turbo update finally

The guys at Turbomustangs say to run the boost reference for the fuel pump off of the hat, because it'll momentarily see vacuum when the throttle plates closed. At least the thread I saw today said that. Makes sense that it would apply to the gauge too.
 
wallaka":2q5dbq1o said:
The guys at Turbomustangs say to run the boost reference for the fuel pump off of the hat, because it'll momentarily see vacuum when the throttle plates closed. At least the thread I saw today said that. Makes sense that it would apply to the gauge too.

Yes sir, that is where the fuel pump is referenced to and it does it's job. That way, a gauge off of the manifold side, I could see what the vacuum side is doing, and it makes the needle jump around more like it is really doing something, ha-ha! I will have two tee's in the vacuum line alone: one for BOV, other for vacuum adv and last for the vac/boost gauge.
I was thinking the other day, when the vac adv does see boost (and I have the dual vac adv/retard) will it move the control arm from the vac canister far enough to actaully retard the timing? Catch what I am saying, the points plate can go either direction back or forth (one way retards, one way advances). Will the boost push it far enough to retard the timing at upper rpms, 'cause you are pushing the adv unit backwards. Something to ponder, maybe this is the trick I have been looking for to run higher timing levels while cruising and retard under boost.
Have a good one.

Kirk
 
Howdy,

Got it All back together on Sat., set my initial timing to "0" degree, and with the vacuum adv connected I am idling at 16 degrees BTDC, and 18"Hg vacuum. This is without the bonnet hooked up. Then I decided to see about this off the throttle bog I have and started playing with the squirter. Seeing if I had too much fuel coming into the venturi's, I decided to go back with the original #31 squirter and ended up stripping out the threads in the main carb body where the squirter screw goes. DOES IT EVER END!?!?!?!?!?!?!?!? Probably not, oh well off to the junk yard. One day I will get to drive this bronco again. I did manage to hook up the air/fuel ratio gauge, and it actually worked...another thing to look at in the bronco...purty. And that's where I stand, I will keep ya updated and have a good one.

Kirk
 
kirkallen143":30ur49j3 said:
Howdy,
and ended up stripping out the threads in the main carb body where the squirter screw goes. DOES IT EVER END!?!?!?!?!?!?!?!?

I think it is a standard #10 (3/16) by 20 TPI?? :?: You might be able to helicoil it...or mix a little epoxy for a quick fix
 
Linc's 200":6aebw799 said:
kirkallen143":6aebw799 said:
Howdy,
and ended up stripping out the threads in the main carb body where the squirter screw goes. DOES IT EVER END!?!?!?!?!?!?!?!?

I think it is a standard #10 (3/16) by 20 TPI?? :?: You might be able to helicoil it...or mix a little epoxy for a quick fix

Thanks Linc,
I have thought about both of those, but was worried about the two slots down inside the threads where the fuel passes. Most JY I went to were only EFI, I have a few more to hit. Thanks again.

Kirk
 
You have a 500?

Very hard carb to find in a JY, best to ebay or go to swap meet.

I like the autolite 2 bbls, they are a good design
 
Well, got me a 350 cfm Holley to go back on the engine (had the 500 cfm before-hand) and if Will (Does10s) can use one, by God I am going to try one, too. Have to wait for the weekend to install, busy work schedule and then I will let you know. Have a good one.

Kirk
 
Good! It makes SO MUCH more sense to me to use a 350.

I just can't understand why some people feel a 500 is an "ideal" carb size for a 200 cube engine!
 
Linc's 200":z98mamqo said:
Good! It makes SO MUCH more sense to me to use a 350.

I just can't understand why some people feel a 500 is an "ideal" carb size for a 200 cube engine!

YOU ARE RIGHT Linc, I have been doing my homework/research and you are right! The 500cfm is too big for the 200, especially under boost! It does not create enough vacuum in the venturi's too pull fuel in from the circuits of the carb (back me up on this). Now for being NA the application is different, it is a "seat of the pants" difference, remember a carb under boost does not abide by the same rules as one NA. It took many searches to find this out, but from what I have read this is so true, on TurboMustangs and here at FordSix.
SO WILL(Does10s) I believe you should stay with the 350 on your Falcon, you can try the 500cfm, but I think you will have the same problems I am having.
An ex. was about a guy with a 350 cheby(blown) and did not have money for the 600/650 DP and kept using his 800cfm carb. No matter how much jetting he put in it just was not enough. He help cure this by switching to annular boosters in the carb which inturn reduced his carb's cfms down to say 700 or 650 (cannot remember), and no longer had the problems he encountered before.
In conclusion, that is why Linc "can do the vodoo that he do, so well" with the 1-barrel. And Will can stomp'em with only the 350cfm carb on his turbo motor.
WHAT DO Y'ALL THINK?

Kirk
 
Ya our 350cfm Holley works great! Although I wouldn't mind trying the 500 mainly because we've got an extra 50cid over a 200.
For a "street" motor it's always better to go with a smaller carb. Large carbs only work well at high RPMs.

When Mike's aluminum head is done, we're going to probably try a 450cfm Holley. Or Demon, Barry Grant etc....
Later,
Will
 
A lot of people that build blow through set ups with big carbs have problems metering the fuel properly under boost, their air/fuel ratio is all over the place.

The smaller venturi creates hella ggod metering signal!! I have only a single number 71 jet in my 1 bbl, but I'll bet the suction on the metering side under boost is intense. Makes for a MUCH more user friendly set-up.

I think if you have a lot of time and patience, in the long run you can indeed make more power with a larger carb....but the key to that is
time and patience.

