zcar? Posted April 19, 2009 Share Posted April 19, 2009 Ok so I got my project up and going. It is a suzuki samurai with a L28 in it that is hooked up to a turbo 350 trans with a custom adapter that I made. The engine is all stock except a 2.5" exhaust and it runs on propane via a impco 425 carb with the Arizona z car intake. My problem is that it is extremely slugish driving around until like 3500rpm. The car revs up when in park just fine, but in drive with the brakes pushed in it will rev up to 1200 rpm and just stay there. the car weighs 3000 pounds has 4.10 diff gears, 1:1 high range and a 2.28:1 low range. High range I cant even drive around and low range is ok but there is not power like with the 5 speed. So should I look into getting a higher stall torque converter or try some lower gears first? im lost on what to do right now. any help is good help and I can answer any questions that can help diagnose my problem. Thanks, Jeremy Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted April 20, 2009 Share Posted April 20, 2009 You need to get a converter with a stall speed somewhere around 2000 - 2400 rpm at the torque your engine is putting out. Possibly one from a 6 cyl. Chevy. or one with a higher rqated stall speed from a V8 - say 4000 rpm stall. The less torque you have the lower the stall speed. You only have about half the torque of a V8, so you can almost double the needed stall speed for a close approximation. You can check with some of the converter companies for their recommendations.... I personally would think about putting in a 700R4 for the low 1st gear and the overdrive... Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted April 20, 2009 Share Posted April 20, 2009 I would recommend getting something stalling around 3000 rpm. Try redneck converters, call them, they build some good stuff and cheap. Around $300 delivered or maybe 325 or so. Find them on ebay alot. Quote Link to comment Share on other sites More sharing options...
zcar? Posted April 20, 2009 Author Share Posted April 20, 2009 thanks guys thats what I thought was going on, I would go 700r4 but there is not an adapter to my t-case and I dont want to buy another one. Jeremy Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted April 20, 2009 Share Posted April 20, 2009 The th350 and 700R4 have the same bolt pattern. Quote Link to comment Share on other sites More sharing options...
zcar? Posted April 22, 2009 Author Share Posted April 22, 2009 they have the same in the frnt but the output shafts are different and the 700-r4 is longer. Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted April 22, 2009 Share Posted April 22, 2009 thanks guys thats what I thought was going on, I would go 700r4 but there is not an adapter to my t-case and I dont want to buy another one.Jeremy I was only replying to your misstatement... Yes it is longer and you may need to get a different yoke, but the cost is far less than a new adapter...and you will have a very nice 3.06:1 1st gear to get that SUV rolling... Quote Link to comment Share on other sites More sharing options...
rejracer Posted April 27, 2009 Share Posted April 27, 2009 I would try Edge, Yank and Precision. Edge is the cheapest. Get a 9.5" converter for best response. Also be aware that stall speed is not the only factor to consider with a converter. STR (Stall Torque Ratio) is very important in how it feels and performs. I personally would do some research on those terms. You did not mention your tire size in your post, so it's hard to suggest ratio's based off of that. 29's and 4.10's would be fine. 33's and up and you will want more gear. Tip: Adjust the highway cruising speed with the gears. A higher stall and higher STR will just rev too much on the highway for my taste without a lockup converter. If this thing is being 4 wheeled set the rock crawling speed with the transfer case, not the diff's. Set the highway cruising speed with the diffs, not the trans/torque converter. Set the around town acceleration and cruise rpm's with the converter setup. Other notes: I would not use a high stall / STR converter in front of a transfer case as when the thing hits (assuming you put your foot into it in low range (not smart)) you will run more risk of breaking drivelines/axles. Real world stall speed is also dependent on the power of the engine. Brad pointed that out as well. High STR converters are very fun, but generate more heat, and throw's effeciency out the door up top. For your setup (this is hard as I'm basing this off of V8 experience) I would go with a 2600 to 2800 stall with about a 2.2 STR. I am assuming you are running 29" tires and don't need gears! So beware! Best thing to do is get advice from a converter builder, noting the application. Quote Link to comment Share on other sites More sharing options...
zcar? Posted April 27, 2009 Author Share Posted April 27, 2009 I have 33" tires right now. this thing is never driven on the street and hardly ever above 40mph the engine is stock so it has however much power a '78 280 has. also im not worried about breaking drivelines or axles they are very strong for what I do with it. I will call a converter place next monday and see what they recomend. Jeremy Quote Link to comment Share on other sites More sharing options...
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