how to adjust shift points.

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how to adjust shift points.

Postby critter » Sun Jul 20, 2008 2:07 pm

how do i adjust the shift points in a turbo 350. i know it involves the screw inside the vacuum modulator, but which way and how far do i adjust it?
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Re: how to adjust shift points.

Postby Rickracer » Sun Jul 20, 2008 3:11 pm

Clockwise raises the shift points, I'd go 1/8 to 1/4 turn at a time. 8)
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 12:39 pm

Rickracer wrote:Clockwise raises the shift points, I'd go 1/8 to 1/4 turn at a time. 8)

Probably bringing back an old thread but it's better then starting a new one. So, is there any rule of thumb for a starting point for the screw? I pulled the screw all the way out today because I thought it was suppose to take an allen wrench and the wrench got stuck in the vacuum port so I had to take it all the way out to get the wrench out. Once I saw that it was actually a flat screw driver I reinstalled it and screwed it in pretty well, maybe too much,LOL.
Is there any kind of "go 6 turns in from flush with the modulator" kind of deal or is it mainly trial and error just adjusting it and driving until you get it to where you want it.
My trans was shifting way too soon, heck I'd be in 3rd almost off of the line at 20 mph. I'd like it to hold until at least 1500 rpm before it shifts to the next gear.
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Re: how to adjust shift points.

Postby Rickracer » Sun Jul 04, 2010 12:47 pm

There's gotta be a nominal setting on them Frank, but I'm not sure what it is. One way to check would be to go ask for a new one, screw it all the way in, counting the turns, then set it back where it was, :thumbup:
Or you can just go in a turn at a time till it gets in the range you're looking for, then fine tune a 1/16 or 1/8 of a turn at a time.
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 12:54 pm

I took it for a little test drive. Getting on it like I normally would during DD it'll shift at 2K rpm and it feels a lot firmer then it was. If I go easy on the gas it'll shift at 1500 rpm and when I really put it to the floor it shifted at 4000 rpm and then shifted into 3rd when I got out of it. Seems to feel a lot better, not sure if I'm "nominal" or not,LOL, but if feels good to me the way it is now. I'll drive it for a couple days and see what I think. Thanks for the fast response, I can always count on Good ol' Rickracer to come thru with a good answer quickly. :thumbup: :thumbup: .
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Re: how to adjust shift points.

Postby excaliber » Sun Jul 04, 2010 1:03 pm

yeah, watch out for the hot exhaust pipe, when your reaching under there to adjust it, don't need to tell you how I know this. :shock:
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 1:22 pm

LOL, yep, I've been there and done that too. Exhaust pipes can burn ya' real fast and you normally hit your hand or arm on something sharp when you're jerkin' it away from the hot pipe too then you've got a burn and a cut.LOL.
It was shifting at like 1100 rpm and they were real soft, it feels a lot better now although I may back it off a couple turns just to see how that effects things or I may wait and talk to Todd about it when/if we install my torque converter and shift kit this coming Saturday.
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Re: how to adjust shift points.

Postby Nivek » Sun Jul 04, 2010 1:22 pm

If you are holding it to the floor and letting it shift on its own 4000RPM's stilll seems a little low to me. I would turn it till it at least shifts closer to 5000 -5200 if you can.
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 1:45 pm

LOL, I don't know if I was holding it to the floor or not to tell you the truth. Once I get a floor shifter in it'll be a moot point because I can manually shift up but it's hard to do with a column shifter.
I took a closer look at where the trans cooler lines go into the trans, totally JB Welded, can't even see the fittings. Hope we won't have any problems getting em' out.
Anyway, once we get the converter and shift kit in then I'll tweak the modulator to get the shifts exactly where I want em' at WOT, for now I just wanted to get em' up higher then 1100 rpm. Heck, the way it was it was shifting at around 3000 rpm at WOT, not even in the torque curve of the motor yet.
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Re: how to adjust shift points.

