Building a slant for torque

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halfafish

halfafish

Damn those rabbits, and their holes!
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I'm always interested in what folks have done to squeeze torque out of a 225 slant. Please feel free to offer your knowledge here!

@Jim Kueneman, in the Peanut Gallery Survey thread, you noted the following:

Too bad you left Az you could have driven our Dart to see if that what you would want. Rusty and I just got a simulation model of the 225 that seem very accurate we could run with different components and relate to mine. Ours is 100% max torque build from 3500 and down and the model shows it.

What are the details on your build to get max torque up to 3500 RPM?
 
For low end torque such as a truck for instance, I would mill the head .100", do a bowl blend, a good proper three angle valve job, back cut the intake valves, use a super six intake and 318 Carter BBD, headers. I would leave the cam stock but use stock 340 springs. I forget which year it is, but there's one stock slant 6 cam that's well over .400 lift. I would use that, or perhaps something similar to a 260 grind from Oregon. Good LOOSE ignition curve with plenty of initial timing and a total of only about 30-32 degrees. It would pull stumps off idle.
 
halfafish said:
I'm always interested in what folks have done to squeeze torque out of a 225 slant. Please feel free to offer your knowledge here!

@Jim Kueneman, in the Peanut Gallery Survey thread, you noted the following:

Too bad you left Az you could have driven our Dart to see if that what you would want. Rusty and I just got a simulation model of the 225 that seem very accurate we could run with different components and relate to mine. Ours is 100% max torque build from 3500 and down and the model shows it.

What are the details on your build to get max torque up to 3500 RPM?
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What do you think you can squeeze out of /6 ?

Displacement and torque are very closely linked, a decent build for the average guy is 1.15:1-1.25:1 tq per cid. 260-280 tq. Which is 173-186 hp at 3500 rpm.

Other then displacement is VE% & Efficiency, compression ratio, free flowing exhaust and intake tract, good tune, custom cam etc...
 
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You guys need to quit screwing around :) . Back in 2006 the 170 slant in my Barracuda made 358 lb/ft torque at 2750 rpm, and I have the dyno chart to prove it
 
Charrlie_S said:
You guys need to quit screwing around :) . Back in 2006 the 170 slant in my Barracuda made 358 lb/ft torque at 2750 rpm, and I have the dyno chart to prove it
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Naturally Aspirated?

Thats 2.11 tq per cid
 
273 said:
Naturally Aspirated?

Thats 2.11 tq per cid
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If I remember correctly, a 150-175 shot of nitrous. Just funning with you guys. :) I'm now up to a 225 shot, in a lighter car, but have not had the car on a dyno since. The Barracuda weighted 3250, and would 60ft at 1.79
"In general", nitrous adds bottom end torque, while a turbo adds top end power
 
Charrlie_S said:
You guys need to quit screwing around :) . Back in 2006 the 170 slant in my Barracuda made 358 lb/ft torque at 2750 rpm, and I have the dyno chart to prove it
Click to expand...
You go boy! You got pictures too! I've seen um. LOL
 
halfafish said:
I'm always interested in what folks have done to squeeze torque out of a 225 slant. Please feel free to offer your knowledge here!

@Jim Kueneman, in the Peanut Gallery Survey thread, you noted the following:

Too bad you left Az you could have driven our Dart to see if that what you would want. Rusty and I just got a simulation model of the 225 that seem very accurate we could run with different components and relate to mine. Ours is 100% max torque build from 3500 and down and the model shows it.

What are the details on your build to get max torque up to 3500 RPM?
Click to expand...

Decked the block about 0.060 to get about 8.8:1 (could have gone a bit more but with a torque cam you get static cylinder pressures high fast at 8.8:1 it is about 175 PSI). Oversized valves, simple clean up on the bowl area, nothing fancy (per Doug Dutra), Oregon Cams 2106, Offenhauser dual 1 barrel to get around 350-400 CFM of carb, Dutra Duals with the 2:1 "Y" pipe back by the transmission crossmember (necessary, joining any sooner puts the tuning up higher in RPM, I was aiming for about 3500 RPM and that is where I got it per the simulations. Further back drive that peak lower in RPM Doug Dutra has put the "Y" back a the rear axle to make more really low power) lighter springs in the distributor to get more advance faster, limited the mechanical advance to about 15 degrees to have about 17 degrees of initial and 32 degrees full mechanical advance and then 18 more for vacuum advance (9.5 on the diaphragm).

