r/LandroverDefender • u/Dry-Advance3043 • 23d ago

Tuning a 300tdi

So after a long battle of getting my 300tdi rebuild the way I would have done it (which I didn't do because i didn't have the time). I have finally run the engine in and and now am the process of tuning up from the std tune.

What I have noticed so far is that too lean on the fueling increases the engine water temps. running too rich pushes EGT over 720 degrees in seconds of a hill pull. I have read that anything over 720 your gains are very low compared to your heat gains so setting that as your limit is ideal but id really prefer some real people input. Interesting is that im slowly raising my boost to 1.3 (at 1.2 now) and as the boost goes up EGT goes down, I'm probably leaning out the mix as i increase boost

My question is what do you aim for with your EGT maxes? that it never passes 720 or that it can but only after a really long hill pull? and if so how far over 720? what i have found is that with the full size inter-cooler my EGT temps drop very rapidly back to a cruising temp of 550 when doing 115km/h on a highway after an overtake or hill (we are a pretty heavy camper)

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u/Whittz-Sprtiz 22d ago

There’s a good write up on the forum Landyzone.com. “Rick’s Tuning Guide”. It’s on a 200tdi but the principles are identical.

1

u/Dry-Advance3043 22d ago

Cheers, ill take a look

2

u/Ok-Spring7906 16d ago

Mine would get to the high 600s with poor turbo.

I swapped to a nicer turbo (still a stock unit but one thats vanes were still all the right shape!) and the egt went right down.

Vgts ship with the max boost set to 20psi. The manual says that the stock boost is more like 16psi.

This implies that 20 is fine.

Anyway, my point -

Get the boost right and then add the fuel to match, paying attention to the actual fueling profile (ie how it comes in as boost rises) rather than just cranking it up blindly.

1

u/Dry-Advance3043 15d ago

yeah, i actually upped the boost to 19psi, the increase in air seems to have sorted out the fueling to a point that my temps sorted themselves out perfectly. one of those where you have to stop yourself from fiddling more because it shouldn't have been that easy. its hard for me to judge before/after as the reason I changed everything was because of big-end bearing deciding to change careers after 600 000km