Dyno results - Tquad vs Holley vs Qjet - tuning issue, too rich

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70GS455

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Recently finished a dyno session on a 482 stroker using a Holley 950 HP ultra, Ken Manley prepped 850 Tquad, and an Everyday Performance prepped 800 Qjet. The big holley gave best results, 595 hp and 622 ft-lb at peak. The Qjet was not far behind, 586/603. The Tquad made 572/597, with a significant calibration issue.

We could not get the Tquad lean enough at WOT. AFRs were below the 10:1 equipment limit, the motor would drown and stumble from the fuel, BSFCs were high, and fuel flow rate was at 286 lb/hr, up from 239 with the QJ. We are pulling over 2" of vac at 6000 rpm, so its somewhat air starved but making decent power.

The sec air door was fully open @ .940", sec butterflies open to 90 deg, leanest sec jets I had at the time of .131, primaries at .095 with 2002 rod, secondary hi speed air bleed opened to 0.041, idle fuel feed at .039, idle air bypass restriction at .043, idle air bleed left alone, primary hi speed air bleed left alone at .080", squirters enlarged. Idle and low speed are great, with a 236/244 cam on 113 LSA. Spring is clipped.

I have since acquired a set of .125 sec jets, and modified a surplus set to accept some screw in primary jets. I have a strip kit.

In addition, I plan to enlarge the primary venturi in the bowl to 1-3/8", and leave the double boosters.

This carb shows promise with decent numbers even though its pig rich. Anyone else run into this?
 
mopar race tips, says, sec throttle blades have to be at 85 to 88 deg , not 90, it affects jetting to sec side, I use a T.Q on 340, have has no issues , my fuel curve is flat , no spikes, up or down. . air door at .725 to . 900 range.
 
I went back to mopar race manual, T.Q. jetting setup is, drop metering rods all way down into pri jet disconnect from the bar ,or make club foot rods from AFB rod, sec blade angles are 86 to 88 deg angle. reason is pri go rich when hooked up at wide open throttle. the club foot rods are hooked up to the bar, remove vac spring from under piston . just food for thought.
 
perfacar said:
I went back to mopar race manual, T.Q. jetting setup is, drop metering rods all way down into pri jet disconnect from the bar ,or make club foot rods from AFB rod, sec blade angles are 86 to 88 deg angle. reason is pri go rich when hooked up at wide open throttle. the club foot rods are hooked up to the bar, remove vac spring from under piston . just food for thought.
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How do you make the rods club foot? Is the idea for them to not raise up out of the jets any?
 
70GS455 said:
How do you make the rods club foot?
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Hand machine them to shape. The shape is hourglass like.
Is the idea for them to not raise up out of the jets any?
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The idea is to keep the primary side lean. Since the venturi is small, they will go rich under a heavy load. The fuel is being sucked out beyond normal operations. This is indicative of the high vacuum reading @ 2 inches. It gets worse (richer) as the vacuum goes up.

What is the TQ model number?
Are the primary base plate bore sizes 1.50 inch?
(Just checking)

Your carb settings are out of wack according to the MP books set up specs. I also never heard of anyone using them on such a large engine. What spurred you on to try 3 different carbs?

This carb (TQ) on this large of an engine is a bit out of my wheel house. So I don’t know how much help I can be but I’m tuned in.

Where are you located?
 
rumblefish360 said:
Hand machine them to shape. The shape is hourglass like.

The idea is to keep the primary side lean. Since the venturi is small, they will go rich under a heavy load. The fuel is being sucked out beyond normal operations. This is indicative of the high vacuum reading @ 2 inches. It gets worse (richer) as the vacuum goes up.

What is the TQ model number?
Are the primary base plate bore sizes 1.50 inch?
(Just checking)

Your carb settings are out of wack according to the MP books set up specs. I also never heard of anyone using them on such a large engine. What spurred you on to try 3 different carbs?

This carb (TQ) on this large of an engine is a bit out of my wheel house. So I don’t know how much help I can be but I’m tuned in.

Where are you located?
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It is a 6322, primaries are 1.5". I'm located in N. Alabama.

The Holley is the dyno operators, I was going to pick the best of between the other 2
 
70GS455 said:
It is a 6322, primaries are 1.5". I'm located in N. Alabama.

The Holley is the dyno operators, I was going to pick the best of between the other 2
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Do you plan on heading back to the dyno with the TQ?
 
