A closer look at dyno data: what gives the most bang for the buck?

[gilitos]

Piranio's website data (http://www.modelaparts.net/dynosheet...ynosheets.html) is a goldmine for real answers to questions about performance mods. It answers questions about heads, carbs and cams in a way that doesn't have to rely on opinions. For example, I've plotted some of the data here:
untitled1.jpg
and it gives us a lot to chew on.

1. By themselves, either a 5.2 :1 Snyder head, a Brumfield head, or a B cam all give essentially the same results: more than 20% HP increase (about 52 max)
2. Adding them together, cam + HC head, gives an additional 10% HP; peaks around 57 HP. Not too much more, but it looks like a lot on the graph, doesn't it?
3. A Brumfield + dual Strombergs and a Snyder 5.2:1 + dual Zeniths are mighty close; about 62 HP, and this is with stock cams.

Confirms what a lot of people opine about a HC head being the single best (and easiest) mod to make.

[Rowdy]

I question which BF head they chose for the test as they do not publish that info. Also I have found the drivability of the BF head to be better than Snydes head, more torque? Likely the case. I hate to compare just the HP as the torque curves tend to be more of what you feel as far as performace. Rod

[29restorod]

Very interesting web site. Thank you for making the chart,and posting it. I now know that my banger from 50 years ago,produced about 60 hp. One of the best improvements I made years ago,was the Mallory distributor. It may not have produced any extra HP,but drivability was greatly improved. My present "A" came with a "Siemens Super High Power"head,and a "B" cam. As soon as I finish the hydraulic brakes, I will add an Ansen single Two barrel downdraft manifold,with a Stromberg 48 or 97,and the Mallory dist. I will then be in Nostalgia heaven,truely reliving my youth.

[Jim Brierley]

More compression and a bigger carb are the 2 easiest and quickest way to increase power, and a stock cam, a B or C, will give you the torque at the speeds that most of us drive. I would go to 6:1 and a Stromberg 97 or a Weber.

[gilitos]

Rowdy: HP is just torque multiplied by RPM:
HP=TORQUE X RPM / 5252
Dynos measure torque. The HP is calculated from the torque using this formula. So for a given RPM, if the HP is higher, the torque is higher.

[CarlG]

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I have the Snyder 5.5 head with a Weber carb, IMHO - a very good inexpensive combination.

[kelley's restoration]

it confirms my mph and et for drag racing my phaeton
2640 lbs
20 flat at 64 mph=about 65 hp
snyders 6-1 stipe cam and duel strombergs
tk

[Purdy Swoft]

A higher compression head will give the biggest boost that you will really feel. Installing a B or other performance cam without raising the compression will give no noticeable increase that you will feel. If the compression is left at 4.22 the engine won't have the power to benefit from the increased rpm that a performance cam will give. Same for more carburetion, it will help some but it won't give that much of a seat of the pants feel. The mallory dual point distributor will help low speed power and driveability as in smoother take offs because it will advance smoother than the stock manual advance and is shown to give a low rpm horsepower increase in the Ron kelley dyno tests. A lightened flywheel won't increase horsepower or speed but will give nearly as much seat of the pants feel of a high compression head in that it will greatly increase acceleration, help save the main bearings and make gear shifting much easier. Add them all together plus a free flowing exhaust and power and drivability will greatly increase. This has been my experience. Dyno tests will vary. I've never heard of a Snyder 5.2 head, I know the Piranio dyno tests lists it that way. Maybe that suggests that the Snyder 5.5 head is only 5.2 compression. Bill Stype did some dyno tests with the Snyder heads that may be interesting to look at.

[Rainmaker Ron]

Originally Posted by Rowdy

I question which BF head they chose for the test as they do not publish that info. Also I have found the drivability of the BF head to be better than Snydes head, more torque? Likely the case. I hate to compare just the HP as the torque curves tend to be more of what you feel as far as performace. Rod

Hi Rod, interesting comments about torque. Back in my stock car days we had a saying that "you brag about horsepower but you drive torque." The stock A develops maximum torque at about 900 RPM.....well below the driving range. When Bill Stipe built my engine he tweaked the cam design until we had maximum torque at 2300 RPM. The engine now has over 20,000 miles and I assure you it is very "drivable." You mentioned driving both the Brumfield and the Snyder head and finding the Brumfield more "driveable." Was this comparison on the same car? What else was done to the engine? Are we talking road miles or just test rides? As I recall you were going to use a Stipe cam, is that what was in the engine? I will never do another full race engine but I am just finishing a 30 closed cab pick up and thinking about just a B carb and Hi Comp head. Where do you stop?
Rainmaker Ron

[Rowdy]

Not in the same car, but were both fresh engines locally built by the same person. Both used reground cams from the same source, but likely still not exactly the same. Stock carbs on both and these were shake down cruises. Both had the same stock gear ratio, so nothing fancy. Just found the one with the BF head to have better acceleration. You are right there could be other factors, this was just an observation from the drivers seat.

