular system (MPS) is highly recommended. If you plan to modify further in the future, or if you want to experiment with different pulley sizes to dial in just the right boost for your car, an MPS lets you swap on a hub (like changing wheels) in under 5 minutes by loosening a few screws. Modular systems go for between $100 and $130, but additional pulleys are only $50-60, and used pulleys are often sold/traded on message boards. Info on SC pulley installation is found here:

http://rivperformance.editboard.com/Supercharged-3800-Tech-c2/Series-II-FAQ-f19/How-do-I-remove-install-a-SC-Pulley-t511.htm

One of the things you'll notice with a smaller SC pulley is louder and higher pitched supercharger whine. Another thing you can expect is increased KR. With more boost comes higher temps inside the intake manifold, which contributes to knock. Smaller pulleys create higher air flow rates than stock. With the PCM adding more fuel, it's a good idea to scan after installation to confirm your air/fuel mixture is where it should be. If scanning indicates that KR has increased, you may need to reprogram the PCM, use an AFC to tune the air/fuel mix, add more modifications to fight knock, or move to a larger SC pulley.

After adding a smaller SC pulley, you may be wondering if a smaller SC belt is needed. In most cases the answer is no, but when running 3.4" or smaller SC pulleys, it's a good idea to increase the diameter of the SC tensioner OR idler pulley to 3.5" to take up slack.

3.5" (90mm) ribbed idler pulley: GM #88909590; Dayco #89004; Gates #38019
3.5" (90mm) smooth tensioner pulley: INTENSE #STP-635; ZZP #ZZ-6R35SM; Gates #38001


Using a 3.3" SC or smaller pulley requires using both 3.5" SC tensioner and 3.5" idler pulleys. This takes up more slack, and ensures the SC does not rub against itself near the tensioner, while retaining OEM belt size. Here are the rules:

-OEM SC belt works with OEM 3.8" SC pulley - keep tensioner and idler pulleys stock.

-OEM SC belt works with 3.6" and 3.5" SC pulleys - keep tensioner and idler pulleys stock.

-OEM SC belt works with 3.4" SC pulley - change one: tensioner pulley OR idler pulley to 3.5" dia. One of these remains stock size.

-OEM SC belt works with 3.3" SC pulley - change tensioner pulley AND idler pulley to 3.5".

-OEM SC belt works with 3.2" SC pulley - change tensioner pulley AND idler pulley to 3.5".

-OEM SC belt works with 3.1" SC pulley - change tensioner pulley AND idler pulley to 3.5".

-using 3.0" or smaller SC pulleys will likely require a smaller SC belt size.

If your car has 85k miles or more, it is a good idea to change all of the idler and tensioner pulleys on both the accessory and SC belts. There are 5 pulleys total that run about $100 for the set. For more info on pulleys/belts:

http://rivperformance.editboard.com/Supercharged-3800-Tech-c2/Series-II-FAQ-f19/-p4782.htm#4782


Last edited by AA on Sun Apr 05, 2015 11:51 pm; edited 3 times in total
Back to top Go down
http://www.cardomain.com/ride/657082/4
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: what pulley should i go to?   Thu Feb 08, 2007 4:03 pm

I am pretty well educated on the fact that a 3.4 inch pulley gets about 25-30 hp and a 3.25 inch pulley will get around 30+ hp... i have a cold air intake and 2.5 inch exhaust straight back from the cat.. no mufflers but i have two 3.5 inch tips they are 18 inches long... i am going to get a 160 degree or 180 degree thermostat?? which pulley shall i go with without gettin knock retard??
Back to top Go down
http://www.rivperformance.com
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18310
Merit : 239

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Feb 08, 2007 4:16 pm

Welcome to the board! A good read through the FAQ will answer your questions in more detail.

A 3.25" SC pulley is out of the question for you with your current mods. Even a 3.4" is risky without a scanner to monior KR. The safest way to go would be a 3.6" or 3.5" SC pulley. Any smaller and you'll need to scan.

A 180 t-stat is best for daily driving.

