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TH350 2400 Stall Questions
Hey there,
I have a rebuilt TH350 mated up to a street 355 right now that I'm having some questions about in relation to my shift pattern and also my converter...... REBUILT TH350, Stage II shift kit, 2400 High stall converter 1.) SHIFTING: I'm no expert in dealing with the TH350 or TH400 with the exception of wrecking a ton of them out of old cars......but so far as I know is the shifting patter (RPM) strictly regulated by the modulator or a combination of factors??? The reason I ask is that mine seems to shift early, or so it seems to me. I have a 3.73 rear end but I can be cruising in third at less than 20MPH.......maybe less than that. I know that first maybe lasts a few feet and second not much more unless I have it locked in manually. I'd really like to have it stay in the gears longer and I know there are adjustable modulators out there...........would that solve it? Or maybe my current modulator is shot as it wasn't brand new. 2.) CONVERTER: Once again, no expert, but I'm under the knowledge that my 2400 stall converter should not allow for a lock-up until that RPM (or close at least) with my foot depressed on the brake (power brakes)???? ----- Because right now if I mat the brakes and try to get my engine speed up before launch it'll start cranking the tires WAY before 2400. |
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Well I'll wack away at #1
You'll be told modulator and you'll be told governor, and both people are right to the tune of 5- MAYBE 10 mph. The valve body is where it lies though. My setup is a carbon copy of yours (more or less) and I governor diddled and vac mod diddled, and if it was medium throttle I could maybe have third come in at 30. Maybe,maybe,maybe. took all my B&M shift stuff I'd just put into the VB out and put in transgo stuff and did notta thing else to gov or vac mod and wam, my third at a heavy PT pops in around 45-50 mph. Nice huh. Therefore It all does not lie in the gov and vac mod. Actualy scarcely little My experience anyway. Only one tranny but God did I monkey a while |
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Converter is normal, you will never get a converter all the way to its rated stall using the footbrakes, it will always overpower them at a lower rpm and spin the tires. Only way to get it to stall all the way up is with a transbrake to hold the trans locked.
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On #2 I'm not 100% sure on why's and wherefores but mine does same.
As for #1 again,go here http://www.transgo.com/rpg_generalmtr.php get the 350 1 and 2 kit, as your installing and the parts in the VB they give you the option of orange spring for normal duty or red for heavy towing, you stick in the red and everything goes up way more than the vac mod or gov can ever give. Like triple the amount. Best money I spent since doing this. When I looked at what I got in this kit side by side with the B&M stuff I just took out I thought, he11 their the same I've been lied to again. Uh Uh their not the same. The transgo used all 4 checkballs and gave equal and firmer shifts than the B&M did with the one ball thats suppossed to firm things and like I said I can still have all the gears in by 20-25 in town but if I pull out on the highway and give a third to half throttle third is a real crisp snap between 45 and 50. frikin sexy Last edited by sooper; 07-10-2010 at 04:48 AM. |
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That is why there's a shifter. If you modify things to the point that you get shifts at, say 3500-4000 RPM, then what happens when you're just driving along at a slower speed than 4K RPM? The engine will just wind along, w/o shifting- I would think that would get old REAL quick! Instead of modifying the governor to do the work for you, invest in a good shifter and shift the gears yourself when you're feeling it. Otherwise, let it shift out where it wants to. Keep the kickdown hooked up, that way you'll get a downshift at the hit of the throttle, should someone try sneaking up on you. Plus it will wind out pretty far w/the kickdown adjusted correctly. Should you want more- use the shifter! |
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Most converter companys rate the stall speed via a big block engine putting power into the converter.
a t-400 governor will have a governor with 1 light spring and 1 heavier spring. Stiffer spring will shift 1-2 gear shift. Stiffer spring works on the 2-3 shift. Generally for higher shift speeds at heavy throttle , cut the inner weight on the governor. This works well with lower gears on the street ie: 4.11 - 4.56 If the electric is hooked to the kick down solenoid , that will extend the shift points too
__________________
At the Bonneville Salt Flats, first gear is known as 130 mph. |
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Cobalt the transgo program kit I mentioned really does do as you say or it does it auto. When it does it auto you can lunk at 25 in third or at higher throttles shift to third at 45. Either or when someone gives me the sneak I dont have to think of the leaver I just nail it,it grabs the lowest possible gear and showers him in rubber. But like I said None of that happened by diddling with gov and mod. Well maybe 10-15%. Not worth talking about. When I called the guy at transgo explaining how his kit looked like what I just took out so how the he11 should it make a difference. His reply "Just wait, you'll see" And I did see |
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In response to Sooper and Cobalt.......the info is very helpful!! Right now I do shift it manually unless I'm just bombing around town.
BUT, the transgo kit sounds about right since I'd like to be able to spool it up by mashing the go pedal to the steel and not necessarily have to manually shift. ------Sooper, if you're in second will it punch itself into first??? Mine currently really doesn't like to go second to first very much at all after it's shifted out. So when you mat it in second and you aren't really already at a decent speed it's alot slower to spool up than if it'd kick down for 10 seconds or so. |
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