I'd really like to see some pics of your Buick, when you get a chance. Thanks.

 

The run of the mill bolt ons should get you there. I would think it would be a little lighter with the all aluminum 5.3. A converter is a great mod. Do you have a clutch fan or electric fans?? Since its a 5.3, you could drop a smaller cam in there for some real added power. Have you checked to see if anyone makes headers??

 

maybe give allen a call

 

Sounds like a cool Buick! I'm also running 18" wheels with 275/55R-18's Michelins on the Envoy XL. Haven't done anything with the exhaust on this one yet, can't stand the droning sound I usually end up with when I do. I may just look at replacing the muffler if I find a quiet enough one. I did replace the MAF with a Granatelli piece I had on my the previous vehicle, a 2000 GMC Sierra SLT 2WD 4-door 5.3L. I did just order a Hotchkiss sway bar kit for the Envoy XL. It includes replacement front bushings, and a larger rear bar with end links and rear bushings, all with lube fittings. Should be quite an improvement. The XL's are stretched 16", and the rear sway bar feels completely inadequate. Drew at Hotchkiss claims they changed the design on the 2004 model though, so I'd call him first if you're interested. If you do decide to order the Diablo Predator, I'd suggest taliking with Johan first. He is pretty up on these, and claims the tuning is similar to the SSR. I never did send him the baseline tune to receive an 87 Octane tune, just got too busy. One of those tasks I need to make time for. But he can provide this if you're not comfortable tuning it yourself. Mostly I've tightened up the shifts and gave it a little fuel / timing.

 

Who's Allen? And yes it has the clutch fan! How hard is it to convert to electric? The 2005's did i think. I was wondering if any headers would work, but i don't want to get to crazy. If i can get this thing to run mid 14's i'll be happy. Next spring i'll be getting a ls1 to play with. Either a z-28 or w-s6! This is just a sickness to keep messing with my wife's car! We have all been there!!!!!!!!!!!!!!

 

i have some custom electric fans for sale that i was goin to use on the I6. But the I6 has an electronic fan clutch so e-fans wont work. It should work to the 5.3 though and slide right into place. And allen, farmtruc, he is a badass tuner, should be one of the sponsors.

 

the exh. i had done custom. i did a magnaflow 3' in and dual 2.25 out to dual exit. The buick has the quiet tunning so i went with the smaller muffler. It is a nice sound getting to speed, but when you reach cruising speed[60-75]it is hardly noticable! I do like it, in fact i wouldn't mind it to be a little louder! So back to other bolt ons, any plug/wire combo? I would like to run a more adgressive tread and do a 285/50r18 or a 285/60r18 but not sure on the hieght? The tire i have now is a 275/55r18 mich. cross trer. I'm am looking for more performance on the highway at higher speeds! I see there is lowering springs out there but i'm not sure if i want to do that. The stock tire dia. is 29.3 i'm at 30.2 the 285/60 is at 31.2. I would like to know if this going to effect performance to much. I know they would fit, this would fill some of the gap without lowering the truck. I don't want to loose my gear/performance though.

 

Need some help on these topic's please!!!!!

 

I'd suggest Bosch Platinum +4 plugs & Magnecor wires. A little pricey, but I ran them on my 2000 Sierra 5.3 and really liked 'em. And looking at the trouble it will be to replace the rear plugs on the 5.3 in this platform, I don't want to do it again. I'll be replacing mine after this year. My Envoy XL came with aftermarket 265/60R18 unidirectional Falkens which were 30.5". They rubbbed on sharp turns, and gave me a lot of unusual tire shake. Just replaced them with the same 275/55R18 Michelins you have. Very smooth ride, and I seemed to gain some better acceleration from a stop. Nice thing about the Diablo Predator, you tune in the tire size, not the diameter, so it's very easy to change. I would not recommend a taller tire, you'll feel the taller gear ratio. You can compare at: http://www.1010tires.com/tiresizecalculator.asp

 

what is the part # for the plugs? And what does everybody gap their plugs at? Also what does the average 5.3 get for mpg?