Big Blue's Transformation

[ArdWrknTrk]

That's an interesting point, Jim. I just sent Scotty a note asking about that. I'll report back when he answers.

I think the answer is to drive it like you stole it All. The. Time.

[85lebaront2]

Could any of this be attributable to the carb you're using, or the fact that it's on an adapter plate?

That seems like having an awfully big plenum.

A shot from the accelerator pump isn't going to do much, and that volume has a lot of inertia going this way and that, that might send confusing signals to the carb.

Those things are mostly meant for WOT drag and pulling vehicles.

There's no flow issue if you keep it at 8k or more.

And, of course read what Scottie said about too big pipes killing response and throttled power.

Jim, the EFI lower manifold is really just a pretty standard 180° aluminum intake, and not even a good high rise one. It isn't until you stick that strange shaped upper section that you have a large volume. I think the issue might be related to the lack of a heated crossover to make sure the fuel droplets are vaporized, and the fact that the runners may be rather smooth inside. That manifold is designed to flow air past the injector nozzles, not keep fuel vaporized between a carburetor and the intake valve.

The other issue, with uneven running could be that the manifold and carburetor aren't optimized for each other, that "universal" AFB is essentially a Chevrolet carburetor and as such may not have optimum fuel distribution on a Ford EFI intake. Many carburetors had small tabs on the boosters to correct for distribution issues. Ford intake manifolds from the FE engines on are very good for evenly balanced flow between cylinders, but, with EFI, air flow not mixture flow becomes the design criteria as the injectors are positioned to put the fuel right where it is needed. Manifold designs for carburetors are set to carry the suspended fuel smoothly into the cylinders, sharp corners, or areas with low velocity will cause the fuel to drop out onto the floor or walls, this is why highly polished insides of manifolds were not recommended for street engines, all out race engines that spend most of their time at WOT are different.

One other item, the EFI heads have the intake ports positioned higher so the injector has a straighter shot at the back of the intake valve, which means there is a greater change in direction where the flow goes into the head from the intake manifold and I suspect that part of the change may be to create some turbulence in the flow to help mix the injector's spray into the chamber and this angle change may be causing some low velocity (part throttle) issues.

[ArdWrknTrk]

Jim, the EFI lower manifold is really just a pretty standard 180° aluminum intake, and not even a good high rise one. It isn't until you stick that strange shaped upper section that you have a large volume. I think the issue might be related to the lack of a heated crossover to make sure the fuel droplets are vaporized, and the fact that the runners may be rather smooth inside. That manifold is designed to flow air past the injector nozzles, not keep fuel vaporized between a carburetor and the intake valve.

The other issue, with uneven running could be that the manifold and carburetor aren't optimized for each other, that "universal" AFB is essentially a Chevrolet carburetor and as such may not have optimum fuel distribution on a Ford EFI intake. Many carburetors had small tabs on the boosters to correct for distribution issues. Ford intake manifolds from the FE engines on are very good for evenly balanced flow between cylinders, but, with EFI, air flow not mixture flow becomes the design criteria as the injectors are positioned to put the fuel right where it is needed. Manifold designs for carburetors are set to carry the suspended fuel smoothly into the cylinders, sharp corners, or areas with low velocity will cause the fuel to drop out onto the floor or walls, this is why highly polished insides of manifolds were not recommended for street engines, all out race engines that spend most of their time at WOT are different.

One other item, the EFI heads have the intake ports positioned higher so the injector has a straighter shot at the back of the intake valve, which means there is a greater change in direction where the flow goes into the head from the intake manifold and I suspect that part of the change may be to create some turbulence in the flow to help mix the injector's spray into the chamber and this angle change may be causing some low velocity (part throttle) issues.

I understand Bill.

I guess I wasn't thinking about how the lower plenum was divided, but still the charge comes out the venturis and enters a larger volume where it loses velocity and gains pressure.

Not having a heated floor to keep the charge atomized/vaporized can't help, and wait 'til winter.

Absolutely with you on texture.

Just like the dimples on a golf ball keep flow laminar and attached, texture in the intake reduces boundary layer and doesn't give the fuel a place to drop out and sit around.

[Gary Lewis]

I understand Bill.

I guess I wasn't thinking about how the lower plenum was divided, but still the charge comes out the venturis and enters a larger volume where it loses velocity and gains pressure.

