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2000+ stall speed torque converter? I need some advice...

Discussion in 'The Garage' started by Topdown, Jun 18, 2003.

  1. Topdown

    Topdown 1/2 ton status

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    When I built my engine, I built it with the specific purpose of High RPM fun... Sand, Mud, Etc... I dont crawl rocks. So, Comp Cams recommends a 2000 - 2200 rpm stall for my TC... I was told by the tranny guys that in something as heavy as my blazer thats the last thing I want to do. Though I believe he was thinking that I do the slow crawl stuff.

    So, for those that run something similar or have run something similar, whats your opinion? Good? Bad? Thoughts?

    I am going to the tranny place today and need the input.
    /forums/images/graemlins/1zhelp.gif
    Thanks
    -Ryan
     
  2. DesertDueler

    DesertDueler 1/2 ton status

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    2000-2200 rpm stall will be fine if you have a few things in order first. First you need an external tranny cooler. The next is you need to gear your truck so you are constatly over the 2000-2200 rpm mark. If you are not, the converter allows slippage and creates alot of heat, which will burn your tranny up quick. So you need to fiqure out what size tires you are going to run, and match the gears so you are atleast in the RPM range at about 45-50 mph.

    Dan /forums/images/graemlins/k5.gif
     
  3. Topdown

    Topdown 1/2 ton status

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    ok... so I will be running 32's with 373 (1900 range @ 50) for the next couple months then I will be going to 4.10's... but that still only puts me in the 2100 range @ 50mph... hmm...
     
  4. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    Ive got a 2300-2500 stall and i love it. I got 33's with 3.73 and it works fine I havent got my other tranny cooler yet but it hasnt burned the fluid or anything yet on it. As far as i can tell everything is working just fine. I did build the tranny up with new pumps, heavy duty sprag, red line race clutches, shift kit, all new hard parts. /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif www.zombieoffroading.8m.net
     
  5. Sandman

    Sandman 3/4 ton status Author

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    I ran a 2400 for a few years and loved it. It does suck in the rocks though. I pulled it because I started getting tired of mud and getting into rocks.
     
  6. Blue85

    Blue85 Troll Premium Member

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    First of all, don't get confused by the term "stall speed". Just treat it like what it is: a relative term for the amount of slippage/torque multiplication. A 2200 rpm stall speed does not mean that your engine has to get to 2200 rpm before anything happens. The rating is based on a certain torque to get a difference of 2200 between the input and output of the converter. The higher the number, the greater the torque output of the converter and the higher rpm your engine will be at while delivering a certain amount of torque with the same tranny input speed. Power is work and since the engine is at a higher rpm and the same torque, it is doing more work. Since the tranny input is at the same speed, the torque there has to be greater. This is similar to a gear reduction effect.

    The only problem is that it's not very efficient. That extra slip translates to a lot more heat. If it is a lockup converter, then on the highway it behaves identical to a converter of any other stall rating. When you are launching, the higher stall converter will pump out a lot more heat. The higher stall also makes compression braking even worse than it already is with an automatic transmission. For drag racing, sand dunes and mud bogs, it is a good idea. For fuel economy, rock crawling and hill descents, it is bad.

    You need to have the torque converter matched to the power band of the engine. The heavier the vehicle, the lower the stall rating needed for the same powerband.

    I ran a 2000rpm converter for a while and it was OK. It improved the acceleration a bit, but for overall performance in a variety of conditions, I think the original choice of stall speed was pretty good.
     
  7. 1972Blazer

    1972Blazer 1/2 ton status

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    I just got a reply back from TCI on the transmission in my 72 Blazer. With the cam profile and the type of driving I do (Daily Driver and Sand) they used my cam profile and recommended using their Truckmaster Transmission ("K" case with 2.79 first gear and manual automatic valve body) and a Torque Converter with a 2600 RPM Stall Speed. This is their reply:

    For the trans use our truckmaster # 311610, this is the 350 for the 205 transfer and has the 275 low gear set installed . For the converter since you do drive the truck I wouldn't go too high on the stall although your cam can stand a pretty loose converter. Use the # 240901 for about a 2600 stall This will let you drive the truck and still have excellent off road performance ThankS WIll
     
  8. Topdown

    Topdown 1/2 ton status

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    good info... Thanks /forums/images/graemlins/thumb.gif. I think I will go with the 2000/2200 TC. I would like more/better acceleration...

    -Ryan
     
  9. ntaj*ep

    ntaj*ep 1/2 ton status

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    I have no input on the subject other than I want a side by side comparison at the dunes............ /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  10. 1972Blazer

    1972Blazer 1/2 ton status

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    That is one of the first things I will be doing when I get it back out of the storage and finish the Paint and few other leftover mods. I used to drive the blazer every day till I pulled it apart for a new motor, which turned into a full blown restoration. It is amazing how everyone in a truck big or small always squares up on the Blazer. It is like they are using it as a toll to see how much testosterone their vehicle has. So I cannt let them win can I?
     
