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The ULTIMATE "Selectable" Locker System! BroughRockridge 4WD IS Taking Zone Offroad Suspension Lift Kits WJ Modular Recovery & Bull Bar Relocation Packages

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Unread 04-23-2013, 08:15 PM   #46
firemanjim7
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Quote:
Originally Posted by Matt1981CJ7

I'm thinking they may be too light.

Plotting your advance curve will confirm.

Matt
All this talk of plotting is making my head hurt. I sucked at geometry. I'm a "feeling in the seat of your pants" kind of guy. But I guess I'll have to figure this whole plotting thing out. I don't do these fancy computer plots though.

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Unread 04-23-2013, 08:26 PM   #47
Matt1981CJ7
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There's no geometry involved. Nor algebra. Nor long arithmetic.

It's simply figuring out how much total advance you have at 3000-3500 RPM.

Matt
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Unread 04-23-2013, 09:25 PM   #48
82JeepCJ7
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Since I never hit over 50mph in mine, I adjusted it to get rid of the ping and called it good.
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Unread 04-23-2013, 10:56 PM   #49
fourbtgait
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Quote:
Originally Posted by firemanjim7

All this talk of plotting is making my head hurt. I sucked at geometry. I'm a "feeling in the seat of your pants" kind of guy. But I guess I'll have to figure this whole plotting thing out. I don't do these fancy computer plots though.

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As Matt says in his next post, plotting your curve is easy to perform. Actually quite fascinating to do, just remember each dizzy/engine is different and try not to base your curve on what someone else's looks like.
I have learned a lot in reading Matt's posts, his comments, search for his thread on doing so.

Russell

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Unread 04-24-2013, 10:32 AM   #50
I6CJ7
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Hey Shawn, doing 58mph (gps) since my speedo is off from the tires. I'm turning 2000 rpms. It will pull and accelerate from there, but makes little difference whether I floor it or ease on the pedal at that speed.
I also dropped my mains in the weber from the 150's to 145's a few weeks ago for better mileage and to lean things out for the summer. It seems to like them better as well, more responsive.
I have a vacuum gauge and will try to plot my timing this weekend, as I may be heading to the big dogs offroad event.

My midrange, pulls very strong, and definitely feel the 258 torque.

Btw, my brother is now dropping an NV4500 and a 11.5-1 compression 400 sbc in his CJ7 in the coming weeks.... I'm a tad jealous..
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Unread 04-24-2013, 11:04 AM   #51
swatson454
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Quote:
Originally Posted by I6CJ7 View Post
Hey Shawn, doing 58mph (gps) since my speedo is off from the tires. I'm turning 2000 rpms. It will pull and accelerate from there, but makes little difference whether I floor it or ease on the pedal at that speed.
I also dropped my mains in the weber from the 150's to 145's a few weeks ago for better mileage and to lean things out for the summer. It seems to like them better as well, more responsive.
I have a vacuum gauge and will try to plot my timing this weekend, as I may be heading to the big dogs offroad event.

My midrange, pulls very strong, and definitely feel the 258 torque.
Refresh my memory: F7 emulsion tubes? I agree with you on the jets. 150s are just too much.

We're also working with a 110 HP engine here. Lugging that shoebox down the road on big tires, pushing 60 mph and asking it to accelerate very quickly is probably asking a little much. On mine, 1st and 2nd would go like hell. 3rd was slowing down and 4th... I don't friggin' think so, lol.

Quote:
Originally Posted by I6CJ7 View Post
my brother is now dropping an NV4500 and a 11.5-1 compression 400 sbc in his CJ7 in the coming weeks.... I'm a tad jealous..
Right on!


Shawn
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Unread 04-24-2013, 12:06 PM   #52
John Strenk
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Quote:
Originally Posted by swatson454 View Post
.....
We're also working with a 110 HP engine here. Lugging that shoebox down the road on big tires, pushing 60 mph and asking it to accelerate very quickly is probably asking a little much. On mine, 1st and 2nd would go like hell. 3rd was slowing down and 4th... I don't friggin' think so, lol.
....
I just realize my Prius has a more powerful engine than my CJ...

