Performance improvement on 300tdi.

[Wave Mountain]

So, the vehicle is stripped down, the lump is out (130,000 miles and running very soundly 2 weeks ago and has been for 5 years). 

Question : Is it worth getting some work done on the engine whilst it is out ? (i don't have time to do an engine re-build as well as the rest of jobs on the vehicle). :

The vehicle will be used daily on Cornwall country roads, lanes and tracks. No offroading, trials etc.

Any thoughts on spend versus power advantage gained by adding a full size 'Allisport' intercooler ? What other options will help with this ? (I don't want to spend out on an uprated turbo). Better quality exhaust manifold ? and tuned (better breathing) exhaust ? Tweak something in the fuel pump ? ..............or not worth doing for the minimal power gain for the £££££ expended ?

New Head Gasket ? Skim Head ? Timing Belt (yes).

 

As ever, i would be grateful of ideas on this.........thanks.

 

[Chicken Drumstick]

As ever this is a how long is a piece of string question....

 

Personally 80-90% of the gains are just by tweaking the injection pump yourself. It'll run way better and feel like it has a 100hp more (it won't of course, but it'll feel it).

Big intercooler can work well, but will certainly require it to be tweaked to see any gains. And the biggest thing it offers is maybe a little less smoke, and the ability to lay on the throttle more and for longer. PEAK numbers are unlikely to be massively different.

 

Different turbos tend to offer a broader powerband, rather than bigger PEAK numbers. But would depend on what you build it for tbh. There is no single setup here. Likewise with head and cam options.

 

For reference I have a non intercooled 200Tdi in my Series 3 and an Allisport tuned 200Tdi with their large front mount intercooler in another vehicle. My brother has a home tweaked stock intercooled 200Tdi and my Uncle has a Jermey J Fearne large front mount intercooled 300Tdi that was installed and tuned by them.

Overall there really isn't a busting difference between the lot. The front mount ones are more pokey and must be making more power. But cost a lot more too.

 

All the fancy turbo's and the like will cost you big time. And I suspect vfm and performance return will be largely minimal. I've seen some claims from guys in the US getting 200hp from a Tdi, but I've never seen any proof and no info, so I suspect it was made up BS.

If you want to look for alternative power adders, then an LPG kit and/or a diesel nitrous oxide kit could be quite interesting. Or consider a Td5 swap.

 

Essentially you could probably spank several grand in mods on a Tdi and still fall well short of a simple mapped Td5.

 

Other option would be to consider a V8's swap. If you aren't doing big mileage, the running costs will be quite similar. And frankly a good Rover V8 will spank any modded Tdi, or Td5 for that matter.

 

However, this is only my opinion. I'm sure other people will have different views.

[monkie]

^^^^Plus everyone loves the sound of a v8

[FridgeFreezer]

Before tweaking stuff I'd make sure everything's in good nick, properly adjusted, etc. etc. maybe look at getting the injectors & pump checked & rebuilt before you start just winding the wick up.

[Wave Mountain]

Thank you all for your thoughts on this I appreciate your input. Suddenly a V8 seems tempting !!!!!  Manual obviously, but injected or NA-Carb version ????

[Wave Mountain]

18 hours ago, Chicken Drumstick said:

As ever this is a how long is a piece of string question....

 

Personally 80-90% of the gains are just by tweaking the injection pump yourself. It'll run way better and feel like it has a 100hp more (it won't of course, but it'll feel it).

Big intercooler can work well, but will certainly require it to be tweaked to see any gains. And the biggest thing it offers is maybe a little less smoke, and the ability to lay on the throttle more and for longer. PEAK numbers are unlikely to be massively different.

 

Different turbos tend to offer a broader powerband, rather than bigger PEAK numbers. But would depend on what you build it for tbh. There is no single setup here. Likewise with head and cam options.

