Modifications in general

ken1mod · April 1, 2006

Gentlemen,

It is important to remember that our trucks are engineered. That is, camshaft, intake tubes and exhaust are designed and tested to have the "best" compromise in overall performance.

When we change anything, we are moving the torque curves around and sometimes this is good and sometimes unpleasant. Many times we are moving the torque curves higher in the rpm range, this often makes more technical horsepower. Often this sacrifices low end torque and power which we all like at the stoplight.

I installed a "more aggressive" cam in a small block once and hated it. It had much less power off the line but pulled like a freight train at 4000 rpm. Problem was that I didn't drive it at 4000 rpm and I wound up going back to a milder cam.

Conversely, I replaced a worn out cam in a 454 with the tinyest, teenyist low lift short duration "economy" cam that crane made and the results were awesome. Driveability went throught the roof and I and my drivers loved it. This vehicle pulled trailers and I once weighed 28000 gcw. (turbo 400 and 4.56 tail gears. It ran and felt like a 12 liter diesel.

Point is, the engineering world is made of tradeoffs and our trucks are not designed by complete idiots (parking brake and ABS designer excepted) and you may be trading something you really like for 5000 rpm hp which is rarely used.

I have yet to read on this site of a "killer" mod that everyone needs.

Think before you spend a grand on a mod you may not like.

Ken

tnord · April 1, 2006

i think this is a very good point that a lot of people don't think about when buying modifications for their trucks.

moving the torque curve up a a few hundred rpm's is exactly what you don't want in a truck. if our small blocks were in a camaro or vette instead, then yeah....the intakes and exhausts of the world are a great idea.

this exact principle is the very reason i won't put intakes, exhausts, or headers on my truck.....all they do is increase power up top. i want more power in the 1200-2500rpm range for when i'm towing, and about the only things that will do that is making sure all your systems are working properly, and an ECU tune. other than that, we're pretty much stuck with what we got.

6Burgh · April 1, 2006

Gentlemen,

Point is, the engineering world is made of tradeoffs and our trucks are not designed by complete idiots (parking brake and ABS designer excepted) and you may be trading something you really like for 5000 rpm hp which is rarely used.

Ken

<{POST_SNAPBACK}>

You forgot the intermediate steering shaft.

michigan2500hd · April 1, 2006

I agree......even though most of us have tried mods we really hoped would be the mod that would give us that tire smoking power that we wanted. As far as the people that design and build these trucks i think they try to find the balance between power, reliability and economy. But there are things that they could do to give us what we are looking for. But they have to deal with the bean counters and pollution control, etc. Take the vortec max......why only stick it in a already loaded ext. cab or crew cab? It could go in any full size truck or SUV the general makes. I would love to have that motor but to have it you have to buy a truck that has ride contol and leather etc. Why not a reg. cab short bed, 4x4 ? That thing would fly and off-road awesome. Just my thoughts.......if GM would listen to the people buying and get their heads out of their butts they could to much better things.

ken1mod · April 1, 2006

Gentlemen,

No replacement for displacement?

Ken

tnord · April 1, 2006

in terms of low-end power........yes that's true.....kindof.

firstruck · April 2, 2006

Interesting thoughts, I could care less about smoking the tires from the line or top end HP. I only need to get from 0 to about 45 most of the time. Is there a mod that lowers(?) the power band. you know just more grunt from the line to even 20 or 30 mph? Besides changing out my 3.73 to 4.10's.

April 2, 2006

One thing we need to remember is that the first thought in "engineering" a vehicle is to satisfy the government CAFE standards. If this was done to truly satisfy the best of both worlds, the aftermarket wouldn't be as big as it is. That being said, I agree that any modification no matter how small can and usually does throw things out of balance. Especially when you consider the fact that the computers in these vehicles control the majority of aspects of your vehicle down to the most miniscule calculations. It's a good idea to research your mods you're planning on performing before you shell out the big bucks.

ken1mod · April 2, 2006

Gentlemen,

Amen.

Ken

Z'06 · April 3, 2006

Hmmm...

silverado3500 · April 3, 2006

I have one mod that will give you tire smokin' performance! It's called the Chevrolet 572

Rolandd · April 3, 2006

Folks,

Don't forget, anyone reading this forum is already way off the end of the bell curve that GM has in mind as the "average" user. The vehicle is engineered with many compromises and features designed to satisfy many needs and constraints. EPA and CAFE standards are one small set of issues, safety and market appearance are others. How many options look good in the showroom but never really get used, how many unseen features quietly do their job flawlessly for the life of the vehicle?

When doing mods one needs to think not only of the immediate gains but the long term issues as well. As teenagers we regularly installed V-8's into six cylinder cars and then saw all kinds of issues crop up from blown spider gears and overheating to excessive brake and ball joint wear. Why do you think you can pull another 20% power from you engine and still get 200,k miles out of the vehicle?

It's impressive that you can get into your truck in any weather and turn the key and go with little more than oil changes, tires, and brake pads for 100,k miles. If you think that any manufacturer in this day and age is cutting corners badly, see if you can keep your computer from crashing in the time it takes to put 10,k miles on your truck.

My guess is one of the highest priorities in the design of these vehicles is reliability, and at $20-40,k+ a pop, people are willing to pay for it. I am not sure that I would want to sacrafice that reliability for a few more horses, although my truck is my business, not my hobby (I have a 67 Charger for that).

--Roland

BigLarryT · May 21, 2006

As much as I'd like to agree with everyone at once,...these vehicles are made the way they are for a reason,...to do a job be it hardware for the weekend warrior, cargo running, soccer mom a to b runner,...they dont' make "hot rods" anymore because everyonebitcehs about gas prices,...maybe i'm retarded here but,...that's what i see,...BUT i still would like to burn the 22's of my 5.3L TahoeZ71,....if it means i have to prepare my wallet for a 572 swap,...SO BE IT!!

Wingnut · May 23, 2006

...they dont' make "hot rods" anymore because everyonebitcehs about gas prices,...
<{POST_SNAPBACK}>

*Clears throat*

*Pops hood*

*Begs to differ*

ken1mod · May 23, 2006

Gentlemen,

I would like to install duals on my 5.3 because I really like the sound of a v-8 into duals. I am scared that I will lose low end torque if I do this. I would really miss the giggles on my and my friends face when I do a burn out. Several posts here indicate a loss in low end performance after messing with the exhaust.

For the life of me I can't understand how lowering back pressure hurts anything. To me, it has to be some sort of tuning issue. Anyone have any thoughts. I won't trade 1 ft pound of torque at 1500 for 50 at 5000.

Ken