Not having a heated floor to keep the charge atomized/vaporized can't help, and wait 'til winter.

Absolutely with you on texture.

Just like the dimples on a golf ball keep flow laminar and attached, texture in the intake reduces boundary layer and doesn't give the fuel a place to drop out and sit around.

Scotty replied with:

Gary,

Are you running a manual transmission?

Yes the plenum area is large.

What is your initial and total timing?

Vac advance?

The HP and Torque peaks are a few hundred rpm over OEM.

I replied with:

Yes, I'm running a ZF5. My initial is on 12 BTDC, and the total would be that plus what your distributor is set to. Ditto the vacuum.

So, would I expect that with the larger plenum I'll have rough running on a carb at part throttle? I wasn't initially planning to run the carb for more than break-in, but I'm so worn out from the whole project I'm thinking of running it longer before going EFI. Is that a bad idea?

[Gary Lewis]

Scotty replied with:

Gary,

Are you running a manual transmission?

Yes the plenum area is large.

What is your initial and total timing?

Vac advance?

The HP and Torque peaks are a few hundred rpm over OEM.

I replied with:

Yes, I'm running a ZF5. My initial is on 12 BTDC, and the total would be that plus what your distributor is set to. Ditto the vacuum.

So, would I expect that with the larger plenum I'll have rough running on a carb at part throttle? I wasn't initially planning to run the carb for more than break-in, but I'm so worn out from the whole project I'm thinking of running it longer before going EFI. Is that a bad idea?

Next round:

Gary,

First order of business is to set total timing to 36* checked at 3200 rpm.

Secondly expecting a carbed combo to pull seamlessly at 1000 rpm with a carburetor is unreasonable and not advised.

Running a bit rough at part throttle seems a combination of timing and carburetion. I'd be looking at AF ratios with a meter and wideband O2

My reply:

Ok, I just got an exhaust system on today with bungs for the O2 sensors, so will put the wideband on and check.

So I need to check total advance and install the wideband. But I'm a bit disappointed with the response about pulling from 1000. The old engine with, supposedly, the Edelbrock cam, pulled like a tractor from 500 RPM. Taking corners in 3rd was easy. But this one doesn't pull until over 1000, and many corners in 3rd pull it down below there.

It feels like the difference between a plow horse and a race horse. (Not that I know all that much about horses.) But I'm worried that the lack of low-end torque will be an issue on the trail. And that worries me.

[ArdWrknTrk]

Next round:

Gary,

First order of business is to set total timing to 36* checked at 3200 rpm.

Secondly expecting a carbed combo to pull seamlessly at 1000 rpm with a carburetor is unreasonable and not advised.

Running a bit rough at part throttle seems a combination of timing and carburetion. I'd be looking at AF ratios with a meter and wideband O2

My reply:

Ok, I just got an exhaust system on today with bungs for the O2 sensors, so will put the wideband on and check.

So I need to check total advance and install the wideband. But I'm a bit disappointed with the response about pulling from 1000. The old engine with, supposedly, the Edelbrock cam, pulled like a tractor from 500 RPM. Taking corners in 3rd was easy. But this one doesn't pull until over 1000, and many corners in 3rd pull it down below there.

It feels like the difference between a plow horse and a race horse. (Not that I know all that much about horses.) But I'm worried that the lack of low-end torque will be an issue on the trail. And that worries me.

You can't have your cake and eat it too.

If you want power (a broad spread of power) you need to move mixture through the engine.

At all speeds, and biased toward high speeds, because that's where potential lies.

Like Bob alluded to the other day. You can tune for torque but Horse Power (work done, watts, btu's, whatever metric) needs to spin the crank.

The pump needs to pump something in order to be effective.

Electric is the way to go if you want 100% torque from almost zero rpm.

p.s.: don't lug your Zf like that. It really kills the case end bearings.

You asked about rollover noise.

No, you can't put it in gear and leave the transfer case in neutral.

The gears are still turning with no load on them.

Put it in gear and keep the clutch depressed.

That's how you can avoid the rollover clack.

[85lebaront2]

You can't have your cake and eat it too.

If you want power (a broad spread of power) you need to move mixture through the engine.

At all speeds, and biased toward high speeds, because that's where potential lies.

