anyone made a idi pulling truck?

[rip van sparky]

Lowering the compression ratio doesn't exactly add more boost. What it does is increase the volume of the combustion chamber. Therefor your turbo will fill a much larger area to the same pressure as before. You will then have a lot more fuel and air expanding (burning) in the same displacement. You are burning the same amount of air/fuel as an engine would be that has a much larger displacement. That is the reason you have to lower the comp ratio to be able to take full advantage of the turbo. The powerstrokes and cummins have 17 to 17.5:1 comp whereas our idi's have like 21?:1. If we were to put as much air as they do in our engines they would simply not be strong enough to keep from blowing apart from the pressure. If you enlarge your combustion chambers to the same size then you could put the same amount of air/fuel in them as high perfomance diesels do (in stock form). The problem is that do to the design of our engines it is almost impossible to get them to start at 17:1. I would think that moderate lowering of the compression ratio to say 19 or 20 would give significant gains in power and still be possible to start. Time and money is all that it would take to find the ideal combination.

 

[Agnem]

I can appreciate wanting to go out and have fun, but going out on the track and getting completely embarrased is not fun. I've watched too many guys do it. They show up with street tires, no locker, and go down the track with 1 front wheel, and 1 rear wheel spinning. Then they get to the end, start bouncing, and SNAP! There goes a U-joint, and the shaft comes flying around banging the heck out of everything. Traction is good, but too much will kill you also. You need RPMS! Speed is essential early on. Once the weight transfer box crosses the point where the pan comes down, that's where everybody stops. Speed and momentum can carry you the extra 6" to 3' needed to beat out the other guy. Since you need RPM's, you need a clutch that will take the heat and engage with enough force to hold. I'm told you can get a slipper clutch for these. A slipper clutch is like a centrifugal clutch that you can also disengage with your foot. Multi-plated and stout for pulling, it's going to last many pulls, where as a factory clutch may be getting swapped out before every show. The combination of RPM's, Gearing, and traction is what it's all about. You gotta keep the traction down so you can spin all 4 wheels to get the speed early on, and then still have enough grip to pull hard when the weight comes on. You might try contacting some of the pro pullers and see if they have any tires that are too worn out for their rigs. They would probably have just the right amount of tread for you.

 

[LUCKY_LARUE60]

Mel you are right to a point about wheel speed, the trick is NOT to spin the tires but get the speed to carry the sled. I have gotten out of tractor pulling but when I was pulling I would try to start the sled moving by slipping the clutch ( I ran a metalic clutch, the hotter it got the better it hooked up) and as the sled started to move then I would fully ingage the clutch and lay into the power untill my engine came to full power (red line on tach) but try to keep the wheels from spinning. It is a very big balancing act and if you are running an engine with small power spinning the wheels will come back to bite you at the big end. Another thing you have to concider while pulling is setup, if you don't have the right setup you are gonna spin the tires sooner and then you are done. If everything is right "YA GOT HER HOOKED UP = FULL PULL"