Thread: 300tdi power boost

hey mate,

recently on mine i started little cheap mods. the first thing i did was to help the breathing. changed the air filter and got a straight though exhaust. i kept to a paper filter and nothing k&n fancy. in my opinion those can let fine particles in. my exhaust system has a can in the middle which is hi flow and nothing on the rear. helps with exit angles as the pipe is tucked away nicely and doesnt catch anything. the middle can is protected as well from structural beams etc. I think its a good design. the exhaust guy that did it for me has plenty of experience with landrovers. its basically the same thing as a mid muffler removal except the other way round. in mine it dramatically increased the driveability. runs a lot smoother.

i also just recently tuned the low end fuel adjustment on the pump. i havnt done the full tweak as i dont have an EGT yet. that helped a bit too.

last weekend i readjusted the valve clearances. that helps too if yours are a bit out and i also pulled out the injectors and cleaned them and put new copper washers (as some were leaking). if yours has done 400k maybe the injectors could use replacing or testing at least. most diesel places test for free.

for those mods i did, the power increase is marginal but it sure runs a whole lot smoother and is nicer to drive. i think once i get an egt i might invest in a better intercooler and then tweak the boost on the injector pump. i think those should create more noticeable power.

all very worthwhile though. just read the fuel tweaking instructions very well and remember that it could be detrimental to your engine if overdone.

I was emailed the following attachments which chart the PRE & POST EGTemps.... There seems to be a max difference of just under 200 (175). There is also one for the Probe at #1 and then PRE Turbo & then POST

This was done via having 2 Probes.... I thought it was very interesting at least......

rob

Originally Posted by isuzurover

Pre turbo the highest you even want to see is 750oC. That is also the max EGT value given in the isuzu manual for the 4BD1T.

Post turbo you have no way of accurately calculating EGT, as the turbine takes variable amounts of heat out of the exhaust flow depending on how hard it is working. So as I said the numbers post turbo (lets say at 750oC pre turbo) will be anywhere between 750 and 450.

Those using post turbo EGT probes usually assume a safety factor of 250-300oC (i.e. tune to max EGT of 450-500) however they have no way of knowing what the real values are.