Thread: Lack of power even after mods

For accuracy, exactly what gearing was changed ? Disco tc or diff , disco tc is higher not lower gearing.

I'm not convinced its the tc if its a disco 1.22/1, my stock 300tdi with auto and 32's pulls quite well but some of that is the auto.

1.22 transfer. Sorry, I always say lower as it lowers the revs.

Originally Posted by BigBlackDog

Do many people run these boost tee roverrescue? Looks like a really good thing, I'd never heard of them until 5 minutes ago. Did some research, I like! Not till I get a boost gauge on though
Sorry, any other dumb question - what is the best place to tap the boost reading from? I'm torn between the intake manifold (that cap bolt at the back) to measure what the engine is getting, or the boost line itself to measure what the turbo is actually doing. Or does it completely not matter?

Yes lots of people.

Best to measure boost at the inlet manifold so you know what is reaching the engine.

Originally Posted by omy130

I've always thought it was a fuel pressure thing. Blknight - how would you check the pressure? I was going to try to make something to check this weekend. Filter is new.

Did drop the fuel tank, blow lines out and put new lift/fuel pump on before original post. Did this as thought not enough fuel in filter when bleeding air out. Same outcome with new pump fitted.

Also was going to look at std versus non genuine fuel filters in relation to opening/holes that would limit flow. Unsure which is on at the moment. Have a tonne of stock bought from people with old 200tdi parts.

MR did not do the timing belt. And doubt they would pull the cover off the check internal timing marks were correct. They did check the timing externally.

The lower gearing came witht the car, then performance mod were added. A note on this, there is more than one disco owner running Tyres at least 31" or larger without the woes I'm experiencing. Unless the diff ratios are different between the 2 makes, I can't seem to nail this one yet.

This is not the first defender owned. Had built a 300tdi defender up to great performance over a 10 yr period before a 'slight' rollover with it being written off. So when getting this one sorted, it should have just been case of buy parts, mod and then it 'should' go better. But not to be. But I'd do have expectations and need to see them a lot quicker that the 10yrs it took for the last defender.

Have you turned up the boost yet?

Originally Posted by omy130

I've always thought it was a fuel pressure thing. Blknight - how would you check the pressure? I was going to try to make something to check this weekend. Filter is new.

Did drop the fuel tank, blow lines out and put new lift/fuel pump on before original post. Did this as thought not enough fuel in filter when bleeding air out. Same outcome with new pump fitted.
is it possible there is air getting in then?

Also was going to look at std versus non genuine fuel filters in relation to opening/holes that would limit flow. Unsure which is on at the moment. Have a tonne of stock bought from people with old 200tdi parts.
potential there but less likely to be your issue

MR did not do the timing belt. And doubt they would pull the cover off the check internal timing marks were correct. They did check the timing externally.
does it blow smoke? revs not climb (or take ages to do so) beyond 2500 - 3000? there are a few hints that timing is out that MR would not likely ignore. whip the cover off and have a look, for peace of mind sake, if you have time

The lower gearing came with the car, then performance mod were added. A note on this, there is more than one disco owner running Tyres at least 31" or larger without the woes I'm experiencing. Unless the diff ratios are different between the 2 makesno, same, I can't seem to nail this one yet.
this is entirely subjective, I absolutely hated my disco on 32' tyres and stock gearing - hill starts required way too much clutch slip. most drivers who are ok with it have auto's, the torque converter compensates nicely, and lets not forget the weight difference between a disco and defender is not in your favour. we can put this to bed tho, how does it perform in low range?

This is not the first defender owned. Had built a 300tdi defender up to great performance over a 10 yr period before a 'slight' rollover with it being written off. So when getting this one sorted, it should have just been case of buy parts, mod and then it 'should' go better. But not to be. But I'd do have expectations and need to see them a lot quicker that the 10yrs it took for the last defender
and right you are, it'll just be that one little thing making everything else you have done not live up to its potential

Stick with it.

Bigbnlackdog,

As Ben mentioned they are quite common and on a 300 where the wastegate rod is a "quadrauple jointed 4 year old wrists" job to get to they are very handy to enable accurate boost adjustment.

The Dawes or needle valve is placed in between the boost source of the turbo and the wastegate actuator. From stock my wastegate was opening at 13psi, I now have it open at about 18-19psi. As mentioned before on low load high throttle inputs (think PDR cruising at 100 off throttle for a dip road seed down to 80 then apply full throttle) the boost will climb higher than that but under full throttle full load (up a slight incline in 3rd or 4th for example) the gate will open at about 18psi.

I see no good reason to measure engine boost at any location besides the manifold. A 300 manifold already has a blanked casting at the rear just asking to be drilled and tapped for a boost sender.

Back to the original problem. I assume simple things like the boost line to the FIP aneroid has been checked for integrity. I would imagine that if you dialed a 300FIP nicely at idle but then never fed it boost to move the aneroid diaphragm at higher outputs it would
"seems to be lackluster in the top end"

I think you really need to go with first principles as Dave said:
-Fuel supply at high throttle is a possibility
-Timing is a possibility (check plunger lift for 100% certainty - this can be done without removing anything from the front of engine)
-Boost leaks
-FIP and Aneroid integrity / settings

Steve

Thanks roverrescue, great information.
I can confirm that if the boost line leaks then it performs rubbish in the higher power. There is a rubber reducer just off the turbo, mine split on the highway. Hisses quite loudly too, so you know something obvious is wrong

Couldn't increase boost by turning actuator rod. So wired waste gate shut and still nil increase in boost pressure at inlet manifold. Now going back to original turbo to chase lackluster issue. Should have swapped turbo results this arvo, all depending on 2 snapped bolts so far.