good news

[19Kgvw]

Good news!! I spent the weekend working on the truck..... it was fun. I relocated my pyrometer thermocouple to the pre-turbo location, I was always a little nervous of the error factor in running the thermocouple post turbo. And... ..... I installed my factory tach (been waiting two years to install) onto the steering column... I fabricated a bracket for the install, works great but covers up the high beam and the lower quarter of the petro gauge, I can live with it. I figure that I'll get flashed if the lights are too bright.



Enough of the I TRIED TO BY-PASS THE CUSSING FILTER chat... ... . here's my questions---



1-- when hooking up the lighting power wire for my boost gage, should the wire go directly to the dimmer screw of the headlight switch or is there a better spot to attach the gauge bulb wire too???

2-- when the truck is loaded, I've been driving the power curve by EGT level and boost gauge, dropping a gear when the EGT got to high or the motor wasn't making any boost... ... . now that I have a tach and can judge the torque curve by RPM, at what RPM will I make max torque and it's non-productive to over rev the motor?? I'm thinking that the torque curve has changed due to modifications I made, but I thought max torque (stock) was about 1800 rpm. I could be wrong on the rpm for torque... ... . I couldn't find a chart.



thanks again for the help, Rich

 

[CrewCab]

1. I hooked it to the radio wiring as it was handy.

2. You wouldn't want to shift at 1800 as you would have no torque in the gear shifted into. When pulling, I usually take it up to 2500 to max to assure it falls into pulling range in the next gear up. Without a load, you can shift at a lower point, say 2200 as you don't need the power in the next gear. I believe it is not advisable to lug the engine and you can't over-rev it so shift at a higher rev.

Terry

 

[JLEONARD]

I hooked into the light for the ashtry because that was handy fro me.

 

[JFitzgerald]

1. I tapped into the fuse for the dash lights. Just make sure you're on the fused side of the fuse, not the side that's still hot if the fuse blows.



2. Here's a link to the stock torque/HP graph for '93. I agree with CrewCab. When I'm towing, I rev higher before shifting so you can be making some power when the rpm's drop into the next gear. Otherwise, it's all smoke, low boost and slow acceleration. Turning up the governed speed and advancing the timing helps it pull through the gears much better than stock. I don't have a tach to give you readings from, I just go by feel.



Got any more factory tachs?

 

[19Kgvw]

1--------hooking up to the fuse, is that where you can use those "T tabs" for easier tapping ability??? and... ..... how do you know which is the "fused (down stream??) side of the fuse??



2-----that's the graph I'm looking for (even though the color for the data points is opposite), it looks like 2100 to 2200 rpm is max but I agree to rev higher so that the engine has some beans to pull the load and has a ability to build rpm!!



thanks..... no other factory tachs, there was some postings a couple years ago and I called a dealer in Arizona... ... . his computer said he didn't have any in stock but when he checked... ... low and behold---- I got lucky!!



I'm a certified "diesel head"!

 

[JFitzgerald]

Fellow Dieselhead,



1. I think someone may make a special tap like you're talking about. I know they do for the spade terminals, but not sure about for the fuseholders. If you have a 12 volt test light or a voltmeter, pull the fuse and check which end of the fuseholder has the voltage. You may have to turn the lights on, can't remember. You want to tap the side without voltage, so the fuse will feed it unless it pops. I just stripped the wire longer than normal and put it between the fuse and fuseholder. Not the best method, but for that low current draw, it's fine.



2. Yeah, I saw they reversed the red and blue. I'd have to guess I'm revving to ~2500 or a little more when I'm really trying to accelerate with the 12-13,000 lb. trailer.



I have heard the factory tachs are long gone. Saw one on a beat up first gen in traffic a while back. Oh, how I wanted to follow that guy home and make him an offer... .

 

[dpuckett]

19kgvw-



I always tapped my guage lights into the dimmer wire- it has been tan/beige in early 91s-93s. Take the dash apart, and right there, coming out of the headlight switch, you should find it. I used a blue wire tap (?) from Auto Zone or Wal Mart. Not sure what the technical term for them is, but they are kind of square, and have a "hole" for your wire to the guage lights to go into, and then just snap the other side on the tan wire, and close the flap. It has a metal doo-hickey that splices into the live wire. I always find a good ground, normally one of the few metal pieces behind the dash. Now that I've made this clear as mud, good luck wiht the install.



When towing, heavy, I always run it up close to the governor before shifting. (20, 40, and 60 mph into 3,4,5, resp. w/4. 10) Lets the engine breathe a little more, and keeps me from lugging the 250K Getrag in the next gear.

 

[phillips5]

When I am pulling hard I run up against the governer mine is set at 2800. When empty and want to gain speed kind of swiftly I mite go to 1900. If I am putting around I mite shift at 1500 and bearly push the pedal to gain speed. I remember a bulliten from cummins it said never lug hard under 15-1600 for more then 1 minute. They say lugging means full metering . I say lugging means anything over 3/4 metering.