Postby cretecrawler » Sun Jul 04, 2010 2:18 pm

So TNFrank what is your present setting at now?? sounds pretty close to what I want too...
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 2:30 pm

I just cranked the screw that's in where the vacuum line goes in a lot,LOL. Didn't really count em' or anything. Just get a flat screwdriver and crank it in then drive it.
I guess I could go out and unscrew it and actually count the number of turns it takes to be flush with the modulator but who's to say that what mine is set at is what you'll get with yours. I'm sure differences in tolerance and manufacture would probably make a difference in what we'd get.
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Re: how to adjust shift points.

Postby cretecrawler » Sun Jul 04, 2010 2:39 pm

I'm sure differences in tolerance and manufacture would probably make a difference in what we'd get.

I am sure this is very true...
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 3:06 pm

IF I were you, I'd just crank it in a couple turns then take it for a drive. If it's not enough crank it in a couple more turns until you find the "sweet spot" that you're looking for.
I do have another question for Rickracer, can you crank em' in too far and mess something up or mess up the modulator?
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Re: how to adjust shift points.

Postby Rickracer » Sun Jul 04, 2010 6:13 pm

I've never actually cut one apart to see if there's anything that would be damaged, but the screw is generally pushing against a spring, if you lightly bottomed it, it shouldn't hurt anything, :? :?
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'93 S10 SB,RC, Comp XR276 Hydraulic Roller, Vortec head 363, 400 + hp, built 700R4, JW 2800 stall lockup converter, 3.73 posi, disc brake, narrowed 8.8 Exploder rear, LS Camaro front discs, Cal-Trac clone traction bars, Best N/A passes to date: 8.0 in the 1/8th, 12.75@106 mph in the 1/4, gonna spray it soon... :mrgreen:
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Re: how to adjust shift points.

Postby TNFrank » Sun Jul 04, 2010 9:22 pm

Thanks. I don't think it's any were near bottom so as long as it's shifting where I want it things should be ok then, right?
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Re: how to adjust shift points.

Postby Rickracer » Sun Jul 04, 2010 9:32 pm

:thumbup: :thumbup:
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'93 S10 SB,RC, Comp XR276 Hydraulic Roller, Vortec head 363, 400 + hp, built 700R4, JW 2800 stall lockup converter, 3.73 posi, disc brake, narrowed 8.8 Exploder rear, LS Camaro front discs, Cal-Trac clone traction bars, Best N/A passes to date: 8.0 in the 1/8th, 12.75@106 mph in the 1/4, gonna spray it soon... :mrgreen:
76 Chevy Vega Drag Car, TWIN TURBO 355, P/G trans w/ brake and JW 4000 stall vert, 4 link back half, narrowed 9", 3.50 gears, 29.5x10.5W ET Drags. Best time9.669 @ 139.79, Latest video: https://www.youtube.com/watch?v=S59riYn ... ata_player
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Re: how to adjust shift points.

Postby TNFrank » Mon Jul 05, 2010 2:54 pm

Took it for another drive to the store today, shifting just where I want it, perfectly. Hitting a bit harder too even though from all accounts just messing with the vacuum modulator isn't suppose to make it do that. Guess it's because the extra rpm is building up a bit more pressure or something. Anyway, I'm happy with it until I can get the shift kit installed Saturday(with any luck) when we do the Torque converter.
Also, I found Type F in the WalMart brand for $2.67/qt so it'd be just under $24 bucks for fluid. :thumbup:
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The bartender asks, "Why are you wearing a paper towel?"
"Arrr..." says the pirate. "I've got a bounty on me head!"
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Re: how to adjust shift points.

Postby superspirit » Thu Jul 22, 2010 1:10 pm

In all honestly adjusting the modulator is not the best way to improve your shift points what you need is a b & m shift point kit, it lets you adjust the govoner in the trans by changing the springs and weights it is far superior for setting shift points. part # B & M 20248 now called govenor recalibration kit used to be a shift point kit. trust me this works awesome once I had it set I could not improve performance by manually shifting this kit allows you to set exactly at the rpm you want your trans to shift at. hope this helps!
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