Converting back to 93 from e85, what's needed
 

I'm looking at buying a car that is setup and tuned on e85. Where I live, e85 is very rare so I would want to convert it back to 93. What's needed to do that? I have no experience with e85.

Thanks

Have to get it retuned for 93

A lot depends on what was done for the conversion to begin with. The big deal with E-85 is that it takes about 20-25% more fuel than E-10 gasoline. For a relatively stock'ish engine, you only need a retune and bigger injectors.

If the injectors are not too big, you can simply retune and you're done. But if they put something like 60 pounders in there, you'll need to swap them out for something closer to stock.

If the engine was built with higher octane fuel in mind, then they could have used domed pistons to get the static compression up around 12-14:1. That's much too high for 93 octane E-10.

Before buying, I'd be sure and ask exactly what's been done.

From what I was told, the compression is around 12.1, the injectors are 60lbs and it has a single pump. The engine is a 406. I would think a 406 could handle 60lbs injectors.

I was told to simply flush the tank and injectors out, and retune it for 93.

Is it that simple?

No, and that static compression ratio is probably too high.

I'm thinking you will need 33-35# injectors for 400 hp on gas.

60# injectors are good for over 700hp on gas in a V8.

The problem with an oversized injector is that they slobber on small squirts.
So idle and part throttle cruise is not going to get good fuel atomization, resulting in rough running and misfires, difficult to tune.

Ok so get injectors to go with a NA 406. Something like svo 42s.

What do I need to do with the gas tank and fuel pump? Can I simply purge all of the e85 out?

Yes, you can simply purge the tank and lines, no big deal there. The 60# injectors are probably too big. But I would try and tune for them anyway, and then see how they do at idle and slow speeds.

That 12:1 static compression, though. That's going to be a real problem for a DD or long distance cruiser. On a hot day, it will be nearly impossible to keep it from knocking.

Changing the pistons might also require a cam change. Again, depends on what's in there.

Thanks for the help guys

The injectors you have now will be fine if you tune it right and have all the injector factors.
You do not need to buy new smaller injectors.

Plenty of small CI FI motors running around in 80+ size injectors with no issues.

Food for thought:
Flex fuel vehicles
Big injectors from the factory.
But run just fine on normal gas.

I will admit my car had some issues with 2000cc injectors.
But we helped by dropping base fuel pressure to 3 bar.

Can I run e89 In a car tuned for e85?
I have a few local gas stations that sell e89.

Do I need to adjust the tune or look out for anything?

I apologize for the what sounds like a really dumb question but I have zero experience with ethanol fuel. It's completely foreign to me.

Thanks

Yes. The tune usually is not that precise. If you're worried about it, you can richen up the fuel map 2-3% across the board.

Just a few weeks ago I tuned a cam (23x/23x) and bolt on 6.0 GTO that had FIC 80lb injectors. Gasoline. Idles smooth and runs hard. Customer wants to go turbo one day. I wanted to make sure the big injectors would work with the provided data. If the tune is good, you'll be fine. All you should need to do is change the stoich and adjust the timing for the reduced octane.

My 80 lb deka injectors (96 lbs at 58 PSI) Idle fine in my 5.3.
I've used the Bosch 2200cc injectors in a stock displacement engine on gas before.

You'll be fine with 60s on a stroker.