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 Post subject: 2 circuit convert!
 Post Posted: Fri Oct 21, 2011 8:12 pm 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
Finally got my 3-2 circuit conversion done! Started life as an older 1050 with straigh boosters but I'm not sure what model this one was. The three circuit blocks had the P/V plugged but no P/V channels drilled. Anyways, I used blank 750 dp blocks from BLP with:
BLP 12 hole annular boosters
.156" angle channel
IFR- .038" in the bottom
Emulsion- 2- .028"
kill bleed-.028"
P/V- .076" plugged to start with
HSB-.025"
IAB- .076"
TSJ- .055.
P/S MJ-94 to start
As far as a driveway tuneup goes, this is the best carb I've ever had! I can kill the engine with any mixture screw and they are at 3/4 turn out now. I'm thinking of going down on IAB thinking it may be a bit lean. Thanks everyone for posting info on this conversion, I think I read everything about doing it first. It's nice to do it myself instead of paying someone. Unfortunately racing is done till spring here in the northwest so won't be till then to get to the track but I'll post results when I do!

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 Post subject: Re: 2 circuit convert!
 Post Posted: Fri Oct 21, 2011 9:12 pm 
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Joined: Thu Jan 29, 2009 10:59 am
Posts: 438
Location: Auburndale, Florida
Welcome to the world of carb tuning. It's a sickness and we're glad you're infected. Misery loves company.

I really see nothing wrong with your calibration other than you don't specify what position the emulsions are in. You are correct that you could reduce the IAB a bit. Try a little at the time as each engine likes different things.


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 Post subject: Re: 2 circuit convert!
 Post Posted: Fri Oct 21, 2011 10:17 pm 
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Joined: Tue Apr 18, 2006 6:38 am
Posts: 11805
Location: Coming At Ya!
Welcome to the "club"! It's amazing how simple tuning can be but it's also amazing how complicated it can be as well. You'll find out that the more you learn, the more you'll find that you don't know and as Bruce says, it's a sickness so to speak. So when you have the gas part where you're comfortable with it, then there's methanol, and E85! =;

Oh, and if you're anywhere near Portland, Or, you might want to look up the guy that gave us that tuneup. ;-)

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Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

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 Post subject: Re: 2 circuit convert!
 Post Posted: Fri Oct 21, 2011 10:50 pm 
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Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
Watch for melting headers... =;


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 Post subject: Re: 2 circuit convert!
 Post Posted: Sat Oct 22, 2011 12:50 am 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
Thanks everyone, you're right it is a sickness. I'm already thinking bout e85, but can't wait to try out this carb at the track. The E-bleeds are in the stock 750 Holley positions. I'm actually in central Oregon but if I knew who tuner is I'd look him up, I go to Portland now and again.
Thanks, Keith

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 Post subject: Re: 2 circuit convert!
 Post Posted: Sat Oct 22, 2011 5:50 pm 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
Hey I forgot say the combo this carb is sittin on. It's a 412 sbc bracket engine with about 11.5:1 and small roller, ported Vic Jr. Heads, super Vic intake, in a 67 camaro at about 2820lbs. The best I've been yet is a 10.02@132 With a T-400 and 2900lbs so looking to be in the 9's next season! The car has been 8.90@148 with a certain builders 1150 but even though i tuned the car 3-4 tenths quicker the mph never changed so when that engine (565) gets back together this carb will go on it.
Keith

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 Post subject: Re: 2 circuit convert!
 Post Posted: Sun Oct 23, 2011 5:23 pm 
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Joined: Sun Nov 11, 2007 10:33 am
Posts: 1293
Location: Montgomery, Alabama
Keep in mind the smaller IAB will also richen up your part throttle.

If you think your lean at idle it's easy enough to find out. Once it's up to temp drop it in gear. Turn the screws out till the rpm almost doesn't change from neutral to in gear.


