57fordguy, I like what you're are thinking of doing here. But I'll throw this out for consideration. In my neck of the woods A day on the dyno, about 6 hours realistically is 500 bucks. So if you plan on doing it and don't have money to burn, get your ducks in a row, header changes and tuning changes with comparative results are time consuming. Not much time to tinker.

Good Luck, we look forward to the results.



ANd now for a dyno horror story- A good friend of mine spent about 6 months gathering parts and building a highly developED 455 Olds. Software showed it was gonna do big HP and like our engines costly due to the style of motor and speed parts available, but none the less he loves 'em.

He used the same dyno and machine shop that I did.

It did make the HP and in and around 20 mins. a cylinder wall collapsed and the entire engine hydraulicked and turned to very small pieces. Nothing was salvagable even the headers cracked, intake-etc. He loaded the contents into the back of his ford pickup with a snow shovel!

First rule: Sonic check the block, he didn't.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

I do have an in-house dynameter and once it’s initially set up for a particular engine family, it only takes about 40-50 minutes to get an engine in place, plumbed, and ready to run.  After being installed on the dyno, it’s essentially like starting the engine in a car and running it through its paces.  On a new engine, the camshaft can be broken in while also simultaneously loading the engine to seat in the piston rings without concerns of any overheating as the dyno’s engine cooling system is constantly refleshing itself.  An actual full throttle dyno pull on an engine will typically take no more than 14-15 seconds maximum and can be shorter depending upon the testing parameters.  The accuracy of the dyno being used will dictate exactly how many pulls must be made per combination in order to get statistically valid results.  My particular dyno is repeatable to within 1 HP between pulls providing that the water and oil temperatures as well as atmospheric variables are kept consistent.  In my case, this means very solid data from a single pull without having to average data from multiple pulls.

In regards to testing header designs, just changing out the headers from pull to pull should suffice without doing a full range of carburetor and ignition timing variables in order to evaluate them.  But on my end, I can also monitor BSFC, air/fuel ratios, and exhaust gas temperatures and if these are changing radically during header changes, then it does point to timing or carb adjustments being required.  Where scavenging is being optimized, then timing and carb adjustments should be revisited anyhow.  And then the question comes up whether to test in an open configuration or with a full exhaust system.  And if with a full exhaust system, then a multitude of other variables crop up such as tail pipe size and length and which mufflers are to be used.

And in total agreement on the interpolation/extrapolation of data.  Trends do become evident when examining the data which then permits additional testing to head off in a more defined direction regarding changes.

 

And this is yet another reason to dyno test.  If you’re going to have trouble with an engine, it’s best to see it on the dyno rather than after going through the effort that’s required in getting it into the vehicle.  And especially if the vehicle has just been freshly painted.

Lorena, Texas (South of Waco)

Second to what Ted's saying, it's also easier to access the engine on a dyno to find or fix problems. You're also able to instrument it better and detect problems immediately, possibly avaoiding a catastrophic event. Tuning will go quicker as you can directly measure the results of your changes as you make them. At the strip, it's much slower and can actually be more costly with fuel used, hauling the car to  the strip, admission fees, wear and tear on the car and the variables of weather and humidity to complicate things.     

Frank/Rebop

Bristol, In ( by Elkhart) 

Hope you guys don't think I didn't like the dyno? It was the best money I ever spent on an engine and would do it again. I agree 100%, just wanted him to know what it might cost him, AND more importantly what I've learned here-the "sonic check".

The thing I most liked about it was, full break-in and a finished engine, no questions -asked engine, ready to go into the car.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

Alan,

        No, just a list of the good and the bad. If, like Ted, I had a dyno in my back yard, it'd be busy.

Frank/Rebop

Bristol, In ( by Elkhart) 

Ted and all:

This is just what I wanted to hear about a dyno.  I been told some horror stories about trying to use dyno shops that really don't know what they are doing, but suspected that exactly what Ted is saying was possible.  I have always wanted to use a dyno, but never had the money or place to do it.  I need to get my engine together and do some long-range planning.

I appreciate the comment about sonic testing.  It is essentially a standard procedure at the machine shop I use.  They are really big block Chevy guys with one guy who has Y-block experience.  They quietly turn out racing engines for a lot of guys in this region and typically work on $65,000 to $100,000 engines.  They have some funny ideas about timing older engines retrofitted with a blower (they think blowers make engines run hot, so keep retarding the timing and locking it in with no advance capability in order to prevent detonation - gee, I wonder why they run hot), but they do very good machine work.  I go to another shop for grinding the cranks so they don't grind off the oil slinger with oversized hones.

