Combine 0-30 and 0-50 to get 40?

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disquek

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Hi,

I'm an SCCA racer in the GTL class. These are tube frame sillouette cars with highly modified engines.

I currently use the Redline 40 Racing Oil.

I'm considering switching to Mobil-1 Racing oil. However they dont offer a 40. They only offer a 0-30 and a 0-50 in their "Racing Only" oils. I want to stick to racing only oils for the additive packages which are tailored to racing.

Can I combine the 0-30 and 0-50 to make a 0-40? I know they will mix. I just dont know if the result is a true 0-40 or if it's mixture of half 0-30 and half 0-50. I might not be articulating that well, so I hope you can understand my question!

Thank you!
-Kyle Disque
 
The way I understand, the viscosity is more of something similar to logarithmic scale as supposed to linear scale.
In other words, the average of equal amount 30 and 50 are not necessarily become 40.

It is an engineering design judgement to see if you really need it to be at 40.
If not then it is fine.
If yes, then you have to find the calculator where you can put all the oil parameters and see if you can get it close or not.
You may need to go with different amount of different viscosity.

Some oil guru here can chime in for you.
 
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I'd just use M1 0w-50 without any mixing. It's on the thin side of 50, so when in use, it'll turn into a 40 in no time.
smile.gif


HT/HS viscosity is at 3.8 cP, so again, typical of a 40-grade.
 
Hi,

Wow, thanks for the quick replies.

Mobil offered a contingency for podium finishers at the SCCA Runoffs. So I have some credit with them to burn. I use their 75-90ls gear lube, and could use the credit for that. But the engine oils are compelling.

I'd also heard good things about the Mobil-1 Racing oils.

That said, I've been very happy with the RedLine Racing 40 and I've been using it without issue for about 8 years. I regularly send in samples for analysis, and it's always been positive.

But as a racer, I'm always on the lookout for the next better thing.

-Kyle
 
Originally Posted By: disquek
Hi,

I'm an SCCA racer in the GTL class. These are tube frame sillouette cars with highly modified engines.

I currently use the Redline 40 Racing Oil.

I'm considering switching to Mobil-1 Racing oil. However they dont offer a 40. They only offer a 0-30 and a 0-50 in their "Racing Only" oils. I want to stick to racing only oils for the additive packages which are tailored to racing.

Can I combine the 0-30 and 0-50 to make a 0-40? I know they will mix. I just dont know if the result is a true 0-40 or if it's mixture of half 0-30 and half 0-50. I might not be articulating that well, so I hope you can understand my question!

Thank you!
-Kyle Disque


Sorry Kyle. Seems like when someone comes to BITOG with a question such as this about all you get is not an answer, but advice that you don't need it, or here is an alternative, or here is what I would do'. Try this calculator http://www.widman.biz/English/Calculators/Mixtures.html and see if it answers your question.
 
Originally Posted By: TTK
Try this calculator http://www.widman.biz/English/Calculators/Mixtures.html and see if it answers your question.

And to expand on this (for Kyle), 40 grade translates to a 100C viscosity range of 12.5 to 16.3 cSt. So, if you want to end up somewhere in the middle of that range (say 14.5 cSt), then 40% of M1 0w-30 and 60% of M1 0w-50 should get you there.

For comparison, Redline Racing 40WT has a 100C viscosity of 14.5 cSt. However, I'd expect this Redline oil to be a lot more shear stable since it's a 15w-40.
 
Originally Posted By: Quattro Pete
I'd just use M1 0w-50 without any mixing. It's on the thin side of 50, so when in use, it'll turn into a 40 in no time.
smile.gif


HT/HS viscosity is at 3.8 cP, so again, typical of a 40-grade.


I agree with QP on this. I'd bet that the Redline 40WT racing oil has a higher HTHS than the M1 0w50 Racing Oil.
 
So it's sounding like the RedLine 40 Racing is a better fit than either/or a combo of the M1 Racing oils?
 
Originally Posted By: A_Harman
Originally Posted By: Quattro Pete
I'd just use M1 0w-50 without any mixing. It's on the thin side of 50, so when in use, it'll turn into a 40 in no time.
smile.gif


HT/HS viscosity is at 3.8 cP, so again, typical of a 40-grade.


