TLKrazey20

Can anyone explain to me the meaning and the purpose (if there is a purpose) of the Compression Ratio of 10.5:1 on the TL type-s and alos explain the meaning and purpose(if any) of the

5-speed automatic transmission with Grade Logic Control and Sequential SportShift™
Ratios (: 1)
1st 2.563 ?
2nd 1.551?
3rd 1.021 ?
4th 0.653 ?
5th 0.470 ?
Reverse 1.846 ?
Final 4.428 ?

This is all greek to me so the simplier the explaination the better.

Tom Blasing

O.k. I'll do what I can .

The compression ratio is measured when one of the pistons is at BDC (Bottom Dead Center) of it's stroke. The air/fuel mixture inside that cylinder at that time is referred to as a 1:1 compression ratio (or known as the same atmospheric pressure as what's around the outside of the engine). When the piston moves up in its stroke it compresses that air/fuel mixture to create heat to help ignite it more easily. The further the piston goes up the higher the compression. For instance, if a piston had a 10" stroke (believe me, our cars don't but to simplify the math...) and the piston moves up to its TDC (Top Dead Center) and leaves a remaining 1" at the top of the cylinder then you would have a 10:1 compression ratio. Engines that have a higher compression (without forced inductions like turbos and superchargers) usually generate a more violent explosion (do to the increased heat) in the cylinder and thusly more power (insert manly grunt here).

The transmission gearing is a little more simplistic (I think). Take, for instance, the first gear ratio of 2.563:1. This means that for every full revolution of the tires ( :1 ) the engine moves 2.563 times, or a little over 2 1/2 revolutions. The higher the number before the " : " sign the lower the gearing and the stronger that gear is. Just don't confuse a lower number with being faster, it can just pull/push more mass. Taking all this into account any ratio below 1.0:1 is known as an "Overdrive" gear, this is when the engine is turning at a slower rate compared to the wheels. There's not a lot of torque there so that's why you have to downshift to get a good launch to pass someone. The 02' and 03' TL's (maybe others) have 4th AND 5th gear below this measurement so they really have two overdrives. That's one reason why our cars can get good MPG on the highway!

Does that help??

BTW- Did you ever whatch a NASCAR Race and the drivers have to hold their speed down to, say, 60 mph while on pit lane. They don't have speedometers in their cars so they figure out what gear to put the transmission in and at what RPM to = 60mph. Cool huh?

r10apple

Oo, oo--I know:
The 10.5:1 compression ration is the cost ratio of a used Acura Vigor to a 2004 TL, meaning you can get 10.5 Vigor's or one TL. If you have a large, extended family this is important in cutting down your drive time. For example, if you had one car and needed to drop off 8 family members and your pregnant wife (1.5) then it would take forever. But if you had 10.5 Vigors, everyone could find their own way and you'd have half a car for the parts you'd need to keep them all running.

The second part refers to the engineer who made it all the way to college, and after bumping up with some Percs, made a transmission designed to...
H=ll, I dunno the answers to your questions...

scalbert? scalbert? Where's someone who knows what they are talking about when you need them. Always chiming in when you don't...

r10apple

...or Tom Blasing. Even if he's wrong, he sure sounds smart!

Tom Blasing

awww...shucks...