Performance Calculations

[jbitzer]

This may seem like a simple math equation but I though I'd better ask the "Experts" to be on the safe side. There nothing worse that false expectations and feeling disappointed as a result.

I have read several threads regarding performance upgrades for my 2000 4.6 Expedition and found a few basics I am looking to do. Below is the list of what I am considering and the "advertised" increase:

MAC #3946 air system - gain of 17.7 HP
MAC #3775 75mm throttle body - gain of 9 HP
Performance tune - gain of 50-60 HP

So am I to understand if I add these 3 aftermarket parts can I expect the sum total of the advertised performance gains (17.7+9+50) and expect a gain of 76 HP or is some other calculation I must use when combining performance upgrades?

I am willing to invest into my vehicle as long as I am able to get a reasonable return on my investment. After researching and reading this and other threads elsewhere these appear to be the top 3 upgrade that will make a difference in HP, torque, and MPG.

I am open to other suggestions or recommendations.

The MAC catalog can be found at the following link:
http://www.macperformance.com/OnlineCatalogs/96Page%2092506.pdf

 

[ELVATO]

I'm no expert, but I highly doubt you are going to get anywhere near 76 HP.

Alot of times, parts don't give out the gains promised.

Just a guess, not based on anything, but I'd say expect something closer to 30.

 

[AvroAero]

You won't get 76 hp. Those gains are only on stock trucks, ussually at different rpm ranges, and aren't stackable.

I've gone through it. One peice of advice would be to start with the largest engine instead of a 4.6. With all my options I'd say I get around 250hp at the wheels. A stock 4.6 probably puts somewhere under 200hp to the wheels. The major problem with that is the power band (which is where higest hp/torque is achieved) is too high.

Tune won't get you 60hp on a gasser.

 

[chuck s]

It's real easy to increase horsepower, just let the engine run faster and keep the air and exhaust open so the torque stays up there.

Horsepower is a formula based on torque and rpm. Torque and horsepower are exactly equal at 5252 rpm in every engine. Every engine. Above 5252 rpm horsepower exceeds torque, below that number it's less than torque.

That's the reason those "400 horsepower" tractor trailers can pull so much weight. They have a couple thousand pound-feet of torque at the rpms they run.

-- Chuck

 

[chuck s]

Forgot the numbers:

Horsepower = torque x rpm/5252

Here's how it works out for the Ford Triton 5.4 V8 (using Ford's specs of 365 lb-ft of torque at 3750 rpm, 85% of that at 1500 rpm and 300 horsepower at 5000 rpm).

Rpm torque horsepower
1500 310 89
3750 365 261
5000 315 300

Yep, less than 90 horsepower gets my trailer rolling quickly. I cruise at about 1800 rpm in 6th gear with the camper in tow. Lots of torque is how this is possible with a "90 horsepower" engine.

-- Chuck

 

[jbitzer]

Sorry for the delay in responding (been swamped) Thanks for the reply everyone.

With this in mind and knowing that I'm not going to get anywhere near 'Advertised' performance, does anyone have any suggestion what upgrade would give me the best performance for the dollar? I may start with just one upgrade and let it run for a bit and then try some others. I could use some HP for acceleration and climbing hills. I have to really give it some gas to climb a slight incline or accelerate on a flat surface once I'm in 3rd gear or higher.

I have small radiator leak I have to deal with first but then might look into something that will make a difference

 

[MaverikDS]

I've been looking at doing some changes not so much for power, but for better MPG. I think the best thing you can do for the power is probably a CAI, I'm looking at the FIPK from K&N and the cheapest I've found is on ebay. Next would be to get a tune, and from what I've read on here sniper is the way to go, and look to talk to Green03 as he can do custom configurations if that is what you would want. It seems like with all other things normal, those are the best options for increasing power as well as MPG. As a computer person, I would still suggest doing one thing at a time, that way if you have a problem you have a better idea of where to start looking to resolve it. Making multiple changes at once can be nice and tempting, but if you get a problem harder to troubleshoot. Good luck with whatever you choose.

 

[SPreston2001]

This might be off topic but how do you actually perform a sniper tune? What would I need to do the tune?