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Bending Wrenches since 73
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156 Posts
Discussion Starter #1
After going to the 615/585 cam and 1.67 roller rockers and up to the Mik 45, I spent some time on the dyno and had to drop the main jet from the 175 to a 167.5. This was with the torque baffle in.
When on the road it had more pull at 3/4 throttle than WOT. The Mikuni tuning manual would have you believe the main jet is too rich. This was not the case as the A/F was observed and corrected to 12.7/1 at WOT.
After 3 Weeks passed I noticed tell tale exhaust carbon coming from between the Pro Pipe end cap and the collector. Obviously there was too much pressure in the exhaust and it was trying to get out any way it could.
I put the open/race baffle in and immediately had to step up the main jet.....
Hmmm more air flow, faster air flow....it went lean...Settled on the 172.5 main jet.
Back to the dyno. Picked up 4 ponies AND 2 lb ft.
Go figure....
Definitely, a moderate built 95" would benefit from the torque baffle. But this build has a whole lotta flow potential and the torque baffle was too much resistance.
 

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7,381 Posts
How was the low end tq with that baffle though. Any time i have used it for any build it had suffered some..??

Edit:....My propipe does the same thing. At the of a short 50-100 mile ride i have about a 2 inch carbon deposit exactly where you do....
 

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O'Rork,
That was a nice lesson in flow dynamics and getting things tuned and matched to the build. Thanks for sharing!

Sounds like a real fun build to ride! enjoy!
 

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TXCHOP is right on here....of course there is going to be carbon at every crack and exit there is on a good pipe, it's called back pressure. I agree you found more ponies on top end because there was better savaging at the higher rpm but my question is how often are you at 5000 to 6000 rpm. If you layered the two graphs (before and after baffle change) over top of each other you would see a big difference in the low end torque and power. There is no free lunch, as of yet, if you gain on top your going to pay on the bottom....if you gain down low you will pay for it on top. It's all in what you want, if your looking for top hp numbers then run the open pipe, if your not all caught up in Horsepower numbers you can concentrate on the power where it's usable.
 

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Bending Wrenches since 73
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156 Posts
Discussion Starter #5
The low rpm torque dip did fall even lower by 6 lb ft. On recovery of the dip, by 2,900 rpm the torque line bested the plugged baffle by 2 lb ft and is holding the plateau an additional 125 rpm or so.
It is definitely running cooler too. I can still cavitate the intake with too much throttle at too low of rpm, though noticeably less than with the plugged baffle. I've still got more flow than the displacement can use until insane rpm....
 

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168 Posts
pro pipe std baffles are easy to modify
split the differance
there is never cake and pie at the same time like posted above
but there is cake and ice cream or pie with ice cream
 

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Bending Wrenches since 73
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156 Posts
Discussion Starter #7
Snuffy and all, well put. Fun with wrenches 101. At least I have an adequate air handling assembly awaiting complimenting displacement. I spose I'll run it till it warrants rebuild then dig in and do the timken, big wheels and big buckets. At least I can say with some authority, a 95" build doesn't warrant 2" hemi heads with floor drain ports.........lazy flow.
It runs good, but it ain't no Benz.
 

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O'Rork said:
Snuffy and all, well put. Fun with wrenches 101. At least I have an adequate air handling assembly awaiting complimenting displacement. I spose I'll run it till it warrants rebuild then dig in and do the timken, big wheels and big buckets. At least I can say with some authority, a 95" build doesn't warrant 2" hemi heads with floor drain ports.........lazy flow.
It runs good, but it ain't no Benz.
you might want to do the Timken sooner rather than later. I know of another one that just grenaded the left roller bearing about a week ago. He's going to post pictures of the carnage. Would hate to see yours come to the same fate.

by the way, enjoy your build and ride it! chasing these numbers will make you crazy sometimes ;)
 
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