Gearz 6 tips to increase fuel economy - Page 4 - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Thread Tools Display Modes
Old 02-23-2010, 06:18 PM   #31
Registered Member
Join Date: Jan 2010
Posts: 28
Country: United States
Good question, but it's true. The government doesn't want it in the oil of street cars. I wonder if a car with that type of oil would pass emmisions in a tightly regulated state.

drifttec101 is offline   Reply With Quote
Old 02-24-2010, 01:44 PM   #32
Registered Member
Join Date: Nov 2007
Posts: 1,522
Country: United States
Location: north east PA
Zinc isn't the problem. It's the phosphorus in the ZDP that clogs up the cat.

Basicly, the zinc was removed to protect the emission equipment, but other additives have taken it's place. So, except for possibly breaking in a rebuilt engine, the ZDP isn't needed. In regards to emission testing, it itself won't show up, but you might be left wondering why you need a new cat before 150k miles.

ZDP was first added to engine oil to control copper/lead bearing corrosion. Oils with a phosphorus level in the 0.03% range passed a corrosion test introduced in 1942.

In the mid-1950s, when the use of high-lift camshafts increased the potential for scuffing and wear, the phosphorus level contributed by ZDP was increased to the 0.08% range.

In addition, the industry developed a battery of oil tests (called sequences), two of which were valve-train scuffing and wear tests.

A higher level of ZDP was good for flat-tappet valve-train scuffing and wear, but it turned out that more was not better. Although break-in scuffing was reduced by using more phosphorus, longer-term wear increased when phosphorus rose above 0.14%. And, at about 0.20% phosphorus, the ZDP started attacking the grain boundaries in the iron, resulting in camshaft spalling.

By the 1970s, increased antioxidancy was needed to protect the oil in high-load engines, which otherwise could thicken to a point where the engine could no longer pump it. Because ZDP was an inexpensive and effective antioxidant, it was used to place the phosphorus level in the 0.10% range.

However, phosphorus is a poison for exhaust catalysts. So, ZDP levels have been reduced over the last 10-15 years. It's now down to a maximum of 0.08% for Starburst oils. This was supported by the introduction of modern ashless antioxidants that contain no phosphorus.

trollbait is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fuelly & Twitter i64w2gohome Fuelly Web Support and Community News 2 09-23-2012 10:03 AM
MPG Data Not Adding Up liniator General Fuel Topics 17 05-31-2012 01:06 AM
searching? blind monkey General Discussion (Off-Topic) 7 01-09-2009 06:16 PM
94 GS-R with VX swap onefastcar Introduce Yourself - New member Welcome 9 07-09-2008 03:12 PM
Miss matched tires zpiloto General Fuel Topics 4 02-16-2007 12:40 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -8. The time now is 09:58 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.