This is fine discussion, there is no argument

I removed ~15lbs (cat and exhaust attenuation valve) from my motorcycle. A bike that weighs 413 with an empty tank and at 8lbs/gal weighs 445 full of fuel. I didn't feel it. The tank is highest point on the bike, I could do a blind taste test and not be able to tell you whether my bike was full or empty

To answer your question, my Tahoe and MR2 both can "feel" a full tank. The Tahoe because Ive just added 448lbs of fuel (56x8) and 240 of that behind the rear axle. She squats and she feels heavier/more sluggish to accelerate and the steering is actually lighter feeling at slow speeds. Full of fuel the Tahoe scales 5920, with 302whp. Already not fast, and on mud terrains I am not trying to set any records either. The MR2 has 130 crank hp on a perfect day with great DA hahaha, so a wet fart can slow that thing down. But aside from accelerating, they both corner about the same FULL to E.

I'd like to point out that my MR2 is a street driven track car that has gotten ~1000mi of track use in the last 2 years. SPEC Miata's (if youre familiar with them) run ~1:36 on my track. My full interior/AC equipped MR2 runs 1:42.xx if I am mean to her, 1:44.xx if I am not trying for a glory lap. My MR2 and I are not slow on track, is my point. There is almost 0 difference in my lap times from FULL to E. When I look at the data my times actually get slower as the day goes on, and I attribute that to tire wear more than anything. The MR2 holds 14gal of fuel, so FULL to E is at most ~112lb delta. Thats using 100% of the capacity. To be frank with you, I don't feel that either haha. And thats a 2800lb car on the scales. I spent $300 on an Anti Gravity lithium battery that was 40lbs lighter than the AGM that came out, I didn't feel that. I also see no lap time difference when I take a passenger. And I've lapped with my ~130lb gf all the way up to my 210lb instructor. Always in the 1:44s

Ok, all my conjecture aside, lets get back to some math

I don't know LS alum to iron either, but the agreed upon number does seem to be 100lbs, thats fine. We can agree on that. We can agree that reducing the weight of the vehicle improves the "fun to drive" factor because the vehicle becomes more flickable, transitions easier/faster and effectively you have stiffened the suspension making the vehicle more responsive

I never meant to argue that the merit wasn't there in doing aluminum or reducing the weight of the vehicle. I was simply pointing out that the "argument" (or statement) that the truck would "handle better" as a result is somewhat false. Understanding of course that the term handling is often used to describe peak G hold capability

Without an aggressive alignment, additional suspension work or stiffer roll bars; your truck is 100% tire limited. I don't care if you have 400lbs of passenger, or 800lbs of fuel or you take 300lbs off the front axle; your tires are your limit (thats true of anything, and thats why better tires are the best improvement you can make to a vehicle)

Granted, you increase that limit with weight changes. But the tires do not function unless they are pressed into the ground. Weight presses them into the ground. Therefore, you have greater traction at higher weight; which is why the iron block mathematically provides more traction

The math is there to support the statement I just made. However the argument is that the change doesn't matter. Whether you pick iron or alum, the change is so small compared to the mass of the vehicle that the "feel" of the vehicle won't change and ultimately for the speeds you should be driving on the street; peak grip won't change enough for you to notice either

My semi-professional, semi-educated opinion is that you should build the motor you want. I put an iron block in the front of a C5. Granted, I know its not ideal but with 11" wide front wheels, Wilwoods all around and 315s out back: I doubt I am going to know the difference. If I had the funds to build identical cars and drive them side by side and the only difference was 100lbs on the front axle, I am sure my short comings as a driver far outweigh (hahaha punny) the weight delta

 

TLDR: Lets all understand that my argument/statements/math is related to this SMALL change of 100lbs +\- 25%

If you put 8000lbs of concrete in the bed, yeah there's going to have some tangible and clearly evident changes to the dynamics of the vehicle, lets be reasonable

I am saying that at 100lbs, the delta is so small; it doesn't reasonably matter. The change exists, in math and on paper; but in a real world scenario; it doesn't matter

Also @zebra and @adriver ; traction limits apply to both axles, not just the rear Traction is a dynamic term that applies to how the tire interfaces and produces friction with the road surface. It doesn't just mean putting power down

 

that's an agreeable speech

 

I just really don't like the gearing of the nv3500, and I don't like how you have to rev it over 4k rpms to get anything out of the 4.8. 1st is short even with 3.42. You have to use second and third for most traffic, and first if people can't see the slinky. When on the highway, 5th is only good if you're over 70, and with the 4.8 you have to go into 3rd until 75 then into 4th. You look, sound, and act like an idiot shifting from 5th, to 4th, to 3rd, to 4th to 5th to go from 70 to 80. I almost always accelerate at 80% or more, and then shift almost right into where I'm going to cruise. They work good together, but its two ugly people going to the bar and both think the other one is going to take one for the team.

