FAQ: Smaller SC pulley? What Size?

With enough modification and tuning, our engines can make lots of power on 91. I remember a guy on the DHP board who tuned his GTP to run high 13s in the quarter with a 3.8" and 87 octane, I believe.

I'm guessing headers, rockers, no cat, and a whole lotta' reprogramming?

Sorry about the location. I updated it. As far as premium, around here it's 93 octane. BUT we also have E85 (105 octane I think I remember hearing someplace). Since I've owned the car less than 48 hours I haven't had time to do to much digging but I will definitely be checking to see if I'm able to convert it. I currently run my Talon on E85 and it's amazing. 30 psi and can't hear any knock for miles. Of course it has a few other "minor" upgrades as well.

I would also just like to throw out there that the Rivi is FREAKIN SWEET!!!! Basically how it all went down was that I liked the way the car looked and felt. I searched for about two weeks for a deal and came across my 98 Supercharged with 144k for $2500. I went and looked at it, needed a new hood, pass headlight, and paint. I am the sales manager at a body shop so this meant nothing to me. The seller of course didn't know that. I drove it and withing 3 minutes of driving the service engine soon light came on. Also upon hard acceleration the car would stumble. I figured it was a misfire, but bitched to the guy about it. We ended up settling on 2k even out the door. Drove it home last night and went to bed. This morning at work I found this site, joined and started reading. Stopped at the parts store on my way home and had them double check the code. Sure enough, misfire, cylinder 4. I picked up a few parts, went home and started working on it around 9:30. I finished up about midnight. The car now has Auto lite 140's, 180 superstat, new auto lite wires, and eliminated stock air box. I cut out the hole beneath the stock box a little larger for increased air flow, and attached a (fake) k&n air filter routing it down into the hole I had cut. I fired it up and it jumped to life. No CEL, no misfire, goes right up to the rev limiter with out any issues, and that SC whine is fantastic. I then proceeded to drive it around for the next hour and a half or so up until a few minutes ago, smoking a civic in the process (added bonus)! This thing is so much fun!

I sold an 03 eclipse that I had lots of parts for and between what I have left and the items I'm going to buy this car should be a lot of fun. It's currently white pearl, I'm going to repaint it white with blue pearl. I have 18" chrome Milani's for it, about 2k worth of stereo equipment sitting in the garage, full LED wireless blue underglow, black out tails, corners, side markers, etc. Black housed halo angel eye prjectors, 12000k HID conversion kit, for sure cat back but preferably headers back, 3.5 SC pully, and last but not least, I'd like to see if I can get my stock sidemount intercooler from my Talon to hook up to it. If so it'll be great news for 3800 SC guys cause dsm guys pretty much give them away ($5-$50)

Either way I'm excited to learn more and play more with this car. It was so much fun, and I haven't done shit yet!

You can retune for E85, you'll need larger injectors and want to find somebody who has tuned a 3800 for E85, but otherwise there's not much more to converting, except that it's permanent - in the sense that if you have retuned for E85, then drive to somewhere you CAN'T get E85, you are gonna have problems unless you carry your tuner and have compensated your old E10 tune for the newer bigger injectors you just added...

You can probably do quite a bit on stock injectors, but you'll max em out pretty quickly.

Yeah, I need to do more research into the available options for tuning these things. With the talon I use Ostrich, an emulator that plugs into the ECU where the chip would be, and then plugs into a laptop. The laptop is my tuning laptop and stays in the car. When E85 isn't available I simply turn the car off, fill it with premium, and load a new bin file I already have programmed and saved to the laptop for pump gas.

Before I had Ostrich, I used a chip. The EPROM ecu's in the 1g dsms are able to read 4 maps on one chip. I had a separate tune for pump economy, pump performance, e85 economy, and e85 performance. I then had a couple wires soldiered on and attached to a toggle switch. If I turned the car off I could toggle between maps. Fill up if needed. start the car. Brand new tune, good to go!

It worked great for a while but I wasn't actually able to adjust anything, it was a set tune which may for some people work out fine. I on the other hand wasn't finished upgrading. So i got Ostrich and can now emulate/tune in real time!

hi, i have a 04 SS Impala, Supercharge,GM. I purchased a 3.4" pulley to replace original , if install pulley will this hurt my engine without modifications.

I wouldn't do it,scan for knock first.Without mods, you maybe just loosing power!!! Retarding timing?

cquintcarlos wrote:

hi, i have a 04 SS Impala, Supercharge,GM. I purchased a 3.4" pulley to replace original , if install pulley will this hurt my engine without modifications.

I do not know how to make the needed mods on a '04 Imp. You can probably find out with a web search.

On a supercharged Riviera, you have to retune the PCM and make some other (mild) mods to get full value out of that pulley. In general you need a scanner that lets you take driving logs so you can see reset the PCM parameters, as well as a tool (usually software for your laptop computer) that lets you make those changes. You need to scan the engien stock first, then make mods and reset the computer one by one. So first you are scanning to see if the computer is already giving the engine "knock retard."

Also in general you will also need to run cooler plugs (maybe autolite 104s) to deal with the additional fuel you will have to program in to get the fuel-air ratio back to correct stoichiometry and to reset the engine fans to come on at 180 deg. F (as well as put in a cooler thermostat).

