We match ford except on viscosity.

We actually recommend 10W-40, this offers the best protection for the
engine. 10w-30 is also acceptable because 10W-40 is harder to find, and
less accepting of neglect when it comes to interval and breaks down faster.

The original ford 5w-20 helps them do two things. It gains them something
like .5% MPG to increase the fleet average for Corporate Average Fuel
Economy*(*CAFE) requirements (important for business) and it gets the
engine past it's warranty period plus a good margin, it is a form of
planned obsolescence since they want to sell you a newer car at some point.
There isn't a purpose in running 5W-20 since you aren't part of Ford's
fleet, and don't help their CAFE numbers. We don't have CAFE requirements
so running it won't help us either, and since we want your engine to last
as long as possible.

The 10w-40 recommendation actually came from a discussion with Boston Bob
about this subject. It is corroborated by "turbo Tom" the  preeminent turbo
zetec tuner in the US. The engine design, average use case and average
required output were the considerations; Bob's experience, Tom's
experience, and our experience were the lenses; Longevity was the goal
behind the choice.

We typically have one, several, or a big bag of reasons why we have done
something in the conversion system. It isn't the case as in single instance
DIY situations that a result or recommendation is anecdotal. It's possible,
but the vast majority isn't.

We also wouldn't void a warranty for such a thing. We could, but we're not
jerks either.

For such questions the best thing is to ask us directly, as I'm not always
aware of when posts like this arise but I try.

Hope this helps,

Jim Akiba

On Thu, Dec 6, 2012 at 1:59 PM, Jarrett Anthony Kupcinski <
kupcinski@gmail.com> wrote:

> Every 5000 miles/6 months assuming normal operating conditions. 3000 miles
> for extreme service conditions. The Bostig recommendation matches Ford's.
>
> -Jarrett K
> 89 Westy powered by Bostig
> > What did the engine manufacturer recommend for the engine when it was
> new in a factory installation?
> >
> >> Bostig recommends an oil change every 3 to 5K using synthetic oil. Since
>