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A different oil question???????


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I have followed all the oil discussions on this forum with great interest and even decided to go with the 5W-50 Redline based on what I initially learned. However, I’m still learning, following and may even go a different route next oil change. There are some extremely knowledgeable people who provide amazing tech data and it is appreciated by a majority of us whither we speak up or not. I like seeing the tech data laid out and then forming my opinion.

 

This brings up an interesting question/comparison of two Ford DOHC 32-V Mod motors and my question. The 4.6 DOHC version (‘03/04 Mach and Cobra) calls for 5W-20 while the 5.4 DOHC (Shelby GT-500) calls for 5W-50.

Is Ford more interested in CAFÉ mpg in one and warrantee problems with the other? Why would two similar modern engines, both supercharged in the case of the Cobra, use such different weights of oils? Does the heavier weight oil give better protection at the expense of economy? Does the lighter weight oil provide better fuel economy at the expense of protection?

 

I’d like to hear some opinions from people hopefully smarter than me on this. Thanks in advance.

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It all depends on how the bearing tolerances, etc. are in the engine as well as the temperatures they plan on running it at. Each engine is different.

 

That being said, my Dad ran 15-40 Rotella T in his 4.6L SOHC crown-vic's that he used for escorting oversized loads and they lasted just fine. Usually got about 250K HARD miles out of them until the engine croaked.

 

That being said, I would just run what they recommend and leave it be. They are 2 totally different engines.

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I have followed all the oil discussions on this forum with great interest and even decided to go with the 5W-50 Redline based on what I initially learned. However, I'm still learning, following and may even go a different route next oil change. There are some extremely knowledgeable people who provide amazing tech data and it is appreciated by a majority of us whither we speak up or not. I like seeing the tech data laid out and then forming my opinion.

 

This brings up an interesting question/comparison of two Ford DOHC 32-V Mod motors and my question. The 4.6 DOHC version ('03/04 Mach and Cobra) calls for 5W-20 while the 5.4 DOHC (Shelby GT-500) calls for 5W-50.

Is Ford more interested in CAFÉ mpg in one and warrantee problems with the other? Why would two similar modern engines, both supercharged in the case of the Cobra, use such different weights of oils? Does the heavier weight oil give better protection at the expense of economy? Does the lighter weight oil provide better fuel economy at the expense of protection?

 

I'd like to hear some opinions from people hopefully smarter than me on this. Thanks in advance.

 

The reason they go with the 5w 50 is that the cylinder pressure from the current blown engine will scrape the lighter oil of the bearing surfaces when using the 5w 20. the rest of the engine is lubricated fine its all about the increased load the blower puts on the oil holding the rod bearing off the crank journal the parasitic loss of the heavier oil will not change the mileage significantly on a car of this nature.....my 2 cents

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The reason they go with the 5w 50 is that the cylinder pressure from the current blown engine will scrape the lighter oil of the bearing surfaces when using the 5w 20. the rest of the engine is lubricated fine its all about the increased load the blower puts on the oil holding the rod bearing off the crank journal the parasitic loss of the heavier oil will not change the mileage significantly on a car of this nature.....my 2 cents

 

 

 

Why would this not be the same issue with the '03/04 Cobra and it's 4.6 DOHC 32-Valve Supercharged engine? Just wondering why one but not the other. Are the two engines that dissimilar? :headscratch:

 

Was it a CAFE mpg issue in 2003 but a longivity issue in 2011 (actually 2007 thru 2012)? :slapfight: Not trying to cause a free-for-all here, but just being inquistive. :shrug:

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Why would this not be the same issue with the '03/04 Cobra and it's 4.6 DOHC 32-Valve Supercharged engine? Just wondering why one but not the other. Are the two engines that dissimilar? :headscratch:

 

Was it a CAFE mpg issue in 2003 but a longivity issue in 2011 (actually 2007 thru 2012)? :slapfight: Not trying to cause a free-for-all here, but just being inquistive. :shrug:

 

 

Just ask one of the teams that builds the engines. I'm sure they post here, no?

 

That would be my shot at it. If they don't know, they are in a position to find out.

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Why would this not be the same issue with the '03/04 Cobra and it's 4.6 DOHC 32-Valve Supercharged engine? Just wondering why one but not the other. Are the two engines that dissimilar? :headscratch:

 

Was it a CAFE mpg issue in 2003 but a longivity issue in 2011 (actually 2007 thru 2012)? :slapfight: Not trying to cause a free-for-all here, but just being inquistive.

 

:shrug:

My guess is that it's the by product of warranty and service repair combined with dyno research.....03-04 was 390 horse I think....550 horse is significantly more load. 390 is 71 percent 0f 550....

5w-50 synthetic is the cheapest insurance you can buy......

2 cents again...

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It's plain an simple 5w50 is better for a high performance engine.

 

 

:banghead:

 

Yeah that makes no sense.