_________________
'98 SC Riviera 268k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch


'05 GTO 49k miles 0-60: 4.8s 16.9 avg MPG Nelson Ledges Lap: 1:26
Because fun
Back to top Go down
http://www.cardomain.com/ride/657082/4
Mr.Riviera
Expert
avatar

Name : Matthew
Age : 31
Location : Florida
Joined : 2007-01-17
Post Count : 4353
Merit : 99

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Feb 08, 2007 6:26 pm

i agree with Aaron, your exhaust mod doesnt really help relieve heat or back pressure, and if the CAI is one of the ebay ones, it's really a hot air intake which can cause more knock when there is heat soak. you can safely drop to a 3.5" IMO if you have a great running and clean engine and some supporting mods like colder plugs. make sure all the maint items have been taken care of before you get the mod bug 3gears
oh, and you should introduce yourself in the welcome page along with pics in the showroom. (so we can properly welcome you and see your ride! )
Matthew

_________________
1996 with 244k miles, L324" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs.
Back to top Go down
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Feb 08, 2007 8:39 pm

thanks i have a home built CAI made out of 3.5 inch stainless steel which is wrapped in heat blocker i sort of went off of what someone else had done with PVC pipe... i will probably go with the 3.4 inch pulley and then see where i am at but yes i will first buy the 180 degree thermostat..... and to Mr. Riviera thats one nice Riv man i really wish i got a pearl white i instead got a black one......
Back to top Go down
http://www.rivperformance.com
Mr.Riviera
Expert
avatar

Name : Matthew
Age : 31
Location : Florida
Joined : 2007-01-17
Post Count : 4353
Merit : 99

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Feb 08, 2007 8:49 pm

i love the black riv's with some dark tint and chrome rims. happy dont forget to get some colder plugs along witht he 180 t-stat. and as Aaron mention'd read that FAQ it has a ton of good info.
congrats on the DIY CAI btw. thumbsup

_________________
1996 with 244k miles, L324" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs.
Back to top Go down
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Feb 08, 2007 9:03 pm

Mr.Riviera wrote:
i love the black riv's with some dark tint and chrome rims. happy dont forget to get some colder plugs along witht he 180 t-stat. and as Aaron mention'd read that FAQ it has a ton of good info.
congrats on the DIY CAI btw. thumbsup
i had already bought some spark plugs they are those NGK or whatever forgot LOL but this may sound silly but i couldnt do the sixth one till i found out i could tilt the engine foward by unbolting the dog bone/!!!!!!! but yes i do need a paint job at least on two panels front left fender and rear right quarter because they had no damage on them i gottem from the junk yard!!! but they were oxidized so im gonna have my buddy paint them for 300 bucks (cost of paint).....lemme kno if thats a good price lol
Back to top Go down
http://www.rivperformance.com
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 7:36 pm

lmao so yah i will probably be modding my riviera this summer i kno i said i was going to sell it WHICH I AM but i really wanna see the potential so i am going to install my FWI and get a 3.4 inch pulley with a new 180 t stat..... and then i am going to buy one of those AFC 2.0 gadgets to add more fuel <<<idk if thats what it does LMAO but yes then i will see if i can keep up to mr SRT-4
Back to top Go down
http://www.rivperformance.com
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18310
Merit : 239

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 7:54 pm

Keep in mind you need a scanner to use the AFC.

_________________
'98 SC Riviera 268k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch


'05 GTO 49k miles 0-60: 4.8s 16.9 avg MPG Nelson Ledges Lap: 1:26
Because fun
Back to top Go down
http://www.cardomain.com/ride/657082/4
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 9:24 pm

AA wrote:
Keep in mind you need a scanner to use the AFC.
http://www.zzperformance.com/grand_prix/products1.php?id=172&catid=107

so to run the AFC i need a scanner??? how come it says "Better than an AFPR, the Mini-AFC allows injector swaps w/o PCM tuning"
Back to top Go down
http://www.rivperformance.com
racinfan
Addict
avatar

