Amsoil 5W-40

[cbutler]

I'm thinking of buying Amsoil 5W-40 European Formula for my 1JZ. I've had good experiences using the Amsoil 10-30, but I figured the 5W-40 would be more suiting.
Anyone used this oil or have any general comments about it?
Thanks.

 

[jdub]

Tell me why the 5W-40 is more suitable?

 

[cbutler]

Tell me why the 5W-40 is more suitable?

I wanted to go as thin as possible for start ups, and I figured stepping up to a 40 weight would provide a little better stability at higher temperatures.
Would you say just stick with the 10-30, or is my logic reasonable?

 

[jdub]

Well...you really didn't tell me why, other than you "figured". I don't mean to jump on you man, but this is the reason guys do the things they do concerning oil. It's not based on anything but a "gut feeling". You do have the right idea for choosing an oil for cold start...a few specifics are in order though

To answer your question, a 40W multigrade is not more stable at ops temp than a 30W multigrade...any high quality PAO or ester based synthetic will handle any amount of heat an internal combustion engine can throw at it...the 40W is simply thicker. Therefore it will also be thicker at ops temp...this is not necessarily a good thing on a stock or mildly modified motor. Thicker oil has a higher resistance to flow; this is going to give you higher psi readings, but you are not getting better flow. The only thing a thicker oil will do for you is thin less at higher temps above what you would see normally (100 deg C)...for 90% of the motors out there, this is not a factor.

Keep in mind the 7M was designed to run a 30W multigrade oil...you're looking at viscosity in the 9.30-12.49 cst range. What you want is an oil that is thin as possible cold and provides a viscosity in this range at 100 deg C.

Here's a comparison of the 2 Amsoil oils:
5W-40 (AFL)
Viscosity at 40 deg C: 79.7 cst
Viscosity at 100 deg C: 13.7 cst
(FYI - this oil is one of the thinnest in it's SAE grade vs other 5W-40 oils available)

10W-30 (AMT)
Viscosity at 40 deg C: 62.0 cst
Viscosity at 100 deg C: 10.7 cst

As you can see, the 10W-30 is significantly thinner both cold and at ops temp. That means the oil will flow better cold and flow will improve due to the drop in viscosity as it warms up. Bottom line here...the 10W-30 is just as stable at ops temp and flows better both cold and hot. It also illustrates a point: You would think the 0W-40 is thinner cold (it is a "0W", right?). Not true...the numbers on the bottle are viscosity range dependant. In order to meet the SAE viscosity requirements for the "40" half, the overall viscosity must be thicker. This is due to every oil thinning as it gets hot...as I said, the 5W-40 will simply thin to a higher viscosity at 100 deg C in order to meet the SAE 40W multigrade spec of 12.50-16.29 cst.

If you want to use a bit thicker oil that is PAO based (just like Amsoil), give German Castrol 0W-30 a look. It's viscosity is 12.1 cst at 100 deg C and 71.9 cst at 40 deg C. There is plenty of info on it in this section. If you want to use the Amsoil products, I would stick with what you've been using or give 5W-30 (ASL) or Signature Series 0W-30 (SSO) a try.

 

[cbutler]

thanks, that helps.

 

[supraguru05]

i switched to 5w-40 in my car from 10w-30 and noticed some improvement in psi in the higher rpms. let me explain. i track my car and my oil cooler was having a hard time keeping up my oil temps were 200-220 at any given point ive since helped that a bit but my 8.5 X 11 cooler just cant keep up. well at these temperatures i could watch my oil pressure (on a aftermarket gauge) start to hed below 40 in the higher rpms i didnt like this simply switching to a synthetic 5w-40 and it kept my pressures around 40-45 at the higher temps and rpms. ive read online that you generally pick the thinest oil that will give you the pressures you want at racing temperature and 40w is about right for my engine at the temperatures it runs. so im kinda backing jdub saying if you dont see a dorp in pressure at the higher temperatures then done switch

if this is completely wrong sorry and let me know

for reference im on a rebuilt motor with new oil pump and drive shaft

 

[jdub]

There are times that are appropriate to increase the viscosity. Running a car on the track with consistent high oil temps is one of them...excessive temps would be in the 230-250 deg F range. A high mileage engine with worn bearings is another. The "Golden Rule" for oil pressure is 10 psi per 1000 RPM. The problem on a turbo 7M is the stock filter head and the squirters...both are "controlled leaks" that tap off pressure to perform their function. Not a whole lot you can do about the squirters except replace the bolts during a rebuild...these wear over time and will become very inconsistent pressure wise...they should actuate at ~40 psi...worn squirter bolts can actuate much lower than that. The stock filter head has a relief valve to the cooler that also functions at ~40 psi...this is why you won't see pressures much above that on a 7M. The solution here is to remove the stock filter head and go with a full flow, thermostat controlled cooler circuit...there's a sticky in this section on how to do it.

I can understand using a thicker oil on the track when high oil temps are a concern...a 40W multigrade is max I would go without additional modifications to the oil system. A better solution is to shim the relief valve on the pump (~5mm) and install a full flow oil cooler circuit with a bigger cooler. However, the work involved in shimming a pump on a installed motor is extensive...planning during a rebuild would be appropriate. In your case guru, oil temps peaking out at 220 deg F is not excessive...you want your oil in the 200-220 deg F range...that is the heart of the envelope for oil operating temps and is the temp the motor was designed to run the oil viscosity wise. You want the oil to reach 210 deg F as quickly as possible to provide the correct viscosity to the engine. A full flow circuit will do that due to the thermostat and keep pressure higher by deleting the stock filter head. Running oil at temps below 100 deg C (210 deg F) will simply result in a thicker oil and a corresponding reduction in flow.

