meathead

can someone break down what this means?

ramilford

It means that the air/fuel mixture at the end of the compression stroke is 11 times smaller in volume than at the start of the stroke.

rets

Here is the additional info.


From How to Help an Engine Produce More Power by Howstuffworks



Increase the compression ratio - Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however, the more likely it is to spontaneously burst into flame (before the spark plug ignites it).

Higher-octane gasolines prevent this sort of early combustion. That is why high-performance cars generally need high-octane gasoline -- their engines are using higher compression ratios to get more power.

VTGuy2006

This phenomeon is known as "knock retard" or just KR. It's a huge performance decreaser. And yes higher octane fuel will help prevent this sort of thing from happening. This is also a problem because compressed air is very hot. Switching to a cooler thermastat will help too and although this will apply to none of you (it may one day), superchargers and turbochargers running high amounts of boost will also jack up the compression ratio which will inevitable cause KR to become a problem, thats why you'll see people buying intercoolers since it will cool down that compressed air tremendously.

BolderKeith

The compression ratio is the volume above the piston with the piston at the bottom of the stroke, divided by the volume above the piston with the piston is at the top of the stroke.

automophile

The intercooler's main purpose is to allow the boosted air to compact a bit as it cools, so even more oxygen gets into the cylinders.

Frankly, I am surprised the TL runs on 93 with 11:1. The new engine computers are doing an amazing job, along with the advanced engine design.

meathead

Thanks!!

mamorgan1

A bit OT but, is it going to be a must that we run 93/premium in our TL's? I used 93 in my Jetta b/c it just seemed to run better. I guess I should expect to go back to 93/premium come mid-Feb.

brahtw8

The manufacturer seems to think so. If you ran 87 the car would not self-destruct, but you would be down on horsepower and the car would knock quite a bit (that "ping" sound) when it was turned off. Over a long period of time it might do some damage, but I don't know for sure.

If you can afford a TL, you can afford 93. If you can't afford 93, you can't afford a TL.

ramilford

Acura recommends 91 NOT 93.

rets

Sorry, above 91 should be fine. Otherwise, I hardly find somewhere selling 91 here...

Gasoline generally has an octane level of 93, but is blended with an octane level of 91 on the West Coast and in some other geographic locations.

fsttyms1

acura recomends any thing over 91. not just 91,