[dbextreme]

Update on my Grand Prix... I threw #1 rod on my 99 GT and it's time for an overhaul!!!! Knowing the weak links of the L36 I found a LOW mileage L26 out of a 2007 Buick that I picked up. I purchased a top swap setup from a member on Grand Prix Forums and had the Gen III blower case ported, intake and heads gasket matched, exhaust opened up some, all polished up ect. Running an XP cam, 42.5# injectors, N* throttle body with LQ4 MAF, 3.4 pulley, SD headers, custom tune PCM from Intense, among other stuff.. I'm ready to get it back on the road and hopefully will in a couple week.. Here's some pics, I'll post more this weekend when I get the block reassembled ready to drop in.

 

[josh89]

Looks like quote the project. Keep up the pics..

 

[dbextreme]

XP cam installed, Double Roller, Studs. Figured I'd mock up some other stuff...

 

[dbextreme]

Also pulled that big ol 3.8 pulley off for a MPS 3.4 setup.

 

[lababy78ta]

What hp range your looking to get after the mods? Sorry if it sounds stupid lol it just interesting your modding the GP i love those cars

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[dbextreme]

I have seen similar builds get ~ 300whp give or take some. I've had the heads cleaned up some with mild exhaust porting along with intake/heads have been gasket matched. I'm hoping with the heads and 3.4 pulley I'll get 300 - 320whp. Now when I go intercooled, that will be a whole new world.

Doesn't sound stupid at all, I'm curious about it to but it's hard to say. I'm guessing based on similar builds. I will dyno the car once it's done, local shop offered up free dyno time because they are curious to!!! lol

 

[lababy78ta]

I have seen similar builds get ~ 300whp give or take some. I've had the heads cleaned up some with mild exhaust porting along with intake/heads have been gasket matched. I'm hoping with the heads and 3.4 pulley I'll get 300 - 320whp. Now when I go intercooled, that will be a whole new world.

Doesn't sound stupid at all, I'm curious about it to but it's hard to say. I'm guessing based on similar builds. I will dyno the car once it's done, local shop offered up free dyno time because they are curious to!!! lol

Lol that's so cool i really like GPs just never think abt tinkering with one but now im seriously curious as to what this baby might put up lol keep updating and videos when its running!! Best of luck man!

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[dbextreme]

Will do, I appreciate it!!!

I know stock GTP's running 8.5:1 are rated at 260hp. Just top swapping a non supercharged motor will give you the all the perks WITH 9.4:1 compression. There's an instant 5% increase putting it at ~275-280hp. Stock cam lift is intake .413/ exhaust .413. The XP cam I am running is .520/.536 with the 1.6 rockers. Decent difference there With the porting work to the blower, intake, and heads along with headers and higher compression and the pulley drop it should pull decent numbers. Probably pull my LT1 car pretty easily I hope.

 

[dbextreme]

Catch up:

Motor is in and bolted up



Starting to hook stuff up, MAF look familiar??



Installing my Aeroforce



Car is alive!!! Still idling high, but it's a cold start. Should be 650 - 700 RPM not the 1100 it's sitting at. Still might have a slight vacuum leak, but well see if it tones down.

*** Video ***

 

[lababy78ta]

Oh man it looks sweet but i can't watch video it shows like a pic not a video maybe its my phone lol can you make a link to video

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[dbextreme]

See if this works better.

2013-04-25181324.mp4 Video by dbextreme | Photobucket

I drove the car today and warmed it up. I'll have to do another video of it on the road and warm idle. Love the cam with the lower idle, it's sitting at 1100 in this video.. But I eased it out today, put 5-6 miles on it. Opened it up once at a 25-30 roll and and wow, after it hooked up it I think I have permasmile... LOL My exhaust will come in next week so a trip to the muffler shop hopefully next Friday or by the weekend at the latest. also I had to order a rebuilt supercharger snout, the seal was leaking BAD on this one slinging oil everywhere, so instead of just replacing the seal I'll just do it all right (should have in the beginning). It should be in Tuesday or Wednesday, I'll paint it and replace the old one... Other then that, everything seems ok.

 

[lababy78ta]

Nothing lol i.think its my phone but anyways why is it idling so high? Did u find a vacuum leak? I bet you had that smile all day long lol...