Name : Joe
Location : Cleveland, OH
Joined : 2007-02-05
Post Count : 567
Merit : 5

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:18 pm

98riviera98 wrote:
lmao so yah i will probably be modding my riviera this summer i kno i said i was going to sell it WHICH I AM but i really wanna see the potential so i am going to install my FWI and get a 3.4 inch pulley with a new 180 t stat..... and then i am going to buy one of those AFC 2.0 gadgets to add more fuel <<<idk if thats what it does LMAO but yes then i will see if i can keep up to mr SRT-4

Well if you were my little brother I'd slap you upside the head. I don't understand why you'd want to waste money doing halfassed mods to a high mileage car that you'll be selling just to "beat" a dodge neon. I'm sure you'd feel real dumb if you ended up blowing the engine/tranny and suddenly your 4k riv is worth 1500. Then you end up dumping 2k into the thing to bring the value back to what it was in the first place and you'll end up netting maybe 1k if you're lucky after the fact.

But you're thankfully not my little brother and I'm just playing the "devil's advocate."
Back to top Go down
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:20 pm

AHAHHAHAHA i really just wanna see the potential and actually the buyer of my car MY FRIEND will want mods
Back to top Go down
http://www.rivperformance.com
deekster_caddy
Master


Name : Derek
Age : 45
Location : Reading, MA
Joined : 2007-01-31
Post Count : 7716
Merit : 109

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:20 pm

Without TUNING - not without SCANNING. You shouldn't be making too many mods or a pulley change without regular scanning. Know your engine, know the paramaters it runs at, know what it means when you have KR and why you have it.

PCM Tuning would take the place of an AFC. Scanning is used to TUNE the AFC. You are seriously changing the parameters from your MAF when you use an AFC. If you don't scan vigorously while TUNING your AFC you are going to do some damage.

You need to scan for MAF Hz, Front O2, MAP, IPW, KR at the very least. With all that info you can start making changes with an AFC.
Back to top Go down
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:25 pm

why do scanners have to be so much $$$$$$$$$$$$$$$$$$$$ lmao
Back to top Go down
http://www.rivperformance.com
deekster_caddy
Master


Name : Derek
Age : 45
Location : Reading, MA
Joined : 2007-01-31
Post Count : 7716
Merit : 109

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:34 pm

Keep your eyes open for a PC based autotap, that's the best. New they run $300. Mine sold used for $200. At that point you might as well spend $400 and get a tuner, that way you don't need an AFC!
Back to top Go down
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:37 pm

i have a laptop and i'm not a ricer but i'd like to have a digital boost gauge and various other info such as KR and AIR FUEL MIXture to be displayed on the lap top is this what the autotap does??
Back to top Go down
http://www.rivperformance.com
AA
Administrator
avatar

Name : Aaron
Age : 40
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18310
Merit : 239

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:40 pm

Yep.

_________________
'98 SC Riviera 268k miles 298 HP/370 TQ 0-60: 5.79s ET: 13.97 @ 99.28 4087 lb 20.1 avg MPG Nelson Ledges Lap: 1:30
3.4" pulley AL104 plugs 180 t-stat FWI w/K&N 1.9:1 rockers OR pushrods LS6 valve springs SLP headers ZZP fuel rails
KYB GR2 struts MaxAir shocks Addco sway bars UMI bushings GM STB Enkei 18" EV5s w/ Dunlop DZ101s F-body calipers
EBC bluestuff/Hawk HP plus SS lines Brembo slotted discs DHP tuned Aeroforce Hidden Hitch


'05 GTO 49k miles 0-60: 4.8s 16.9 avg MPG Nelson Ledges Lap: 1:26
Because fun
Back to top Go down
http://www.cardomain.com/ride/657082/4
deekster_caddy
Master


Name : Derek
Age : 45
Location : Reading, MA
Joined : 2007-01-31
Post Count : 7716
Merit : 109

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Feb 28, 2007 10:48 pm

Gauges and even better - recordings! The ability to export your scans so others can help you out is the real benefit to an Autotap.
Back to top Go down
Jason
Aficionado
avatar

