Thread: TDi 300 & Turbo Lag

yep, that will help, many go to 75mm pipes.

have you tweaked the fuel pump at all ?

it made a very nice difference to mine...

G'day Incisor

I've not done the fuel pump yet. I'll mod the exhaust to the outlet id of the turbine and see what difference taht makes

I have a stock exhaust (soon to be 76mm) on the disco. I don't notice turbo lag.

Why are your revs below 1700 rpm in 5th accelerating up an incline?

I would be in 4th in that situation.

Adjusting the injection pump only costs a little time and will give good performance.

My guess is that you will still have to adjust the pump to realise any benefit from a larger exhaust. And certainly to gain the performance to justify the $$.

Originally Posted by Stevo_62

G'day Incisor

I've not done the fuel pump yet. I'll mod the exhaust to the outlet id of the turbine and see what difference taht makes

The outlet on the disco turbine housing id is 56mm, same as the exh pipe on my disco when I bought it (AFAIK it is a stock system).

Just for my 5 cents worth,
The dreaded 300tdi goes slow up hill problem.
I think my first post on the previous site was titled 'my discovery is a slug' or words to that effect. 2 1/2 tonnes of vehicle pushed/ pulled by a 4 cylinder 2.5 litre motor.
I think nissans in the 3lt and 4.2lt are 6 cylinders.
my first 4wd was a lada niva the most capable 4wd i have ever driven, aside from going under water very little would stop it,even when loaded to the hilt. But then I too was possessed by the 'it won't go up hills problem',changed over to a webber carb, then a 2' exhaust system. made a better noise but thats about it.

I stopped further midifications when a mate of mine brought me down to earth by pointing out the little 4wd was like a little truck, so henceforth you drive it like a truck. Meaning, it goes fine on the flat, but just wave to people in cars as they overtake you going up hills.
While i was a bit possessed when i first got the disco, i was comparing it to the pajero, that I had as well, same size motor turbo deisel but about 700 kg difference in weight, but it too was no gazelle up hills.but quicker than the disco.

If my little blurb has bored you i apologise, but my point is they are no speed machine, so i think they should be driven accordingly. I don't believe adding and subtracting engine and ancillary parts to make them go faster is worthwhile.
other than that good luck

john

G'day John

Thanks for your ten cents worth. I agree with most of what you have written. I'm really not interested in the speed as I feel that in that area given its a 2.5l and it weight in at 2.180T it does very well.

What I'm really keen to remove is the 2 - 4 second lag at the bottom of the torque curve. I have a gut feeling that reducing this as much as possible will contribute no end to its long term sustainability in my possession and I also suspect it would reduce the wear and tear on the drive train as well.

For me its all about making it smoother.

Originally Posted by JohnE

Just for my 5 cents worth,
The dreaded 300tdi goes slow up hill problem.
I think my first post on the previous site was titled 'my discovery is a slug' or words to that effect. 2 1/2 tonnes of vehicle pushed/ pulled by a 4 cylinder 2.5 litre motor.
I think nissans in the 3lt and 4.2lt are 6 cylinders.
my first 4wd was a lada niva the most capable 4wd i have ever driven, aside from going under water very little would stop it,even when loaded to the hilt. But then I too was possessed by the 'it won't go up hills problem',changed over to a webber carb, then a 2' exhaust system. made a better noise but thats about it.

I stopped further midifications when a mate of mine brought me down to earth by pointing out the little 4wd was like a little truck, so henceforth you drive it like a truck. Meaning, it goes fine on the flat, but just wave to people in cars as they overtake you going up hills.
While i was a bit possessed when i first got the disco, i was comparing it to the pajero, that I had as well, same size motor turbo deisel but about 700 kg difference in weight, but it too was no gazelle up hills.but quicker than the disco.

If my little blurb has bored you i apologise, but my point is they are no speed machine, so i think they should be driven accordingly. I don't believe adding and subtracting engine and ancillary parts to make them go faster is worthwhile.
other than that good luck

john

Your kidding right?? if you can get significant gains in power for no cost and a little time, you shouldn't bother??

ADrian,
I'll have a play while I'm fitting the other bits if you like, I can't let you watch,or i'd have to kill you....
Small pump mods are all that is usually required. Especially if you want smooth bottom end and aren't wanting heaps of top end, the exhaust mods will help there but not necessarily at 1700 rpm.
The only other way is to source a turbo with a higher A/R ratio exhaust housing, giving heaps of gas speed low down, but these generally upset the revability as the housing becomes restrictive at high gas speeds.
I have seen some huge performance gains down low with the Tdi, BUT, this has come with a bit of initial smoke as the fuel gets injected early to aid quick spoolup. After the boost comes in though, the smoke dissappears and the EGT's drop off. Makes them behave like a 4 litre engine though....


JC