Dual exhaust - surprise increase or imagination?
 

I finally put duals on my 221ci 34pu yesterday. I drove it around town a bit and really didn't notice anything other than a sweeter sound. Today, I took it out on the 4 lane and I was shocked at the difference starting arounf 40mph and up. Is a fairly noticable increase in power and smoothness to be expected or is my mind playing games with me? Of course my wallet is somewhat lighter!

Re: Dual exhaust - surprise increase or imagination?
 

This is a question that JWL should be able to answer. Somewhere in the back of my mind he has tested duals vs single exhaust and found no real significant difference in performance.

Re: Dual exhaust - surprise increase or imagination?
 

Either way, it's worth it, isn't it Jack? Used to get at least 10hp just with a wash and Simonize, empty the ash trays and sweep out the mats as I recall. ..B.

Re: Dual exhaust - surprise increase or imagination?
 

You are right, Lawson. But it's the sound that counts.

Re: Dual exhaust - surprise increase or imagination?
 

Folklore has it there were three basic things a young hotrodder did 'back-in-the-day' to gain more power.
Dual Carburetors
Dual Exhaust
Aftermarket Cylinder Heads.

Dual exhausts should make a differance, after all the original Ford set up was pretty woeful so just about anything should (at least theoretically) be an improvement.

Re: Dual exhaust - surprise increase or imagination?
 

This is a topic I'm glad to see as I want to put duals on my 36 and wondered what improvement it would make. Anyone try putting headers on a 36 without modifying the battery box?

Phil
Chambersburg, PA

Re: Dual exhaust - surprise increase or imagination?
 

Nothing sounds better on a flathead than just a simple gutted muffler.

Re: Dual exhaust - surprise increase or imagination?
 

The dual exhaust didn't make much, if any, difference on the engine JWL tested in his book. However, it was an 8BA. Compared to a '34, the exhaust manifold passages of an 8BA are huge. I think there's a good chance you gained some usable HP, especially at higher RPM levels. Anyway, I'm sure the sound was/is worth it.

Re: Dual exhaust - surprise increase or imagination?
 

Fe26, is right on,did it as a teenager,and do now .not just for looks either,there is a power gain. Harold, central coast Ca.

Re: Dual exhaust - surprise increase or imagination?
 

On my '46 with a 59A running Fenton headers,dual exhaust with Smitties I definitely noticed an increase in performance over the stock single system.
In Roger Huntington's 1951 book "HOW TO HOP UP FORD &MERCURY V8 ENGINES" he notes about a 7% HP loss with stock system and up to 10 % gain in peak HP with headers,duals and less restrictive mufflers. Really only noticeable at higher RPM's.
These seem to be common figures among the Hop Up books of the '40's & '50's. How true is up for speculation.

Re: Dual exhaust - surprise increase or imagination?
 

https://www.youtube.com/watch?v=NmyQsMCgpXEhttp://


hope this works!

Re: Dual exhaust - surprise increase or imagination?
 

There are MANY myths still roaming around out there. Some will never die. The thought that a tiny little 221 engine is going to become supercharged by installing a dual exhaust system is one to smile about. Either something was seriously wrong with the original system or someone changed the engine at the time the exhaust system was being worked on.

Re: Dual exhaust - surprise increase or imagination?
 

I really feel like I got an increase on my 8BA when I installed headers and dual smitty's. The lore is that you can't 'feel' a difference unless you add on 15 horsepower (to a typical V-8...) and I'm sure I got nowhere near that, but my seat-of-the-pants meter says she got a hitch in her get-along.

Re: Dual exhaust - surprise increase or imagination?
 

years ago i worked in a auto repair shop & the owner had us shine the hood when ever we worked on a car. he said the owner would think it runs better most of the time he was right

Re: Dual exhaust - surprise increase or imagination?
 

Logic dictates that duals with stock manifolds would provide a VERY small increase in revving capabilities, good headers would add a bit more, but actual hp gains will only come when the rest of the engine is modified to take advantage of the better exhaust. The whole point of a good exhaust system is not to sound good, but to give the increased duration of the cam a decent shot at getting rid of the increased quantity of fuel/air from the multiple carbs and better porting/valve flow. Of course, the better sound is just as important. :D

Re: Dual exhaust - surprise increase or imagination?
 