 

For reference I have a non intercooled 200Tdi in my Series 3 and an Allisport tuned 200Tdi with their large front mount intercooler in another vehicle. My brother has a home tweaked stock intercooled 200Tdi and my Uncle has a Jermey J Fearne large front mount intercooled 300Tdi that was installed and tuned by them.

Overall there really isn't a busting difference between the lot. The front mount ones are more pokey and must be making more power. But cost a lot more too.

 

All the fancy turbo's and the like will cost you big time. And I suspect vfm and performance return will be largely minimal. I've seen some claims from guys in the US getting 200hp from a Tdi, but I've never seen any proof and no info, so I suspect it was made up BS.

If you want to look for alternative power adders, then an LPG kit and/or a diesel nitrous oxide kit could be quite interesting. Or consider a Td5 swap.

 

Essentially you could probably spank several grand in mods on a Tdi and still fall well short of a simple mapped Td5.

 

Other option would be to consider a V8's swap. If you aren't doing big mileage, the running costs will be quite similar. And frankly a good Rover V8 will spank any modded Tdi, or Td5 for that matter.

 

However, this is only my opinion. I'm sure other people will have different views.

 

18 hours ago, Chicken Drumstick said:

As ever this is a how long is a piece of string question....

 

Personally 80-90% of the gains are just by tweaking the injection pump yourself. It'll run way better and feel like it has a 100hp more (it won't of course, but it'll feel it).

Big intercooler can work well, but will certainly require it to be tweaked to see any gains. And the biggest thing it offers is maybe a little less smoke, and the ability to lay on the throttle more and for longer. PEAK numbers are unlikely to be massively different.

 

Different turbos tend to offer a broader powerband, rather than bigger PEAK numbers. But would depend on what you build it for tbh. There is no single setup here. Likewise with head and cam options.

 

For reference I have a non intercooled 200Tdi in my Series 3 and an Allisport tuned 200Tdi with their large front mount intercooler in another vehicle. My brother has a home tweaked stock intercooled 200Tdi and my Uncle has a Jermey J Fearne large front mount intercooled 300Tdi that was installed and tuned by them.

Overall there really isn't a busting difference between the lot. The front mount ones are more pokey and must be making more power. But cost a lot more too.

 

All the fancy turbo's and the like will cost you big time. And I suspect vfm and performance return will be largely minimal. I've seen some claims from guys in the US getting 200hp from a Tdi, but I've never seen any proof and no info, so I suspect it was made up BS.

If you want to look for alternative power adders, then an LPG kit and/or a diesel nitrous oxide kit could be quite interesting. Or consider a Td5 swap.

 

Essentially you could probably spank several grand in mods on a Tdi and still fall well short of a simple mapped Td5.

 

Other option would be to consider a V8's swap. If you aren't doing big mileage, the running costs will be quite similar. And frankly a good Rover V8 will spank any modded Tdi, or Td5 for that matter.

 

However, this is only my opinion. I'm sure other people will have different views.

So Chicken Drumstick, if it is to be a Rover V8. What sort of mileage can I expect from a manual efi or efi with LPG ?

[Chicken Drumstick]

Unless you have a want, there is no need to go carb tbh. EFI is dynamically better. You don't need to go the whole hog with megasquirt, the stock EFI would be fine as a sound starting point.

3.9, 4.0 or 4.6 would be my choice of engines. And should be a fairly easy swap into a 300.

A good 3.9 with a couple of bolt on mods should be close to 200hp.

If you are doing say 4000 miles a year or less, then the fuel cost difference to a Tdi is quite small. If you are doing 10,000 miles a year, then you might want to look at fuel costs a bit closer.

 

I have a 4.6 RV8 p38a Range Rover. Despite a 4 speed auto and weighing a lot more than any of the Tdi's I mentioned earlier, it is substantially quicker than all of them.

[reb78]

I wonder if the cost difference of a V8 to a Tdi is actually quite a lot less than we often quote if the Tdi is tweaked to give better performance. My 200tdi manages 23mpg in the real world. I know some acheive near to 30mpg and some I've read are less believable of up to 40mpg, but with my truck, even if i turn the fueling down and back to stock, I am lucky if I can get to 28mpg if i drive sensibly (that's with a roof rack and AT tyres, but also an overdrive fitted).