Rusty's has a much more radical cam and ported heads as he wants high RPM horse power at the cost of lower RPM torque, I wanted lower RPM torque at the expense of high RPM horsepower. This website seems to reduce the size of the images sorry about the resolution. I am making about 245 ft-lbs at 3400 RPM peak and 175 HP were Rusty is at 250 ft-lbs at 4000 RPM and 205 HP at 4700 RPM, but at low RPM I am making over 35 ft-lbs of torque a more driver RPMs. It will take a lot of tuning to get much more. If you think about a 318 the displacement of the cylinder is EXACTLY the same as a 225. If you look at a good head for a 318 you can get 260-280 CFM out of it. Even with Rusty's extensive work on the /6 head it can not break 200 CFM. If we could get a good head for the /6 then you could potentially reach the 300 HP without a ton of tweaking and tuning.

Untitled 2.jpeg
 
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100 shot of nitrous, instant torque
A member here is running a 225 shot on a 170 with stock internals
 
Jim Kueneman said:
Decked the block about 0.060 to get about 8.8:1 (could have gone a bit more but with a torque cam you get static cylinder pressures high fast at 8.8:1 it is about 175 PSI). Oversized valves, simple clean up on the bowl area, nothing fancy (per Doug Dutra), Oregon Cams 2106, Offenhauser dual 1 barrel to get around 350-400 CFM of carb, Dutra Duals with the 2:1 "Y" pipe back by the transmission crossmember (necessary, joining any sooner puts the tuning up higher in RPM, I was aiming for about 3500 RPM and that is where I got it per the simulations. Further back drive that peak lower in RPM Doug Dutra has put the "Y" back a the rear axle to make more really low power) lighter springs in the distributor to get more advance faster, limited the mechanical advance to about 15 degrees to have about 17 degrees of initial and 32 degrees full mechanical advance and then 18 more for vacuum advance (9.5 on the diaphragm).

Rusty's has a much more radical cam and ported heads as he wants high RPM horse power at the cost of lower RPM torque, I wanted lower RPM torque at the expense of high RPM horsepower. This website seems to reduce the size of the images sorry about the resolution. I am making about 245 ft-lbs at 3400 RPM peak and 175 HP were Rusty is at 250 ft-lbs at 4000 RPM and 205 HP at 4700 RPM, but at low RPM I am making over 35 ft-lbs of torque a more driver RPMs. It will take a lot of tuning to get much more. If you think about a 318 the displacement of the cylinder is EXACTLY the same as a 225. If you look at a good head for a 318 you can get 260-280 CFM out of it. Even with Rusty's extensive work on the /6 head it can not break 200 CFM. If we could get a good head for the /6 then you could potentially reach the 300 HP without a ton of tweaking and tuning.

View attachment 1716059831
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It's not necessarily that I WANT high RPM horsepower.....I'm kinda boxed in using the pistons I have which means I have about a 10.5 compression ratio, which will require a fairly large cam to run on pump gas. Coupled with the 4.11 gears and the T5 transmission I plan to swap in, it should still have some good grunt down low! The engine I have now loses very little on the bottom end now, even with 3.23 gears. I theorize that it's the long stroke of the 225 that helps out there.
 
RustyRatRod said:
It's not necessarily that I WANT high RPM horsepower.....I'm kinda boxed in using the pistons I have which means I have about a 10.5 compression ratio, which will require a fairly large cam to run on pump gas. Coupled with the 4.11 gears and the T5 transmission I plan to swap in, it should still have some good grunt down low! The engine I have now loses very little on the bottom end now, even with 3.23 gears. I theorize that it's the long stroke of the 225 that helps out there.
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It's all give and take... you current build has more than stock, not as much as my 2106 naturally. The newer build pushes the peak of everything out 500 RPM and more so the model predicts a good 20 ft-lbs of torque loss in the new build over the old at 2000 and does not cross over to be more than the current until 3500. The gears will help for sure.
 
The torque is down about 17% and the gears will get you about 13% more so a net loss of 4%. Should be similar to the existing down low.
 
Jim Kueneman said:
It's all give and take... you current build has more than stock, not as much as my 2106 naturally. The newer build pushes the peak of everything out 500 RPM and more so the model predicts a good 20 ft-lbs of torque loss in the new build over the old at 2000 and does not cross over to be more than the current until 3500. The gears will help for sure.
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And see......this is where I question the program. The next engine has more compression, less camshaft and WAY MORE cylinder head AND good quench.....so I still think something's missing from the equation. It's still a ton of fun putting it all in to see what comes out and I appreciate your time on it more than you know. I wish we were local to each other. We'd get into all sorts of mischief.
 
diymirage said:
actually, its not, but thanks for playing
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Yes, it is. Look at the top of the page. It clearly says "Slant 6 Engines" so yeah, it is in the slant 6 section of the forum.
 
Since when does an engine have to have a lot of horsepower and fuel mileage to be a subject of affection.

I love my slant and it gets horrible mileage (worse than a 318) and not much torque, and it's slow. (Most new cars are faster)

Since the 68 dart got rear ended, I'm moving the slant and OD to a clean 75 dart body.

I love my slant because I am living in a free country where I do what I want.
 
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