I just bought a new truck, the rebates are incredible right now so I couldn't pass it up.

What I bought is a 2004 Silverado Regular Cab Short Bed Work truck Package (plain jane as it gets these days, though still pretty nice) and the only option is the 4.8 V8. I didn't want a V-6, and there was 1 unit like this in Texas that was still availible in white (I like white paint, simple and cooler in the summer months) luckily I was able to get it transfered to my local dealer, and this was the only white one without being a Regency package with a 4.8 and 5 speed manual trans. Truck was REALLY cheap too!

I drove it today, but won't take delivery until Tuesday. It runs okay, has lots of high RPM power but is seriously lacking in the 1000-4000 rpm range compared to the engines of yesteryear models. The rev limiter also seems to cut out the engine just a little too soon, it is pulling very hard then all of a sudden it cuts out, about 5600 rpm. I'd like to extend that to about 6000 rpm though I'll probably be shifting at about 5800 rpm. Hitting that rev limiter can seriously slow you down.

I don't really plan on making this a hotrod truck, but I would like to do a few simple things to get better performance out of it and was wondering what you all would recommend for it.

Some things I have already started to consider are:

1st Cutting off the stock muffler and tailpipe and installing a 40 series 2 chamber flowmaster with a turn down in it's place. I love the flowmaster sound especially with a manual transmission.

2nd Hypertech Power Programmer III Raise the rev limiter and run the 93 tune. is this any good? Are there better solutions out there for stock trucks?

3rd The truck came with a 3.42 open differential rear axle (no locker). I would consider upgrading to a locking diff because if you nail the throttle in first gear at about 15 mph it breaks the tires loose something terrible till you get into 2nd gear.

I realize there may be some "free" mods for these trucks, but I don't want to do anything that is going to void the warranty on my engine or transmission, the rest of the truck I could care less about.


There is so much information here that I am going to have to sit down and read up, but I figured if I post what I got you guys could easily point me in the right direction without searching for hours through old posts.

Thanks!

Chris

 

I basically started out with the same thing but in an 01 model. I got a Hypertech tuner a set of Gibson headers, ASP underdrive pulley and was very satisfied with the results. I would suggest an Eaton posi but stick with the 3.42's since the 5 speed has such a low gear.

 

I've got the '02 same truck. Stuck in 390 posi, long tube headers, and flows and that deff. helped the pickup. The pp3 imo stinks unless you run the 93 octane all the time $$$, but I have and it does help with rev limit and getting the mph right after gears. With a couple more bolt ons I run mid high 9's in the 1/8th on stock tires, but my sincro's are already going in my 5spd.

 

thanks for the responses. I am wondering about the durability of the 1/2 ton version of the 5 speed myself. If they make them like they used (88-92) 92 was the last year I owned with a 5 speed before now, then I wonder if it will hold up to anymore hp than the stock 4.8 already puts out. Rated at 285hp is that RWHP or crankshaft HP?

I have been looking at the parish8 truck videos and drooling over the turbo setup, but I will probably never go that extreme on this truck.

Also I have heard recently of a "new" way of installing turbos on pretty much anything buy sticking the turbo inline underneath the truck on the exhaust pipe that is already there. Anyone have expreience with that?

How does your truck run with the 87 tune on 87 octane gas? Does it knock if you try to use the 93 tune with 87 octane gas? Theoretically wouldn't it make more power with 87 octane running the 93 tune if you didn't have detonation problems?

 

Get rid of the 3.42 open Diff , best think I have done to my truck performance wise ...

3.42 = crap

get 3.73 or 4.10

 

The turbo your talking about is the sts turbo system(that's the only one I know of). Just do a search on it here or ls1truck forum plenty of info and guys that already have it. Don't even think of running 87 on the 93 tune you won't be able to hear your radio . I think that 285 is to crankshaft although give it time I'm sure someone with better knowledge will come along. I don't know if they fixed the prob with the 5spds from what I've been told they undersized the clutch slave cyl and at wot when you make the shift from 2nd to 3rd its like you don't even have the clutch engaged because of the lack of clutch fluid. I saw how to fix the problem once on a website and never been able to find it again. So if you don't race it you shouldn't have any probs. Sorry so long winded maby somone will come along and tell us both the whole truth
Josh

 

Uhm, doesn't the slave cylinder only assist in disengaging the clutch?

Also to the guy who says 3.42's suck, is you truck an auto?

And I will probably go to the local tracks every now and then with some friends and race. Bone stock racing is kinda fun, as long as it's not brackets....

 

Yeah you can pull out of 2nd but can't get into 3rd. Not real knowledgable about it but that's what I remember about it. The racing is fun but I've already started to wear my sincros out so I had to quit. Full size chevy forums have a sticky in the performance section as to all the bolt-ons. But if I had to do it again I would save my money from all the little bolt-ons and just s/c. Just my 2cents tho. The 3.42 do suck and open diff suck worse just wait till it rains and you can't get under the red lights all I ever did was spin til I got posi

 

285 hp is definately crank hp, not wheel hp. Posi will be an awesome addition to your truck once you have the power for it to make a big difference.

I would reccomend a tune from nelsonperformance, or pcmforless, because they will net much more hp, and you can have them set whatever rev limiter you want.

Flowmasters have the best sound in my opinion, but do not give the best power. Magnaflow, or some others are known for better performance.

Free mods include a TB bypass where you can disconnect the two bottom coolant hoses that go into the throttle body, and then connect them together. I have seen a dyno on an F-body where this gave a 6hp difference. That is the only real "free mod" that I know of unless you want to cut a hole in your airbox.

The "new" way of mounting the turbo is an STS turbo kit. It mounts the turbo where the muffler goes, and gives really good power per dollar. Supposed to be really easy to install, and actually give you about 3-4 more mpg on the highway. Seems like a perfect addition to me

 

3.42 are crap with an auto but not a manual, the auto has a 3.07 low gear and the 5 speed has around a 4.03 low.
Auto 3.07 x 4.10= 12.58,
Manual 4.03 x 3.42 = 13.78 total first gear reduction. So the manual has a lower first gear with 3.42's then the auto with 4.10's