My 2004 Monte SS/SC has been parked for awhile as the inspection expired. I finaly figured out all the problems with it. I Still have to change a wheel bearing and I have a fresh brake kit to put on it. I should have it back on the road soon. Once I have it back on the road I would like to put a smaller supercharger pulley on it but am unsure what size to go with and if it will get me the power i want.
The car has a K&N cold air intake kit, ZZP 1.0 PCM, ZZP 3" cated downpipe, resonator delete, one range colder ngk v-power spark plugs, and a 180 degree thermostat. I allways burn 93 octane.
I really want the car to be at least able to run with cars such as a stock LS1 Trans Am. ZZP includes a 3.5" pulley for their stage 2 kit which is a similar setup. But then Intense gives a 3.4" pulley with their kit that doesnt include a downpipe or even ubend delete. I feel like I have seen other members running a 3.4" with about what I have or less. Does anyone think I'll be ok with the 3.4" or should I play it safe with the 3.5" I do have a way to monitor the KR and I currently get 0. Will this even get me the power I'm looking for? How about if I add a front power log, could I use an even smaller pulley?
I'm open to doing more upgrades if I need to I just dont wanna do anything too crazy. I think a cam or rockers or an intercooler are out of the question for right now.

So my real questions are what size pulley would you recommend with my current setup? And if that wont get me the power I'm looking for what else do I need to do?

 

I think you can get an OBD scanner from amazon or ebay for cheap, connect it to your phone to read KR.

You must scan first, as you could have knock currently. I had more mods than you with a 3.4" pulley and had 10*+ of knock.

 

When you get a pulley, I'd definitely get a modular hub not just another press on. That way if / when you want more it's just a few bolts and you're done.

As for pulley size, I think it depends how open you are to more mods after. If you just want to stick on a pulley and be done, I'd probably just go 3.5" as it's likely to have less KR than the 3.4" with your mods. But if you're ok modding a bit more, I'd probably go 3.4" then add supporting mods to get it knock free.

As nitehawk mentioned, I wouldn't be too surprised if you end up with more knock than expected when dropping. But if you're really starting from absolute 0 KR, you're in a better position than most.



IMO, you're still going to come up way short with what you're currently looking at. Stock vs stock you're talking almost a 100 whp deficit (190-200 whp vs 290ish whp). A 3.4" with basic supporting mods will get you 230, maybe 240 whp at best. You're still going to be 40-50 whp down (plus in a platform that wont launch as hard from a dig). The weights of the two cars are close enough as to not really help you either.



That's a tough one as you've already ruled out IC, cam, and rockers.

Avoiding those, I'd say E85 + huge pulley drop would be ideal. Certainly less ideal, but meth injection is another option, albeit a bit more risky.

If those are out, you dont have many options left. You have to just keep chipping away at bolt ons (EWP, ported blower or gen 5, bigger TB, etc etc) but bang for the buck wont be all that great.

 

I cant get E85 in my area. I could get 110 octane race fuel but I'd rather not have to run that all the time. I dont trust a liquid cooled intercooler with a pump. My old 1990 Thunderbird SC had an air to air intercooler with an Eaton M90. Is it possible to do that on these cars? I might eventually be open to doing rockers if they will make enough difference, I'd really rather not have to do a cam though. I may just have to take the power I can get for now. If I get the 3.4 pulley for now and end up with 10 degrees of knock I risk blowing the engine right? Is it really safe to go with a pulley that will create knock and try to get rid of it with upgrades later? Sounds like I should go with the milder pulley now, do more upgrades, then get more aggressive with the pulley after. Is it safe to assume the 3.5" would be relatively knock free on my current setup or should I really have more upgrades before even running that?

 

Certainly possible, but not easy. A lower adapter is available for RWD platforms that could be made to work, but its $1000 AUD for the plate alone, plus piping, the IC, and custom work to make it fit FWD. TBH if you're hesitant about even doing rockers, this wouldn't really be an option for you.