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[dbextreme]

dang phones!!!! Try the Youtube link.. LOL

Grand Prix GT Top Swap XP Startup - YouTube

I thought I might have a vacuum leak, but I also I am running an open downpipe at the moment so no back pressure might be causing it also. My fuel trims are off a bit to, so the Front O2 might be reading wrong since it's close to the flex in the header right before the opening... I can't do much until my snout gets here, mufflers should show up about the same time so I'll fool with it more after I get my exhaust on it and see how it does then. After I drove it today it's around 800 - 900 so a little back pressure might put me right where it should be.

And yeah!!!! my cheeks hurt!!!! LOL

 

[lababy78ta]

Holy sh#t it sounds good man even with exhaust like that lol i can't wait to hear it with exhaust done... N yeah your right its probably not vacuum leak.. How many lbs of boost you running? Are you using same fuel injectors? Fuel pump? How abt any upgrades to ignition?

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[lababy78ta]

Nvm i see your running 42.5 injectors lol missed that part

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[dbextreme]

Thanks! I can't wait either!! I had a hard time picking mufflers because of sound. I'll end up with 2.5" from the header flange back, new 2.5" Y pipe going into two Borla Pro XS Mufflers, stock tips. Right before the Y I'll have an electronic cut out just in case I want loud every now and then.

Fuel system is just the 42.5 #er's instead of the stock 36#. I wanted to go 60# to run E85, but NO stations close to me... Maybe one day. But when the fuel system starts to fail I'll beef it up.

Ignition, stock. I have not researched it a lot, and the only upgrade I'll end up doing is wire size. I'm running stock wires at the moment, Copper Autolite 104's, and I won't touch MSD coil packs for these cars due to the nightmares I've heard.

Boost was holding at 9psi WOT. Now with the supporting mods, and the cam overlap it's where it's suppose to be. I will purchase more pulleys (I have a 3.4 on the car, I have a 3.5 and 3.8 laying around, want to get a 3.0 - 3.3) and play around with different pulleys vs KR. Knock kills these motors. I'd like to have the smallest pulley with 0 KR.

I'll end up getting a new transmission before I go further with it. I hope mine holds up for a while, we'll see.. LOL But next motor upgrade will be an intercooler with a Gen V supercharger (04+ supercharger) but for now, I'll enjoy the extra power and sneak up on some tuners and other V8 cars..

 

[lababy78ta]

What advantages has a gen 5 supercharger over your gen 3? Also smaller pulley more knocking? You mean the supercharger pulley? Sorry for questions but i like to learn lol

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[dbextreme]

The Gen 5 is a LOT more efficient then the Gen 3, it's like it already has extensive port work and tighter tollerances. Runs cooler also.

Yes, smaller supercharger pulley can mean more knock. Because you are building up more HOT dense air. Main thing that kills knock is getting the air as cool as possible. Cool dense air makes for a happy motor. Things I did to help with that was install headers to help flow. I deleted my EGR so I'm not sucking exhaust gas back into the supercharger. I will install a fenderwell intake to move the air filter into the big empty space between my front bumper cover and inner fenderwell. After the fenderwell intake, I'm hoping I can drop a pulley size or two.

For each supercharger pulley change (.1") equals ~7hp increase. Each degree of timing due to Knock Retard equals ~5hp drop. So if I am running a 3.4" pulley right now with 0 KR at WOT I'm possibly maxed out. If I put a 3.3" pulley I might see 2* of KR at WOT. What that means is I gained ~7hp from the pulley drop, but I'm losing ~10hp from the timing change... So not only am I possibly causing damage to the motor with KR, I'm ultimately losing ~3hp running a smaller pulley.

Hope this makes sense.. LOL And I'm learning also it's all new to me, especially since mine didn't come supercharged originally. I get the benefits of the higher compression. Doesn't help with KR, BUT I don't have to build as much boost to make as much power..

 

[lababy78ta]

Lol it does make sense but why drop the pulley size if your losing more hp due to timing retard? Smaller pulley more boost?

 

[dbextreme]

I wouldn't, I'll play with the pulley sizes and see which one is the best to use and run with it. I constantly scan for KR, among other parameters.

Cooler allows you to build more boost, from what I understand.. lol so if the smallest pulley I can run now is a 3.4" and get 0 KR, I can now put an intercooler on my car and probably get down to a 3.0" pulley and get 0 KR because the air is much cooler. Again, if I understand correctly..