I get what you're saying about more weight helping with traction; I just don't think it really applies in a pickup with the 'longer than a car wheelbase', where the engine is directly over the front axle. Front traction is never a problem for me unless I take a hard right turn at 30 and the road is trash. Its absolutely not going to help with traction in the rear, and going lighter in the front should theoretically help (by shifting the weight balance). If I thought I would notice it, then I would be able to measure gram weight with my fingers. I'm not trying to say its going to make a big difference, just more or less coming up with theoretical PROS and CONS.

The only reason I can probably notice the difference in the fuel tank is because I don't carry a spare tire. If I full throttle, I'll spin tires if I'm less than 3/4 of a tank, and I always try to fill up if I know rain is coming for days. Without that spare tire and an empty tank, there's nearly no weight over the rear half of a pickup when compared to a car.

 

Based on all your comments about the 4.8, an upgrade to a 5.3 won't make your driving experience much better. When going to a 6.0... that is enough difference to change your driving style significantly. You will 100% remove all that unnecessary shifting from your life. The 5.3 will be better but you'll still hate yourself when you have to downshift instead of lug 5th for a split second.

 

Our trucks have the engine behind the front axle center line, not on top of it.Traction is the definition of friction between the tire and the road surface. Increasing weight increases traction, period. That is not a debate or conjecture, its a fact that all auto manufacturers use in their design. Its also why mid-engine cars accelerate and corner better than front engine, because the weight (and therefore the polar moment) is where it needs to be to aid......traction lol

Adding weight improves traction. It doesn't matter if its a pick-up or a moped

If you really wondered, or thought it was a benefit; the lower weight motor will help economy as well. Probably more tangibly so than cornering ability

I still think you should build the motor you want, you'd be splitting hairs trying to chase minute gains otherwise

 

that's because you've got a gutless 4.8, and having more torque will definitely change the way you drive. shoot, with my 5.3 & 4x4, i rarely ever got to 3k RPM unless it was for a specific reason. i often cruised at 45-50mph in 5th without lugging (especially with the 4.30s but even 3.73s weren't bad above 55... and that was on 33s. a 6.0 will even be okay (not great, but alright) with your current 3.42s since you've likely got ~30-31" tires.

if the transmission gearing's what you're worried about & you'd prefer it shift like a sports car, you'll need to swap in a T56 from an F-body, GTO, or CTS-V (latter two preferred for the M12 gearsets)... or come to think of it, maybe a TR6060 from the non-Corvettes could work, too. either way, being 2WD opens up more transmission options, especially since you don't tow (which would kill one of those 6spds).

yep

i'm pretty sure we all realize he's talking about rear-wheel traction in relation to front-wheel traction as the CG slightly moves aft with a lighter block, whereas you're talking about overall traction going down with less weight. you're both right on your separate arguments.

either way, driving with no spare & little fuel doesn't lend to a lot of grip in either scenario. as for removing weight from the front end overall: i don't think he's gonna be driving fast or hard enough to worry about the slight increase in understeer potential.

 

ps - you've likely seen that the nv3500 used different (better) gear ratios in the dodge trucks & S10s, RPO M50... but before going down that rabbit hole, the transmissions ain't interchangeable because the dodge has a different bolt pattern & input shaft while the S10 has a different tail shaft.

m a y b e... there's a potential to rebuild a MG5 transmission with M50 gears inside, but i ain't looked into that. i simply did a nv4500 swap & drove it like a 4spd.

 

It sure looks like its over the axle to me, if the center of the engine is behind the axle, its only by a few inches at most. Yeah, but until I mount my engine in the bed, this is the only real option there is to move some of that weight back.


265/70/17s. I'm really not trying to fly through the gears, I'm more about staying in one. I don't need to or try to speed/power shift, I just like to be able to hold a gear to keep that torque steady or steadily increasing so I have the most control. In 10 years of owning this truck, I have never taken it to the track, and the only time I've gone from 0-80+ is when leaving a gas station off the highway. I think most people here are trying for the 1/4 mile, I'm trying to better my pickup for 400 miles of highway.


Thats the plan. I read there was a dodge HD trans that was able to handle 15% more than ours, but if it was even possible to make that work that's about the closest 2nd place to the nv4500.



JUST IN CASE ITS NOT CLEAR, THIS IS GREAT. THANK YOU ALL FOR CONTINUING TO ENGAGE IN THIS.

 

yeah, the Dodge swap won't work. looked into that long ago.
the gearing of the NV4500 will favor your 3.42s, and you can plan on never using 1st... or if you're feeling brave & want all 5 gears, you could go 3.08 rear & plan to only use 5th for interstate cruising.