Yeah that's a tough one.
It might be OK but what if it's not!
I personally would try it, cuz I'm all about learning, and posting up results. And I'm not afraid to back up and start over. But
Bakerlite brought up a great point. It's all about VE. If your Dcr detonates with an 850, but does not, with a 650, Hey run a 650. On the street,most will never know the difference. Or delay the secondaries some until the engine has had time to rev up. Or try a spreadbore. Now that's good strategy.
The Dcr numbers., are a fixed ratio as already mentioned; just like Scr But the
EFFECTIVE ratio can be down at 4/1 at idle, and could easily be as high as the Scr at peak torque,and if the VE climbs to 105%, then the effective would be higher than the 11.5 Scr.
>This is why reducing the the throttle setting when you hear detonation, reduces it or eliminates it. Think about it.. Nothing else has changed; not the Scr, not the Dcr, not ignition timing. The only thing that has changed is the amount of air being ingested, the effective compression ratio, or VE.
>When I put my combo together in 99 I was fully prepared to choke it with a smaller carb. On the shelf I had an AVS, a couple of AFBs, a few TQs, and some Holleys from 600 to 750, and a really small one. And if that didn't work I already had the water injection system picked out. I was not backing out. I was both feet in!
>As it turned out, my target 8.8 Dcr was not that high.Sixteen years later I read about guys pushing over 9/1 on pump gas. Mine just happens to be OK on 87E10. So almost obviously , I have lots of headroom. Just as obviously, I am in the thick of things. I can run almost any street cam from 268 to 292 with the same set-up. The 268 puts me at 8.96/185psi.The 292 puts me at 8.3/168psi, still pretty good.A teener cam would put me at
[email protected] of these days I might just try it,lol.
> So if my combo at 8.85 burns 87E10, and an estimated 9.2 needs 91, would it be safe to say that 9.0 could burn 89? IDK. And I wouldn't want someone else to make that jump on their nickle, on the strength of this post. Would I try 200psi? Yes I would.
> but it matters not, I am at the small end of the scale as to total chamber volume. At 76.3 I have no place to go. At least not easy or cheap. With the possible exception of an .028 gasket. But that is gonna drop my Q to .023, so I would be looking to cut the crowns. That's a lot of work and money to gain just a little Scr .Sometimes it's best to just leave good-enough alone.
BTW I have the small-chamber aluminum Eddies., and this post is all related to aluminum heads, in case that's not clear.