My engine plans have not changed much. I have the LZ Stromberg 97 carb, 5.9 BF head and the B330 Stipe cam sitting here waiting for me to become employed again so machine shop work can begin. Thinking of adding a Burlinton crank to the mix along with incerts, so not going to be a weak engine at any rate. Like my aims have always been with this car is a Delivery that really delivers. If this had been a more complete and correct car to begin with I would consider a different restoration goal. But it is what it is, so going to as closely as I can copy what was done to the Splinterbox minus full pressure oil system as I know this combo is already a proven performer. Rod

[BRENT in 10-uh-C]

Originally Posted by gilitos

Confirms what a lot of people opine about a HC head being the single best (and easiest) mod to make.

I guess there was a time when I agreed with "everyone else" but I'm not so sure I agree with your statement any longer. Now where the difference comes in my view is that almost every Model 'A' we restore is fitted with a 3.27 or a 3.54 rear end ratio. I think most would agree that a brand new Model 'A' was capable of 60 mph off the showroom floor, and could easily cruise at 53-55 mph back then. This happened with a stock Model 'A' camshaft (NOT a regrind or a Model 'B' cam). With a 3.27 gear ratio in the rear end, that 52 mph now equates to 60 mph.

The negative thing I always hear about engines that are pulling this gear ratio is they don't have enough torque to pull it. Again, most people have worn camshafts or re-ground camshafts that have totally altered the power bands from where the torque is needed, --and a H/C head does not cure this. Therefore, the thing I feel is the biggest bang for the buck is a Stipe IB330 or IB335 camshaft which has the ability to increase the torque band and lower the rpm in which the engine enters that power band.

Now I agree there are some folks out there that have the desire to be able to drive in the 65-70 mph range with their Model 'A', but I believe most people want a car that they can maintain 50-55 mph safely. Traveling at 55 mph with a 3.27 gear ratio is equivilent of driving 47-48 mph with a stock ratio. That according to my calculations is between 1825-1850 rpm, --which is nicely located within the Stipe cam's power band which allows the vehicle to maintain that speed while encountering hills & overpasses on secondary roads.

.

[hardtimes]

gilitos,
Thanks for your info and reference info.
I've looked over piranos site. I have a question...about one of his stated combos, i.e.- using stromberg "82" carbs. I've never seen a stromberg 82. Anyone know what year engine this carb originated on?
BTW..I agree with you stmt about a higher comp head being single easiest improvement (and more bang for buck). I'm wondering why no one (dyno) addressed the addition of an improved/free flowing exhaust system..for performance improvement?

[BRENT in 10-uh-C]

Hardtime, likely there was a misprint meaning a 81, --or what was originally found on the V8-60. IMHO, this is another one of those things where Stromburgs got a bad reputation. A V8-60 only had like 140 cubic inches compared to a Model A's 201. Having a carburetor that was sized to feed an engine over 25% smaller doesn't sound like the proper thing to make power. So if the 85 horse had 221 cubic inches, doesn't that seem to be the better match? I think that most carbs back then got their bad rep becuae they leaked air due to warpage and seeped fuel due poor gaskets and power valves. I have used dual Holley 94s on the street with adjustable jets and power valves with great success (i.e.: smooth acceleration and no stumble or flat spots).

I believe there have been articles out there showing back pressure between an original exhaust system, an Aries, and the old Midas manufactured system. I think the biggest thing why tests like this are so vague is an engine is nothing more than an "air pump", and everything is contingent on air flow in and out, volumetric efficiency, chamber design, and valve flow. A dyno operator can also manipulate numbers to project better readings in a specific area letting other readings become compromised.

