Been lots of tuner questions of late and was holding back till this one
and Turtles comments...which almost had me spit my coffee all over the
keyboard... :B
So think it's time to touch on the why and how of all this
The tuner has become yet another fashion statement crowd 'gotta have' item
Boils down to this:
increasing the PSI on the piston topsThat is all there is to it, but the devils details is in how to attain
that and keep EPA happy. It is no longer just a Calif registered vehicle
that must toe that line, but 50 state requirement. Plus the government
has made it a federal issue and also say that in some areas...they do
NOT check...often
With current design/architecture of our ICE's, the main way is to
increase the combustion temps. As ICE's work by capturing the rapidly
expanding gases inside a closed container (the cylinder...head area,
cylinder walls and the moving piston top)
Then the complexities of that...meaning that the 'moving piston' will
see reduced PSI as it move away from TDC and will it continue to have
enough PSI to continue to push on the crank. There is much just in this
area of physics
Then the exhaust stroke. Some/most designs use or take advantage of
a continued burn to push out the gases into the exhaust port married
with the piston reversing directions to push the gases out. Part of
this is called 'scavenging'. Velocity and inertia are the key components,
plus more
Some other attributes that tuners touch on to acheive higher PSI's
on the piston tops...
Timing is the main one, even diesels (spark before TDC on a gasser
and on a diesel, the squirt before TDC)
So the piston is moving up on it's compression stroke will have the
above BEFORE TDC. So it is now compressing the gases that are also
now expanding at a fast rate. This will increase the PSI on the piston
tops at TDC, which will have a GREATER push on the piston tops as it
transitions to moving down (pushing on the crank)
BUT...there are issues with pre-ignition on gassers. Think explosion
as a 'normal' gasoline ignition is a 'burn' vs pre-ignition which is
an explosion.
Explosion...think of hitting the top of the piston with a hammer vs
pushing on it with your hand...a very fast hand...but no where near
the speed of an explosion
This is why most tuners set at their highest power gains requires use
of higher octane gasoline. Octane is the measure of the fuel (gas)
resistance or speed to ignite
Longevity is yet another consideration. With higher PSI's comes higher
rates of wear. Currently, our ICE's do NOT self heal themselves and
the tolerances (gaps) increase.
This means that the 'seal' between the various openings will NOT hold
that PSI just on the piston tops, but allow it to bleed off. End result
is lower PSI all over inside the combustion chamber. Therefore less
PSI on the piston top...this opposite to the goal in all this
Much, much, much more to this, but just touching on these in hopes
folks considering tuners will understand
As for warrant and law normally referenced as the basis for claiming
warranty...yes, it was enacted to help the consumer against fraudulent
denials from the OEMs, but there is fairness involved...that is the
OEM has the right to deny if you changed the specification of their
product.
Increasing HP is a change in their specification. That means higher
loads on components & sub-systems that is above their basis for
their MTBF
So tuners do these and much more to gain higher PSI's on the piston
tops...but...the OEMs have to meet SMOG regulations. They face
huge fines if they so not...even revoked license to sell products
until they meet those regulations.
Tuners 'fool' most of the system requirements (feed back) to the
ECU. So the ECU will NOT go into limp mode or some other mode
Plus the OEMs no longer have these feed back loops in volatile memory.
Meaning that it is now locked in memory, even with a power removal
cycle. They can read what the ECU has been using for it's sensory
feedbacks.
This is where they can and do deny warranty...I would if it was
my product and my consumer came in to lie (fraud) that they messed
with my product to then claim warranty
-Ben
Picture of my rig1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...