Pointless post maybe, but V8 economy on a run will probably come close to that of a tweaked Tdi, so perhaps backs up the points above (and it seriously makes me consider what engine I will try next).

[Wave Mountain]

I do very low daily mileage in the lanes and tracks of north Cornwall. Will definitely want a manual gearbox though. Will have to do some research on what gearbox works with xfer box etc.

[FridgeFreezer]

I'd sling the TDi truck back together and sell it and just buy a V8 vehicle complete, should come out in profit as no-one wants the fuel bills. Much easier than farting about doing swaps & informing the DVLA & modified insurance etc. etc.

Edit to add: As Reb78 suggests, the running costs may be closer than you think. You can compare them with this tool:

 http://fuddymuckers.co.uk/tools/mpg.html

what I made.

[Wave Mountain]

Good point Fridge Freezer ! Hmmmmmm food for thought. Maybe have one of each !!!!!!! Just have to find the ££££££££ !!!!!!!!

[GW8IZR]

When I swapped out the 4.6 v8 and fitted a 300 TDI into my 90 the fuel consumption on a 250 mile run changed from about 21mpg to about 32mpg

On short journeys it changed from nearer 11mpg to about... 30mpg,  so if you do lots of short runs its perhaps a consideration.

At the same time I changed from mud tyres to new AT tyres which I assume are a bit better so the consumption and running cost doesnt change that much..

[Chicken Drumstick]

I think your numbers are out. A Tdi will vary a heck of a lot more than 2mpg going from short to long journeys. Especially if you are claiming a 50% reduction in mpg on a V8...... Nothing tallys up I'm afraid.

 

Also 11mpg from an RV8 says it's broken.

My 4.6 p38a is used 100% for short journeys, light off roading and putting my foot down. The OBC is currently reading 17.1mpg for the past 4000 miles.

On the occasions I have taken it on a run 20-22mpg is the norm.

I also have a TR7 V8 which does the same mpg as the 2.0 litre used too in it. Easy mid 20's and that's running a 4brl carb.

 

As for Tdi's, my tweaked Disco (Alliposrt tuned and front mount) did 19-21mpg on 33" tyres. My 300Tdi D90 used to do 23'ish mpg, but I did drive it like a loon to be fair. My brothers 200Tdi does 27mpg average running about and similar for my uncles 300Tdi.

 

If I were working figures out, I'd say a yearly average for an EFI V8 would be 18mpg and for a Tdi 26mpg. Both capable of getting lower and higher mpg under differing conditions.

 

6mpg difference over 4000 miles a year works out to be about £360 fuel difference for the year. Or an extra £36/month to fuel a V8 over a Tdi.

Certainly not snubbing this as nothing, but in the realm of motoring costs it really isn't all that much. And of course you'll get the much better performance, noise, throttle repsonse and a better balanced vehicle due to the V8 weighing less.

[Chicken Drumstick]

2 hours ago, FridgeFreezer said:

I'd sling the TDi truck back together and sell it and just buy a V8 vehicle complete, should come out in profit as no-one wants the fuel bills. Much easier than farting about doing swaps & informing the DVLA & modified insurance etc. etc.

Edit to add: As Reb78 suggests, the running costs may be closer than you think. You can compare them with this tool:

 http://fuddymuckers.co.uk/tools/mpg.html

what I made.

Only trouble with doing this is, apart from a couple of exceptions, factory V8's a wheezy low CR 3.5's on carbs. Which while nice, won't set the world on fire with performance. Swapping in a 4.6 will still require the call to the insurance. And the DVLA aren't really an issue with engine swaps, even diesel to petrol. It's just one form, no money and a few weeks waiting for the return paperwork. 

