258 RPM Range - Page 3 - JeepForum.com
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post #31 of 37 Old 05-13-2013, 06:52 AM Thread Starter
Neuner-9R
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Quote:
Originally Posted by Matt1981CJ7 View Post
Well, you've had some of the best CJ mechanics on this forum all tell you that manifold is the way to go. Your posts indicate that you still don't quite grasp that concept.

Matt
Where, when?



No, this Mechanical Engineer understands just fine.

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post #32 of 37 Old 05-13-2013, 07:04 AM
Matt1981CJ7
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If you understand, why do you keep relating performance characteristics that have nothing to do with the type of vac source to the dizzy?

There are three basic things that manifold vac does for performance:

1. Stronger, smoother, cooler, and more fuel efficient idle.

2. Improved cold starts

3. Improved low-end, low load, performance.

And, in case you were wondering, here's the '85 4.2L vacuum layout. As you can clearly see, it has straight manifold vac to the distributer.

Matt
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post #33 of 37 Old 05-13-2013, 07:27 AM Thread Starter
Neuner-9R
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In your thread about advance timing you're needing a lot of help, now all of sudden you know it all?

http://www.jeepforum.com/forum/f8/he...curve-1238634/


You call my advance curve off of the ported vacuum '80's' and now your posting a diagram from the 80's which uses manifold?


Read the comments below the main article from this posting:

http://www.jeepforum.com/forum/f8/ti...asics-1230121/
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post #34 of 37 Old 05-13-2013, 07:42 AM
Matt1981CJ7
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Again, you are confusing issues.

Re-curving the centrifugal advance is a completely different issue than the vac advance. The two perform completely different functions. The former relates directly to engine RPMs, while the latter relates to load and vacuum pressure. Centrifugal advance influences the power curve, while vac advance doesn't.

As for your attempt to discredit me, yes, 2 years ago I knew nothing. But I listened and learned from the brightest minds, here, and now I pass that knowledge on. You're free to ignore it, but then again, you did ask.

Matt
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post #35 of 37 Old 05-13-2013, 09:52 AM
fourbtgait
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Quote:
Originally Posted by Neuner-9R
In your thread about advance timing you're needing a lot of help, now all of sudden you know it all?

http://www.jeepforum.com/forum/f8/he...curve-1238634/

You call my advance curve off of the ported vacuum '80's' and now your posting a diagram from the 80's which uses manifold?

Read the comments below the main article from this posting:

http://www.jeepforum.com/forum/f8/ti...asics-1230121/
You could do worse not listening to Matt as well as several others on here. Sometimes it takes awhile to wrap your head around things but it helps to use google to research and back up what they say.
And two years is long enough to learn, accept things if you delve into it. With Matts help/advice at times, my CJ runs great at all rpm's, speeds.
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post #36 of 37 Old 05-13-2013, 10:14 AM Thread Starter
Neuner-9R
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Originally Posted by fourbtgait View Post
You could do worse not listening to Matt as well as several others on here. Sometimes it takes awhile to wrap your head around things but it helps to use google to research and back up what they say.
I agree. Like Matt said, I sought out his help. I wanted to give it a try to see if mine could be improved upon but it didn't, just as it doesn't work for others out there.

I have done 'google research' and there are plenty to also counter argue. Pick your side and you can find reasons. Even if you search outside of the 258 realm and into the rodders world you will see the same arguments and "internet facts" all over the place. The Smart Responses are the ones who state that you should do what is best for your setup.

Not arguing against trying Manifold since it's been proven for some setups to work better. If you did the 'google research' as well, you would note many arguments and proofs for either side. Just don't act like it's a stamp fix for it all because it worked for your setup. Don't jump down on me because I find Ported is better for mine.
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post #37 of 37 Old 05-13-2013, 12:32 PM
fourbtgait
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Im not jumping down on you and I do agree one fix does not work for all. I grew up with manifold vacumn, never realized the world transitioned to ported.
Strangest thing i found on my Jeep is that the BBD carb does not produce ported vacumn until a higher rpm which negates vacumn advance benefits at low rpm operations.
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