Alky question.... figured you turbo folks might know ;)

[420]

I'm considering putting an 8-71 or 10-71 blower on a 9.5:1 compression 468 BBC. It would have a DFI fuel injection system on it.

Now, the DFI setup allows me to intergrate a boost sensor with the kit. I want to run 93 pump gas in the motor, and use an Alky setup akin to what you folks run. Is there any reason you can think of that I couldn't have the alky kit set to come in at maybe 5 lbs of boost ? Bear in mind that I would run a timing retard while on 93, and only need the alky then. I would be running 110 or 116 octane at full timing. Thoughts, comments, ideas? Thanks!

- Matt

 

[BLACK6PACK]

Don't know why it wouldn't work. You would probably need a fairly big bottle and jets, but it should work fine. You'll probably be surprised at how well it will run on alky.

http://www.geocities.com/rad87gn/tech/SteveCkit.html

 

[HossV6]

Your best bet would be to get a good knock sensor and go lightly tinker with it on some back roads to see what PSI it starts to knock at, then have the kit turn on a couple of PSI lower than that. This way, you don't risk drowning the spark and getting the most out of the alky setup at the same time. With a 9.5:1 CR, I would imagine you can run up to 7 or even 8PSI w/o the alky; that is, provided you're running mild timing.

If you're really hardcore about it, go with the multi-stage kits that turn on different solenoids at preset boost pressures. You could run a major amount of alcohol like this with 468 cubes. Someone on this board has done a DIY kit like this. Maybe they will read this and chime in. HTH

 

[Joe 1320]

A multi stage kit would be the hot setup. You could even have multiple settings for different octane.

 

[blackbuick87]

Actually 9.5 to1 is a lot of compression for a blown BBC. Do you have flat tops or domes? Domes will have more tendency to knock. I would run a HOT MSD type ignition and turn the alky on around 5psi.
Two stage would definitely be the way to go. Turn on a small jet at say four pounds and a bigger jet at 7 lbs or so, depending on what size pulley and what your total boost is going to be.