Low compression-high boost, or high compression-low boost?

[Howie]

i''ve never had that problem. I run the MSD BTM which allows me to run a very high advance to help with starting the burn early and get a good, clean, and complete burn in those big chambers. Plus it's multiple sparks.

[Splitdog]

I always ran a locked dist @ 30. Retard for boost. It liked 30* because I too had the hemi cut heads. Takes longer to burn. I had no issues with it like this though.

[Howie]

30* is VERY high to run on a boosted engine. I can't believe it doesn't knock like crazy when boost kicks in. And it may, but you don't hear it. 24* is all you should run on a turbo with a locked ignition.

[Chip Birks]

30* is VERY high to run on a boosted engine. I can't believe it doesn't knock like crazy when boost kicks in. And it may, but you don't hear it. 24* is all you should run on a turbo with a locked ignition.

He did say he retards for boost.

[Howie]

By turning the distributor?

[Chip Birks]

I ran almost 25psi with 9.4:1 comp on straight 91 octane. The car is intercooled, but wasn't spraying meth. I think chamber design is a big factor in detonation resistance too. I backed the compression down to 9.1:1 with a new a set of heads and put e85 in before turning it up and running almost 28psi on the track. I'm sure it would go there on pump gas with a little methanol spray. Maybe I'll put gas back in it this year. Maybe not, e85 is definitely nice stuff.

[Chip Birks]

By turning the distributor?

Probably electronically, hard to turn the distributor while driving.

[Howie]

You could if you had really long arms!

[Howie]

In my turbo/ FI instructions written by Pat Downs of CB, it says not to run over 15lbs boost without using Race gas. Just an FYI.

[Chip Birks]

In my turbo/ FI instructions written by Pat Downs of CB, it says not to run over 15lbs boost without using Race gas. Just an FYI.

I'm not too worried about Pat's opinion here. He's just trying to cover his rear end. That's a good general rule of thumb. My car is intercooled, has good ignition control, and good fuel management. It also has unique piston tech in play, lets it do the impossible

[Clonebug]

15 lbs. boost is boring once you've tasted 20-22 lbs.
Always have to have mooooore!!!!!!!!!!
I need to get a MapDaddy installed.........250 kpa limit isn't going to cut it....

[Splitdog]

I'm running 30* locked and pulling .8*'s per lb of boost. (after 2 lbs-Mallory Hyfire). So, at 15 lbs, (my max), I'm pulling 12.4* from 30*. So,17.6* at full WOT. I also have water/meth inj. Which is a must, in my book. I have my motor apart now and am addressing other issues. It's at Roger Crawford's getting the heads reworked a bit. I had .220 deck height (!) and spark plugs were not located to Roger's satisfaction. So, I'm looking forward to a bit more power, and less detonation issues. (I broke a cylinder at 219.7 hp). 78X90.5, 40X 37 valves, FK41 cam, Holley 350 2bbl. Wheel dyno: Max power 219@ 4900 rpm. Max torque 245 @ 3800 rpm. And makes left turns in 3rd gear. I had 7:1 ish compression, and am looking to keep it around there. Maybe 7.5:1.

[Splitdog]

All that trouble I was having last year was because the carb was a 350cfm and I was pulling around 400 (@5000 rpm). I since switched up to a 500 cfm 2bbl Holley. Also went 94's. (78X94). I also put in an FK41 cam. The thing runs great now and it dyno'd 235hp @ 4900 at Roger's again. I have 7.2:1 static comp, and .060 DH with 78cc chambers. 68cc in the heads, and 10cc in the dished pistons. Very nice combo.

[buguy]

That's awesome! Big power and low rpms.

[woodsbuggy1]

How much boost you running now and what fuel?
Kenric