Like Bob alluded to the other day. You can tune for torque but Horse Power (work done, watts, btu's, whatever metric) needs to spin the crank.

The pump needs to pump something in order to be effective.

Electric is the way to go if you want 100% torque from almost zero rpm.

p.s.: don't lug your Zf like that. It really kills the case end bearings.

You asked about rollover noise.

No, you can't put it in gear and leave the transfer case in neutral.

The gears are still turning with no load on them.

Put it in gear and keep the clutch depressed.

That's how you can avoid the rollover clack.

Many years ago I did some cam research and what I found was interesting, Gary should remember the old Buick Nail Valve engines, the ones with the valves vertical in the heads with the strange 90° rocker arms. Due to the small valves Buick used a rather high lift cam and these engines were saddled with Dynaflow transmissions mostly. They had a lot of low end torque.

The idea is that for torque you want a mild duration high lift cam, for horsepower you can do better with a longer duration lower lift cam. Modern engines now get the best of both worlds with variable cam timing and even duration. One of the reasons hot rodders in the 50s liked the Cadillac OHV V8, it had plenty of torque but would still rev well due to the OHV heads better breathing. Best description I ever heard for the HP vs Torque, HP is how fast you hit the wall, torque is how far you take it with you.

Luxury car engines were built for years to have lots of torque to get 3 tons of steel moving, the 430 MEL engine is a great example, 375 hp at 4600 rpm, 490 ft-lbs torque at 3100 rpm, great big heavy hunk of cast iron that could wring a drive shaft in two and required a special oversized Cast Iron Cruise-O-Matic to handle the torque, damn things would smoke rear tires with a 2.69 gear!

[grumpin]

Many years ago I did some cam research and what I found was interesting, Gary should remember the old Buick Nail Valve engines, the ones with the valves vertical in the heads with the strange 90° rocker arms. Due to the small valves Buick used a rather high lift cam and these engines were saddled with Dynaflow transmissions mostly. They had a lot of low end torque.

The idea is that for torque you want a mild duration high lift cam, for horsepower you can do better with a longer duration lower lift cam. Modern engines now get the best of both worlds with variable cam timing and even duration. One of the reasons hot rodders in the 50s liked the Cadillac OHV V8, it had plenty of torque but would still rev well due to the OHV heads better breathing. Best description I ever heard for the HP vs Torque, HP is how fast you hit the wall, torque is how far you take it with you.

Luxury car engines were built for years to have lots of torque to get 3 tons of steel moving, the 430 MEL engine is a great example, 375 hp at 4600 rpm, 490 ft-lbs torque at 3100 rpm, great big heavy hunk of cast iron that could wring a drive shaft in two and required a special oversized Cast Iron Cruise-O-Matic to handle the torque, damn things would smoke rear tires with a 2.69 gear!

Nice, very nice exhaust!

[Frank Wyatt]

Nice, very nice exhaust!

Yes, sounds great and looks great as well.

[ArdWrknTrk]

Many years ago I did some cam research and what I found was interesting, Gary should remember the old Buick Nail Valve engines, the ones with the valves vertical in the heads with the strange 90° rocker arms. Due to the small valves Buick used a rather high lift cam and these engines were saddled with Dynaflow transmissions mostly. They had a lot of low end torque.

The idea is that for torque you want a mild duration high lift cam, for horsepower you can do better with a longer duration lower lift cam. Modern engines now get the best of both worlds with variable cam timing and even duration. One of the reasons hot rodders in the 50s liked the Cadillac OHV V8, it had plenty of torque but would still rev well due to the OHV heads better breathing. Best description I ever heard for the HP vs Torque, HP is how fast you hit the wall, torque is how far you take it with you.

Luxury car engines were built for years to have lots of torque to get 3 tons of steel moving, the 430 MEL engine is a great example, 375 hp at 4600 rpm, 490 ft-lbs torque at 3100 rpm, great big heavy hunk of cast iron that could wring a drive shaft in two and required a special oversized Cast Iron Cruise-O-Matic to handle the torque, damn things would smoke rear tires with a 2.69 gear!

Inertia is how far you move the wall.

Torque is your 0-80 time

Horsepower is your 80-160 time.

If you want to optimize torque then you need long small runners and roller only cam profile.

And you want to get rid of that exhaust and go back to cast manifolds.

You probably want that Quadrajet you were talking about the other day too.