I've been reading about exhaust systems and mods and I am curious if all the HP and torque gains add up with each mod. I mean, product literature says you can get

Air Filter 3-5HP
Cat-back 10-20HP
Headers 5-10HP
etc.

does it all add up? i mean, if i were to theoretcially do just the above 3 mods on a truck, would I really get an added 18-35HP?

my estimates on each mod may be off, but i think you know what my question is.

 

read the fine print on the lit! That is why they give you such a big range in HP improvement.

the moral of the story is YES it will all add up just not as much as the mod lit leads you to believe.

 

The HP gain for each mod may or may not be at the same RPM range.

So one mod that produces say 10 HP gain ( i.e. Electric Fans ) might not be at the same place that another mod ( like headers ) produces the say 10 HP, which could be all together different then peak HP.

So while you may take a SWAG at a 18-35 HP gain, that is only if all the mods add the HP at the same RPM, again which may or may not be at the peak HP point.

This is part of the range that mods list, and under a given test condition, not specifically corrected dyno HP numbers.

Take a look at the altitude of the R&D shop, it might be at sea level, or slightly below sea level.
If you are in Denver, don't expect to get even close to the R&D dyno'd numbers. Also was the R&D shop air conditioned, vs being open like most dyno shops. This could produce better dyno numbers have cooler more dense air for the dyno runs.

Aside from HP numbers, what happens to TQ is another question. A mod might add HP, but leave TQ flat, or reduce it at some point. I don't have a specific example of this, but it all theory it might happen.
This would cause the truck to butt-dyno to feel like it is towing a Chevy with the parking brake on. So while Hp was increased, TQ was decreased / left flat, and the net result is the truck seems to be slow off the line, but take off like a raped ape in the 60 mph hammer down / roll on butt-dyno test.

Sorry for the rambling, just a few things to think about when looking at mods.
Also don't confuse the butt-dyno feel of lack of back presure to be a loss of TQ. I think some complain of a loss of TQ from butt-dyno testing, and it is a case of a reduction of back pressure, which makes the butt think the truck is not launching the same, because it is not working as hard to get rid of the xhst.

Best way to track all of it is to dyno stock and each step, or at least get a G-Tech for the 0-60 times. This is the real world street test method I have switched to. Dyno numbers are nice, but it does not tell me squat. Sitting on a drum the truck had x, and now has x+45. beyond bragging rights, nothing else useful.
The higher end G-Tech has a HP / TQ function in it now, so if you can get to a scale and get a weight, you can use this as well. All for the cost of 2 or 3 dyno sessions. Use the Dyno session only when you need a wide band A/F reading for tuning reasons is my new use for the dyno.

Good luck, and let the mods begin.

 

thanks for the info. i am not actually going to mod yet, but i am in the market for an '04 F-150 and I am checking out mods. of course, i'll have to wait until the right mods become available for the new design. thanks again. and by the way, what is a dyno?

...be nice to the noob. until i get the new F-150, i drive a volvo wagon. this will be my first truck.

 

BrewMaster

Do your research before opening your wallet. Actually if you have the correct parts the sum of the parts can be more than the parts individually. There is plenty of junk out there. Example: K&N - while likely the most advertised intake on the world, it doesn't produce the most horsepower. For similar price AF1 gives you a stainless tube rather than cheap plastic and more horsepower but no ads in every car mag in print.

This is not a commercial. Invest a couple of bucks and speak to Anita or Mike at Performance Products (get the number from computer chips section under posts from "Superchips Distributor"). At least check out the brands they are selling on their website (troyerperformance.com). You obviously can buy from whomever you choose. I have spent some thousands of dollars modding an F-150 and an Explorer with their guidance and am quite happy with the results. Most of the online sellers are only interested in 'banging the cash register'. "Who cares what we sell, so long as we sell!"

Before you spend a dime figure out where you want to go. If you need smoking tires in first, second, and third gears clearly you are in supercharger territory.

 

Before you buy that new truck is the time to call Mike Troyer. Then he can explain the advantages/pitfalls of certain truck configurations.