Had my car tuned today (Stock block,Vortech S/C, ID725's, Walbro, full exhaust, MREV2/spacer, etc...) and the tuner recommended 20w50 and said at a minimum to run 15w40. Said it would help seeing how the motor is making much more hp/tq than it was designed for. He said 5w30 was way too thin and I risk a spun bearing. Any thoughts?

Had it to 363 hp on a mustang dyno and had him bring it down to 346. Car pulls pretty nice. EXACTLY what i wanted.

 

Anyone?.. I've searched through the FI oil threads and people seem to merley just list pretty much every oil type they are running such as 5w30, 10w30, 0w40, 15w40, 5w50, 15w50 and the one I am inquiring about which is 20w50.

I've researched online and most people run 20w50 that have looser bearing tolerances, but that is usually on built motors. I'm 100% internally stock with 56k. They also run it with oil consumption issue, which I do not have.

I trust the tuner, but just want a better explanation than "it's better". I know the book says 5w30, but that's NA and I'm FI now, so is 20w50 the way to go and why?..

 

I don't know what his reasoning is but the best way to figure things out is to get used oil analysis done on what you're currently using... Blackstone Labs is the facility I send mine to. It costs 25 bucks for a report and they go into great detail about contaminants as well as the presence of a variety of different engine materials that may or may not be at expected levels and suggesting premature breakdown of components based on the material.

That will give you a baseline on the oil you're currently using and will let you see how its holding up. I don't think I've ever seen mention of 20w50 for a G35 just because you're FI on a stock block.

Did he give you a reason?

 

Mid tune he called me over and asked what weight oil I was running and I informed him 5w30. He seemed shocked and advised me to run a thicker oil and suggested changing it before we made any more pulls as 5w30 is too thin and I risk a spun bearing... like I said, he said 15w40 at a minimum and said 20w50 if it was his car.

So out went the freshly changed 5w30 (150 miles) and in went new Amsoil 20w50 he had... He took a look at my old oil. I'm not sure if he saw something that worried him during a pull or what, but oil was clean and so was my magnetic drain plug.

To be honest it had/has me a little worried, thus explaining my curiosity to why 20w50?...

 

What kinds of vehicles is he used to working on?

 

Everything from what I understand. He has experience in various platforms and programs. Apparently he is one of the go to guys in Texas. His name is Steve Kan @ PRT Performance and he is from what I gather a " Rotary God" as someone put it.

There was mainly RX7's there, but there where also some G's, Z's, 300zx's and DSM's.

He had a G there he said was his that was fully built with a modified turbonetics kit.

Im still baffled by the 20w50 suggestion... Also my SES light came on today. P2A00. Bank 1, sensor 1 "range/performance"... Which is the primary wideband sensor in the header pre cat. Always something!

 

I'm not an expert but I've seen over on my350z that some with built blocks prefer thicker oil, has something to do with the clearances most machinists use. Been running 5W-30 for the past 2 years but I plan on using something thicker as well.

 

There has to be a reason to suggest the thicker oil... Is it for oil pressure due to it being thicker at temp at high RPM where it is making the most power/stress?..

The GTR as many of us know is recommended to use 0w40. I'm not trying to turn this into another FI oil thread. Just would like to know why we did what we did and how it is better in preventing a spun bearing using 20w50 over the manufactures suggested 5w30. Again, I understand 5w30 is recommend for NA.

 

bump

 

I don't know if this is any help to you but all my boosted friends across different platforms usually run 15-40 from stock to fully built blocks, not sure about 20-50 though

 

Yes- that's what I'm running in the 300v formula but a lot of guys prefer rotella. Going to see how my next UOA comes back and see...

 

I'm strongly leaning towards a 40 weight. For my stock block and power level, John over at Z1 suggested to stay with the 5w30 and personally not run anything thicker than 10w40...

 

From all my personal research I think I have it narrowed down to either Mobil 1 0w40 or Shell's Rotella T6 5w40. Looking more into the Rotella as I have been reading nothing but great things for boosted applications ranging from numerous platforms both foreign and domestic.

 

Personally, I use motul 8100xcess 5w40 and have no complaints about it.

 

Decided on and picked up some readily available Mobil 1 0w40 and a the slightly larger Mobil 1 filter M1-110. I am just shy of 7 quarts with the pan and cooler. (only need 6 qts every change due to the oil staying in the cooler and lines as I do not drain it.)

Got the recomendations for the Mobil 0w40 on the stock block from Seb @ Specialty Z.


As someone stated, if its good enough for the GTR its good enough for my Vortech supercharged G. Ill probably end up doing a oil analyisis on the second change for the heck of it. If I do Ill throw the results on here.