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300 TDI lack of power on hills

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300 tdi ac tdi
10K views 12 replies 13 participants last post by  mdcoa 
#1 ·
I recently installed a freshly rebuilt 300 in an 1988 Defender. It came complete with the R380 and 1:4 transfer case. Two issues, one engine winds out with a top speed of 60-65, causing the waste gate to dump. I attribute this to the 1:4 and most likely because this had a 2.5 It probably has 4:7 gears. Second issue is lack of power on hills. With the suspected gearing hills should be an issue. So it seems either lack of fuel or lack of air or both, Thoughts?
 
#4 ·
When you did the engine re-build what head gasket did you put in? Did you install a re-built turbo or the old one. Did you do anything to the injection pump? How are your air intake hoses? Did you use the factory Defender 300 Tdi set up? All of these things could be causing you to not have enough power on the hills.
 
#6 ·
I'm on my phone and not looking at a ratio calculator, but even a 1.4 with a 4.7 diff is pretty low. If you know you have a 1.4:1 TC, then swap to 3.54 diffs and cruise much faster!



However, if you hate the hills now and are rolling 4.7's, then poor performance on hill climbs is another issue......a 1.4:1 and 4.7's should climb a hill like a raped ape.
 
#9 · (Edited)
I recently installed a freshly rebuilt 300 in an 1988 Defender. It came complete with the R380 and 1:4 transfer case. Two issues, one engine winds out with a top speed of 60-65, causing the waste gate to dump. I attribute this to the 1:4 and most likely because this had a 2.5 It probably has 4:7 gears. Second issue is lack of power on hills. With the suspected gearing hills should be an issue. So it seems either lack of fuel or lack of air or both, Thoughts?
Are you sure it's lack of power on hills or lack of gearing with plenty of power... who knows?

From the factory:
The gearing of series differentials are 4.7.
The gearing of a Defender-Style vehicles is 3.54.

I don't mean to sound callus, but you need to know exactly what you have in terms of engine and gearing.
Otherwise, no one here can assist you in locating a solution.

You could have a 1.6 transfer case if it wasn't changed with the engine conversion, but based on your statements, you really don't know what you have.

Are you 100% sure the wastegate is opening and not the air intake hose collapsing and shutting down the air to the turbo?

I think you need to explain your issues in terms of what is happening.
Instead of saying "causing the waste gate to dump", you need to explain that you are loosing boost, because I ask again how do know the wastegate is dumping boost?
Did you mount a camera under the hood?
 
#10 · (Edited)
Lack of power? or will not sustain speed up hills ?
in my 130 i run a 300tdi vnt turbo, ported head and full intercooler, pined pump,r380/3.54 / 1.4 tbox ...
smooth take off power nice lane change capability
MAX cruise 72-75 mph on the flat
uphills losses anywhere from 5-10 mph all depends on the grade
i had the 1.2 box in it and up any grade was annoying 20+mph drop unless you down shifted and booted it
make sure you get a egt gauge
 
#13 ·
What everybody said. You should be able to get the SN off your T-case and figure out what its ratio actually is (IIRC the Ashcroft site has reams of information on transmissions and ratios), and you can jack up a wheel and turn it and count driveshaft revolutions and figure out what your diffs are for sure.

And an EGT gauge might help with power problem diagnoses--if you have a fuel starvation issue (due to bad lift pump or a restriction somewhere in a line or filter) that's causing inadequate power on hills, it'd reflect in EGTs that are not rising like they should on a hill with your boot in it. I just had this happen--if I hadn't had an EGT gauge, it'd have taken me who knows how long to sort out. It still took me way longer than it should've . . .

Does your fuel line by any chance run through the original gasoline fuel filter? If so, that could be causing a starvation issue right there.

For what it's worth, in my Disco I initially had the 1.4 case (which was the factory case for 300tdi defenders, but not for 300tdi discos), but hated it. I now have a 1.2 and am much happier--there's something to be said for not needing to shift into second gear until one is mostly through the intersection. And she can go 80-85 all day on the flat, which is much faster than I actually do drive, but it's nice to go 70-75 without feeling like I'm wringing the engine's neck. And there's no low range ratio difference between the 1.2 and 1.4s, so I lost nothing off road.
 
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