 

Corvette ZR1 uses 5w-30 and that has a blower and puts out more power than GT500

Dodge Viper makes 600HP N/A and uses 0w-40.

 

http://www.chevrolet.com/assets/pdf/owners/manuals/2010/2010_chevrolet_corvette_zr1_owners.pdf

Edited by xjrguy
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:banghead:

 

Yeah that makes no sense.

 

Corvette ZR1 uses 5w-30 and that has a blower and puts out more power than GT500

Dodge Viper makes 600HP N/A and uses 0w-40.

 

http://www.chevrolet.com/assets/pdf/owners/manuals/2010/2010_chevrolet_corvette_zr1_owners.pdf

 

 

Why even question it? Ford requires 5-50 "B" spec. If you have any aspirations to keep your factory warranty, and there are ways to know, use what is required. However, you don't have to use a specific brand as long as it meets the spec. BTW, I believe the law states that if you are required to use a specific brand, then the manufacturer must supply it. As a conspiracy, this could be the reason for the rare spec, not many options out there that meet the spec.

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Why even question it? Ford requires 5-50 "B" spec. If you have any aspirations to keep your factory warranty, and there are ways to know, use what is required. However, you don't have to use a specific brand as long as it meets the spec. BTW, I believe the law states that if you are required to use a specific brand, then the manufacturer must supply it. As a conspiracy, this could be the reason for the rare spec, not many options out there that meet the spec.

 

 

 

Hi,

 

My reply was directed towards the "It's plain an simple 5w50 is better for a high performance engine." by ME32.

 

Anyway, I use Rotella T6 5W-40 and have been the past 5500 miles with absolutely no problems at all. (from break in to current time)

 

It's a known fact that the Motorcraft B spec 5W-50 shears down to a 40 weight oil, then a 30 weight oil within a couple thousand miles and that is based on oil analysis by a 3rd party firm.

 

How many GT500's are running around with 5w-30 in the sump due to dealer tech ineptitude? I'd probably bet quite a few.

Edited by xjrguy
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Why would this not be the same issue with the '03/04 Cobra and it's 4.6 DOHC 32-Valve Supercharged engine? Just wondering why one but not the other. Are the two engines that dissimilar? :headscratch:

 

Was it a CAFE mpg issue in 2003 but a longivity issue in 2011 (actually 2007 thru 2012)? :slapfight: Not trying to cause a free-for-all here, but just being inquistive. :shrug:

 

IMO most SAE20 grade oils are too light for the Terminator motors, as the HTHS (High Temp High Shear) viscosity is often too low (< 2.9 cP) to offer adequate protection when running an engine hard. Red Line's 5W20, with its HTHS viscosity of 3.3 cP might be an exception though. Europeans like even higher HTHS oils (greater than 3.5 cP) for their high performance cars based on ACEA A3/B3, A3/B4.

 

And there's probably more GT500s running around with 5W20 in the sump than 5W30.

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:banghead:

 

Yeah that makes no sense.

 

Corvette ZR1 uses 5w-30 and that has a blower and puts out more power than GT500

Dodge Viper makes 600HP N/A and uses 0w-40.

 

 

 

The manual does specify that the 5W30 oil must meet GM4718M, which is GM's high performance oil spec. But it looks like almost any brand of API approved synthetic oil meets it.

 

http://www.gm.com/corporate/responsibility/environment/maintenance/gm_approved_engine_oils.pdf

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IMO most SAE20 grade oils are too light for the Terminator motors, as the HTHS (High Temp High Shear) viscosity is often too low (< 2.9 cP) to offer adequate protection when running an engine hard. Red Line's 5W20, with its HTHS viscosity of 3.3 cP might be an exception though. Europeans like even higher HTHS oils (greater than 3.5 cP) for their high performance cars based on ACEA A3/B3, A3/B4.

 

And there's probably more GT500s running around with 5W20 in the sump than 5W30.

 

 

I used to use 0-30 German Castrol in my LS1 car because Mobil 1 5-30 would burn off (shear down, slip by the rings, blow out the PCV, who knows?). After about 2500 miles I would be down over a quart. With the 0-30 GC, I would be down about 1/4 quart.

 

I think Mobil 1 changed something, perhapse for the Dexos certification, because I now run 5-30 mobil 1 in my LS7, and in 500 miles it has not budged a bit on the oil level. Also, the 5-30 mobil 1 has a cSt at 100*C of over 11. IIRC, it used to be in the 10's.

 

All the XW-XX information out there is just bunk. That is too broad. It's like me saying "Hey, what do you drive?" and you say "A Ford". Well, yeah, but it could be a 1990's Escort, or your GT500. Similar with the big numbers on oil. Sure, it's 5 Winter-30, but it may be a very thin oil quite near the 5 Winter-20. Or it could be thick, and near the 40. No way to know unless you read the small print on the website.

 

Also, add packs play a huge role in engine wear as well.

 

www.bobistheoilguy.com is a great place.

Edited by JWG223
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