If you just put the pulley on the engine will start knocking from the extra air, the computer will sense that the fuel-air ratio is off (the knock sensor will fire) and retard the ignition timing, basically negating the pulley's effect except you might notice an extrakick from a standing start. It's the kind of thing where you get that extra kick from the standing start then once you are revved up somewhat the computer starts backing things off as the engine starts to knock.If you push things to the point where the engine knocks anyway, then you'll just grenade it and trade the scraps for a used Yugo. There's more but this should get you started. Just like in school, if you want to pass you are gonna have to do your homework. All of it. You are in for either learning to tune the engine computer or having it professionally tuned, finding out which plugs (cooler) you need to run, and if you want to go smaller than 3.4" a new downpipe and exhaust 'cause IIRC the stock exhaust won't move enough air (it is enough for a 3.4" I am told).

Impala forums include:

http://www.naioa.com/v2/modules.php?name=Forums&file=viewtopic&t=37955

http://www.impalaforums.com/forced-induction/75-04-impala-ss-drop-down-supercharger-pulley-how-small-is-too-small-2.html

Good luck looking.

Albertj

Everything else aside... the Impala has a U bend in the exhaust. Right where the 02 sensor plugs in. For those who haven't seen these in real life, it takes the pipe to pretty much half diameter.
cquintcarlos, look under your car right where the exhaust comes down from the engine, you will see what I mean. A 3.4 without removing the U bend WILL cause you major problems.
http://www.wbodystore.com/grandprix/U-Bend-Bypass-Pipe-p-96.html
The linked part will fix it up. It fits right in.

Well, I took a chance I replaced oregenal pulley from my 04 SS Impala supercharge,GM to a 3.4" . I drove it from phoenix,az to toscun,az. WOW it did wonderfull do problems.

Your goin to blow it up!!!

Carlos, i would really listen to the advice these guys have been telling you. They are speaking from there own experience in blowing there own cars up and learning what not to do. Just a few small mods will do wonders for your new pulley. If you dont want to any mods then just dont push the car to hard, if you drive normal you should be fine. but really whats the fun in that? I would hate to see you lose a really nice car when you can stop it from blowing up. this is just our opinion and you can do what ever you like, we're just trying to help..

Sure, you might be fine driving long trips on flat ground, but when you push the gas to the floor or go through the mountains, that's when you'll get a problem.

I just ordered a 3.5 pulley and was wondering what size belt i would need to get for it, its a 96 series II sc, Thanks

You can use your stock belt. See page one of this thread for different options.

I just spent over an hour and about $250 worth of belts and pulleys (not including the s/c pulleys) to figure this out so It's probably worth sharing lol. It's info I needed anyway

I'm running a full size 2.25" intercooler and a smoothflow belt wrap and found the best belt to use for the riv since our tensioner and whatnot is a little bit different than the w-body's. The goal was to have one belt that can run anything from ~3.4" all the way down to a 2.55" supercharger pulley, using a couple idler/tensioner pulley sizes as necessary. Something to note is the smoothflow belt wrap kit needs to be shimmed up from the blower a little to work on the riv's setup primarily to open up the pinch gap of the belt. I tried a few different heights from 1/4" to 1" but found 1/2" higher to be ideal (high enough to keep clearance enough but not excessive (negating the affect of the belt wrap) for all the pulley combinations and have good clearance for the #6 plug wire to coil). With that, the magic belt size was 73.3" (Gates part# K080733)


I test fitted all the combinations I could have a use for and took measurements of the resulting clearance in the pinch area and tensioner position. The belt wrap has a 3" smooth pulley on it fyi.

The area I measured clearance at is where I'm pointing to in the above picture - where the belt comes close to touching its self.

All the following combinations are good:

2.55" s/c pulley, 3.0" tensioner, 3.5" idler : 1/4" clearance; tensioner good
2.70" s/c pulley, 3.0" tensioner, 3.5" idler : 7/16" clearance; tensioner good
2.80" s/c pulley, 3.0" tensioner, 3.5" idler : 9/16" clearance; tensioner tight
2.70" s/c pulley, 3.0" tensioner, 3.0" idler : 3/16" clearance; tensioner good
2.80" s/c pulley, 3.0" tensioner, 3.0" idler : 1/4" clearance; tensioner good
3.00" s/c pulley, 3.0" tensioner, 3.0" idler : 1/2" clearance; tensioner good
3.20" s/c pulley, 3.0" tensioner, 3.5" idler : N/A (remove belt wrap); tensioner good
3.3+" s/c pulley, 3.0" tensioner, 3.0" idler : N/A (remove belt wrap) untested

Hey everyone,

im thinking of getting a hogan down pipe an i was wondering what you guys think a safe SC pulley size is for my riv.


mods on the car already

short ram intake
cat back exhaust
3.5" SC pulley
180* stat
9mm wire set

Without some valve lift increase, 3.5 is a good place to be. 1.9 rockers or a cam would be next on your list. Until then you can increase performance quite a bit by tuning your WOT timing.

What are you using to tune?

i havent tuned it yet im on a budget so its kind of one thing at a time for me.

but what are good options to tune?

HP Tuners is the most common place to get started for 3800s. There is an older tuner out there called DHP PowerTunr but they are not made anymore, software is a pain for it.

If you want to do any more than you have now, you will really need to tune. Also you will really need to increase engine airflow (valve lift/duration) somehow.

thanks

When I replace my stock SC pully with a 3.6, do i also need to replace the belt with a smaller size? Or is there some way that i can just adjust it to tighten it up without having to replace anything else?

no need to put in a different belt. the tensioner will take up the slack.

Alright thanks man. I was hoping i wouldnt have too

go into the search bar and look up what others have done to their series 2 rides. lotsa good info