Hi,

Well it's simple.

I want more toruqe... I've done a search and couldn't find anything that answered this please share your wisdom.

What can I do to get more torque.

Rule 1 this car must be driveable or push those limits.

Rule 2 No turbos or super chargers

Rule 3 I don't care about cost, or petrol cost etc

Rule 4 assume it's a stock 225 with a 904.

All I want to do is work out how to get more torque and what is required.

thanks alot!

Ben

Tell us about your engine. I got quite a bit more torque by installing larger valves, porting the head, milling the head for 8.5:1 compression, 390 Holley on an Offy intake and 2 1/4" exhaust to a Walker Dynomax Super Turbo muffler. It's not exotic at all. It runs about 17 flat in the 1/4 mile with a stock column shifted 3-speed and 3.21 geared rear axle. Oh, yeah, stock 1967 camshaft too. I could bump the cam duration and compression up a little more and still have something that idles very well and makes good low speed torque. All you have to do to improve torque is improve cylinder filling.

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Joshua

I believe this is what we all want, an improved torque curve... Now, do you want low end torque (most efficient) or mid range torque (engine that comes on strong and keeps pulling)

The best way to improve low end torque is to maximize your "stoichiometric burn" also referred to as perpetual burn. This is when optimum air fuel ratio increases overall power up to 25% by just tuning it for "optimum burn" I have a cheap o2 sensor set up from MSD that allows me to get optimum burn at idle, off idle and through the engines torque curve.

In other words have you tuned what you already have? If so how are you tuning? Reading plugs? Test and tune? These are all ok methods but a true gas analyzer will allow you to maximize your engine time for whatever fuel you are tuning to. And the MSD timing control in the car will allow you to variate based on changing conditions. In essence allows you to be "fuel injected" just you become the computer.

A high power ignition, a carb jetting kit, an o2 sensor and a timing controller will allow you to achieve this on ANY engine. I have transferred my setup to a dozen or so cars and it is all now in my 440 motor home.

This is true to ANY internal combustion engine. TUNE what you have first.

Once you have done this and you want more power you will no where to go next because you will discover your "weak" link. Most weak links on slant six cars are the gears.

Give me a rundown of your set up, gear, stall, cam, intake, carb, compression, etc... If stock just put stock.

Hi,

Thanks and also thanks @ Josh about the cylinder filling, I've never looked at it like that.

a 225 slant it's been ported and polished.
Stock cam.
New upgraded ignition and msd blaster coil (big one) very good setup was expensive to :/...

What I plan to do:

Bigger valves 1.70 I and 1.44 E (think this is the standard upgrade).

Shave the head to 10.0:1 compression

install 350 holley with the new aussie speed intake. Unless I can get a carb slightly bigger.

Haven't really done anything to tune the car as such apart from the timing. I plan to get the correct sensors etc for air fuel ratio.

I'm interested more so in just what generally improves torque on a stock engine starting from the basics but i guess I'm already fairly close ...?

I'd really like to get as close to 400NM of torque. (not the pounds per foot)

Ok, sounds like you are looking for a long hard pull.

The combo you are describing sounds like it would definitely provide for more nm ft of torque...

I like the 10.1 compression ratio, there is a reason so many killer performance engines were 10:1 from the factory. I have found that 2 gallons of 116 leaded to 12 gallons of 92 unleaded is cheap and works well.

Make sure you match your carb, intake, valve size and cam. Packing or filling the cylinder with an optimized air and fuel ratio is a great concept that = power across the board... But if your cam is closing the door on the air and fuel it can't get to the party. Stock cams did not optimize velocity or volume. Why would you use a stock cam with the other upgrades? It may nullify some of the gains you might see otherwise...

Choose a carb and intake and then match cam and valves based on CFM, would hate to see you weaken your vacuum signal and decrease air velocity...

So your looking for 300 lbs of torque....

Don't know much, but AggressiveTed did a torque build I believe and had good results. From what I know yes compression increases torque, but has a diminishing return on what you gain versus detonation. So this is to say that 9.0:1 would be better for a lesser build, so on and so on.

