Danny, not to jack your thread but my question is relevant,,,I believe.
Robby - Some of the chip packages state you need a CAI and a Cat Back
system and use premium grade gas to get the full benefits of the performance chips.
Do they improve performance? I guess we have to define what that
performance would be.
Low end speed: Better hole shot
Greater Torque: Better towing ability
Upper end speed: Go faster
Improved gas mileage at nominal operating speeds.
Reduced greenhouse gas effects which reduces global warming.
Makes your butt look smalller.
Fair questions that often come up.
First, the re-programmers (chip)
Basics: Since we are not changing the mechanics of the engine, those being cylinder pressure (cam timing) or compression ratio, the reason they recommend premium fuel is because they are advancing the timing throughout the rpm range.
Regular fuel would detonate with the advanced timing.
Because the timing is advanced and usually the injector pulse width (open time) is a bit longer, the low and mid range power comes on at a lower rpm.
This is that increased 'crispness' off idle you feel and because of the timing and fuel changes, torque will begin to rise at a lower rpm......both timing and increased pulse width will increase power and torque to a small degree.
So, item 1 and 2 are valid from the standpoint of crisper response and a bit more torque.
Remembering that torque is primarily a function of stroke (leverage on the crankshaft), by pushing harder on the piston we can increase it somewhat but the leverage stays the same......kind of like a 150 lb man pushing down on a breaker bar versus a 200 lb man doing the same thing.....one will push harder, but the bar has a limitation before it fails.
Speed: Horsepower is speed.....torque is how fast it gets to that speed.
Since we are feeding a bit more fuel and advancing timing to take advantage of that fuel, the engine can run up a bit faster before it runs out of horsepower, or, in other words, turning at a speed that that is now becomming limited due to cam timing.......it cannot pump any more air.
Improved mileage: Potentally there because if the engine is making more torque, to achieve the same torque that was required to go, say, 60 mph,
you now can maintain that same speed with a lessor throttle opening.
Greenhouse effects eh?
The amount of energy required to create the various components likely negates the greenhouse effect coming out of the tailpipe.....IMO, bogus call to make us feel good about spending money.
The suggestion of Cold Air Intakes and cat back exaust to maximize the effect of the modification applies only to wide open, high RPM operation.
The engine (a air pump in disguise) only pumps air at a given rate based on RPM.
So, if we are cruising at 65 mph and say, 1800 RPM the cfm requirements have not changed....the engine is moving the same amount of air it always has.
But, in a wide open situation, at the VERY TOP of the engines RPM limits there is a possible benifit from reduced pumping losses (intake restriction, exaust restriction) because we are bringing in a bit more fuel that needs to be exausted.....this again assumes the exaust manifolds are not the restriction point (but trust me, they are the culprit).
That may have helped,