Why 10W-30 In a Honda S2000?

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My Owners Manual says to use 10W-30 in my 2004 Honda S2000. I figured that was old data until I went by Honda Dealership to get the special OEM Oil Filter (PCX) that is specifically designed for S2000 and see ALL S2000's are supposed to use 10W-30?

Why? Can anyone explain by a 5W-30 is not recommended? Out of all the Honda vehicles I saw on this chart in the Honda Dealership, the only one with a 10W-30 recommendation was the S2000?
 
Is the required oil conventional? Often conventional 10W-30s require less viscosity index improver polymers, and are thus less likely to shear in service, than 5W-30 conventionals. With synthetics, this is largely not an issue.
 
Didn't ask or see whether they recommended synthetic or Dino. Assuming Dino.
 
I'm sure that Honda is assuming that conventional oil will be used, or is at least allowing for that possibility. A conventional 10W-30 is generally more shear-stable than is a conventional 5W-30, and I'd reckon that that's why the 10W-30 recommendation is made. That engine is their only engine that revs to 9,000 rpm or higher, so they likely wanted the extra stability that the 10W-30 grade provides.
 
Originally Posted By: Hokiefyd
I'm sure that Honda is assuming that conventional oil will be used, or is at least allowing for that possibility. A conventional 10W-30 is generally more shear-stable than is a conventional 5W-30, and I'd reckon that that's why the 10W-30 recommendation is made. That engine is their only engine that revs to 9,000 rpm or higher, so they likely wanted the extra stability that the 10W-30 grade provides.


I agree, I'm even surprised they didn't specify a heavier weight, probably they didn't because of fuel mileage considerations.

BTW, aren't most Honda's spec'ed for 5W-20 weight oil? My son's 2001 Honda Civic is.
 
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Does the 2004 S2000 manual also indicate that a synthetic 5w-40 may be used in extreme conditions or similar language? My 2001 did and I believe Honda spec's 5w-40 for the ROW.

I always used Redline 5w-40 in mine, while it may not have made much of a difference it was comforting when I was playing around w/ the 9k redline.

w
 
Originally Posted By: wings&wheels
Does the 2004 S2000 manual also indicate that a synthetic 5w-40 may be used in extreme conditions or similar language? My 2001 did and I believe Honda spec's 5w-40 for the ROW.

I always used Redline 5w-40 in mine, while it may not have made much of a difference it was comforting when I was playing around w/ the 9k redline.

w


I don't have the manual...
 
NateDN10 and Hokiefyd are correct.

Originally Posted By: wings&wheels
Does the 2004 S2000 manual also indicate that a synthetic 5w-40 may be used in extreme conditions or similar language? My 2001 did and I believe Honda spec's 5w-40 for the ROW.

I always used Redline 5w-40 in mine, while it may not have made much of a difference it was comforting when I was playing around w/ the 9k redline.w

Yes Honda recommended 5W-40 for cold temperature starting not high temperature protection.

RL 5W-40 with it's HTHSV of 4.6cP is effectively a very heavy 50wt oil, actually heavier than M1 15W-50 at operating temp's and therefore massively heavier than necessary for the S2000 engine. I'd be surprised if the oil pump ever gets out of by-pass mode at high rev's.
A suitable RL oil choice would be their 0W-30.
 
Honda recommends conventional 10W30 and synthetic is allowed. 5W40 is recommended for colder climate.

Honda developed/tested the S2000 engine in the late 1990's, conventional 5W30 wasn't as shear stable as of 10W30, therefore they recommend 10W30.
 
Originally Posted By: HTSS_TR
Honda recommends conventional 10W30 and synthetic is allowed. 5W40 is recommended for colder climate.

Honda developed/tested the S2000 engine in the late 1990's, conventional 5W30 wasn't as shear stable as of 10W30, therefore they recommend 10W30.


I understand but they still made the s2000 in 2009 and they still recommend 10w-30. I can't believe Honda is unable to keep up to date with the changes in oil formulation.
 
Originally Posted By: NateDN10
Is the required oil conventional? Often conventional 10W-30s require less viscosity index improver polymers, and are thus less likely to shear in service, than 5W-30 conventionals. With synthetics, this is largely not an issue.


