Thread: Raising boost on a td5

Originally Posted by sierrafery

If the snorkel's intake is toward the front it might increase the flow at high speeds in some cases(i've seen a few) so make a test with it turned back to see if there's any difference or not.

Makes no difference on a TD5. The ram air effect is essentially myth.

Originally Posted by Tombie

Makes no difference on a TD5. The ram air effect is essentially myth.

nonsense. it has an effect, just need to be going over 200 to notice it.

Originally Posted by Eevo

nonsense. it has an effect, just need to be going over 200 to notice it.

Exactly No production LR has ever seen it happen

Ok, so I got hooked up to a nanocom yesterday, warm day and readings as follows, not my bag this, so not really sure what it all means (answers in blue) ?


(for all the presented figures +/- 5% is acceptable)

MAF(air flow) = 55-60 (54) at idle growing with revs up to 600 or above at 3000+rpm (315) ... to not exceed 680 then it cuts out

AAP(ambient pressure) = real ambient pressure on barometer in kPa,(100) around 100 must drop up to 2-3 units to 3000+rpm, more decreasing of that value related to the acceleration should indicate that the air beyond the filter is less than required.

AAT(ambient temp) -only Eu3/15-16P engines = real ambient temp on thermometer

MAP(manifold absoolute prssure) = with AAP at idle growing to 230 at full load (216 @ 3,300 rpm)... TURBO PRESSURE = 1.3 at max load (101 kpa at idle)

CYLINDER BALANCE = +/- 4 is good - all Ok

IAT(inlet air temp) = AAT + 10 to 30 depending on outside temp, engine coolant temp and boost(meaured with the car's coolant gauge at middle)...also it can be much higher if non-cooled EGR is still fitted

COOLANT TEMP = 70 - 115 (80) gauge stays at the midddle, the gauge will go to red zone only at 120 and the electric cooling(aircon) fan kicks in at 110 and stops at 105... normal operating condition around 90 (91.9 after run)

FUEL TEMP = around 10 less than coolant temp (84.9)

THROTTLE
ACCEL. WAY 1 - about 0.3 - 0.8V with the pedal released, about 4.7V with pedal to the maximum position
ACCEL. WAY 2 - about 4.7V with the pedal released, about 0.3V with pedal to the maximum position
ACCEL. WAY 3 ? this track must have values very near to the second track.(only 15P-16P engines)
ACCEL. SUPPLY ? this value must stay between 4.9 a 5.1


So I am thinking this went pretty well (?), interesting that my MAF only read 315, does this mean it does need a clean ? Having lengthened the wastegate adjustor back (now 11 threads visible) I had re-attached the MAF sensor on Friday and hadn't made any noticeable change, so thinking was that it was working OK. Thinking I am not going to play with the turbo boost anymore and concentrate on saving for my re-map.


Welcome any feedback anyone has to these readings as I am totally out of my comfort zone here. Many thanks as always. Matt.

Hi, the MAF reading is very low ar high revs, at that difference i doubt that a clean could help you nless it's very dirty or there's a restiction in the intake though the MAP should be lower too, IMO a new one is required.

Originally Posted by Tombie

Makes no difference on a TD5. The ram air effect is essentially myth.

I dunno what that "ram effect" is in reality or how can it be scientifically linked to a car's intake. What i said is based on nanocom readings with snorkel intake directed both ways... the difference was between 5 - 30 units starting from around 90km/h the higher the speed was the greater the difference, made this test on 3 different td5's and one of them which was the most tuned(stage 2 with direct exhaust and boost box on std tyres) exceeded 680 at 135 km/h, swapped MAFs and did the same then topped up at 660 with snorkel turned back. I agree it's not physicaly noticeable while driving except that case when it cuts out, but the readings are quite relevant though I'll make some records next time when i'll have the chance to do that or do it yourself if you have nanocom and watch the difference

I met up with Wardy1 on Saturday who kindly linked up his Nanocom and we went for a drive, MAF read up to 600, but Wardy1 thought it was 'gutless' at the higher revs, and that must be a fueling problem, most likely MAF, we cleaned mine out, and then swapped his over and went for another drive. It was better, but did not really make the difference we were both expecting. Better than mine though.

Is there anything else I should be looking at, Wardy1 mentioned the fuel pump, but we didn't have the time to dig any deeper. Thanks Wardy1, he was a great help and more than happy to share.

Update, I cleaned the MAP sensor yesterday with contact cleaner and has made a significant improvement.


More grunt as it revs and the Disco is changing gear at different placed than usual - much happier. A fair bit of black liquid came off when I cleaned it and also the electrical connection had some oil in there. For a 5 minute job, I recommend everyone should do it !