Guys,

Why do our trucks die out or not accelerate as hard and as fast beyond 65 MPH? Mines will accelerate like a champ up to this point, but has less and less grunt pass 65-70 MPH. I have the 1715 Micro Tuner, but can tuning alone help me to accelerate hard through...say 90+ MPH? A local mechanic told me that the only way to get there with a truck was to go with a charger. Unfortunately, I can't go that deep in my pockets at this time for a charger? Maybe I am getting all I can out of the 4.6?? I know the mods I've added has made a BIG difference in the stock performance of my '98.

Thanks in advance.

 

One word: Aerodynamics.
Make that two words: Poor aerodynamics.

Drag increases with the square of speed, so twice the speed takes 4x the power.

 

Thanks Jordan...I probably did not explain the issue correctly, but when I compare our trucks with some of the competition I have driven with comparable HP, the competition accelerates hard through speeds above 70 MPH. I am pretty sure a charger with take these heavy machines of ours from zero to hero with ease but I was trying to get there from here without the cost of a charger.

 

the drop in gearing from 1st to 2nd gear is the blame- not close enough- mike troyer will even tell ya this -thats why for best et's in the 1/4- first gear should be taken to 5400 rpms-phil

 

Hi crain,

I agree with Jordan (not Mike), it's a matter of aerodynamics combined with the power-to-weight ratio - and in your case, you have compounded the high-speed performance further by having that 3" lift installed, so it's even worse aero-wise.

Also, once you get beyond 1st gear, you don't have anywhere *near* as much torque multiplication - 1st gear in the 4R70W automatic is 2.84, 2nd gear is 1.55, and 3rd gear is 1:1 - so it pulls like a bandit thru 1st, and it's not too bad thru the first half or so of 2nd gear. But by the time you hit 70-80 MPH, and always by the time you hit 3rd gear (1:1), there is no more torque multiplication as you're in 3rd and the TQ is locked - and aerodynamics simply take over. This is why the rate of acceleration drops so drastically in *any* truck or SUV as speeds increase, none of them will ever accelerate at higher speeds like they do in 1st & 2nd gears, whether it's your truck, the ones you're running against, or anyone else's truck or SUV. Heck, my truck will rip off 0-60 times under 4 seconds, and runs the 1/4 mile in the mid-11's - but once it hits 3rd gear at 80 MPH, though it still pulls "strong," it's nothing compared to the pull in 1st & 2nd gears.

The reason other trucks are leaving you behind at 90 mph is simple - they have a better power-to-weight ratio - or a better combination of power-to-weight ratio and aerodynamics - period. The only way to fix that is to add more power, and you already know all of that.

Now, can more power be added via tuning alone, even though you have the 1715? Yes, absolutely! We can easily add more power and performance with our *custom* tuning over what the 1715 Micro Tuner will deliver - our power & performance gains from our custom tuning for your truck are generally about 50% higher than what you get from the 1715 Micro Tuner.

Your best bet at this point, in terms of best bang for the buck, is having us do the custom tuning to get the most out of what you already have - and you have some nice mods there with the intake, cat-back exhaust, the headers, E-fans & underdrives - it just needs to be maximized in an appropriate *custom* tune. Remember, although the 1715 will certainly work with the mods you have listed, it's really intended for the stock to lightly modded trucks - so even though it can be used with other mods, it's not going to be optimal - our *custom* tuning will be able to get the most out of what you already have, and get the best possible performance for you.

I would suggest giving us a call to go over this in more detail with you - our number is listed just below - but then you probably already know that, too.

Best of luck whatever you decide,

 

Mike,

Thanks for the reply...I will give you a call on this after the holidays when there's more money in my pockets. I like the sound of the custom tuning you offer and probably adding a TB, MAF (if you recommend), and whatever else short of a SC. The only problem with adding mods to increased performance, it's hard to stop, at least for me. I always want more and have no desire to go back to stock 4.6 performance.

 

Hi Crain,

Thanks for your post, and welcome to the club - once you start modding, is can be hard to stop for a true hot-rodder - if more feels good, then a LOT more will feel REALLY good - and there is no such thing as "too much." Been there, done that - lived it darn near all my life.

Enjoy your holidays & talk to you soon!