Dynoed my 427so Cobra today.... interesting to say the least!

[Excaliber]

When I remove the side pipes and bolt on my shortys I can FEEL the difference big time. MUCH faster with the open headers.

Standard TKO type trans could either .6 or .8 in 5th gear, for sure it's overdrive, use 4th on a dyno. With the Richmond running in 4th (not 1 to 1 in 5th) I would expect a substantial drive train loss, that pretty much kills any dyno numbers and puts you back to square one.

[427Aggie]

What air cleaner were you running on the 2 fours when you dyno'd it? If its those little chrome things one for each carb..then I know where some of the power went.

On my ERA I gained over 40 lb of torque from just changing to the stainless pipes with less restrictive mufflers...and 18-20% loss would be about right...Again if you have those 2 chrome air cleaners on the carbs those will suck the life out of a motor because it can't get enough air!

matt

[neverwouldof]

Originally Posted by 427Aggie

What air cleaner were you running on the 2 fours when you dyno'd it? If its those little chrome things one for each carb..then I know where some of the power went.

On my ERA I gained over 40 lb of torque from just changing to the stainless pipes with less restrictive mufflers...and 18-20% loss would be about right...Again if you have those 2 chrome air cleaners on the carbs those will suck the life out of a motor because it can't get enough air!

matt

The sidepipes are less restrictive and baffeled. They are not quiet by any means and were designed to be less restrictive then the sidepipes originally on there. I did question the air cleaners.... they are the double 8" round oil soaked style like K&N. Just looking at them i couldn't imagine getting a great deal of air through. However , what other choices do i really have in that?

Thanks for your inputs!!!

[eschaider]

Look at your A/F ratio. You start to go lean at about 2200 rpm. You reach a maximum lean of nearly 18:1 A/F ratio before 3000 rpm. You don't come back to the ranch until almost 4000 rpm. You have a fuel delivery problem! Don't know where it is but you have it big time. You might check float levels, needle and seat assemblies (less likely). The fuel pump's ability to supply high volumes on short notice, with adequate pressure ...

Engines make power by burning fuel. The more you burn (at the right A/f ratio) the more you make. Timing is absolutely essential to making power, be sure to check out your ignition system.

When you fix it get ready for robust numbers and performance and a lot of driving pleasure. Low speed torque is the stuff dreams are made of.

Ed