Thread: 4BD1T Turbo Sizing and Performance Prediction.

I was thinking a temp gauge for the intake temp to see if intercooler is doing it's job when worked. I want to do the same on mine, was thinking even those cheap digital thermometers from eBay might do the trick, just tape the probe to the intake pipe? Hope you get it sorted.

Originally Posted by Vern

What tune do you have on yours dougal, as I wonder if yours struggles like this, in particular with no inter cooler?
If I back it off to 22psi, turn the fuel screw in a bit and see how that is, may do all my tuning with the camper on though as that will be the cars main purpose.

I'm still using the T25 turbo which is a bit smaller (~10% smaller based on turbine flow) with no intercooler and I'm wastegated to 20psi. EGT tuned to hit 750C after about a minute of sustained load.
I tried this one with the wastegate blocked, hit 24psi with no reduction in EGT and power would hit a wall around 2500rpm. Wastegated to 20 (measured at the pipe into the manifold) it pulls to around 3000rpm.
I get 10psi boost by about 1200rpm if I'm horrible to it (4th gear at idle, plant foot and watch the needle climb).

My engine is factory T and has a boost compensator. But this is full open by about 7psi (needs a stiffer spring) so doesn't really affect much.
I have 20psi boost by about 1800-1900rpm. Geared for 2000rpm at 100km/h and it'll pull pretty much any open road hils in 5th without losing speed.
Comparison wise it drops all 4 cylinder family cars on hills. A current hilux (~125kw and half a ton lighter) is a bit faster uphill. I'm confident an Amarok would leave me behind in all situations.

Towing wise I don't have anything around 1 ton to compare. It's usually either light empty trailer or another vehicle which is about 3T all up. The towing speed limit here is 90km/h which makes for 1800rpm and 5th gear a bit too tall. My last towing exercise was that 300tdi rangie on a trailer at 600m altitude. Went well in 4th. The altitude made 5th quite hot on the flats.
Mine does get hot driving up a mountain range here (~1700m altitude), but my current fans don't suck enough and my factory temp gauge is a waste of time. It doesn't boil or anything, but definitely runs hotter.

For your setup these are the things I'd check.
1. Move boost gauge to the intake side of the intercooler.
2. Get an indoor/outdoor thermometer and tape the lead to the intake piping after the intercooler so you can see how hot it gets. Most of them read to about 70C.
3. A drive pressure gauge would be really helpful.

See how your boost and temp numbers into the engine compare.

From here I'd look at boost and injection timing. How advanced are you running?
It will depend on what the temp and pressures above tell us to decide where to go next.

Originally Posted by Dougal

But do you also have a restriction gauge on your air cleaner to show how much vacuum it is sucking against?

no I don't, not sure I have the space for it to fit unless I can remote fit it. Was wondering if its just running out of air

Originally Posted by Vern

no I don't, not sure I have the space for it to fit unless I can remote fit it. Was wondering if its just running out of air

Valid question, you're running a snorkle? While it's still building useful boost it might be struggling to suck. A drive pressure gauge would show this too as exhaust drive pressures will increase as the turbo works harder.

There is a fitting on the outlet tube of your donaldson aircleaner. The Donaldson Informer can be screwed straight in or on a pipe to a remote location. They use 1/8" NPT fittings, but 1/8" BSPT fittings work because the threads are plastic and push around a bit but still seal.

yeah, its just in a bad location, underneath, so I could not read it, will get one and remote locate it.
Will relocate the boost gauge to after the intercooler, I can find the right bits in the shed, i'll run both boost gauges, and get temp sensors as well and see what I can find.

Take it for a lap with out the element check the timing and valve settings and check your getting full travel on pump.Took my A4 3.0 tdi for its first run in 6 months yesterday decided my 110 was gutless noisy smelly thirsty handled like crap, vibrates and uncomfortable.Still trying to work out why I continue to drive it instead of the Audi

This is what I have so far
@100k, 14psi, 620egt, 52-54c pre inter cooler, 40-45c post inter cooler, 5th gear, slight incline

@100k, 10psi, 450egt, 48.9c pre I/c, 38.9c post I/c, 5th gear slight decline-flat ground

@100k, 10psi, 311egt, 48.1 pre I/c, 38.1 post I/c, 4TH GEAR, undulating to flat ground
@100k, 20psi, 660egt, 57c pre I/c, 44 post I/c, 5th gear, undulating with the right foot planted.

All this whilst towing my 900kg camper and a bit of black smoke

Originally Posted by Ancient Mariner

Take it for a lap with out the element check the timing and valve settings and check your getting full travel on pump.Took my A4 3.0 tdi for its first run in 6 months yesterday decided my 110 was gutless noisy smelly thirsty handled like crap, vibrates and uncomfortable.Still trying to work out why I continue to drive it instead of the Audi

Ooooh that sounds a bit hard for my pea brain. Am guessing timing hasn't been touched since 1983 as this engine only has around 100kk on it. Full travel on the pump, as in full throttle?
Am enjoying my iload work van more at the moment, and I hate that