Is this going to be driven on the street mostly ? Or are you going for a stock look ? If not just go with the Holley . With that many cubes I am not sure if the TQ or Qjet will give you any better driveability .
 
All of the TQ tuning stuff is in the MP engine book, if you have one. It details it pretty good.

I still think the Holley will ultimately win out here.
 
http://www.moparts.org/Tech/Archive/fuel/34/bulletin34,p15,carb.JPG

Keep tuning you'll get there.

A very WISE man once said to me after I asked him about improving the Holley Design "Fix a Holley and it will work like a Carter."

Did you pull the plugs after the run to see what they looked like?

How smooth did the engine run with the different carbs?

What ignition did you use?
 
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mbaird said:
Is this going to be driven on the street mostly ? Or are you going for a stock look ? If not just go with the Holley . With that many cubes I am not sure if the TQ or Qjet will give you any better driveability .
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Mainly street, almost exclusively. Want a more stock look, plus I like the street manners of the spread bores more.
 
RustyRatRod said:
All of the TQ tuning stuff is in the MP engine book, if you have one. It details it pretty good.

I still think the Holley will ultimately win out here.
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Yeah, will probably make the most power, but drivability may not be as good
 
Hysteric said:
http://www.moparts.org/Tech/Archive/fuel/34/bulletin34,p15,carb.JPG

Keep tuning you'll get there.

A very WISE man once said to me after I asked him about improving the Holley Design "Fix a Holley and it will work like a Carter."

Did you pull the plugs after the run to see what they looked like?

How smooth did the engine run with the different carbs?

What ignition did you use?
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Well it's an A-body, but its a GM A-body, so don't kick me out of the club lol. I used an HEI with a Performance Distributors rev limiting module
 
Pictures of this beast? I'm a big Byoowhack fan.
 
70GS455 said:
Well it's an A-body, but its a GM A-body, so don't kick me out of the club lol. I used an HEI with a Performance Distributors rev limiting module
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You get the OK & nod for having a combo of (GM) "A" body and the try out of the TQ.
:lol:
Heck, that Rochester did pretty darn good though!
 
I like the notion of keeping it stock looking while maximizing performance . Try to find a 1000 cfm TQ Super comp or whatever they were called ? I used to have one so you would think I could remember ...lol
 
!

DB3FB458-1E11-4956-BFDE-93C71290F6EF.jpeg
 
70GS455 said:
Well it's an A-body, but its a GM A-body, so don't kick me out of the club lol. I used an HEI with a Performance Distributors rev limiting module
Click to expand...

Try a Crane HI-6 CDI and a PS92 coil.
 
rumblefish360 said:
!

View attachment 1715641287
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There is no logic to removing the outer venturi on a Carter solid fuel metering carb. If its the early emulsion design I can understand it as it now becomes a single stage booster like a Holley and you can use air bleeding to get the booster to come on sooner but the design of the the triple venturi is such that it creates so much vacuum that no air is required to get the booster flowing at lower rpms and therefore no air bleeding to interupt the fuel flow. Essentially you get air and fuel mixed together out of the booster of a Holley so some cylinders get more fuel or air depending on how well its entrained. The Carter does it with the fast moving air in the primary booster so the air gets fuel not fuel and air. Now think about what that does to the distribution between cylinders.

This is what the original inventor had to say about its efficacy:

"The fuel is conveyed from the restricted orifice in the jet member 28 through a cross bore 34 into a vertical bore 35 and from this bore the fuel flows through a cross bore 36 into the nozzle chamber and on up through the nozzle 27 through which it is discharged into the venturi 20. The fuel comes out of this nozzle with some velocity and is discharged into the most rapidly moving portion of the air stream as it passes through the venturi 20.

The walls of this venturi serve as baffles to straighten out the flow; of the fuel. thereby preventing it from striking the walls of the air chamber or the conduit 8 until after it has been vaporized by additional air entering the venturis '19 and 7. I consider this an important feature of the invention, for tests have shown that when liquid fuel is per mitted to strike the outer wall of the mixing conduit, it is likely to be carried along in liquid form by the air stream in such a way that vaporization and distribution are not efficiently accomplished.
By the above arrangement, I am enabled to avoid the necessity for mixing air with the fuel in the fuel passageways and nozzles which would cause the delivery of the fuel in slugs and generally inefficient operation of the carburetor, particularly at low speeds."

So the triple booster design offers better vaporization and distribution and since you tune to the weakest cylinder........

And that was 1930!
 
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