[GW8IZR]

32 minutes ago, Chicken Drumstick said:

I think your numbers are out. A Tdi will vary a heck of a lot more than 2mpg going from short to long journeys. Especially if you are claiming a 50% reduction in mpg on a V8...... Nothing tallys up I'm afraid.

 

Also 11mpg from an RV8 says it's broken.

 

Maybe not in your world..

 

The figures I've given are my experience and if you knew me you would know that I dont lie and my vehicles are very well maintained.

Hey ho!

[Bowie69]

I will only drop to 11mpg when I've been off road all day.

Otherwise 15+mpg all the time, and that is running serious muds and a cage.

[qwakers]

i got my  4.0 P38 down to 6mpg

 

i was driving it (like a tw@) across town then home then across town then home,for an entire tank. never getting warm and a big grin on my face every time i buried my right foot. which i did as often as possible...

 

so id say 11mpg in a defender in town is feasible..

[GW8IZR]

2 minutes ago, qwakers said:

so id say 11mpg in a defender in town is feasible..

For sure , as I said 11mpg on short runs compared to 21 ish on long runs.. if you are making a decision about an engine swap / fuel choice you kind of need to know what to expect in as many situations as possible - rather than an average which might not be how you plan to use it.

Funny though, no matter how hard or carefully I use the TDI and in whatever situation each tank returns the same mileage +/- a little bit.

I don't factor in dentistry and hearing damage though :-)

[qwakers]

and the fact that you cant run a v8 on cherry.... ahem... 

Edited November 2, 2016 by qwakers

[Chicken Drumstick]

Well I don't know how you guys get such low mpg. The white 90 in my avatar is a factory 3.5, took it to an ALRC national the other year. Drive there and back plus a days competition and some running about. 17mpg overall. Running about is more like 15mpg though. But it's a low CR twin carb with an LT-85.

Also used to use a 3.5 early 5 door Range Rover with an LT-95, driving it flat out would result in 12.9mpg overall.

All the V8's I've run were more economical than my 2.25 Series was. And despite that being dreadful on fuel, never anywhere near as bad as 11mpg.

Even my V12 Jag was better on fuel and that was 100% a play thing.

On the flip side I used a Td5 manual D2 earlier in the year for a few weeks. I actually like it a lot, but even driving it gently resulted in 26-27mpg...

 

[ianmayco68]

Hi all, sorry to jump in on the thread but I've got a 300tdi 90 sw which I have just brought as a project and I was considering swapping the 300tdi engine for a TD5 as Chicken Drumstick mentioned in his 1st post, has anyone done this mod and does anyone know to a write up or article anywhere that some one has written on how they did it ? Have done a search but only ones I could find were for a disco300tdi to a td5 swap. would like to know whats involved and whats needed so I can price it up.

cheers Ian

[timc1967]

My 4 litre hi compression rv8 carburettored 110 is getting about 14 and a bit mpg consistently.

I wanted carbs for simplicity, reliability and servicability. I realise efi is quite simple but I had a RRC with efi problems (hunting, cutting out) and spent a fair bit on "specialist" help and ended up getting a new block and still having the problem. This was 20 years ago but still don't want to go that way again for the time being. 

The insurance are happy with whatever I do to the engine as long as the cc remains the same so I could convert in the future if I wanted. 

However, I don't feel the need to go fast around town, just hearing the v8 gurgling is fine, hold onto gears rather than charging around working the steering and gears hard. on the open road it easily gets to 80 on the speedo, just give enough stopping distance.

Edited November 5, 2016 by timc1967
Typo

[Wave Mountain]

This is a change of thread, but hopefully all of you in the thread will have an opinion : 

My build is a nut and bolt job on a 130 mile 1998 300tdi. QUESTION : Should i change the engine & gearbox mounts as a matter of course ?? I know they are not expensive, but i am trying to refurb as much as poss and not spend out on unnecessary items ???????????

[daveturnbull]

Only if they are starting to look past their best. 

[Wave Mountain]

19 minutes ago, daveturnbull said:

Only if they are starting to look past their best. 

Thanks.