Which synthetics? The only 5W30 I have seen in service that does not shear into the 20 grade range is Red Line. I have seen some UOA's were Amsoil SS has sheared and oxidized back into the 30 grade range but not too many.
 
Originally Posted By: Gebo
Originally Posted By: HTSS_TR
Honda recommends conventional 10W30 and synthetic is allowed. 5W40 is recommended for colder climate.

Honda developed/tested the S2000 engine in the late 1990's, conventional 5W30 wasn't as shear stable as of 10W30, therefore they recommend 10W30.


I understand but they still made the s2000 in 2009 and they still recommend 10w-30. I can't believe Honda is unable to keep up to date with the changes in oil formulation.

To change oil viscosity from conventional 10W30 to anything else, they have to do complete test and submit the result to EPA. That may cost a lot of money, since the sale volume of the S2000 was so low, it didn't make sense for them to spend money on the test.
 
10w30 also has a lower HOACK volatility rating, which may have some bearing on theirs oil choice. 5w30 is not a miracle oil that many think it is.
 
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Originally Posted By: dave1251
Originally Posted By: NateDN10
Is the required oil conventional? Often conventional 10W-30s require less viscosity index improver polymers, and are thus less likely to shear in service, than 5W-30 conventionals. With synthetics, this is largely not an issue.


Which synthetics? The only 5W30 I have seen in service that does not shear into the 20 grade range is Red Line. I have seen some UOA's were Amsoil SS has sheared and oxidized back into the 30 grade range but not too many.

No one said a typical GP III based 5W-30 synthetic didn't shear and a 10W-30 dino will also shear. It's just that a 5W-30 dino could shear to an unacceptable viscosity level.


It's the resultant viscosity that matters
 
Also, the s2000 was a specialty car that sold in small numbers to people that were generally automotive enthusiasts. The engines were not used in any other car. It simply wan't worth the time and money for honda to re-certify the F20C/F22C engines on other oils as time passed. Same reason the ford gt500 calls for 5w-50. Does it really need it? Probably not. But it's a small volume car with a unique engine that's designed to be driven very hard, so they specify something that's going to survive anything you can throw at it.

Plus the F20C/F22C are known to consume lots of oil (just like all 90's honda vtecs seem to) so that's probably why they chose 10w instead of 5w.
 
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Originally Posted By: CATERHAM
NateDN10 and Hokiefyd are correct.

Originally Posted By: wings&wheels
Does the 2004 S2000 manual also indicate that a synthetic 5w-40 may be used in extreme conditions or similar language? My 2001 did and I believe Honda spec's 5w-40 for the ROW.

I always used Redline 5w-40 in mine, while it may not have made much of a difference it was comforting when I was playing around w/ the 9k redline.w

Yes Honda recommended 5W-40 for cold temperature starting not high temperature protection.

RL 5W-40 with it's HTHSV of 4.6cP is effectively a very heavy 50wt oil, actually heavier than M1 15W-50 at operating temp's and therefore massively heavier than necessary for the S2000 engine. I'd be surprised if the oil pump ever gets out of by-pass mode at high rev's.
A suitable RL oil choice would be their 0W-30.


I would be hesitant to use an 0w-30, but if I did it would be RL's. Given the recommendation of 10w-30 here and 5w-40 for ROW, it appears that someone at Honda felt this engine had higher then typical viscosity needs. This is my somewhat experienced opinion...and we know what most opinions are worth...

My question would be why the ROW (Europe and Japan) recommendation, at least when I had mine from '01-'05, was for 5w-40 if the engine did not benefit from a higher viscosity?

I just did a quick check of the Castrol and Mobil UK websites and they still recommend 5w-40 and 0w-40 respectively. Mobil's tech folks here recommended 0w-40 when I contacted them back in '03 before I did a few HPDE's in California w/ the car. Obviously there is a lot at play in manufacturers' oil requirements: CAFE, anticipated use, etc. but I find it hard to stray too far from the handbook.

To summarize, I'd guess that the F20/22 engines do benefit from the higher viscosity..again, one finance guy's opinion on an engineering topic..
 
Originally Posted By: dave1251
I have seen some UOA's were Amsoil SS has sheared and oxidized back into the 30 grade range but not too many.