It is easier to work the bugs out of a smaller carb.
 
Alright fellers, got the 7448 on and after sorting out a few bugs (my mistakes basically) it is back and running. I tried it with the vacuum adv hooked up and do not like it that way. I had to set my timing so far retard it was bad off the line and getting into the higher rpms. I had to use the port off of the pcv and tee'd from there to the vacuum adv (cause that is the only one). I did the same for the boost/vacuum gauge, but it never read boost, only vacuum...what the...Now that I don't understand. So I hooked the boost gauge up to the bonnet and it reads fine. Why would you not see boost under the throttle blades at this pcv port?
The wastegate actually started opening finally, too, you can hear when it does into the exhaust at @ 10-12 psi. How would I lower my boost, a different canister/actuator?
With this 7448 carb I am using the 4412 metering block and it runs very well, nice crisp throttle response and no hesitation when lightly accelerating the gas. The 4412 carb had this problem with hesitation off the line. I figured using this since the pvcr's are all ready drilled to 0.0625" (the 4412 block) and it would save me a step. I am running the 68 jets (still too rich) and a 8.5 PV, and the A/F meter reads on the rich side, but not really rich (a dyno to come much later to confirm this). For now I will do the old fashion read your plugs method.
I am going to play with timing some more, probably no vacuum adv and mech only (I have mine limited to 12*) and put total timing somewhere around 20 to 25*. Since I run such high boost on pump gas (93 oct), I will stay at the lower level (20* total). I'll keep you updated, later.

Kirk
 
kirkallen143":19zsfien said:
and the A/F meter reads on the rich side, but not really rich ..... For now I will do the old fashion read your plugs method.

Reading plugs is an art and not very easy to do correctly.
The A/F ratio gauge allows for a MUCH faster learning curve. Use it instead.
 
Howdy fellers,
Last night got the engine running really, really good. I ended up starting with 68 jets, then to 65's and ended up installing the 61 jets (which came with the 7448 carb), at idle it is on the rich/almost stoich of the A/F meter. I have the orange pump cam in the #2 position and a 0.028" squirter and a 8.5 PV. I am still taking it easy (gun-shy from blowing 3 head gaskets already) at least until I get some break-in time for this engine.
I turned down the boost, now at almost 5000 rpm I am seeing @ 10 psi from the bonnet, and I set the timing at 8* initial with a total of 26* at 3000 rpm (and no vacuum adv). The engine runs like a top and I have not been this excited in a long time, last night was a good night (had to celebrate with an evening cocktail, well two or three)! You can drive normal or romp into it for some fun...now this is where I begin. On the A/F meter I am getting a lean situation when I get heavy into the boost. Should I start at the PV and go to a 10.5, or drill the pvcr's bigger, or change the size of the high idle bleeds? When I got on it up to 5000 rpm, the A/F meter went off scale to the lean side, so I do need more fuel. Don't forget at idle I have @ 19" Hg, that's why I say the PV first.
Anyone have any recomendations?

Kirk
 
Anything less than 10.5 inches, the power valve is open. So by the time you are making boost, its alreay wide open.

Try drilling the PVCR's a little more... go slowly! If you need more sizes of small drill bits, let me know.

Your a/f ratio is NOT a wideband, corrrect? Be very careful, you are skaiting on this ice (or thin head gaskets) without one. On a non-wideband, stoich is 14.7 and that is too lean for boosted (need to be 12:1 or less)
 
Howdy again,

Well I opened up the pvcr's last night to 0.078" and put in the 9.5 PV with the 61 jets. A little better, when boost comes on meter reads not as lean, but at idle it is still a little rich. I bought some 0.059" jets to try and will give a shot with the 10.5 PV. Took some vacuum readings last night: 18" Hg at idle, cruising was around 18" to 12" Hg (it all depended how heavy your foot was on the accelerator) and a heavy foot ( full accelaration) it was down to 3" - 0" Hg.
I now have a miss at cruise (2500 rpm) in 5-10 sec intervals, not a bad one just a little short miss, but the engine still runs good. Think this could be fuel or spark? I did finally get an electronic dizzy from the JY, but I still don't mind adjusting points, so it is not in yet.
I will try the engine with the 10.5 PV first, and check my fuel pressure reading to be sure it is working under boost. Then start to drill the pvcr's in small amounts to see what happens. Like always I will keep you updated, have a good one.

Kirk
ps. I measured the 7448 metering block pvcr's-- 0.054". The 4412's were 0.0625"
 
I would def get that duraspark in there as you need a good solid powerful spark under boost. I was gonna ask which metering block you are running but I guess either way it has bigger holes in it now :P
 
Well I think I have found my problem, stock fuel pump cannot keep up. I believe Dan (import killer) had this very same thing happen to him. So I guess it is time to fork out more money for the Carter super strip pump. I have already disassembled the armature from the stock pump to put in the Carter and get it ready it for boost referencing. Oh yeah, my wife said it was OK too, she said I had already spent too much anyways on this dang project, you might as well. Now that is a first!
The stock pump would only get me up to 8 or 9 psi under boost, that is why I was having that lean spike under hard acceleration. I did put in the 59 jets (0.058" call size), and I will keep them in there for now. I also installed the 10.5 PV, but might go back down to the 9.5 or 8.5, it loads the engine up when in 2nd or 3rd at low rpms.
Linc don't say it, "I told you so!"
It will probably be Tuesday before I get back to a computer, sorry for the wait , but I will keep you updated as always.

Kirk Allen Jorden
 
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