4.6 towing performance

[Guest]

I own a 99 Expy with a 4.6L and 3.55 gear ratio.
Mainly city driving, thats why I opted for the 4.6.
Looking at purchasing a 23 ft TT with a dry weight of 3700 lbs.

I heard that upgrading the exhaust system can give better perf.
any recommendations, etc, to increase towing power.

thx.

 

[Guest]

Change the rear end. Lower the final drive to 3.73 or more and you'll see a vast improvement in towing. But it won't be cheap, especially for 4x4.

Cody

 

[Guest]

thank-you, I do own a 4x4, and have considered that option.
as you say, pricey.
Any increased torque by changing out the stock exhaust to a
cat back or something similar?

 

[abbyzdad]

Deano
A cat back will help but you also need to let more air in. On my 97 4.6L I did exhaust first (cat back single in dual out) and noticed a little better performance. Installed a K & N drop in filter and that helped too. I also drilled 1 1/2 holes in my airbox so the airflow wasn't restricted to just what comes thru the snorkel in the fender. I didn't get any more mpg but did notice it pulled quicker off the line and seems to rev faster.

good luck, Brian

 

[Guest]

Thanks for the info on air intake, Brian.

I'll be taking it in soon for the exhaust upgrade.

Deano

 

[Guest]

Another thing is check into a non stock computer chip (Hypertech, Superchip, etc). If you go to the bother of modifying your exhaust and intake then you might as well optimize timing/air-fuel ratios, etc. in order to achive maximum "bolt on" gains.

I must admit though I did this with my 2001 RAM 4x4. It has a 5.2 L with a 3.55 rear end. I modified the air intake to an AIRAID and the exhaust to a Dynomax catback system then added a modified PCM chip. The results were NOT stellar if even discernable.

But the 3.90 rear end, though not cheap, was a HUGE leap in low end torque. The real problem here is the fact that the truck doesn't have a 5.9 (360) in it or a Hemi. But a 3.55 IMO is simply to high of a ratio for pulling anything significant with any engine IMO. Even guys that pull with F350 Powerstrokes, like my dad, use 4.11:1 rear ends to pull with.

Good luck

Cody

 

[daoud elmassri]

Cody start at the junk yard for your rear end and front end it is alot cheaper u can get a use good used 3:73 from them . You might even be lucky and fine a K&N cold air intake like I did I got it for 20 bucks . I had also a 4.6 in my 2000 expedition it was a dog it had a hard time pulling my 24 ft Grady White I tryed a lot of difrent things and finaly bot a recked 2001 expedition it had the 5.4 with tow package W/R 100 transmission 3:55 possy rear end I took every thing out of that truck it was a good doner . I made some of my money back from some of the part I did not need good luck hope this was helpfull.