Wha? When? Huh? Links?I may have missed them, that's for sure.
 
Originally Posted By: wings&wheels
Originally Posted By: CATERHAM
NateDN10 and Hokiefyd are correct.

Originally Posted By: wings&wheels
Does the 2004 S2000 manual also indicate that a synthetic 5w-40 may be used in extreme conditions or similar language? My 2001 did and I believe Honda spec's 5w-40 for the ROW.

I always used Redline 5w-40 in mine, while it may not have made much of a difference it was comforting when I was playing around w/ the 9k redline.w

Yes Honda recommended 5W-40 for cold temperature starting not high temperature protection.

RL 5W-40 with it's HTHSV of 4.6cP is effectively a very heavy 50wt oil, actually heavier than M1 15W-50 at operating temp's and therefore massively heavier than necessary for the S2000 engine. I'd be surprised if the oil pump ever gets out of by-pass mode at high rev's.
A suitable RL oil choice would be their 0W-30.


I would be hesitant to use an 0w-30, but if I did it would be RL's. Given the recommendation of 10w-30 here and 5w-40 for ROW, it appears that someone at Honda felt this engine had higher then typical viscosity needs. This is my somewhat experienced opinion...and we know what most opinions are worth...

My question would be why the ROW (Europe and Japan) recommendation, at least when I had mine from '01-'05, was for 5w-40 if the engine did not benefit from a higher viscosity?

I just did a quick check of the Castrol and Mobil UK websites and they still recommend 5w-40 and 0w-40 respectively. Mobil's tech folks here recommended 0w-40 when I contacted them back in '03 before I did a few HPDE's in California w/ the car. Obviously there is a lot at play in manufacturers' oil requirements: CAFE, anticipated use, etc. but I find it hard to stray too far from the handbook.

To summarize, I'd guess that the F20/22 engines do benefit from the higher viscosity..again, one finance guy's opinion on an engineering topic..

Searching the ROW to see what's recomended doesn't make a lot of sense to me. There is no evidence to suggest CAFE had any influence on the oil recommended for the F20/22. And as has been mentioned the 5W-40 rec' was made for cold starting below -10C.
From the sound of things this newly acquired car is going to be driven normally here in NA. A light 30wt oil (HTHSV 3.0cP-3.2cP) is the preferred viscosity that Honda recommended and I see no reason to deviate from that.
If the OP was going to track the car, I'd suggest first installing a good oil pressure gauge and fine tune his oil viscosity choice based on that.
 
From the 2004 Owner's Manual:

"An oil with a viscosity of 10W-30 is preferred for optimum fuel economy and year-round protection in your Honda. You may use a 5W-40 oil if the temperature in your area goes below 0F (-20C).
You may use a synthetic motor oil if it meets the same requirements given for a conventional motor oil: it displays the API Certification Seal (10W-30 SL Energy Conserving on oil cap) and it is the proper weight. You must follow the oil and filter change intervals given on the maintenance schedule."

You should be able to download the manual on Honda's website. The F22C1 engine received dummy head honing to help improve machining accuracy and stabilize piston movement. So it is rare that you will see any oil consumption like a F20C1. It does shear oil though. I have done at least 5 UOA's over the years on my 2004 AP2 with 10W-30, 0W-30, and 5W-30. It's a wonderful little engine, and probably the most fun car I've ever driven. Be very alert to a pending mis-shift (money shift). Other than running low on oil, a mechanical over-rev can spell doom.

I think Honda just didn't want to spend the money to re-certify the S2000 engines for a 20 grade oil, or a 0W/5W oil for that matter. That would be a tough sell to the bean counters. But staying with what Honda recommends won't handicap you at all.

Good luck and have fun in your new toy.
 
You'll see a number of silly replies, especially when you consider that this car was current during Honda's twenty grade era.
The answer is simple.
Use a 10W-30 or a 5W-40 in your S2000, and the engine will be just fine.
I would ignore those recommending other grades, since I doubt that they have the experience in designing and building high revving fours that Honda does.
Honda had a reason for the oil grades it specified.
Use those recommended grades and sleep easy.
Ignore the internet experts, since in this case, you really do have a highly stressed engine.
Has there ever been a normally aspirated car engine with higher specific output that you could buy off a dealership floor?
 
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