Looks like 10:1 will work, but than you want a "smaller" cam to keep up your torque, so what was the benefit of running all premium?

I've built something similar and raced Joshie's build, and while it isn't a 300ftlbs it sure is a nice set-up. I've added a bigger cam and such and like the older set-up better. I ran an 819 cam and lower gears.

Most normally aspirated stock engines make about 1 ft/lb torque for each cubic inch of displacement. A decent hot rod engine can usually do about 1.25 ft/lbs which is 283 ft/lbs on a 225, but this will take very good coordination of head flow, valve timing, intake flow and exhaust scavenging. Proper tuning of mixture and timing are not to be overlooked.

The stock, gross rated 1bbl 225 was 145hp and 215 ft/lbs torque. 295 ft/lbs or 400 Newton/meters is a 37% increase. I'm not saying it's impossible, but it may be tough going.

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Joshua

Joshua,

Would adding one of the longer runner Aussie manifolds help? I love the torque I am getting with my build, but often thought that one of those new manifolds with longer runners might add a little more...... :shrug:
I know Chrysler did a lot of work with ram tuning.
I did get a set of Engine Builder valves to install next.

What are your thoughts?

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Yes it will, we had a round house discussion about the clifford hpak manifold vs. the Aussie at Woodburn. General consensus was the long runners on the clifford brings things in sooner (at a lower rpm)...the shorter runners will come in a bit farther up the rpm band...if you split the clifford plenum you will get better midrange torque and less reversion....Mostly your experience will be the step up you get when you hit the ram runing band...

-D.Idiot

DI,

Does the longer runner Aussie manifold increase/add torque over all, like 30 or 40 foot pounds?
is there some added value of torque increase or not?
or does it just shift existing torque lower down in the rpm band?

Example: Could you say that adding a Clifford long runner intake will add 25 foot lbs of torque? verses and Aussie longer runner manifold might add 35 foot pounds or what ever the number might be?

If not rated in foot pounds, could they be rated in percentages of improved torque over stock? :shrug:

I know it's based on a given build but someone must have some dyno experience with these manifolds compared to a stock setup.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

I don't think anybody has done this yet...given a few articles I've seen the length of runner moves the torque improvement lower in the RPM band based on longer length...Doc has had more experience with the Aussie and the Clifford both...I hope to acquire an Aussie sometime in the near future to compare (of course if the universe stops throwing clifford and Dutra paks in front of my face I can put my money toward that!!!!)

Based on tests I've done with the hpak and using the Gtech there is a definate increase in power when keeping the rpms in the 3500-5000 rpms range...about 15-20% depending on build...seat of the pants feel from myself and other passengers during some rural test runs feels like at that range it grows a "7th" cylinder...

Off idle torque is much more improved than the same build with the super six (initial feel, since I was able to run the Comp 252 with the super six then dial in the hpak initially...)

I'm looking for an article that better defines ram-tuning and runner length in mathematics/formulas to look at the "theoretical" side of this ...

-D.Idiot

Maybe look at what Chrysler did in the early '60's with their Cross Ram engines. The Cross Ram 383's in Dodge and Plymouths and the 413's in Chryslers made their torque in the mid rpm range with the loooong runners (like left carb feeding the right side engine long) At mid range rpm's, the runners kinda "forced" the AF mix into the cylinders like a supercharger. The Max Wedge engines used short runners for torque at high rpms.

Too big of an exhaust pipe will kill your torque at low rpms.
Little pipes will bring on the torque sooner.

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aed

- @ beauregaardhooligan.

Hi, So if I get a larger exhaust system I could be comprising torque?

I got a pair of extractors installed and the pipe out from them is 2.5 Inches. so if I went to 3 inches I thought it'd have more of a suction effect?
I chose the three inch exhaust because of the noise. I'm guessing this suction effect either doesn't exist or is very little. I just wanted it to be big enough so there wasn't a bottle neck kind of effect from cylinder to exhaust.

The way I understand it, you want small pipes close to the manifold to keep the velocity up and increase scavenging. You can go with a larger pipe farther back.
This only applies for low rpm torque. You can make more torque with big pipes but only in the higher RPM range, which /6s are not known for.

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aed