E85

[Hib Halverson]

Originally Posted by XfireZ51

For those of us that have been following the C7 saga, there's been lots of chatter over the use of E85. Some have shown dynos +40whp with a tune.
For the most part it sounds like using E85 is a matter of tuning for E85. Not much else required at least when it comes to C6. More timing, more compression w no knock. The LT5 is not timing limited, you just lose power.
Any thoughts?

If you could solve the problem of adequate fuel delivery---E85 runs at a lower AFR than straight gasoline---the next biggest problem you'd have with E85 is all the fuel system parts which corrode. Some of a C4 Corvette's fuel supply system will be damaged or destroyed by E85.

That said, the reason some folks are interested in E85 is that it allows a significant increase in compression ratio because of its approx. 105-octane. That also could allow more spark timing, but typically, an LT5s spark cal is close to optimum already.

I would think an LT5 with stock CR wouldn't have much to gain with it, but an engine with 13:1 or so would.

[Paul Workman]

Hmmmm.... Just another potato for the stew pot:

If, as it seems, 11:1 compression is a bit low for E85, then would not a stock compression LT5 be a candidate for FI? How much boost would be the equiv of 14:1 compression?

Would FI on a stock LT5 be more $$ efficient way to add hp than sleeve n stroke I wonder????

Interesting topic...

P

[Schrade]

Is there a difference in vapor pressure of E85, as compared to gasoline? Enough that you get better vaporization in the ports?

[Hog]

Originally Posted by Schrade

Is there a difference in vapor pressure of E85, as compared to gasoline? Enough that you get better vaporization in the ports?

Ethyl alcohol(ethanol) has a melting point of -114ºC (-173ºF) a boiling point of 73.8C(165ºF) and has a Latent Heat of Vaporization of 855 kj/kg (kilojoules per kilogram-or 361 Btu/pound)

Gasoline has a latent heat of Vaporization of 140 Btu/lb
Methanol is 474 Btu/lb (British Thermal Units/Pound)

The fuel is in a position to affect tempeature for a very short time. Much shorter time than in an appplication like an 8-71 blower with carbs on top. Direct injection makes this time even shorter.

peace
Hog

[Hog]

Somewhere I posted that the cooling effects with DI would not be as great as with PFI.
This was incorrect, the cooling effects are greater with DI than with PFI. This is because with PFI there is significant wall wetting and charge contact with the intake valve.
With DI the entire fuel charge removes heat from the inate air charge only as there is no contact with the backside of the intake valve or with the cylinder head wall.`
This is one of the reasons why DI can run higher static compression ratios than PFI.
These cooling effects wouold only be greater with any alcohol use.

BTW The new GEN 5 LT1 uses 125 lb/hr injectors, but they cannot be directly compared to PFI injectors. They inject for a much shorter time than PFI injectors.

peace
Hog