I will try to start assembling an engine while proceeding with my house, just as soon as I get a roof on things including the garage.  I have the crank ground and the heads ported, but no work done on the block, decking the heads, ordering pistons, or anything else, other than piling the bearings and h-beam rods in a box with the block.  I guess I had better at least order some more parts to add to the pile and finish my research on the cam.

Thanks for the ongoing tips, comments, and advice.  I will keep you posted about my progress in the future, with the goal of doing some dyno testing before finishing this project.

I am finishing a big project at work and then off to Arizona next week for another project, so may not be in communication for a week or two.  If I don't reply to anything on this forum, it is not for lack of interest, but because I am tied up on other stuff for awhile.

Mike K

Frank,

Wow! If I remember some of the stuff I have read about the F-code setup, you are exceeding stock performance by quite a few horsepower.  Do you think a guy could duplicate your performance using an e-code repro?

I have a couple of cars besides the current Fairlane 500 for this blower project.  One is a Custom 300 with a 3-speed and overdrive powered by a 312 that my brother rebuilt in about 1969 or 1970.  I don't know what he put in it, but it is probably a good engine to rebuild again.  Back then, we were always told not to bore over more than 0.060 inches, so our blocks are still generally good if the main bearing webs aren't cracked.  I don't know the rear end either, but assume it is stock.  I bought the Custom in 1966 for $127 when I bent up both doors on my Fairlane 500 and was crawling in and out of the windows.  I drove the thing from Montana to California and then up to Seattle before giving it to my brother when I got a 57 wagon which I also still have.  It has a 4.10 or 4.11 rear end and a thee-speed and overdrive.

I have two or three e-code manifolds, but only one set of really decent tea pot carbs that I have on an Edelbrock 257 manifold on my brother's old convertible.  I was thinking that I might come close to the type of performance you describe above if I use the Edelbrock 257 manifold or port out an e-code manifold.  I could also make life simple and put a good modern carb on one of the Blue Thunder manifolds from John Mummert.

All my heads are 57 312 heads so I will be dealing with relatively high compression, depending on how I build the motor.  In the late 60s and early 70s, we put in domed pistons with high compression and added aviation gas to the fuel.  Those y-blocks would tear the splines off a normal 3-speed Ford transmission, but worked good with a top loader.  I have no idea what horsepower they made, but they were pretty ferocious and would beat most of the cars in that era, including some of the 409 Chevy Corvetts.  We used either stock exhaust manifolds or Hooker Headers.  I still have one set of the Hooker headers on a 312 in a convertable.

Our engines tended to blow up fairly early in their life, but we weren't babying them.  The main problems were thrown push rods and scuffed cylinder walls and cracked rings from the aluminum pistons heating up (as well as from detonation if we tuned them wrong) plus burnt valves because we could not afford stainless valves or stelite or stainless valve seats.  When we weren't adding av gas, we added a little diesel or kerosone to the fuel to keep them from knocking.  We probably did not have enough expertise to know how to build those motors properly, but they would work good for quite awhile considering how hard we used them.  I am not sure what kind of compression we can run now with today's gas, so that will be another area of inquiry from guys like you when I get this first project done.

I don't know if my 312 heads are posted or not because I haven't had them off the cars for 40 years and didn't know posts existed back when I worked on them.  If I ever get this blower project done, the next one will probably be to fix up the Custom 300 as an e-code repro and see what kind of performance I can get using either some tea pots or some of the WCFB's I have.  The latter are in very bad shape and not the original dual quad setups, but have the small carb base for a Y-block intake.  These are all thoughts for the future.  I need to concentrate on the blower project right now but want to try a normally aspirated engine project in the future.

Mike K

Since we last exchanged information, I obtained "Practical gas flow by John Dalton" and "Supercharged! - Design, testing and installation of supercharger systems" by Corky Bell.  I am waiting for some backordered books about exhaust tuning.

