"POWER NATION" slant six build

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RustyPlymouth said:
not yet. found a nice pair of drag radials. picking them up next week. then i just gotta wait for the track to open. the tune im running is good but its rich. gonna shoot for 25psi soon without changing anything else see if it leans it out a little. noticeable difference in power between a lean tune and a rich one. lot more power with the lean.
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Thanks for the update.

What do you call "rich" when running 15 pounds of boost?

Just curious...
 
at the 17psi im running (still havent turned it back up after the new brpv) rich is dipping into the 10's on the afr gauge. i need to take some jet out of the primary but its just been to cold to mess with it.
 
RustyPlymouth said:
at the 17psi im running (still havent turned it back up after the new brpv) rich is dipping into the 10's on the afr gauge. i need to take some jet out of the primary but its just been to cold to mess with it.
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Yeah; that's just a bit rich.

I have just the opposite problem, @10 pounds of boost, it goes dead lean (18:1) at full throttle when I open the secondaries... Gotta fix that! I'm thinking go up 10 sizes (78 to 88 on the secondaries.) It's fine, on the primaries 12:1, cruaising.

What do you think, Junior?
 
if you wanna shoot me a message on facebook im on there more then i should be. we could get it figured out quicker then the back and forth on here.
 
RustyPlymouth said:
if you wanna shoot me a message on facebook im on there more then i should be. we could get it figured out quicker then the back and forth on here.
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I have a lot of trouble negotiating Facebook; I'd rather just use email. Mine is: [email protected]



Just send me a blank one...


It goes immediately to 18:1 as soon as I hit the throttle and the secondaries (mechanical) open...
 
is that from a dead stop, roll or brought up on the converter? have you stayed in it long enough to see if it comes around? mine does that too. you have the same problem i do, to much carb. there just isnt enough vacuum signal coming from the slant to pull the fuel through the boosters right away. you could make it up by trying the 50cc accelerator pump and playing with the pissers and the accelerator pump cams. or im sure you dont want to hear this, go for a smaller carb. cfm requirements dont change because of the turbo. the 390 is still the go to carb. if i could have found one cheap i would have run one. they do make them in the double pumper configuration, they are popular/required in a lot of circle track racing. i have a 650 on now, i have a 600 sitting in my garage waiting on the hangar18 mods. im hoping the smaller venturis will make better use of the limited vacuum signal.
 
RustyPlymouth said:
is that from a dead stop, roll or brought up on the converter? have you stayed in it long enough to see if it comes around? mine does that too. you have the same problem i do, to much carb. there just isnt enough vacuum signal coming from the slant to pull the fuel through the boosters right away. you could make it up by trying the 50cc accelerator pump and playing with the pissers and the accelerator pump cams. or im sure you dont want to hear this, go for a smaller carb. cfm requirements dont change because of the turbo. the 390 is still the go to carb. if i could have found one cheap i would have run one. they do make them in the double pumper configuration, they are popular/required in a lot of circle track racing. i have a 650 on now, i have a 600 sitting in my garage waiting on the hangar18 mods. im hoping the smaller venturis will make better use of the limited vacuum signal.
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That is from a 30mph roll in 2nd gear 1.55:1 X 3.55; 26"-diameter tire... about 3,000 rpm.

Stayed in it about 7 or 8 seconds... no change. That is a 650cfm; I had a 750 on there...

I JUST changed out the jets in the secondaries from 82's to 94's... we'll see how that works. I may put a 50cc accelerator pump on both (all 4 bbls) ends, if that doesn't work with some bigger squirters... Not worried about drivebility or mileage since this is JUST a racecar that will be trailered to the strip and back home; almost never driven on the street.

Did you see my request that you email me?
 

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is it revving/accelerating when it does this?

i did see the request for email. i hardly ever check my email though. if you wanna start a new thread on here that might be better. lol
 
RustyPlymouth said:
is it revving/accelerating when it does this?

i did see the request for email. i hardly ever check my email though. if you wanna start a new thread on here that might be better. lol
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It makes about 150 (estimated) horsepower when it does that 18:1 business.

I put some 94's in the secondaries yesterday; let me see what that does...:coffee2:
 
RustyPlymouth said:
yea see what the extra jet does. are you running a power valve?
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Aaron built this carb and he said it had a boost referenced power valve, but I removed it and must have messed it up when I did, because it doesn't seem to be working since I put it back in....
 
the great thing about it being a racecar is that you dont need the power valve. i would take it out all together and put a plug in. get it all done with the jets. that way it cant leave you hanging and melt down your engine if it doesnt open for some reason. 76 primary and 86 secondary jetting worked well for me before i figured out the power valve thing. should be a good starting point for double digit psi and a 650 carb.
 
RustyPlymouth said:
the great thing about it being a racecar is that you dont need the power valve. i would take it out all together and put a plug in. get it all done with the jets. that way it cant leave you hanging and melt down your engine if it doesnt open for some reason. 76 primary and 86 secondary jetting worked well for me before i figured out the power valve thing. should be a good starting point for double digit psi and a 650 carb.
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Thanks, Junior; that is probably what I will do...
I want to reiterate that this is in no way Aaron's fault; I am sure it was working properly when he sent it to me. I am the one who screwed it up... fr sure...

Bill, the ham-handed mechanic:eek:ops:
 
carb is a carb. they run different on different engines. they always need a tune for the specific engine they are on.
 
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