[Purdy Swoft]

Not for the sake of disagreement but I prefer the 3.78 gear ratio. I have from time to time took the speedster up to speeds of 75 mph for quick bursts just for the thrill or fun of it. We are happy to cruise the roadster at 50-55 mph. Deb has took it up to 65-70 a few times out on the four lane. Low and mid range power is what I prefer. We run winfield super street 3/4 race cams ground by Bill stipe and 5.9 heads and couldn't be happier. If we are going somewhere in a hurry we prefer the air conditioned comfort of the Tahoe. It is really too hot here in south west Alabama to enjoy driving the model A's at this time.

[CarlG]

Originally Posted by Purdy Swoft

...It is really too hot here in south west Alabama to enjoy driving the model A's at this time.

What! No Air Conditioning in your Speedster?

[Purdy Swoft]

No air condition, no windshield and the wind feels like the heat from a blast furnace. I know I spend too much time at the computer but it is just too hot to do much out side. I went out and aired up a few tires that were getting low on some of the model A's this morning before it got really hot but still got wet with sweat.

[hardtimes]

Originally Posted by BRENT in 10-uh-C

Hardtime, likely there was a misprint meaning a 81, --or what was originally found on the V8-60. IMHO, this is another one of those things where Stromburgs got a bad reputation. A V8-60 only had like 140 cubic inches compared to a Model A's 201. Having a carburetor that was sized to feed an engine over 25% smaller doesn't sound like the proper thing to make power. So if the 85 horse had 221 cubic inches, doesn't that seem to be the better match? I think that most carbs back then got their bad rep becuae they leaked air due to warpage and seeped fuel due poor gaskets and power valves. I have used dual Holley 94s on the street with adjustable jets and power valves with great success (i.e.: smooth acceleration and no stumble or flat spots).

I believe there have been articles out there showing back pressure between an original exhaust system, an Aries, and the old Midas manufactured system. I think the biggest thing why tests like this are so vague is an engine is nothing more than an "air pump", and everything is contingent on air flow in and out, volumetric efficiency, chamber design, and valve flow. A dyno operator can also manipulate numbers to project better readings in a specific area letting other readings become compromised.

Well, what you said re volumetric efficiency and exhaust tuning/flow is the out side of that pump and that's why I remarked about it.
The little V8-60 had a whopping total of 136 cubes with one 81, which lead me to my present useage of the 81 (times 2)! My B has about 210 cubes and is very happy with two 81s. As far as bad rap is concerned, I listened to Jere Jobe and other carb gurus of do mine. A compliation of their input/thots made things come out better than expected. There's an ole saying: 'figures don't lie, but liars figure'. Since I ain't good at figuring (barely passed trig/logrithyms), I do admire figurerers talents, especially those guys with fancy/expensive machines !

[Arlen]

Im in the Dallas club with Dennis Piranio. He has done several workshops for the club over easy ways to increase a cars hp and still look stock. Im trying to remember all the figures but I think it was actually an Aires Muffler that added the most hp. I think it was about 10hp. The Snyder head added around 9hp, and the Brumfield added about 10hp. I think it was the B ground cam that added around 4hp and a B intake manifold and carb adding about 3hp total for the combo. It was decided in the workshops that the HC head and muffler were the easiest to install and kept the motor looking stock while adding nearly 50% hp. I dont think he has ran a Dyno on the new even higher Synder head. Piranio offers a service of boaring out a stock intake manifold to B size. Its an easy way to add 1.5 hp and nobody ever knows it. Great company located in North Texas and builds a really beautiful motor.

[pat in Santa Cruz]

I agree with Brent about Bill Stipe's 330 cam. It really woke up the Brumfield head. I couldn't be happier with it.

I don't know if an Aries muffler "adds" 10 HP when compared to an original Ford muffler. I think the cheapo repo commonly found on an A took it away in the first place. With an old rusty repo muffler, I suspect the engine loses even more HP due to clogged baffles.

[Marco Tahtaras]

Originally Posted by Purdy Swoft

Not for the sake of disagreement but I prefer the 3.78 gear ratio. I have from time to time took the speedster up to speeds of 75 mph for quick bursts just for the thrill or fun of it. We are happy to cruise the roadster at 50-55 mph. Deb has took it up to 65-70 a few times out on the four lane. Low and mid range power is what I prefer. We run winfield super street 3/4 race cams ground by Bill stipe and 5.9 heads and couldn't be happier. If we are going somewhere in a hurry we prefer the air conditioned comfort of the Tahoe. It is really too hot here in south west Alabama to enjoy driving the model A's at this time.

That cam choice is the reason you prefer the 3.78 gears. It has more duration which moves the torque curve upward reducing low end performance.