Name : Jason
Age : 34
Location : Comox, BC, Canada
Joined : 2007-01-23
Post Count : 1378
Merit : 64

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Mar 01, 2007 1:21 pm

you should sell your chrome centercaps to me and tell your friend they fell off...
Back to top Go down
http://www.cardomain.com/id/Doctor_Meltdown
T Riley
Guru
avatar

Name : Travis
Age : 27
Location : Your wife's box
Joined : 2007-02-08
Post Count : 5125
Merit : 9

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Mar 01, 2007 1:24 pm

Jason wrote:
you should sell your chrome centercaps to me and tell your friend they fell off...

hahaha i can get u four of them for 100$ if u want shipped!!!
Back to top Go down
http://www.rivperformance.com
Jason
Aficionado
avatar

Name : Jason
Age : 34
Location : Comox, BC, Canada
Joined : 2007-01-23
Post Count : 1378
Merit : 64

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Thu Mar 01, 2007 1:25 pm

check your PM
Back to top Go down
http://www.cardomain.com/id/Doctor_Meltdown
superivi
Rookie


Name : Zack
Location : Indiana
Joined : 2007-06-30
Post Count : 17
Merit : 0

PostSubject: pulley install   Wed Jul 11, 2007 6:02 pm

do i still need the scanner if just swap in a 3.5" pulley?? or should i wait??
thanx again guys..!!!
Back to top Go down
SpaceBar
Aficionado
avatar

Name : Patrick
Age : 31
Location : Quincy, MA
Joined : 2007-04-08
Post Count : 1199
Merit : 3

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Jul 11, 2007 6:26 pm

You SHOULD get a scanner to begin with. If your car has knock now you don't want to be adding more by dropping pulley sizes. You could see if theres anyone near you who has a scanner that will scan for you (riv people or try a grand prix club).

You should also put in some colder plugs (autolite 104s or 605s) and a lower t-stat (180*) just to help out.

How many miles are on the car and what year?
Back to top Go down
http://community.webshots.com/user/xspacebarx
1998 Riv
Expert
avatar

Name : Dave
Age : 57
Location : In The AZ Oven
Joined : 2007-01-17
Post Count : 4502
Merit : 44

PostSubject: Re: FAQ: Smaller SC pulley? What Size?   Wed Jul 11, 2007 11:19 pm

I had negligible KR with my stock 3.8 pulley. In the 1's, max. Then I did a couple supporting mods, like AL605 plugs, 180 t-stat, K&N filter. Bought a 3.6 mps kit, and swapped pulleys. Finally found time to scan with the 3.6, and I spiked at 6.15 deg of KR. You know the moral of the story. Scan first.

I've ported a spare front exhaust manifold, and ordered a 3" DP, hopefully those additional mods will bring things back down to an acceptable KR level. But what I really need is someone to tune it.
Back to top Go down
Rivgirl06
Amateur
avatar

Name : Jen
Age : 30
Location : Big Rapids, MI
Joined : 2007-03-26
Post Count : 24
Merit : 0

PostSubject: Smaller SC Pulley   Thu Aug 02, 2007 8:05 pm

Looking to go smaller guys, wheres a good source to get a 3.5 or 3.4 pulley? Also, does anyone have a scanner or know someone with a used scanner so I can tune the pcm?
Back to top Go down
 
FAQ: Smaller SC pulley? What Size?
View previous topic View next topic Back to top 
Page 1 of 13Go to page : 1, 2, 3 ... 11, 12, 13  Next
 Similar topics
-
» FAQ: Smaller SC pulley? What Size?
» Can't remove crankshaft pulley on '99 hijet
» L36 top swap
» Whats the diameter of the output shaft on a 13.5hp IC?
» LT2000 Engine Pulley Max Size?

Permissions in this forum:You cannot reply to topics in this forum
Riviera Performance ::   Supercharged 3800 Tech :: Series II Engine & Transmission-
Jump to: