Thread: 300tdi Mild performance enhancements?

I'm convinced that it is easy to be fooled into thinking that a change in the amount of power available constitutes a lot of power available.

I have seen a few instances of that over the years. When I was at uni, I borrowed a friend's step-through Honda 50 a few times and was quite impressed with its acceleration, so I arranged a drag race with a mate who drove a 1934 Chev. I had been a passenger in the Chev a few times and had never felt any burst of power.

The race was an embarrassing defeat for the Honda. The constant torque of the Chev engine was more than a match for the burst of power from the Honda when it hit the power band.

Years later when Honda brought out the two stroke MT 125, I owned a four stroke SL 125. When I rode the MT, I was convinced that it accelerated much more quickly than my SL125, so I arranged another drag race. The result was that the four stroke and the two stroke had identical acceleration. The difference was that the two stroke lagged behind while it was out of the power band and surged forward when it was got into the powerband. The surge of power when it hit the power band had confused me. The four stroke SL125 was a fairly extreme example of a constant delivery of power (even if there wasn't much power). In fact between about 2,000 and 9,000 revs, the torque never fell below 92% of maximum torque. Torque curves don't get much flatter than that.

The constant torque of the SL125 is probably similar to the torque delivery of the 4BD1T. It helps if the torque is there all the time.

A similar misconception is common in the kayaking world. I have known a lot of people swear blind that a SOF is faster than a rigid hull. They are confusing responsiveness with speed. A light SOF (or indeed any light kayak) surges forward with every paddle stroke while a heavy kayak gradually builds up speed. They might have the same top speed but the lighter kayak feels faster because you can feel the response to every paddle stroke. I have a SOF as well as my strip built kayaks and my data logger tells me that the SOF is no faster than the rigid hull kayaks with similar dimensions.

If the supply of torque is constant, it is easy to believe that there isn't much power available and if there is a surge of power, it is easy to forget that it wasn't there all the time.

First up.

move the sense for the waste gate actuator from the side of the turbo to the back of the inlet manifold.

then fit an EGT and boost gauge.

work out what its doing, then work out what you want it to do and how you want it to "improve"

in most cases most people are happy with just the result from moving the actuator sense and then fiddling the boost compensator to suit.

then its just a case of shifting the fuel screw redoing the compensator and if you cant get there with minor changes you're going to be looking at exhaust changes, timing and a bit more work.

the limit of the stock turbo is in the 22-25 psi range and your stock tune is going to be in the 15-17 psi range


the TD04 on a 200tdi manifold is probably one of the easist and better turbos to use and can be had as a watercooled turbo.

http://www.aulro.com/afvb/discovery-...ng-tdi-d1.html

theres the setup in mine.

Originally Posted by isuzurover

Lol. I owned a 300 and a 4BD1T at the same time. Anyone who thinks a 300 can outperform a 4BD1T is suffering from some serious delusions.
Tweak a 2.5L all you want, the 3.9L can still run more boost and fuel safely - which means more power and torque. End of story.

(I will let you all go back to polishing the proverbial now)

I can fit a 5.9 Cummins in my defender that can beat your Izuzzuu so your point is what exactly?.The guy asked a simple question about tuning his Tdi,not a ****ing contest. Pat

Originally Posted by PAT303

I can fit a 5.9 Cummins in my defender that can beat your Izuzzuu so your point is what exactly?.The guy asked a simple question about tuning his Tdi,not a ****ing contest. Pat

Pat, your responses and comments liven up the dullest thread, (not that this is) I look forward to them, very succinct, should start a sticky in your honour...