Always keep in mind that pressure is resistance to flow...increasing pressure by shimming the pump relief valve or removing the "leak" caused by the stock filter head will improve flow at a given viscosity, but only to the capacity of the oil channel in the block and the bearing clearances. Increasing pressure by increasing viscosity is the last option IMO and that is going to depend on what you have done to the oil system to handle it.

Guru - I'll make the same suggestion as above. If you want a bit thicker oil, German Castrol 0W-30 fits the bill nicely and is a true PAO synthetic...running it at the temps you posted are a breeze for this oil.

 

[supraguru05]

thanks jdub for reference im on a na block so no squirters here and im on a full flow cooler setup with a remote filter and mocal thermostat. my coolers just a little undersized. i didnt shim the pump tho and done really plan on it. im working on extending and baffleing my oil pan next. ill your input definitly helped ease my mind about the oil temps but im still going to grab a bigger cooler when i get time

 

[jdub]

If you are going to remove the pan, shimming the pump relief valve will be easy to do...it's a worthy mod IMO...4-5mm washer thickness is plenty. Since you have the Mocal thermo, a larger cooler will not over cool the oil...it will provide extra cooling capacity when you take the car to the track.

 

[Amontgomery]

I was told by the previous owner of my car to run 15w-50 in my motor. Supposedly this motor was freshly rebuilt with less than 5000 miles on it or so. Being 50 weight and grossly out of the recommended viscosity range for a stock 7m, is this hurting the performance or reliability of my motor? It does not make sense to me why this would be recommended if you are talking about 40 weight being more than an average driver would need.

I am still running a stock trim CT-26 with stock injectors and AFM. The only modifications have been a full turbo back 3" exhaust with DDP, and 2.5" aluminum hardpipes to and from the intercooler. Supposedly the head is also ported and polished but I have not had the manifolds off of it to see with my own eyes. I do not beat on the car, I will have a hard pull occassionally but when I am driving around town I am very easy on it.

 

[jdub]

Your logic is correct...read this:
http://www.supramania.com/forums/showthread.php?t=41775

The immediate thing you will see with a thick oil is a drop in gas mileage. The oil will work, but over time is not optimal for the motor. My personal preference for oil is German Castrol. There are several threads in this section on it.

 

[Amontgomery]

Thanks for the info. I will see if I can't pick up 6 quarts of synthetic today and go ahead and change it out. I have been noticing very poor gas mileage as well as unusually high oil pressure at idle with almost now changes from idle pressure to oil pressure at 100mph with the engine at full boil. Idle will be 35-45psi and pressure under strain will be 45-50psi.

 

[ModularTurbo]

this is slightly off topic but I would just like to say that I have taken the Amsoil T101 training and jdub is blowing "my mind" you sir have most defintely earned the oil and lube expert title that you have.
WOW
you know your shit

 

[ModularTurbo]

Oh and by the way Amsoil is awesome I use it in everything I own.

 

[Alpinesupra]

jdub,
the thread that you posted with got-turbos happens to be a friend of mine and the local supra shop owner aka the mk3 supra legend here in the dfw area is a even better friend of mine.
recently i have gone through fully building my motor and the trials and erors and now have about 2500 to 3000 miles on the motor (7m), but ever since ive known him he has had me running 20w-50 oil in the summer time which does get over 100 degrees in the summer then swap it out for 10w-30 for the winter time in both my stock na motor and my used to be stock turbo motor and never once has it been synthetic oil.
but from what your saying i should be running a 10w-30 or 10w-40 weight oil in the 7m??
i am due for a oil change i guess im not dailying the car so im in no hurry at the moment but i wanted to be running either amsoil or royal purple or model 1 synthetic 10w-30 oil in my brand new motor all the time summer and winter what do you think sir if you dont mind me asking???

thank you
-sean

 

[jdub]

First Sean, read this:
Motor Oil 101 - Dr AE Haas

And the link in post #11 above...both links might open your eyes as to why you don't want to run a 20W-50

You should be running a 0W or 5W-30...don't let the 1st number fool you...that is the cold viscosity of the oil. I does not mean the oil is "thin"...at ops temp (100 deg C), the 2nd number is what you look at. German Castrol 0W-30 (Grp IV PAO) is 12.1 cst at ops temp...most 30W multigrades are in the 10-11 cst range at the same temp. GC is actually just below the lower end viscosity for a 40W oil.
BTW - There is no such thing as an oil that's too thin at cold start

You might want to read a bit more in this section about RP oil (search). Amsoil (Grp IV PAO) is good, but it's expensive compared to the other alternatives available...I would choose Red Line (Grp V ester) 5W-30 if I wanted to spend that kind of $$$ on oil. Mobil 1 is not a true synthetic; it's a Grp III hydrocracked dino oil. If you decide to go with a Grp III, Pennzoil Platinum 5W-30 is a much better choice. Here's a thread on a couple of the oils you are asking about:
http://www.supramania.com/forums/showthread.php?t=38768

Don't forget to run a good filter...Wix is excellent choice. Here's a thread on that subject as well:
http://www.supramania.com/forums/showthread.php?t=42763

 

[Alpinesupra]

jdub,
thank you for your answer i will more into those links when i get a better chance (at work right now).
and its currently got regular 20w-50 pennzoil platinum in it and it also has a wix filter on it also.
thank you for your help..

-sean

 

[TurboI6]

How about Amsoil Signature Series 0W-30? This used to be their Series 2000, which I've used for a long time in all of my cars.

 

[jdub]

What about it? A rather broad question
It's Amsoil's flagship oil and my post above (#16) applies.

 

[wiseco7mgt]

Why are wix filters good? If you going to the trouble of finding the highest quality oils for your car why not just use a K&N high peformance oil filter to match?