Upgrades to my Avalanche

I'll play 250 rwhp & 315 ft/lbs. Tim I towed my car with my brothers truck to the picnic , boy that was different. I'll stick with my diesel. His truck wasn't under power but had to down shift on every incline and got terrible gas mileage just pulling trailer and car.

Rick:)
 
yeah I know the feeling...I keep telling myself it's a daily driver
 
Well, that was.....disappointing :( Final numbers are 257 rwhp / 274 rwtq :confused: What happened....well apparently more air in equals more HP. More air out equals less torque. In talking to Omer, maybe different gears will help. He is calling axle boy (a specialized axle and differential shop) to set something up for me using 4.30 rear gears. I told him I didn't want to suffer too much on the highway, and he assured me that he could care for that in shift tables or something. So, we'll see
 
Tim Isn't 4.30 grears going to KILL any fuel mileage, I mean it should pull a house down but what 5 miles to a gallon

Rick:)
 
His reasoning is that my current gears are 3.73, I have 20" wheels with a tire that measures 31 1/2" diameter and that I effectively end up with a much lower rear gear ratio. Not sure how to do the math on that, or if that is something that I can prove out here, but will be doing some research to find out.
 
So, you picked up 30 HP. and lost 15 Tq.

Tire size - that's interesting.

So what would happen if you just bought bigger tires? Or even bigger wheels?
That should change something right?
 
No, smaller tire diameter would help, larger just make it worse. Slap on a set of 14". :)
 
Actually to correct this, I would have to go smaller or stay the same and swap gears - front and rear. I did a little research. The diameter of the tires I took off, 265/70/17 is 31.7. The tires I have, 275/55/20 is 31.9. So doing calculations according to this site - http://www.ehow.com/about_6591408_tire-size-effect-gear-ratio.html - the difference is less than 1%. So I don't think my gear ratio - 3.73, is affected that much. I think a change to 4.10 would suffice.

For the price of a diesel - initial outlay, maintenance and fuel, I think I can afford to do some other updrades. Plus I won't have a monthly payment. Still wondering about a supercharger :rolleyes:
 
There was a local guy at Omer's shop last time I was there that had a stock GMC pick-up with a 5.3L that raced it. He made intake, exhaust, and computer mods.

Wouldn't your goal to get and extra 80-100 RWTQ?
How can you get there?
 
Major mods at major cost. Not sure if I want to spend it for 4 or 5 times a year that I haul the trailer. Kerry posted several ideas above. Seems like omer has changed his mind on superchargers :rolleyes:
 
On the engine work/Swap article - about 10K parts and labor - not worth it IMHO.

On the STS system - didn't read it - already know about those. Impressive. How much?

Third option - wait a couple of years - and we'll both go out and get new trucks.:D
 
Tim,

Many turbo purists turn their nose up at the STS system because of the long intake runner length and theoretical increased turbo lag. But in actual practice they have proven to be very effective with no perceived lag. I looked long and hard at an STS system for our 4.6 DOHC.

However don't let the purchase price deter you. I shopped around and found a Paxton Novi system for the 4.6 that was new in the box that a guy in Arkansas never installed. He paid $5800 for it new. I bought it for $2500 cash. New in the box with everything included.

Watch eBay and craigslist for an STS that would fit your truck.

Another note: the STS does not require a change in exhaust manifolds or intake manifold as required by most turbo installations. That makes the installation much simpler and less expensive. It also gives you the opportunity to remove the turbo system when you sell your truck to either resell to recoup your original cost or use on another vehicle. Not so with any other system or with internal engine modifications.

Keep in mind that a turbo builds boost as load increases...exactly what you want for towing. When not under load it operates much like a naturally aspirated engine. One common response by STS owners was that their street fuel economy actually increased after the installation when the engine was not under boost.

I would take a very serious look at the STS system for what you are trying to accomplish. Find and talk to another owner that has one on his truck.

Kerry
 
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