134HP @152 ft-lbs Torque IC+Traction motor.

Would you guys hate me if I made a Hybrid CJ?
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Unread 04-24-2013, 12:10 PM   #53
swatson454
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I just realize my Prius has a more powerful engine than my CJ...

134HP @152 ft-lbs Torque IC+Traction motor.

Would you guys hate me if I made a Hybrid CJ?
With probably half the engine size and 3 times the fuel mileage, too!
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Unread 04-24-2013, 12:14 PM   #54
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Popular mechanics converted a dodge charger to hybrid.

The put a motor between the driveshaft and yoke and batteries under the back seat.
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Unread 04-24-2013, 12:25 PM   #55
I6CJ7
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Yup, F7 emulsion tubes, and whatever air correctors you decided on. And I think I have 50 or 55 idle jets in can't remember. Idles amazing with a lean miss about every 7-8 seconds, still running the 2 range colder plugs as well.
True about the horsepower, my buddies Cbr1000 has more Hp than my 258... I'm going to hate my brother when he gets his on the road. I told him I'll have to get a slightly over bored 396 BBC, so we can battle 400 smallblock vs. 400 big block!
Of course my 258 runs so good, it'll never die lol
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Unread 04-24-2013, 01:39 PM   #56
Matt1981CJ7
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Who are these clowns at CRT, anyway?

In a PM, Jim told me CRT is now recommending he switch his vac advance to ported.

Do these jokers even know what the vac advance does, or how it operates?

Matt
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Unread 04-24-2013, 01:43 PM   #57
swatson454
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Originally Posted by Matt1981CJ7 View Post
Who are these clowns at CRT, anyway?

In a PM, Jim told me CRT is now recommending he switch his vac advance to ported.

Do these jokers even know what the vac advance does, or how it operates?

Matt
Don't you find that stuff amazing.

I'll see your and raise you a lol


Shawn
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Unread 04-24-2013, 02:01 PM   #58
Matt1981CJ7
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Originally Posted by swatson454 View Post
Don't you find that stuff amazing.

I'll see your and raise you a lol

Shawn
I always forget about the "rant/scream" smiley. That's a good one.

I'm all in with the "Dancing Salad"

Matt
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Unread 04-25-2013, 04:23 PM   #59
swatson454
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Screw CRT. Here's something you can try since you like road testing.

From David Vizard's Smallblock Chevy book:

"At this point I'll assume you have an HEI with a selection of advance springs and adjustable vacuum. The first step is to install the strongest springs at both locations on the distributor's advance mechanism. If your vehicle is a manual transmission, all of your tests can be done on a lonely stretch of road with a stopwatch. The technique involves choosing a suitably low starting rpm and timing the vehicle between two speeds. Let's assume that the motor has the potential to pull from 1,500 rpm. With the strongest springs installed, take off and have the clutch fully engaged in second or third gear at an rpm lower than the test's starting point. For example, we're working here with 1,200 rpm. Floor the throttle and time how long it takes to reach 2,500 rpm (my insert: floor it at 1,200 rpm and time it from 1,500 to 2,500 rpm). Progressively lighten up the primary spring until the best 1,500 to 2,500 rpm results." DV

Me again. I'm going to paraphrase this part because it's buried in a lengthy section on timing automatics. From here, you'd run either stopwatch trials from 2,500 rpm to redline or you could go for top speed. Increase the initial advance no more than two degrees at a time until your time or mph falls off or you hear detonation. If you hear detonation at a lower rpm, you may want to add the next heavier spring on one side of the advance mechanism and keep going with your high-speed testing. If you find out that you started your initial spring test with too much timing to begin with, you may have to pull several degrees out and start over. It's a little bit of back and forth but you can narrow it down nearly as good as being on the dyno.

Clear as mud?


Shawn
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Unread 04-25-2013, 05:14 PM   #60
firemanjim7
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Thanks Swatson. I've been alittle busy to work on the jeep lately I haven't given up on it though. Just those dumb a$$ e's at CRT.

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