TBH, it would be pretty dumb to put on a pulley, see you've got 10 degrees of knock, and still go out and beat on the car. Certainly could destroy a piston doing that, but anyone who did that deserves it, as that's the whole point of scanning. I was just assuming youd want to keep modding if you were serious about keeping up with LS1s.

That's the other nice thing about modular pullies though - you could buy both (or even a 3.4 and 3.6) and test each out. Then decide if you want to mess with more mods to run X pulley knock free, or if you just want to pulley up without more mods and sell the others.

Unfortunately no one can definitively answer that as we have no idea how close to the limit your setup is now. You could be .1" of pulley before starting to pick up KR. The further from stock size, the quicker the heat picks (and also knock).



One other option to throw out there depending how serious you are about wanting to run with LS1s - what about ditching the M90 for a turbo setup? Certainly a bit more expensive route, but you gain power from not having to turn the blower and from a more efficient system (especially intercooled).

 

Unfortunately the budget wont allow a turbo conversion. I can put maybe 500-1000 dollars into it at the moment then I could slowly do more mods over time. Sounds like it probably wont be enough to get me the power I want at the moment. I will get the modular pulley system. Do you think I should try the 3.5" and see if I get knock or maybe just start with the 3.6". I was thinking for my next step I would try the front power log if it will help me maybe the rear too. I could try to seek out a gen 5 supercharger from a junkyard. Is it a direct bolt on or do I have to change other parts to go with it? Is it much better than just getting a ported version of the supercharger I have? Also could I run 110 octane and a real small pulley just for the track and switch the pulley back after or would that require a completly different tune?

 

Also it's worth noting I was at 0 KR with just the zzp pcm, k&n intake, and 180 stat. Definitely before doing plugs and downpipe. My old cat was bad due to a stuck open fuel Injector before I bought the car and I think the cat may have been partially plugged. I dont think I checked KR when I first bought it so I dont know if it had any KR bone stock. Plus it came with the k&n intake when I bought it.

 

Well for reference, I had (basically) the same mods as you then dropped to a 3.4 and still had 0*-.3* KR..

As already suggested do the modular pulley and be sure youre always scanning for knock. Id also stick with copper plugs.


EDIT: Wait sorry, I also had headers before I dropped sizes.

 

I'd probably try a 3.5" given it sounds like it's been pretty clean on knock. I'd at least check the various forums to see if you can get the pulley used, they're usually pretty available, especially the larger ones.

Wouldn't touch the rear outside of for a turbo setup with the downpipe connection removed. The front and rear manifolds are very different in design.

Ported gen 3 is basically the same performance as a gen 5. The gen 5 does have a few oddball things about the install, but nothing too crazy.

I wouldn't for 3 reasons:
-Stock injectors will only get you to ~300 whp give or take. Thatll prevent you from going too crazy on the pulley without going lean.
-Similar issue for the fuel pump, although I'm not sure how much headroom there is on the stock monte pump.

It seems odd to upgrade the above two just for occasional track trips.


-Lastly is the tune. I'd tune a tiny pulley car different from a big pulley car. One big concern is the throttle % for PE enable (ie getting AFR below 14.7). With a tiny pulley, this has to be moved down much further as boost hits at lower TP. You dont want to be in full boost at 14.7. You also hate to tune it too low for your big pulley or you'll waste a bunch of gas from tripping the threshold more.

 

It sounds like I should go with the 3.5" pulley. I'm gonna get the front power log too. In the near future I might also get a 3.4" pulley to try and if there is knock I will go back to the 3.5 until I do more upgrades. Also, I'm gonna start checking local junkyards. I might be able to get a good deal on a gen 5 supercharger. One more question. I have a 2003 Cadillac Seville on its last legs that's just about ready for the junkyard. I dont want to keep putting money into it. Is the throttle body on that car the one people are upgrading to or are there different northstar throttle bodys?