BigMikeATL

I've recently acquired an 8 with a greddy turbo and was curious... for those that have a similar setup, what type and weight oil are you using?

Also, what are your thoughts on using the Sohn Adapter in a turbo'd setup?

This isn't intended to start a flame war. There are many threads for that and I've read them all. I'm just asking about this particular scenario mainly because Mazda recommends conventional oil for the renesis and greddy recommends synthetic fort he turbo.

ChrisRX8PR

iTrader: (1)

I would suggest changing to 5W40 or 10W40. The turbo will make your oil way thinner than it currently is and going a bit thicker will help protect the engine from the new heat.

Cheers!

Chris

9krpmrx8

iTrader: (46)

Mobil1 0W-40 and yes I run a SOHN, I have for years.

BigMikeATL

I've been running conventional 10w40 in my non-FI'd 8's for years and most of the experts swear by it given that I live in the southeast.

I just put RP 15w40 in my turbo'd 8, though I'm debating whether I should use the Sohn and just run Mobil 1 to lubricate the crankcase.

BigMikeATL

Did you stick with stock OMP levels?

bose

iTrader: (5)

I use Mobil 1 0w40, seems to be working as described.

9krpmrx8

iTrader: (46)

As long as you use a x-40 oil and change it regularly you are probably good to go. How often you change you roil is really more important than what oil you use. But, most turbo experts recommend using a good synthetic. I am not running stock OMP settings. I use Idemitsu in my SOHN and I don't premix my gas.

It's really all for nothing though, a boosted Renesis won't live much past 30k no matter what you do. Unless MAYBE if you set max boost to 5-7psi and don't drive in the heat much.

RotaryMachineRx

iTrader: (1)

I run 5w-30 full synthetic and I premix idemitsu, no sohn adapter, currently at approx 30000kms running strong.... I live in a relatively cooler climate than these fellas though and running in hot weather is not typically a large issue.

Edit: Running 9 psi

BigMikeATL

Interesting. This engine and turbo have over 40000 miles on them. Do the stock seals suck that bad?

BigMikeATL

My main concern is metering synthetic into the engine since it doesn't burn the same way conventional does... though conventional burns and leaves it's own lovely mess behind...

9krpmrx8

iTrader: (46)

It's the exhaust design of the engine mainly, the side seals just don't hold up. But overall turbocharging just adds additional stress in a lot of way to an already largely unreliable engine. Add a harsh operating environment to that and you just have a recipe for early failure.

9krpmrx8

iTrader: (46)

That is all BS parroted claim from people who have never tested that claim. The facts are that until there is a some real scientific testing, no one can say one way or another.

As for the SOHN, well injecting clean and cool two stroke that was designed to burn and not leave behind excessive residue just makes sense over dirty crankcase oil.

But again, there has been no real testing on street cars of premix so it's all guess work really. It's not really a valid comparison but in race cars powered by the Renesis, premixing the gas has proven to increase engine life when the factory oil metering system is retained.

BigMikeATL

Yeesh. I'm starting to think that buying this car was a mistake...

Granted, I've also owned two NA's 8's and other than the typical quirks, they've been pretty reliable.

BigMikeATL

My thoughts exactly.

9krpmrx8

iTrader: (46)

Proper prior planning. It's weaknesses are no secret.

Carbon8

iTrader: (4)

IMO this thread is for any 8, not just an FI.

9krpmrx8

iTrader: (46)

I agree.

WTBRotary!

iTrader: (6)

Call me crazy... Just thought of this, and it may be dumb but why not turbo an 8 and just run 5 psi boost max... It'll make the 8 more peppy but shouldn't put too much strain on the seals... Sure, maybe only get 50hp but hopefully it'll be a reliable 50hp

Carbon8

iTrader: (4)

Someone's already been working on a similar idea, it is theorized that in the upper RPM band 1 PSI of boost has the potential to yield 20BHP.

WTBRotary!

iTrader: (6)

^^^ perfect... So sounds like 5 psi max would be perfect... Who cares if it's only ~50hp, as long as it spools up fast at low rpm, that would make the 8 quite a bit faster...

Brettus

iTrader: (2)

Because it's too much fun running 10 or more

After a few engines and lots of turbo miles I have settled on 5w40 synthetic and running the stock OMP with increased settings and no premix (12-14psi boost). If I track the car I will add a little premix at that time but not for normal motoring.

BigMikeATL

How many miles do you usually get off your turbo'd engines?

Do you wait for a seal to fail or just rebuild them at regular intervals?

Brettus

iTrader: (2)

Usually ? LOL !

Let me put it this way - if you don't break anything and service it well and run up around 7-8 psi I can see the engine lasting 60000 miles + before it would be worn out .

BigMikeATL

That makes me feel a lot better. I'm not sure how well the last owner cared for the engine/turbo, but they seem healthy as far as I can tell. If I get 15-20k out of this motor (which would put me at the 60k mark), I'd be a happy camper.

9krpmrx8

iTrader: (46)

Good luck having enough self control to run just 5psi. Once you get a taste of 10psi you are done.