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 Post subject: Re: 2 circuit convert!
 Post Posted: Mon Oct 24, 2011 12:46 am 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
Thanks Scott, I'll give that a try. Thats a new one for me, thanks for the tip.
Keith

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 Post subject: Re: 2 circuit convert!
 Post Posted: Mon Oct 24, 2011 8:08 am 
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Joined: Mon Oct 29, 2007 7:07 pm
Posts: 1422
Location: Florida
The idle air bleed and idle jet control fuel for the transition circuit. The jet controls overall fuel, the bleed controls fuel amount and duration of the transition circuit. Idle is further leaned by the mixture screws as needed. Idle needs less fuel than the transition circuit, it's under a lower load than when on the transition circuit and as a result less fuel.


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 Post subject: Re: 2 circuit convert!
 Post Posted: Wed Nov 02, 2011 5:00 pm 
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Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Any report for us Keith??

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running E85
Best ET 8.07
Best MPH 170.71
Barry


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 Post subject: Re: 2 circuit convert!
 Post Posted: Thu Nov 03, 2011 2:02 am 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
Haven't been able to do much with no tracks to go to around here Barry, the last nearby track(within 250 miles) quit for the season in October. I just got the car out of the trailer and into the garage to do some fine tuning and try Scott's suggestion on turning the mixture screws with the car in gear and see what kind of rpm change there is. In moving it to the garage I let it get up to about 140* and it wouldn't idle on it's own till about 120* or so but at 140 it is very crisp and responsive! I can't wait to get this thing to the track, in 4 months! #-o I am going to also do an e85 1050 to try out also. To anyone who is hesitant to do this let me say that it's easier than you think if you just read the sticky a few times, everything you need is in there. For a driveway tuneup, this thing way better than my hp950 i had on there. Thanks for everyones help, I'll let everyone know how it goes.
Keith

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 Post subject: Re: 2 circuit convert!
 Post Posted: Thu Nov 03, 2011 4:53 am 
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Joined: Wed Apr 19, 2006 8:20 pm
Posts: 5852
Location: N.J.
Keith, I had an idle issue also with mine and it was as easy at going from a .065 IAB to a .070 IAB and idles just fine.. =;
Idles right at 1200 rpm in gear...

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running E85
Best ET 8.07
Best MPH 170.71
Barry


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 Post subject: Re: 2 circuit convert!
 Post Posted: Thu Nov 03, 2011 6:27 am 
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Joined: Sun Nov 11, 2007 10:33 am
Posts: 1293
Location: Montgomery, Alabama
Don't expect it to idle perfect when cold. It's not slobbering fuel now and there is no choke. Just sayin,


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 Post subject: Re: 2 circuit convert!
 Post Posted: Thu Nov 03, 2011 1:56 pm 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
Don't get me wrong guys, I totally understand it shouldn't idle without help when it's cold. I'm stoked that once it warms up it idles so nice. Most my other carbs will develope an odd resonance or something that I'm thinking has a lot to do with an overly rich idle circuit, maybe fuel burning in the headers or something. Anywho, it's gonna be a long winter waiting to get to a track, got a few things to do to the car this winter to keep me busy in the mean time. Thanks guys.

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 Post subject: Re: 2 circuit convert!
 Post Posted: Sat Apr 07, 2012 11:47 pm 
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Joined: Sun Jul 10, 2011 6:32 pm
Posts: 24
Location: Central Oregon
FINALLY got to the track with my converted carb. Got some fine tuning to do but got some personal bests! 9.900@134.21, over a tenth better with more in it I'm sure. Some of the guys that know my combo, budget motor, we're amazed. Just knowing where I need to adjust makes tuning so much easier. Unfortunately I took my small jet box instead of the larger jets but I know what do now. Seemed a hair lean with a 93/94 jet with no PV an a .025" MAB, 2 jets smaller dropped 1.5 mph, and a little rich in the pits which I suspected may happen. Thanks everyone and I'll keep you posted.
Keith

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