Hey Brenden, sounds good, so does Ella Mae! Thanks

Re: Dual exhaust - surprise increase or imagination?
 

Thanks for all the reply's. Another thing I noticed - I'm running a separate temp gauge for each side and the pass side (where crossover pipes converged) was always running 15* hotter. I always thought it was a diff in the cheap gauges but after installing the duals, both sides now match in temp. It is a 221ci but a 1942 Canadian military - not the original. I drive "Lil Red a lot and know her qualities and it sure feels like she has an extra something above 40mph. But as noted above, a polished car also seemed to run better. Anyway, it was worth the effort and hope you all can enjoy your rides today.

Re: Dual exhaust - surprise increase or imagination?
 

As a kid with no $$, I asked in Pep Boys if a chrome exhaust extender added horsepower? The answer was YES: 5 HP.
I then asked how much gain wilth a rusty extension stolen for Jessie's Junk Yard in Cross Keys, NJ ...
clem

Re: Dual exhaust - surprise increase or imagination?
 

Jack
How is your exhaust routed? Original manifolds?
Did you move the battery?
Brian

Re: Dual exhaust - surprise increase or imagination?
 

Only way to prove the point is on a dyno and measure the actual horse power before and after. My 35 rebuild has only just started but there is already a nice set of ceramic coated headers on the shelf that will supply dual exhausts. Expected HP gains? Who cares , we all know it will sound great!!

Re: Dual exhaust - surprise increase or imagination?
 

Phil, here is how they are routed on my '36. The headers and extensions came from Red's Headers. Everything fits good. Ed

Re: Dual exhaust - surprise increase or imagination?
 

Jack 34pickup ...........................
I think that it has been proven, over and over, that dual pipes do not help performance, for the flathead FORD, except for modified engines in a very high RPM. The seemingly backward original system has tested out to be plenty adequate for our daily driving.
BUT, who cares, they sound GREAT ! Especially, when you block off the heat risers with nickels. Sometimes, pennies fall through.
MIKE :)

Re: Dual exhaust - surprise increase or imagination?
 

cross keys is a great little place.

Re: Dual exhaust - surprise increase or imagination?
 

The routing was difficult as besides the batt box being in the way, I have Richard's hyd master cyl kit installed. I also had to use the original front output cast manifolds as there is only a small clearance between drivers side and the steering box on a pu. No one makes a header that will miss the steering bax that I know of. The bender was pretty skillful and ran both left and right side towards the middle behind trans mount. They spread out some and up towards the bed and Smithy's run parallel to the driveshaft and above the suspension. Finally, out of the Smithy's and down and out under the rear axle. The ends are short and turned down slightly at the gas tank. You really can't see them unless you get down and look under. I used 1 3/4" to the mufflers and 2" out.

Re: Dual exhaust - surprise increase or imagination?
 

Thanks.

Re: Dual exhaust - surprise increase or imagination?
 

Yes Bassman/NZ got it right. Harold, central coast Ca.

Re: Dual exhaust - surprise increase or imagination?
 

A big thank you to Ed Pitts for posting the pics of those headers. That does it for me! I'm getting a set of Red's.

Phil

Re: Dual exhaust - surprise increase or imagination?
 

I am pretty much convinced that dual exhausts do not do that much for performance, BUT do help in getting heat away from the engine compartment.
1. The headers do not hug the block, as the original manifolds do, allowing air to flow between the block and headers.
2. The R/H manifold does not have to carry the heat of
eight cylinders, but only four, as the L/H manifold heat has already been carried away.
3. There is no crossover pipe, in front of the engine, to blow heat back across the engine.
It would be interesting to know if a study has ever been done on this. These are just my observations.
MIKE :)

Re: Dual exhaust - surprise increase or imagination?
 

I removed the headers from my '50 this past winter and put an all new single exhaust system on and it seems to run consistently a few degrees hotter.

Re: Dual exhaust - surprise increase or imagination?
 

Re: Dual exhaust - surprise increase or imagination?
 

