Originally Posted By: Lubener
Originally Posted By: Jimzz
Originally Posted By: Lubener
Back in the 60's and 70's, those big V8 engines were being started with batteries having 500 cca's. I think it's overblown today even with all those additional demands modern cars have.
And those motors also had less compression on the engine as well. There are plenty of economy cars with 13+ compression ratios today.
When I was a young tech you can turn a motor over by hand easy. Many cars today I pull the plugs as its much more difficult when they hit compression on newer cars.
Name some. I don't of any that are that high.
Many Mazda 4cyl motors run at 13 and some 14 to 1.
https://en.wikipedia.org/wiki/SkyActiv
Now compare that to the GM 3.8 that ran 8-9 to 1
https://en.wikipedia.org/wiki/Buick_V6_engine#LC4
Or most V8 small blocks averaged around 8-9 to 1. Some would go higher but that was special builds and many were known to knock if not setup right.
https://en.wikipedia.org/wiki/Chevrolet_small-block_engine#Details
They are doing everything they can to squeeze more power and gas mileage out of smaller engines and high compression ratios is one place they try to get as high as they can. It also makes it a pain in the rear if you work on one and need to rotate the motor also.
Originally Posted By: Jimzz
Originally Posted By: Lubener
Back in the 60's and 70's, those big V8 engines were being started with batteries having 500 cca's. I think it's overblown today even with all those additional demands modern cars have.
And those motors also had less compression on the engine as well. There are plenty of economy cars with 13+ compression ratios today.
When I was a young tech you can turn a motor over by hand easy. Many cars today I pull the plugs as its much more difficult when they hit compression on newer cars.
Name some. I don't of any that are that high.
Many Mazda 4cyl motors run at 13 and some 14 to 1.
https://en.wikipedia.org/wiki/SkyActiv
Now compare that to the GM 3.8 that ran 8-9 to 1
https://en.wikipedia.org/wiki/Buick_V6_engine#LC4
Or most V8 small blocks averaged around 8-9 to 1. Some would go higher but that was special builds and many were known to knock if not setup right.
https://en.wikipedia.org/wiki/Chevrolet_small-block_engine#Details
They are doing everything they can to squeeze more power and gas mileage out of smaller engines and high compression ratios is one place they try to get as high as they can. It also makes it a pain in the rear if you work on one and need to rotate the motor also.
