JWise

Perusing the Mobil 1 website tonight, I noticed Mobil 1 Extended Performance 15W-50 is being discontinued in May 2009, to be replaced by Mobil 1 15W-50:

http://www.mobiloil.com/USA-English/...ce_15W-50.aspx

This non-Extended Performance variety being brought back appears to be the older blend with the higher zinc level. However, I also noticed Mobil has a new line of racing oils coming out:

http://www.mobil1racingstore.com/buyracinglubes.html

The racing viscosities aren't suitable for our application (thickest is 0W-30), but they appear to have much higher zinc content, i.e. twice as much as their street oils per the FAQ link on the 0W-30 page. As such, I was wondering if one could blend in 1-2 qts of this with the old formula Mobil 1 15W-50 to raise the zinc level even further without diluting the viscosity too much.

They don't recommend the "racing" oils for street use, but that appears to be due to its effect on modern emission control equipment, which is probably less of a concern for us (particularly those running without cats).

Any thoughts regarding blending this as I've proposed? Any other high zinc oils out there?

hacker-pschorr

If you really think your car needs more than the 1300ppm the 15w-50 has, I would just pour in a bottle or two of STP oil treatement (blue or red bottle) it's just thick oil (thinner in the red) full of ZDDP (Zinc)

http://www.mobiloil.com/USA-English/...duct_Guide.pdf

The lack of zinc started with the GF-4 oils that have 900ppm or less. 15w-50 is not rated for GF-4, reason why it has the higher levels.

One bottle of STP has 1900+ ppm in a 1 quart bottle. There are other ZDDP additives out there, this brings up the next issue, can too much damage the motor?

AO

The EP formulation had Phosporus levels of 1200PPM. I never found the Zinc levels. This new, er... old formula has Phosphorus of 1200PPM (same) and zinc of 1300PPM. I have a feeling this is a marketing exercise, but I think it's safe to continue to use.

Other high Zinc and Phosphorus oils include:
Amsoil HPS 20w-50
Redline 10W-40
Redline 20W-50
Brad Penn 20W-50

hacker-pschorr

I just filled up the 928 with VR-1 racing oil, 20w-50 for the street. $3.89 per quart and the "old" ZDDP levels.

Just to play devils advocate on this issue. When was the last time anyone reported a cam / lifter wear issue? This is not the same as a stuck lifter.
The reports of cams wearing down due to now ZDDP levels I've found are on cars running very radical cams with very stiff valve springs. The 928 does not fall into this catagory, so I cannot help but wonder if we are all crying wolf on this one.

$.02

RKD in OKC

Locally in OKC I've seen an Audi A4, 996 Turbo, and a 93 Targa all have catastrophic valve train failure in the last 8 months. The cam shafts actually broke. Haven't personally heard of any valve train failures like this before. These were all well maintained stock cars NOT radical cams and stiff valve springs. All 3 failed on highway road trips and the owners said they were just cruising along with traffic and bang. They all used Mobile 1 because that's what the car came with.

JWise

Thanks for the responses so far. Sounds like Mobil 1 is still a good choice for my street application, and blending is probably not necessary.

Further research of recent RL oil threads also turned up Greg Brown recommending Torco SR-1 as a high zinc alternative, in addition to the brands mentioned so far in this thread.

I have an oil change pending, and want to make sure I'm not putting anything harmful in there. Thanks again.

EDIT: Hadn't seen RKD's Mobil 1 incidents out of OKC. Hmmm...maybe I should use an additive with M1, or go with Amsoil or Torco. Don't want to take a chance on messing up a set of GT cams.

IcemanG17

Jarrod
Interesting....its been well documented in old school pushrod engines that the "new" lower levels of zinc can cause substantial damage very quickly.........typically in the cams and lifters....

I use ONLY amsoil racing 15-50 in both my 928's..it has a higher level of ZDDP but I'm not sure exactly how much..... All I know is I almost ventilated my block from rod bearing failure in the widow after 10 hours of on track runnning....I'm sure the amsoil helped....but how much...I dunno

jcorenman

Wow! Do you know what oils were they running?

JWise

RKD mentioned M1, but I would suspect not the 15W-50 we use. As mentioned above, it appears to be the GF-4 rating of the thinner viscosities that have lower zinc levels. Still, I hate to take chances...

AO

Yeah, we should be careful here. All Mobil 1 oils are NOT created equally.

GregBBRD

Torco TR-1 indeed has the proper zinc and phosphorus levels. Also cuts down oil consumption issues, signficantly!

blown 87

I will no longer use Mobil one of any grade in any car that comes in my shop.

jcorenman

Understood, and agreed with regards to the GF-4 spec. I was just curious about the weights. The problem is when a company uses the same trade-name (e.g. "Mobil-1") to cover a wide range of product, then everything gets tarred with the same brush.

RKD in OKC

I will check for sure which M1, they are all local PCA members. When I asked they just said Mobile 1.

The A4 guy has 2 944 Turbos and he is using Joe Gibbs in them now.

sendarius

Here in Oz, Mobil don't sell 15W50 Mobil 1. I can buy 0W50 and 5W50, but nothing heavier.

With our moderate to hot temperatures (we don't print freezing points on our thermometers), I don't understand this logic, but it has driven me to other oil brands for the 928 (good old Fuchs 20W50 alleged dead dino food).

With the Fuchs, oil pressures seem fine, and I haven't put enough miles on either 928 to tell if wear is an issue. ZDDP levels are supposedly up where they need to be, as well.