Again, The red car MPH's the same in a quarter mile with manifolds and an X pipe, full exhaust system, mufflers (Flowmasters) and tailpipes, as it did with open headers. I removed 75 lbs of exhaust system with the headers. The obviuos conclusion being it made MORE HP with an X pipe and mufflers than with a set of ancient Hedman headers and open headpipes. The X pipe does work in my situation.

Frank/Rebop

Bristol, In ( by Elkhart) 

Well that answers a "BIG" question on my new exhaust system. But I'm going to wait and see what the figures are for the "X" configuration compared to it first. Thanks so much for the figures.

                                    Michael

Michael

Sandy Valley, NV

Charlie.  Thanks for sharing your data as that is a wealth of information.  You can likely get a better picture of how the curves look by simply graphing all torque data to a single graph and all the horsepower info on another and then observing how the different runs overlap or intertwine with themselves.  I do this frequently with engine dyno data as peak numbers rarely tell the whole story.

Lorena, Texas (South of Waco)

Hello Seppo,

My spreads are also growing with rpm, but at a much smaller rate than yours.  All my curves are nice, smooth, and fairly even progressions all the way to the max hp and torque readings (probably due to the small engine).  You can almost hear it in the dyno video Tim posted.  Tim also posted the Bonneville record run (camera in the truck) and you can hear the smooth, even climb in rpm while in 3rd and 4th gear (both videos are in the "Racing" section in the Maxton Record Run post).  The non H pipe setup tailed off at a faster rate after both max torque and max hp than did the H pipe setup.

No H pipe & No Mufflers

hp @ 4800 = 196     hp @ 5000 = 199     hp @ 5200 = 203

H Pipe & Mufflers

hp @ 4800 = 200     hp @ 5000 = 205     hp @ 5200 = 210.5

H Pipe Only

hp @ 4800 = 201     hp @ 5000 = 206     hp @ 5200 = 212

Hope you find this interesting.  It is nice to answer technical questions once in a while instead of just reading the posts.

Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

Hey Charlie! There is that 200 rpm variation between the first and the second and third pull. How much does that affect to those hp numbers and torque numbers?

I checked our dyno results and at the last pull as for an example the difference between 4200 rpm to 4400 rpm is 8,2 horse powers. 4200 / 304,3 versus 4400 / 312,5 .

Between 4400 to 4600 rpm the difference is even bigger. 312,5 versus 324,0 HP.

Hmmm... interesting.....

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

Charlie,

Interesting question.  The following are the comparisons of torque changes at 3500 and 4000 and max output RPM.

No mufflers, no H pipe:  110 ft lbs @ 3500   145 @ 4000   211@  4800

H pipe with mufflers:     105 ft lbs @ 3500   140 @ 4000   216 @ 5000

H pipe without Mufflers: 110 ft lbs @ 3500   145 @ 4000   217 @ 5000

The H pipe seems to have less torque in the lower rpm range?  Somewhat even at mid-range?  More at the max torque output rpm?  I do not think I would have expected these numbers.  This data certainly does not promote the H pipe for street use.  A street setup engine with these tests would likely show more accurate comparisons.  I trust the DynoJet dyno for accuracy, but as you know there are so many variables to consider to get the data more reliable.  Inputs like temperature and humidity (it was intermittent rain and sunshine), engine temperatures (we didn't log the engine temps for each run), etc, you get the idea.

I don't think I would make a decision on H pipes for street use based on this data, but I do believe an H pipe would help torque in street engines.  Let's see what happens with the X pipe.

Thanks for the comment Chuck.

    

Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

Charlie, I think I would also test the X configuration for the crossover pipe. Supposed to flow even better! Records are gonna fall! Chuck in NH

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

It will be cool to do them all just to see what happens.

How did average torque and horsepower compare in relation to the base-line averages?  I guess more easily stated, did it enhance the entire power band or did favor the bottom end or top end?

Lawrenceville, GA

Charlie,

Thanks for the comment.   You are so correct about the apples to apples comment.  Time and money just will not allow for everything at once.  I really just wanted to know if we were headed in the right direction.  We dyno'd yesterday and today I am removing the old engine and there is no looking back.

I may still do the apples thing.  With the new engine, I will probably chassis dyno with both brands of mufflers along with H pipe vs X pipe system to get even better comparison numbers.

I would love to answer regarding the "average numbers", but I didn't understand the question.  Please help me. 

 

Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

Excellent! How much did the H-pipe help with the average numbers?



Why not go ahead and do the x-pipe and dynomax mufflers for an apples to apples comparison? With the new engine, the numbers will be meaningless in relation to this engine.


Lawrenceville, GA