2007 Zx-10

What makes this engine different from others just because it's an S2000? what does Honda recommend for the Civic SI? 5w-30 is recommended by most engine manufacturers these days, including BMW as far as I know...look, factories come up with strange reasons for all sorts of things, it's not the holy grail you think it is...Mazda warns not to use synthetic in rotary engines, yet it's been proven by a myriad of users synthetics are nothing but good in rotary engines

2007 Zx-10

http://townhall-talk.edmunds.com/dir...w/.efc6d19/967

http://www.8thcivic.com/forums/showthread....astpost&t=59740

according to that link, 5w-30 is factory recommended for the Si

it's likely 10w-30 is "grandfathered" into the manual for the S

124Spider

Ok, so you think that Honda just mindlessly specified 10W-30 for this engine, when 5W-30 would be better (apparently, because "bikes" and BMWs use 5W-30)?

Go for it....

ps--Mazda says to use dino oil in my RX-8; I do. It has never been "proven" that synthetics are better, and dino does just fine; modern dino oil is so good, I have no concerns that synthetic would be better when the manufacturer specifies dino oil. My Miata is specified to use 5W-30; the engine builder says to use 10W-30; I use 10W-30, cuz he builds great engines, and I believe that he knows what he's talking about when he's taken the engine apart and put it back together.

But if using 5W-30 with your AP2 somehow gives you a feeling that you know more than Honda about our engine, good for you.

2007 Zx-10

nope, I didn't say that...Honda developed recommendations for this engine back in 1999 (or earlier) before use of thinner oils was widely accepted...of course they don't want to flip-flop on that recommendation...again, why would they recommend 5w-30 for the Si?

I've run synthetic in my FD RX-7 for over 10 years, so have plenty of other people...it looks fine at tear-down...I do not think it's good to run synthetic in the oil metering pump because 4 stroke oils aren't designed to burn and can leave deposits, I run Idemitsu rotary pre-mix

slipstream444

There's more to the oil than the rating stamped on the bottle. There's a lot of cross over in viscocity on the market. Redline's 5W40 almost looks exactly the same as their 10W40 on paper and there are a number of 10W30s that look nothing more than repackaged 5W30s. It's important to look at the manufacturer's specs for the specific oil you're looking to use. I personally use a 5W30 in colder environments because it flows faster at startup. There are those on the site that use 0W30 for the same reason. However, I now live in Florida and will stick with 10W30 year round due to the fact there is a notable difference in Amsoil's 5W30 and 10W30.

FTR - I used Amsoil 10W40 in my 10th Anniversary RX-7. I also ran a small amount of one of their 2 cycle oils in the gas. That's how I got introduced to Amsoil - I used to buy it through Mazdatrix. The car suffered a thrown apex seal due to detonation - the turbo manifold to turbo gasket had a tiny upward facing leak that acted like a blow torch and super heated the intake - and blam! I was then running on 4 chambers instead of 6. I was in college and ran the car like that for 3 more months. Eventually sold the car with the spare motor and I helped the buyer tear down the engine. The housings were prestine - not a single mark from the damaged ampex seal, which is almost unheard of following an apex seal failure. He put a new seal kit on the car and it ran like new. That's why I still use Amsoil - and why the guy who bought my RX-7 uses it too. He'd never seen such a perfectly clean motor after chucking an apex seal.

2007 Zx-10

I run Mobil 1 15w-50 EP in my FD RX-7, which routinely sees 15 psi boost, primarily because of the ungodly fuel dilution...but as you said, the engine looked pristine at the last tear down

2007 Zx-10

http://www.mobiloil.com/USA-English/MotorO...ance_5W-30.aspx

[QUOTE]Our lineup of Mobil 1

2007 Zx-10

too bad these guys don't run a comparison test, huh?

http://www.asmeconferences.org/IJTC07/pdfs/Sample.pdf

Jay2000

WOW, I must be a complete idiot than, I run Amsoil series 2000 , 0-30 weight because it performs better than the 10-30 by amsoil. If I am not mistaken the 0,5,10,etc is the flow rate(how fast it gets through the engine at start up or something like that) and the 30 is the weight at temperature. It is all a matter of opinion and what you like and think is best for you.

124Spider

From your lips to God's ears.

WOW, that puts things in proper perspective! Thanks for setting the record straight; all this time, I thought science might have something to do with it, but it turns out that it's just "a matter of opinion and what you like and think is best for you."