One thing starting to emerge from this research is that exhaust requirements for supercharged engines are not the same as for regularly aspirated engines.  Most of the info out there does not apply to supercharged engines.  The book by Corky Bell provides a lot of formulas, which when I compare them to the results of published dyno tests in some of the magazines, including Y-Block Magazine, appear to work fairly well.  In general, the advice about supercharged engines is that bigger is better, but when you start crunching numbers, the objective with the header primaries is to make them big enough that rate of gas flow does not exceed about 250 fps.

Ted Eaton, earlier in this thread, reported good results on a drag racing application with 2-inch primaries.  In a detailed conversation with Jerry Christenson, he thought 2-inch primaries would be big enough on a supercharged, 331 cid Y-block with ported heads.  Gord McMillan has got good results with 1-5/8 primaries on mildly boosted engines like I propose and did not think I should go bigger than 2-inch on the primaries and 2-1/2 on the collector and tailpipe because I might loose low end torque.

When I worked through all the formulae in the book by Corky Bell, the results indicate that for my application, 2-inch primaries are what I should use for the predicted exhaust gas flow under boost at maximum rpm.  As Ted Eaton pointed out, these designs are unique for each engine, so what applies to my engine may not apply to another.

Based on the foregoing considerations, my header design should be simple, right?  Well.....maybe not.  I am using a centrifugal supercharger which does not even begin to make boost until 3200 rpm and peaks at 6200 rpm.  Accordingly, the engine may act more like a normally aspirated engine until boost starts to come up.  The question is, how much effect does the header design have at the lower rpm's?  Some of the stuff I am reading says none at all, just get rid of all the back pressure, other stuff says low and mid-range torque will be effected by header design.

Here is what I see emerging for my application.  First, the cam design will have the most influence over torque and the range of rpm where maximum torque occurs.  I am not sure to what extent the historic experience offered about header influence on torque may have been influenced by cam design.  Secondly, if I do not have any backpressure or it is less than 0.5 psi in my exhaust, I don't see wave forms and exhaust gas inertia having all that much effect, in other words, if the pressure stays so low as to be hard to measure, that indicates that gas inertia and waves in the exhaust gas are not interfering with the exhaust process.  However, thirdly, part of the exhaust gas theory is to try to create a negative pressure at the exhaust port just as the valve opens.  Accordly, low measurements on a pressure gage don't mean zip if you are trying to measure a negative pressure, so the pulse and scavenging theories may have some value, particularly at no boost or low boost.  Fourth, (and I am waiting for some back ordered info on this), the length of the header primaries effects the rpm range where the torque occurs, assuming the pipe diameter is matched to the gas flow.

In summary, it looks like 2-inch primaries are big enough for my supercharged y-block.  The cam design will be a lot more important than anything else.  I will still design the header primary pipe lengths to maximize low to mid-range torque, so far as the exhaust goes, recognizing that the supercharger will have more effect than anything at the higher rpm where boost increases.  The latter principle will also apply to the cam design, it does not have to be too radical for the supercharger to do its job, so long as I have been paying attention to maximizing airflow through the head.

That is about the extent of my progress on this question to date and I appreciate all the input you folks have provided on this.  If I learn anything more, I will add it to the thread.

Mike K

Frank (pegleg),

Regarding your January 3 comment about 1-3/4 pipes for your mildly supercharged car, the gas flow calculations in Corky Bell's book "Design, testing and installation of supercharger systems" will let you make sperate predictions about the primary pipe size and tailpipe sizes required for your application.  Without doing the calculations, but considering what I have been reviewing, my guess is you will find 1-3/4 inches is plenty big.

The other thing the experts writing these books say is that short primary pipes are appropriate for wide-open racing applications because they shift the torque curve into the higher rpm's where more power is generated.  This may not be the way to go on a street car because you will be weak on torque in the low and mid rpm's.  Again, this will all have to match up to your cam design and where it generates torque plus what you intend to use the engine for.

If I am understanding what they are saying, primary pipe diameter has to be sized for gas flow and probably does not affect anything but potential backpressure and restriction on the exhaust.  However, primary pipe length may have an effect on the range of rpm where torque occurs.  Evidently, with enough supercharger pressure, the latter effects may go away.  For those of us using relatively mild boost superchargers, the length of the header primaries may still be important (my interpretation) until our supercharges start to generate boost at the higher rpms.

Mike K

http://www.mustang50magazine.com/techarticles/29618_short_long_tube_headers_test/index.html

Just one test, but gives you an idea how this particular engine responded to different headers...

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)