Well, to put this thread to rest, I took 'Lil Red up Pine Grove mtn yesterday and realized that the "extra snap" was more imagination than anything else. I've driven that mtn enough times to have a good feel about speeds at certain points. Although I still pulled it in high gear, I did not see any gain in speed at certain markers. Sooo. . . my wallet is lighter, I can say i have duals but any gain was minimal to say the least. But . . . she sure sounds good!!

Re: Dual exhaust - surprise increase or imagination?
 

Sounds great! I need to put headers and duals on our 47 Merc.

Bob -Hampshire, Illinois

Re: Dual exhaust - surprise increase or imagination?
 

This brings up an interesting point. Remember the flathead hop-up books from the 50s? In the main they were great books, but they had an interesting flaw..... and it relates to this topic. They optimistically gave figures for hop-ups, for example (from memory) 10hp for exhaust, 15 hp for dual carbs, 10hp for milling the heads, 5hp for porting/relieving, etc etc. What they didn't mention was that those figures did not apply on their own, they were interactive. A 10hp increase for duals/headers is feasible..... in a big bore stroker running high compression, long duration and induction to suit.
This brings to mind another phenomenom. In the 50s, guys (some) were running 125-140mph in street roadsters on the lakes. Ray Brown was a typical example. How the hell did they do that? :confused: To build a flathead today to run those speeds, and yet still be your daily driver as they were, would require the winning of the Texas state Lottery !! A conundrum indeed. :D

Re: Dual exhaust - surprise increase or imagination?
 

Here's a pic of my coated headers made by flatattack in Aus. It will fit a standard 21 studder 35 with stock steering box and starter motor. Remember our steering box is right there beside the starter!! Have new alloy heads as well!! Very minor relieving, porting, new valves, guides, and adjustible tappets. 040 over pistons. The valve seats and decks of the block to be machined soon. Can't wait to put it together with a nice set of stainless dual exhausts. I put stainless dual exhausts on my roadster in 1987 and haven't touched them since.

Re: Dual exhaust - surprise increase or imagination?
 

I run a 6V OPTIMA battery in my '35 woodie, turned 90 degrees so the long dimension is running fore and aft. Easy to make a box or frame to hold the OPTIMA and allows room to run the drivers side exhaust pipe outboard of the battery and inside the frame rail.

http://i299.photobucket.com/albums/m...e/IMG_1286.jpg

Re: Dual exhaust - surprise increase or imagination?
 

"Especially, when you block off the heat risers with nickels. Sometimes, pennies fall through."

The cost of buildung a flathead continues to rise astronomically...that's a 5-fold increase in cost over the traditional pence!

Re: Dual exhaust - surprise increase or imagination?
 

I believe Joe Abbin tested a stock '40 Ford system back-to-back with standard headers and Belond-style "W" headers. I think the "W" headers made the most, but we're talking 6-8HP max, if I'm recalling correctly.

The grin factor is worth it regardless!

Re: Dual exhaust - surprise increase or imagination?
 

Bruce Lancaster .......................
Sometimes, you just have to step-up, "bite the bullet" and "take your licks".
MIKE :)

Re: Dual exhaust - surprise increase or imagination?
 

Yeah, you just have to shell out if you want a flathead. It's not like an SBC that can have its risers blocked with pieces of beer can aluminum from the ditch...

Re: Dual exhaust - surprise increase or imagination?
 

For those running 6-Volt systems, the battery interference problem can be resolved (as per the post above on 35-36) by using an Optima battery. For my own 34, I made a battery support with a very thick floor that mounts the Optima on its side with the terminal posts facing toward the center of the chassis, and raised up to near the floor. This allows the LH pipe to pass below the battery without the pipe hanging too low. As Jack posted, my 33-34 hydraulic brake setup precludes running the pipe toward the inside of the original battery and support. The new support installs (like all my stuff) using only original factory holes.

Someone might post that the heat from the pipe will "cook" the battery, but I have been running it like this since 2004 with the same battery. If the battery is being cooked, it must like it???

The above solves the pipe routing problem, and access to the battery is still through the original hole in the floor and cover.

BTW, I used 37-41 original manifolds, as I was in a hurry to get the car going for the PRC RR for 2004. This "temporary-took-one-day" system worked out so well that I never changed it...