FAQ: Smaller SC pulley? What Size?

I put in a 3.4"pulley, 180 degree thermostat, and autolight 104 spark plugs and I run just fine to 4K rpm with no knock. Above 4K I get about 3 degrees knock. The purist will complain about that but that is what the knock sensor is there for. If I was drag racing I would be concerned but for everyday driving I am never above 4 K rpm. The 3.4" pulley makes pulling away from a stop really satisfing and when I want to pass somebody on a 2 lane road I'm up to 90 by the time I get around the vehicle. I say don't worry about a 3.4" pulley. Afterall, it isn't like we have a stinking U-Bend to get rid off.

With all due respect, Riviera96 is entitled to his opinion. Maybe driving under 4k RPM works for his driving style and his particular car. But for those reading this thread in hopes of modifying their Riviera safely, and still being able to drive a Riviera the way it was designed to be driven, this type of thinking can lead to serious problems. The last I checked, passing someone is most safely done at WOT without worrying about crossing a premature RPM threshold.

First thing to realize is that RPM isn't the only thing affecting knock levels. During most normal driving, it's more about load. If your engine knocks at 4k RPM, it will likely knock at 3k RPM when going up a steep hill (increased load). Even a slight grade can create significant KR in overdrive with TCC locked-up (which it is most of the time), and this will occur at very low engine speed, between 1500 & 2500 RPM.

Similarly, because lower gears present less load to the engine, 4k RPM in 1st gear may not see as much KR as 4k RPM in 2nd gear, and 4k RPM in 3rd gear presents a tremendous load to the engine - a car with zero KR 99% of the time will see some knock under this condition.

Having said all of that, high-RPMs do in fact encourage more knock during WOT acceleration. If your engine is seeing 3º KR at 4k RPM, you will probably see at least 5º at 5k RPM, and possibly 8º or more KR up around 6k RPM. GM designed this engine to shift at 5400 RPM during WOT, and it will let you get very close to 6k RPM by holding out 2nd gear.

So the point I want to make is this: running a SC pulley that's too small for your mods is limiting the performance potential of your car. Is this why we mod?... to make our cars slower than factory? Not me. Even a stock engine starts making its real power at 4k RPM, peaking at 5200 RPM. With additional breathing mods, that peak occurs closer to 6k.

Using a 3.4" SC pulley without sufficient supporting mods will increase both torque and knock levels. If you want to use the extra torque, you need to worry about how to deal with the knock. Otherwise, you're take a risk that could eventually lead to serious trouble.

I didn't get the chance to drop the pulley today because it took me 6 freaking hours to change my plugs cause I had no damn monkey hand....

I'll drop it tomorrow and let you know the results of the 3.5 Idler...

EDIT:

Oh shit...I can't put on the Idler tomorrow because Eric just mailed it and I don't have it yet...

I'll do it next week when I install the Aeroforce gauge.

Chicken wrote:

I didn't get the chance to drop the pulley today because it took me 6 freaking hours to change my plugs cause I had no damn monkey hand....

I can pack mine in ice and ship it to you.Should still work fine.If not I will have to rob another zoo.

3 busted knuckles too late!!

What mods would I need to go to a smaller pulley?

I'd spend some time reading this guide:

http://www.regalgs.org/forum/viewtopic.php?t=26380

Or this one: https://rivperformance.editboard.com/series-ii-engine-transmission-f4/modding-how-do-i-make-the-car-faster-t23.htm

is it safe 2 swap the stock pulley 4 a 3.4 pulley on a stock riv? Looking 2 put a intake, and a 180 deg thermasat after swap. Would I run into any cpu problems? Sorry I'm new. Thanks

do they sell a 3.6 pulley? And if they do will it be all right 2 leave the stock down pipe in the car? This is my daily driver so I dont realy have any time 2 put it in the shop 2 get it welded. Thanks 4 the great welcome guys! Thanks sorry if I'm a pain again I'm new.

I run a 3.5 pulley with stock downpipe and exhuast and my car runs great....I did however put in a FWI, AL104 sparkplugs and a 180* thermostat. All cheap and easy mods.

thanks man were can I get a 3.5 pulley?

many places....the best around here are Intense racing and ZZ Performance....I prefer the ZZP pullies....you'll need a MPS....its a hub that the pulley bolts to for easy changes.....you'll also need a pulley removing tool....you can buy or rent them from Intense or ZZP or some of the guys here will lend you theirs...theres also The Pulley Boys, and Thrasher who sells pulleys...

before you do this though I recommend the change of colder spark plugs, thermostat and at least a gutted airbox with k&n filter....

http://www.zzperformance.com/grand_prix/products1.php?id=205&catid=111

Thanks man 4 all the help. I will deff do the therm, plugs, and intake first. Thanks 4 the sight.

Josh, you do NOT want to run a 3.4 without several supporting mods in place first, plus have the ability to scan for Knock Retard (KR) before dropping pulley sizes. Look at all the mods in my sig. I've got a problem somewhere, as I had to go back to a stock 3.8 pulley and still am seeing up to 6+ degrees of KR.

Take the time to put your car info in your default signature, and spend some time reading the FAQ sections. All the info you need can be found here, but you need to put in the effort to read existing threads.

Agree with Dave. We want to help you make your car perform. If you read this entire thread from page #1, I think you'll start to understand things.

does anyone live close to the port saint lucie florida area that can scan my car for kr after i do the 3.5 swap with al 104 plugs and zzp 180deg therm?

After I did my mods, I immediately bought and installed an Aeroforce gauge...its a great gauge that has many parameters for scanning including knock.....its a simple install, basically just plug and play....

....problem is, it doesn't have the ability to program.

from: https://rivperformance.editboard.com/series-ii-engine-transmission-f4/which-spark-plugs-wires-should-i-use-t26-75.htm

what else are you doing to support the 3.4?

3inch exhaust., intercooler, plugs, 3.4, PCM, headers, fuel rails, down pipe, cat delete, MAF,and mabey a Gen V, or whipple. thats the direction im going in

lyonsperformance wrote:

3inch exhaust., intercooler, plugs, 3.4, PCM, headers, fuel rails, down pipe, cat delete, MAF,and mabey a Gen V, or whipple. thats the direction im going in

3in down pipe and cat delete, 104s, intake should be good for a 3.4"

a full size intercooler will get you down to about a 3.1 alone pretty much.
Anything beyond that whether it be with an upgraded blower or not will require all the fuel system mods and obviously tuning.

If you do plan on doing all the stuff for sure, my suggestion to you would be to start with a set of nice headers, the plugs, intake if you haven't already done it, and might as well knock out the rest of the exhaust while you're doing the headers. That would be a very good way to start - all good supporting mods and all necessary for any of your future mods. (assuming you don't turbo)

lyonsperformance wrote:

3inch exhaust., intercooler, plugs, 3.4, PCM, headers, fuel rails, down pipe, cat delete, MAF,and mabey a Gen V, or whipple. thats the direction im going in

Plans for a used DHP or an HP Tuners?

Just FYI, before I did any tuning I had a lot of KR on the 3.4 that didn't go away until I put in 1.9 rockers. That air needs to go somewhere... Start with a MPS and 3.5, and drop pulleys again after all the rest is on there. Oh, and if you aren't doing it all together, SCAN SCAN SCAN. Don't run that 3.4 if you don't know how bad your KR is.

Yes, the pulley drop should be FAR from the top of the list of mods.