Thread: Working to drop my pulley size. Some questions about the process..

Man, am I glad some people are as stupid as I am to want to modify these 3800s.

I've been doing some digging around on the forum, getting my learn on in places like blueguy's 'Safely modding your 3800' and Reptile's 'Octane/KR explained' threads. I'm really grateful for the guys on this forum putting the time in to help newbs like me.

However, I still had a couple questions when it comes to the process of getting my car ready to take a pulley swap. Some of those questions are as follows..

The first one's gonna piss you guys off: Do I really need to upgrade my intake if I don't plan on dropping below a 3.4" pulley?

Sorry, but from all of the discussion about the gains it actually makes...I had to ask. I just don't know a ton about the differences about HAI/CAI systems, and I don't want to install one or the other and realize it was a mistake. Some guys think the difference from the stock setup is negligible to begin with. (I was also concerned about ambient temps, as they vary from -10 to 100+ in Iowa.) What do you guys think?

Second one: Can I upgrade my spark plugs to desired now, or will I have to change them every time I want to drop the pulley? I really just plan on doing everything that's necessary and then going down to a 3.5 or 3.4, I was just curious what you guys thought was best. Not trying to be cheap, just don't want to buy a set or two when I don't have to.

And last but not least...if I throw some headers on, can I call it good on the exhaust?

The stock air box is crap, at the very least you should gut it and use a k&n drop in panel filter. If you're going to mod then you should just upgrade, a diy one will work just fine. I had/have, but not currently using, and CAI the was in 2 pieces for the North Star maf. It was nice because in the winter I would just use the short piece and not have to worry about sucking bug road crap from it being in the fender well. You can put 104s in with the intake and a downpipe and then change the gap when you drop pulleys. I'm running 104s gapped at .055 with a k&n intake, ubend delete and zzp catback and don't have any issues. These motors like copper plugs best and they need to be changed out more often but that doesn't mean every 10k under normal driving.

The stock catback is restrictive and could cause some knock if it's too restrictive with your mods. But I don't see why not. Headers are not an easy install but are worth it. If you're sticking with stock exhaust I recommend SLP or the speed daddy one.

If you're looking to drop pulley sizes you gotta do headers first. Really any performance gaining mod on these cars needs to begin with changing out the headers. Otherwise you're just waiting for a KABOOM to happen. I'm no expert, just a couple notches above a noob, but I have done enough work and research to know you need those headers done first. That will open up so many other mod opportunities. And from what I have gathered, you don't need to change the intake to run a 3.4 setup. An actual COLD air intake setup will help. This setup in the link below is pretty solid, best one I have seen on here. There's an actual effort being made to suck in cold air, vs. just a cone right next to the throttle body.

http://www.grandprixforums.net/threa...derwell-intake

Originally Posted by Swiggles

The stock air box is crap, at the very least you should gut it and use a k&n drop in panel filter. If you're going to mod then you should just upgrade, a diy one will work just fine. I had/have, but not currently using, and CAI the was in 2 pieces for the North Star maf. It was nice because in the winter I would just use the short piece and not have to worry about sucking bug road crap from it being in the fender well. You can put 104s in with the intake and a downpipe and then change the gap when you drop pulleys. I'm running 104s gapped at .055 with a k&n intake, ubend delete and zzp catback and don't have any issues. These motors like copper plugs best and they need to be changed out more often but that doesn't mean every 10k under normal driving.

The stock catback is restrictive and could cause some knock if it's too restrictive with your mods. But I don't see why not. Headers are not an easy install but are worth it. If you're sticking with stock exhaust I recommend SLP or the speed daddy one.

Originally Posted by CHI2000GTP

If you're looking to drop pulley sizes you gotta do headers first. Really any performance gaining mod on these cars needs to begin with changing out the headers. Otherwise you're just waiting for a KABOOM to happen. I'm no expert, just a couple notches above a noob, but I have done enough work and research to know you need those headers done first. That will open up so many other mod opportunities. And from what I have gathered, you don't need to change the intake to run a 3.4 setup. An actual COLD air intake setup will help. This setup in the link below is pretty solid, best one I have seen on here. There's an actual effort being made to suck in cold air, vs. just a cone right next to the throttle body.

http://www.grandprixforums.net/threa...derwell-intake

Here we go...

Thanks for the input, guys. I appreciate the outside perspective, I've definitely got some research to do before I start pulling anything apart!

My first build was a top swap with headers and intercool so I went full out from the start. I plan to do a GenV with 3.5-3.6 on plogs.

I really like that intake!

Toss a cone filter on the end of the MAF, get a 180* in there, plugs/wires (I'd run the 104's and gap them @ .050" because I'm lazy and don't care to go back...I also usually get 10-15k out of 103's and 25k+ out of 104's...copper plugs last quite a bit longer than most people like to think)...also...motor mounts are on the of the most overlooked things on these cars...get poly upper square/circle inserts...and either get new lowers or solid rubber lower mounts. Worth their weight in gold for the money.

As for the exhaust if you're not wanting to mess with headers...clean up the castings on the front manifold (for free), or go snag up a Front Powerlog...and lastly...a 3" downpipe...catted or not, up to you. I'd run catless and keep the stock catback. It flows MORE than enough for your setup...usually when you start finding power levels north of 300~ WHP...that's when the catback needs upgraded.

Lastly...tune the thing. If you could get all that done and meet up with someone...like this GTPower guy (who knows his sh1t)...or someone in the general area...you'd be more than fine.

You are getting a lot of differing advice. There are lots of paths to follow, but all should involve watching knock retard. Get KR to zero first, then consider dropping a pulley size.

Originally Posted by b4black

You are getting a lot of differing advice. There are lots of paths to follow, but all should involve watching knock retard. Get KR to zero first, then consider dropping a pulley size.

Agreed! Stock these cars have some knock. Flow mods, intake/exhaust will help lower the knock and then finish it off with tuning before you slap a pulley on.

If you don't want to spend money on a tuner then you should get a gauge to monitor, I prefer Aeroforce intercepter but they make some blue tooth ones that link to your smart phone. Do some research though because not all will display knock and some that do might not on some cars. Aeroforce is nice because it's on all the time I'm driving and you can set up warning lights so when it starts to see knock at whatever you set it to then lights come on to tell you to let off the gas.

I'm going with headers, just to feel safer. Lol and I'm probably going to go turdbo later on, after I get done up here in Alaska... I wonder what -50°F intake temps will do to kr... Lol route a FWI through the foglamp housing for maximum cold.

You can reuse a front plog if you turbo, you won't be able to use headers. You can reuse the rear plog if go with the z3 turbo kit, which I have for sale, or the cartuning kit since they both utilize the rear manifold