  11. Topdown

    Topdown 1/2 ton status

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    Exactly... thats exactly how I feel every time I drive the /forums/images/graemlins/k5.gif The only trick now is to get it running right again and get it back on the road /forums/images/graemlins/confused.gif

    /forums/images/graemlins/thumb.gif
     
  12. Topdown

    Topdown 1/2 ton status

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    Ok... after reading for hours and hours it seems that most people have no fricken idea what the stall speed is about. Fortunately the internet is an ever flowing well of knowledge... the fountain of youth for ideas, knowledge and exuberance. Unfortunately there are just as many dumb-a$$ people posting crap they have no idea about as there are reputable folks that do.

    So, after searching through the ones that do versus the ones that dont, I think I found the answer to the question: Do I need a non-stock converter and if so, how high a stall speed? Well, the answer is: Maybe. With the Cam I run (224/230 duration @ .050) and the 1.6 ratio rockers add in the high-flow heads, I should need a converter with a stall of roughly 1000 over stock (stock is roughly 1200 - 1500 rpm). So, I would need a stall speed of 2200 - 2400 rpm. Now, assuming that I crawl rocks, a 2400 rpm stall is bad juju, generates too much heat. But, since I dont do rocks, (just dont take me back to tijuana) just street, sand & mud, the 2200 - 2400 RPM stall will work well for me... good strong starts and strong mid-range.

    Phew... damnit, I never wanted to know this much about transmissions and torque converters. Ignorance is bliss, and I am the happiest fat man on the planet.

    Thanks for reading along...

    -Ryan
     
  13. Topdown

    Topdown 1/2 ton status

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    just checked your pics, looks good /forums/images/graemlins/thumb.gif. How do you like your Pro Comp tires? I have heard they are loud but have never heard them personally. How do they compare to a BFG MT? Just curious...

    Thanks /forums/images/graemlins/thumb.gif

    -Ryan
     
  14. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    I love these 33in Xterrain's they havent let me down or the ppl i have pulled out. On the road they arent too loud. Once i get my 6in susp. lift ill get some 37in xterrains. the tires on dustins yota are pretty much BF MT's and i have gone thur where he got stuck in his 6in lifted Yota. They like to dig and grab and throw roosters sky high so cleaning them is easy. They are almost like a bogger in the design but last a lot longer. 40-50,000 miles. Get some today!! /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif www.zombieoffroading.8m.net
     
  15. Blue85

    Blue85 Troll Premium Member

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    I have never had BFG MT, only ATs, so I can't really compare. The tread patterns are basically identical, so it would all have to come down to wear characteristics. When my Pro Comp MTs were new, they were quiet. This continued after my first tire rotation. On my second tire rotation, I reversed direction (diagonal cross) and ever since, they have sounded like an MT. It was clear at that point from looking at the tiny shallow siping that the wear was happening mostly on either the leading or trailing edge of the lugs (not sure which), which explains increased noise from going the other way. I had nieve hopes of the noise decreasing again as the wear balanced back out, but as everyone knows, tires never get quiter again once they are loud.
     
  16. Blue85

    Blue85 Troll Premium Member

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    [ QUOTE ]
    Xterrain's ... They are almost like a bogger in the design

    [/ QUOTE ]
    Hard to see the similarity. The X-terrain is more like a radial Baja Claw, with wider lugs. A bogger is split down the middle with dual paddles on each side. The X-Terrain is a Chevron design, with the split staggered from side to side. The bogger has much deeper lugs and a higher void ratio. I'm not saying that X-terrains are not good, they just really can't be compared to boggers.

    But we are off topic now... /forums/images/graemlins/1zhelp.gif
     
  17. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    Umm yes which is why i said Like a bogger and not a bogger....... yeah they are like a BAJA but not a baja.....they are in a class of there own........
     
  18. Blue85

    Blue85 Troll Premium Member

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    You're right. Both tires are round and black. But that's where the similarity ends. One is bias ply and the other is radial. Totally different tread patterns. The X-terrain has more in common with a BFGoodrich long trail T/A ( /forums/images/graemlins/rotfl.gif) than it does with an Interco Super Swamper Bogger.

    I hate to continue on this pointless, off-topic conversation, but I am getting the sneaking suspicion that you work for Pro Comp, Cooper or 4WPW. /forums/images/graemlins/thinking.gif
     
  19. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    Ummm no Damn i wish i could draw a pic on here..... SO anyways if you look at the paddle type looking tread design of both the tires youll see that they kinda KINDA Look alike ONe is chopped up more with tire siping and what not and different lug design and Totally different tread depth and different RUBBER compound.... See they both go the same direction so they are kinda alike We both Win by saying Sure they both go the same direction so they are kinda in way alike....
     

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