Performance Tuning 80 series Diesel Engine

crazy clark here is a useful write up for you- http://lcool.org/technical/80_series/1h … p_adj.html

This info applies for a 1hdt also. Is your old mans truck a 12 or 24 valve. My 12 valve auto I used to own was exactly like what you explain, could hardly even break into a roundabout it was so sluggish. Its the offboost characteristics that do this. I took it to wopass and he transformed it very quickly into a completey differant truck, it would launch off the line even with a big trailer. Take note of the bit in the link talking about turning the wheel under the offboost comp. We turned mine 5 clicks but its totally up to you and depends where your starting point is also. This is the adustment that makes the big differance. Its quite fine and hard to feel so be carefull and take your time remembering what you have done. Take small adjustments and then drive. You will know when you have it because all of a sudden it will be a very differant truck. I also bought a 4wd bits intercooler and upped boost to 16 psi and gave the mainset a little bit more fuel. I have found on my 24 valve that I now have, that simply removing the emmisions stuff and installing an intercooler it has had much the same affect, as the 24 valve model comes with emmision gear that the 12 valve doesnt. The emission gear controls to some extent the offboost, therefore removing it makes a very noticable gain, easiest way to get rid of it is contact warren and buy a top mount. Either way I recommend intercooling. If you have the 24 valve model remove the emmision gear before you adjust anything, you may not need to. Its good he has a 3 inch exhaust that will help with egts. The aim of tuning is to get a puff of black smoke offboost, but it should clear once its making full boost. Lots of black smoke at full throttle is not what you want. Remember that high egts are bad, having said that small offboost adjustments are pretty safe on these engines and have run mine hard for years, dont be too gready on the main set adjustment screw only give it a little, and if you up boost you will want a 1/4 to 1/2 turn on that. Here is another link just look at the photos shows what to look for http://www.tlocuk.co.uk/forums/viewtopi … a75d7e12e5