I agree with QP on this. I'd bet that the Redline 40WT racing oil has a higher HTHS than the M1 0w50 Racing Oil.


That's the good advice that the OP SHOULD be getting when asking questions on BITOG.

The M1 0W50 has an HTHS of 3.8...which means that in the bearings, where HTHS is what counts, it's about the same as regular M10W40...this particular oil (M1 0W50 racing) just happens to have silly KV100 numbers for an oil that has only 3.8 HTHS.

If you want a 40, then M1 0W40 itself is used in quite a few race engine.

Or stick to Redline.
 
Originally Posted By: Quattro Pete
Originally Posted By: TTK
Try this calculator http://www.widman.biz/English/Calculators/Mixtures.html and see if it answers your question.

And to expand on this (for Kyle), 40 grade translates to a 100C viscosity range of 12.5 to 16.3 cSt. So, if you want to end up somewhere in the middle of that range (say 14.5 cSt), then 40% of M1 0w-30 and 60% of M1 0w-50 should get you there.


Doing that would put the HTHS around 3.6...comparable to Redline's regular 5W30, and presumably their 30 race as well.
 
Originally Posted By: A_Harman
Originally Posted By: Quattro Pete
I'd just use M1 0w-50 without any mixing. It's on the thin side of 50, so when in use, it'll turn into a 40 in no time.
smile.gif


HT/HS viscosity is at 3.8 cP, so again, typical of a 40-grade.


I agree with QP on this. I'd bet that the Redline 40WT racing oil has a higher HTHS than the M1 0w50 Racing Oil.


Yes I agree with both here.

As QP said, the M1 0W50 with a HTHS of 3.8 cP is really a 40 grade oil where it counts. For example M1 0W40 FS has a HTHS of 3.6 cP and GTX 15W40 has a HTHS of 4.0 cP, that's two regular 40 grades bracketing your "50" grade.

As AH says, your RedLine 40 grade probably has a higher HTHS than the M1 0W50. So no need to mix the M1's, just use the 50 grade as is, if you want to try the M1 racing.
 
you could do a mix and send it in for VOA and see what the viscosity is. Might be a little expensive to get it to the correct viscosity but you should find a definite answer to your question.
 
Originally Posted By: TTK
Originally Posted By: disquek
Hi,

I'm an SCCA racer in the GTL class. These are tube frame sillouette cars with highly modified engines.

I currently use the Redline 40 Racing Oil.

I'm considering switching to Mobil-1 Racing oil. However they dont offer a 40. They only offer a 0-30 and a 0-50 in their "Racing Only" oils. I want to stick to racing only oils for the additive packages which are tailored to racing.

Can I combine the 0-30 and 0-50 to make a 0-40? I know they will mix. I just dont know if the result is a true 0-40 or if it's mixture of half 0-30 and half 0-50. I might not be articulating that well, so I hope you can understand my question!

Thank you!
-Kyle Disque


Sorry Kyle. Seems like when someone comes to BITOG with a question such as this about all you get is not an answer, but advice that you don't need it, or here is an alternative, or here is what I would do'. Try this calculator http://www.widman.biz/English/Calculators/Mixtures.html and see if it answers your question.


You don't need it, or here is an alternative: If you want to change, go with the 50

Here is what I would do: I'd ignore those calculators. They'll give you a number, of course, but its relationship to reality will be unknown.

In general a 50:50 mix will be skewed towards the lower viscosity component.
 
Ok. So from a protection perspective, it seems like the consensus is that the RL is at least the M1's equal when comparing Racing Only oils.

How about from a horsepower perspective? What do we think could be gained from the M1 or the RL?

-Kyle
 
Personally I would target a HTHS viscosity then go with the lowest KV100C and highest flash point engine oil that achieves that, and not pay for redundant W grades.
For your type of racing, you need more than a few HP that a light weight engine oil will achieve. Instead, improved intake port velocity and resulting throttle response.

To achieve that... you need to think outside the box and distance yourself from pack mentality.
 
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