I read over on the motor trend site that a trailblazer from the GM performance division w/ the 4.2l was twin-turboed, running 8.5lbs of boost, and it was making about 400HP. I believe all they did was change the cam and lowered the compression , and tuned it of course. Here is the article: http://motortrend.com/future/concept...zer/index.html

I would rather see this be thier SS model than one with 6.0. Typhoon 2?? What if is was done right w/15lbs of boost? 500+HP???

I also read somewhere they single turboed the 3.5l inline 5 (the 4.2's little brother in the Canyon and Colorado) and it made 350HP. Not bad for a 5 cyl.

Anyway, my wife has the an 02' Envoy SLT, loaded w/ the 4.2 inline 6. I have to say this is quite an impressive engine w/ 275 HP and 275 TQ and a volumetric effeciency of 94%. The engine is super smooth at idle all the way up to the redline (inline 6's are naturally balanced engines). It is also quite as a whisper. The acceleration is very linear with the flat tq curve and the hp peaking high in the rpm's. On the highway @ 65mph it will climb to higher speeds quickly and not have to down shift. The overall ride on these trucks are silky smooth, especially on the highway. Gas mileage around town averages 15.5-16mpg, on the highway it is easy to see 24mpg.


Someone does make a supercharger kit for the 4.2 ( I forget who) and I do believe nelsonperformance can tune the 4.2's.

The only gripe I have with with this truck is that the thing slides sideways very easily in the snow with 4wd on. I have a good felling that is was because of those stock POS michelin cross terrain tires. I just replaced them (got 60% of the price under warranty from michelin) with the proven michelin LTX M/S. Waiting for some snow to see if this cures that problem.

=Dave

 

my wife wants one. the one we were gonna buy last year was purchased by our neighbor. go figure.

 

That's some good info on the TB's. I'd like to have one. I have always talked about how I liked them since they came out. Just recently my bud that always helps me got one. I converted him from Ford to a real truck. He finally agreed I guess that the TB is a nice truck too since he just got his wife one.

 

Exactly what i was thinking

 

unfortunately, we can't wait until spring '05. It has a great volumetric efficiency. Does Allen or MTI tune these?

 

I don't think there is tuning available fort a TB yet. I hope I'm wrong though cause I would really like to have one of those.

 

how about 1/4 mile times can it keep up with a mustang . my mom is getting one

 

I have a TB EXT with the 5.3, its not as fast as my truck, but my truck is probably 600lbs lighter i'd guess, with more work done to it. It certainly has more power than the I6 did tho in the couple I tested prior to buying ours. Tried both a 4x4 4.2 for a weekend in the mountains, and a 4x2 4.2 on a 24hr test drive. Very happy with out 5.3 though.


Now blown chevy, when are you going to hook me up with a free radix and install for the opportunity to prototype a system for a '04 TB with the 5.3? A couple other well known companies have already tested with mine, so I know the drill. How about it eh?

 

i'd be up for a radix on it. we may get it this weekend.

 

i raced my 4.2 270 hp '02 SLT Envoy against my buddies 04 Silverado with the 5.3 and extended cab and the race was pretty close down low, but the Envoy pulled up top about a car to 80 mph, both being bone stock.