detonation prevention
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Buggsy
- Posts: 1455
- Joined: Tue Jan 01, 2002 12:01 am
detonation prevention
At a crossroads in my build. 2332 with Engle 100 on 114 LDA, air to air intercooled. I can keep a tight deck at 9.5 to 1 compression, or add the .060 copper head gaskets, lose the deck, and end up with 8.5 to 1 compression. Street driven buggy, 9 psi boost, 93 octane pump gas. How much difference does tight deck really make in helping to control detonation? Machine work (hemi, dished pistons) is not an option.
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Piledriver
- Moderator
- Posts: 22863
- Joined: Sat Feb 16, 2002 12:01 am
(at least the following should tell you my opinion on if squish is good...)
Consider a set of these. Seriously.
http://www.aircooled.net/new-bin/viewpr ... 14&cartid=
For a little background:
http://www.theoldone.com/articles/The%5 ... ad%5F1999/
Endyn considers 14:1 to be a "low compression" blower motor, with their piston/chambers. In fact, they really don't worry about CR at ALL, as long as the CC geometry is correct, for best supression of preignition.
The top link will get you those mods, prepackaged for an ACVW, from a VERY reputable supplier.
The chamber mods to get a correct fit are supposedly trivial.
(ask Muffler Mike, from his threads, it was possibly the only thing that was easy on his NA Squishie build)
Before you blow me off as completely nuts...do a little reading , and consider this combo, with the above pistons, set for ~15-17:1 CR:
Suppose you decided to "be different", and asked Web to just tack an extra ~40 degrees of intake valve opening onto your favorite cam, well into the compression stroke.
You would now have a "Miller Cycle" engine.
What is obvious to me is that is you effectively now have "boost controlled" variable "valve timing", more boost, the more you can stuff the motor with A/F mix, as your "effective" intake timing will grow with boost. The correct CC/squish will prevent preignition.
I'm also going to make a guess and say you would have a very _efficient_ engine...
It would also lower the static CR to something manageable for starting...
And probably get decent mileage tooling around town, with nice low head temps.
Just trying to implement some good 50+ year old technology in our 70+year old motor design.
Mine will be Wasser based, so the pistons will be simpler, 15CC combustions chambers and all.
Consider a set of these. Seriously.
http://www.aircooled.net/new-bin/viewpr ... 14&cartid=
For a little background:
http://www.theoldone.com/articles/The%5 ... ad%5F1999/
Endyn considers 14:1 to be a "low compression" blower motor, with their piston/chambers. In fact, they really don't worry about CR at ALL, as long as the CC geometry is correct, for best supression of preignition.
The top link will get you those mods, prepackaged for an ACVW, from a VERY reputable supplier.
The chamber mods to get a correct fit are supposedly trivial.
(ask Muffler Mike, from his threads, it was possibly the only thing that was easy on his NA Squishie build)
Before you blow me off as completely nuts...do a little reading , and consider this combo, with the above pistons, set for ~15-17:1 CR:
Suppose you decided to "be different", and asked Web to just tack an extra ~40 degrees of intake valve opening onto your favorite cam, well into the compression stroke.
You would now have a "Miller Cycle" engine.
What is obvious to me is that is you effectively now have "boost controlled" variable "valve timing", more boost, the more you can stuff the motor with A/F mix, as your "effective" intake timing will grow with boost. The correct CC/squish will prevent preignition.
I'm also going to make a guess and say you would have a very _efficient_ engine...
It would also lower the static CR to something manageable for starting...
And probably get decent mileage tooling around town, with nice low head temps.
Just trying to implement some good 50+ year old technology in our 70+year old motor design.
Mine will be Wasser based, so the pistons will be simpler, 15CC combustions chambers and all.
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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500LbGorilla
I have a set.
Pretty tough to get 15-17:1 compression on the ACVW with them, unless you have a pretty damn long stroke, and trick heads.. but the issue is deck..not compression. I run 12:1 at a 0.055 deck with them and it works well for me.. I have had some trouble getting them set up right, but it's all worked out and they kick ass. I'm also getting about 25MPG with my jetting and timing still a little off, and 300 degree head temps with 044s.
Pretty tough to get 15-17:1 compression on the ACVW with them, unless you have a pretty damn long stroke, and trick heads.. but the issue is deck..not compression. I run 12:1 at a 0.055 deck with them and it works well for me.. I have had some trouble getting them set up right, but it's all worked out and they kick ass. I'm also getting about 25MPG with my jetting and timing still a little off, and 300 degree head temps with 044s.