ISR mod and Deckplate!
 

Waste of time. Best performance will be seen by simply removing the elbow that goes into the fender and a quality air filter.

You can do the ISR for a purely cosmetic improvement if you want but no performance.

I too had many questions about the "ISR" and "deck plate" mods
i asked my father a master mechanic for going on 30 years now and told him the way they were done. he says and i quote..."unless you make the throttle body larger, these modifications would be pointless.. you may get more air to the throttle body but its still only going to take in the same amount."

has anyone ever done both mods and had actual proof that it added more power?
i took duct tape and covered the slot in the silencer box and it made a noticeable louder intake noise when flooring it but, just because it sounds faster doesn't mean it really is.

He is correct. There is no power to be gained with the deckplate. Just remove the elbow that goes into the fender and you have the best intake you can get.

I have proven that a "cold air" intake actually causes a loss of power in my dyno test:

http://www.pballandmore.com/images/4...comparison.jpg

222.92 hp vs 216.76 hp = 2.76%

Well within the margin of the error of a dyno. This is not proof by the very definition.

It is when I made about 10 back to back pulls and changed the intake on the dyno, twice actually since I didn't believe the numbers myself, with the same results each time.

Put on the cold air intake, loose HP, put on stock intake, gain it back.

Dynojets are very consistent BTW.

These results were also seen by gadget as well as others. I am far from the only one, just the only one to post the dynos.

Did anyone ever figure out why removing the fender elbow causes a positive change? I mean like, why does removing it increase performance or does it at all.

It is because it is a smaller diameter then the rest of the intake and most importantly the throttle body. Thus causing a restriction and a loss of power.

With it removed the whole intake is at least the same size as the throttle body so with a good filter there is nothing to be gained by cutting holes in the system except it sucking in hot engine bay air instead of cold fender air.

6 hp on a 5,000 Lbs truck is not perceptible. And probably not repeatable on a dyno.

Its not worth the effort.

What I can't figure out is why people do the deck plate mod. It converts the factory cold air flow into hot air flow from the engine compartment. What would make more sense would be to put a small air scoop on the passenger fender to get cool air to the air box. Sorry for being logical.

To me the ISR mod looks a little ghey. Elbow mod and araid MIT is what I have and it cleans up the engine compartment as well. It's been 130K since I modded it, no issues.