Hello all, I am planning to go to my local junkyard soon and take the supercharger out of an '04 Supercharged Impala or a '97 Grand Prix GTP, and was wondering what I need to do it, and roughly how long the process would take, as I plan to do an L67 top swap soon on my '03 SS. Apart from the supercharger, is there anything else that I should grab while I'm there? Let me know, thanks!

 

That's the downside to a top swap, you need practically everything external to the engine block. The blower needs the lower intake to bolt to, you need the heads (and their valve covers) to work properly with the new intake, you need the higher flow injectors, the fuel rail to mate to the new injector holes, the throttle body to bolt to the sc, the maf and map sensors, the balancer to add the 2nd belt circuit, all of the stuff on that belt circuit - the coil pack bracket, idler, tensioner, etc etc.

Just the SC alone is only a tiny piece of the puzzle. About the only stuff you're going to leave are the exhaust manifolds, the front engine cover, the water pump - stuff like that.

 

Damn, seems like an extensive process but I’m willing to put the work in to get it done. I figure a few days at the junkyard to get everything I need? Also, is there an updated guide for the top swap for a 6th gen monte? I’ve read around a bit but can’t seem to come across someone that has pulled off a top swap recently but I doubt it’s changed much over the years

 

Not at all, this should be under a full day, even for a first time.

The only thing that's a pain is the balancer. I don't know how tight of a budget you're on, but if you've got an extra $100 to throw at it, I'd really think about just leaving the donor balancer and buying an aftermarket replacement. The rubber is probably deteriorated pretty bad on the donor car anyways, so its a major labor saver and you get a fresh balancer that'll last the life of the car.


Not sure I've ever come across a guide / write up for top swapping. The thing is, you're just taking off stock parts and putting other stock parts back on - so 99% of the necessary info is contained in any OEM repair manual for these engines. There really isn't any custom work being done on the mechanical side of things.

There's only a few differences I can think of:
-Wiring. They sell a cheap adapter harness for the only 2 differences.
-Tuning. You can send your pcm off to get tuned or mail order one and return your core.
-Fuel rail connection locations - several options
-Knock. You need to figure out what you're going to do about knock. Your bottom end has higher compression than a stock supercharged engine. Even stock supercharged engines have some knock from the factory on premium gas. So you need to do something to reduce knock or your going to kill all of your newfound power gains. A few options:

1 Request reduced timing in the tune. Not a great option as you're throwing power away and will need a retune to get it back.
2 swap to a larger supercharger pulley. This will make less boost, and be less prone to knock. Also not really ideal as you're still throwing power away, but at least you can swap pullies yourself easily once you've converted to a modular hub.
3 Do mods to reduce knock. Best option as youll end up with even more power in the end, but also costs more money up front.

 

Neat, will definitely be saving this for future reference. And as of right now, money is not an issue cause I have around $1200 saved up to spend on my car. Thank you for all of your help and finally, which OEM manual would provide instructions on how to remove the parts? I was thinking Haynes maybe but it says they have no info on supercharged models. Nonetheless, maybe it's a very similar process and I can just replicate what they do on the L36 models on the L67.

 

The Helm manuals are the gold standard for gm at the diy level. If you go for them, Id check eBay or online used bookstores first. They're very expensive new, but resale value is fairly poor when people sell their cars / no longer need them. Ive seen them go for under 25% of retail on the used market.

The nice thing is removal is the easy part as you don't have to worry about which bolt goes where or torque specs. You just look at the outermost component (fuel rail for starters) and remove that, then the next thing on top and the next thing. May even try searching YouTube for head gasket replacement on a SC 3800 - removal of the top end is identical to that.

Biggest suggestion for me is bring a box of small ziplock baggies and a sharpie. Make one bag for each component (ie fuel rail, supercharger, etc). Id also take some pics before you get started (as you likely won't want to once you get greasy). If you ever come across certain fasteners that are unusual - make note on your bag (ie a part is held on with 5 of one type of bolt and 2 slightly shorter ones- make a note of where the 2 short ones go).

It'll be obvious to you what bolt goes where that day, and maybe even the next week. But if you don't put parts back on your car for say a month, youre going to look at the pile of hardware and go 'oh crap' if you don't take the time to label things now.

 

Let me emphasize how important this is. After my Nissan engine has been sitting in pieces for the last 3 months, I have no idea where any of the bolts go. Ill figure it out because ive been thru this a couple times now but if it were my first time doing this, I would be completely lost and probably wouldnt be able to get it back together.

 

Yeah, these Helm books are very pricey out the gate. If I were to buy a used one, would a manual on any L67 car suffice for what I need? I know the engine itself is the same on all of the cars with it, but I just want to be sure.

Removal is always easy but when it comes to putting stuff back on it gets messy for me. I´ll for sure take videos/pictures of the fasteners as well as label baggies with parts as you said.

 

Yes, just make sure its an l67 car and not a l32 (04+ gp). Would be ideal if you could find a cheap used one for your year (or even an 04) as it would cover both engines, but I know availability is all over the place on the used market.

 

Just throwing this out there.... Possibly grab the entire L67, motor, trans, wiring and PCM. Get it all. Might be more worth while.