Compression ratio?
Thread Starter
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TReK
Joined: Jul 2017
Posts: 3,387
Likes: 488
Compression ratio?
What is the compression ratio for the Bosch 4.6 V8 (04 Discovery 2)?
I am curious about the supposed need for premium gas. Why?
I would think a slow revving, low oil pressure engine would not have high compression. That detonation from lower octane (87) would not be an issue?
Do these engines run poorly with anything below 91-93 octane?
Can anyone explain?
Thank you
I am curious about the supposed need for premium gas. Why?
I would think a slow revving, low oil pressure engine would not have high compression. That detonation from lower octane (87) would not be an issue?
Do these engines run poorly with anything below 91-93 octane?
Can anyone explain?
Thank you
TReK
Joined: Nov 2011
Posts: 2,748
Likes: 506
From: Seattle, Wa
I believe it also has to do with how the computer is programmed regarding the fuel to air mix etc.
Be sure to use Top Tier premium as well, the cheap gas without additives will gunk up your injectors and you will lose performance and spend more money via less efficiency anyway.
Be sure to use Top Tier premium as well, the cheap gas without additives will gunk up your injectors and you will lose performance and spend more money via less efficiency anyway.
Baja
Joined: Aug 2013
Posts: 5,845
Likes: 368
From: Near Bordeaux, France
What is the compression ratio for the Bosch 4.6 V8 (04 Discovery 2)?
I am curious about the supposed need for premium gas. Why?
I would think a slow revving, low oil pressure engine would not have high compression. That detonation from lower octane (87) would not be an issue?
Do these engines run poorly with anything below 91-93 octane?
Can anyone explain?
Thank you
I am curious about the supposed need for premium gas. Why?
I would think a slow revving, low oil pressure engine would not have high compression. That detonation from lower octane (87) would not be an issue?
Do these engines run poorly with anything below 91-93 octane?
Can anyone explain?
Thank you
https://www.etuners.gr/fuel/
Thread Starter
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TReK
Joined: Jul 2017
Posts: 3,387
Likes: 488
This may help you understand the differences. IMO you should be running RON 98 minimum or 93 PON. IMO 87 PON is for parts cleaning or lawn mowers
https://www.etuners.gr/fuel/
https://www.etuners.gr/fuel/
I wouldn't put that 87 in anything I owned. I ran it the first few year I had my D2, because I was totally ignorant. I had issues with O2 sensors, coil packs, and since I have changed to premium I haven't had any issues with combustion. My cats went bad, but they were overdue anyway.
Rock Crawling
Joined: Mar 2012
Posts: 378
Likes: 94
Static Compression ratio is only one variable that determines the octane requirements
the combustion chamber and piston shape is unaltered from 1960. Modern designs have shapes that turn more of the combustion to power rather than heat. Since these engines are less thermally efficient hot spots are more likely and high octane is required. It's also why a 3.9 has a giant 3 core brass radiator
the combustion chamber and piston shape is unaltered from 1960. Modern designs have shapes that turn more of the combustion to power rather than heat. Since these engines are less thermally efficient hot spots are more likely and high octane is required. It's also why a 3.9 has a giant 3 core brass radiator
Thread Starter
|
TReK
Joined: Jul 2017
Posts: 3,387
Likes: 488
This may help you understand the differences. IMO you should be running RON 98 minimum or 93 PON. IMO 87 PON is for parts cleaning or lawn mowers
https://www.etuners.gr/fuel/
https://www.etuners.gr/fuel/
I've only put gas in this one 3 times, and only 93 octane.
Quality wise, the engines on these seem like junk compared to Japanese or U.S. vehicles. And part prices...
Someone please explain to me why I still like this thing so much!?