Good evening all.

Who has the twin inlet by Forby 4x4 and how do you like it?

Me.

Love it.
Does it improve the air flow ? ..... It must do, right, in an engineering gas dynamic flowy sort of way.
Does it offer more power and accelleration ? ..... Hell yeah, heaps
Can you feel this increase ? ..... Hell yeah, you feel it in the cheeks and and it flattens womens breasts.
Have you a measurement of any proof ? ..... well no, not really, but if you know any women that would like to give it a go ?

miktdish said:

Me.

Love it.
Does it improve the air flow ? ..... It must do, right, in an engineering gas dynamic flowy sort of way.
Does it offer more power and accelleration ? ..... Hell yeah, heaps
Can you feel this increase ? ..... Hell yeah, you feel it in the cheeks and and it flattens womens breasts.
Have you a measurement of any proof ? ..... well no, not really, but if you know any women that would like to give it a go ?

View attachment 311472

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I didn't even know these existed. Does it actually make a difference on its own or do you need to upgrade/tune the rest of the engine to match?

I already have a full width intercooled but I have a stock tuned fuel pump atm as I let my new to me engine bed in. I am not interested in huge power and reliability/longevity is more important to me but a mild uplift in power and torque is of interest.

landy-lee said:

Good evening all.

Who has the twin inlet by Forby 4x4 and how do you like it?

Click to expand...

I have this manifold on my 200Tdi. The biggest thing I noticed was a smoother running engine. Using a smartphone app I also saw a 0.6sec decrease 50-75mph sprint, which would suggest a power increase too.

I think they must work in terms of greatly influencing the air flow to the inlet ports

but

the weight of that outer inlet being unsupported by anything worries me that it will come lose in any kind of ruff stuff

well my 2 c worth

dag019 said:

I didn't even know these existed. Does it actually make a difference on its own or do you need to upgrade/tune the rest of the engine to match?

I already have a full width intercooled but I have a stock tuned fuel pump atm as I let my new to me engine bed in. I am not interested in huge power and reliability/longevity is more important to me but a mild uplift in power and torque is of interest.

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I was being a tad flippant. I'm not sure if it makes any real life difference although it should (as @300bhp/ton said) give a more even inlet feed across all 4 cylinders so should make the engine run a tad smoother. A mate of mine who work in offshore Gas doesn't think it will make much, if any, of a difference.

The volume of high pressure air is significantly greater than the given demand at each or all of the inlet ports (he argues) so the likelyhood of a pressure drop is insignificant. Pot 1 doesn't reduce the pressure to pot 4 even if they opened at the same time.
Another friend who does fluid dynamics says it will smooth out the flow so would offer an advantge.

It's a great discussion point over a whisky or three.
I'm siding with @300bhp/ton

The outer inlet pipe is a very light, nicely tigged alluminium tbe, the elbows and inlet tubeing hold it quite tight.
I've done a few offroad things and can't see it moving to be honest.

300bhp/ton said:

I have this manifold on my 200Tdi. The biggest thing I noticed was a smoother running engine. Using a smartphone app I also saw a 0.6sec decrease 50-75mph sprint, which would suggest a power increase too.

Click to expand...

Disco or Def engine?
If def engine have you any pics?

miktdish said:

I was being a tad flippant. I'm not sure if it makes any real life difference although it should (as @300bhp/ton said) give a more even inlet feed across all 4 cylinders so should make the engine run a tad smoother. A mate of mine who work in offshore Gas doesn't think it will make much, if any, of a difference.

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And this I guess is what I am getting at. If we were working with highly tuned performance engines where such balancing would make a significant difference I would understand. But as we are working with an agricultural low tune state diesel does such an item make any noticeable real world difference or am I better off spending the money on something else (like more sound proofing!).

@miktdish what intercooler you running? Turbo? and pump tweeks?

Nice engine bay btw

My thoughts:
Only one cylinder sucks at a time, so having a higher volume of high pressure air (turbocharged pressure) close to the inlet valve is probably a benefit. So the two pipes and larger bore should in theory be a benefit - but just because of the volume increase.

landy-lee said:

@miktdish what intercooler you running? Turbo? and pump tweeks?

Nice engine bay btw

Click to expand...

Dual inlet manifod fred ...

I have an Alisport full width intercooler

and a Turbo Technics VVT

lynall said:

Disco or Def engine?
If def engine have you any pics?

Click to expand...

Disco 200Tdi engine, but in an 88 coiler.

miktdish said:

Dual inlet manifod fred ...

Dual inlet manifold - installation

Today I got my new dual inlet manifold from Fourby. Asa i'm currently waiting for my turbo rebuild to come back, i'd thought i'd just start off by posting some pics of the manifold adding pics as I fit and test. I've also fitted a larger intercooler (see here...

www.landyzone.co.uk

I have an Alisport full width intercooler

Installing an Allisport full size intercooler to a 300tdi

This https://www.allisport.com/shop/performance-products/intercoolers/land-rover-defender-300-tdi-intercooler-kit/ It's a tad complicated but the car was sold to me as a 300tdi but it is turning into a bit of a mongrel (which to be honest i'm mightily ****ed off about). The engine is...

www.landyzone.co.uk

and a Turbo Technics VVT

View attachment 311563

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Have you left the pump stock? i have herd that your better with stock pump settings with the vgt. what egt you seeing up hill putting down the gas?

Yes, stock pump.
Haven't got a EGT gauge fitted yet, haven't found one at the right price ...

Am looking for one of these ...

K series thermocouple and a cheap gauge off ebay etc.

miktdish said:

Dual inlet manifod fred ...

Dual inlet manifold - installation

Today I got my new dual inlet manifold from Fourby. Asa i'm currently waiting for my turbo rebuild to come back, i'd thought i'd just start off by posting some pics of the manifold adding pics as I fit and test. I've also fitted a larger intercooler (see here...

www.landyzone.co.uk

I have an Alisport full width intercooler

Installing an Allisport full size intercooler to a 300tdi

This https://www.allisport.com/shop/performance-products/intercoolers/land-rover-defender-300-tdi-intercooler-kit/ It's a tad complicated but the car was sold to me as a 300tdi but it is turning into a bit of a mongrel (which to be honest i'm mightily ****ed off about). The engine is...

www.landyzone.co.uk

and a Turbo Technics VVT

View attachment 311563

Click to expand...

Have you any guess as to how much power its making in this state of tune? How does it compare to a standard TDI and/or a standard 3.9 V8?

Also just my 2p as a mechanical engineering student (so not actually qualified) - Some here seem confused between flow and pressure and "amount" of air. The important quantity of air is the mass, and for maximum efficiency, you want it to be cold, but thats not what this is about. Imagine it this way, youve got a big pressurised tank of air, kept under pressure in this case by the turbo, and the pressure is allowed to escape by opening the inlet valves on the engine. Imagine that on the standard inlet, the pipes between the tank and the valves arent all the same size, some are like a straw, some are like a garden hose. Obviously more air will flow through the garden hose than through the straw. Obviously this is an exaggeration, but you get the point.
Another relevant point that was pointed out by raptorgarages video was the point that almost every blown 300tdi headgasket blows on cylinder 3, which is the one with the highest flow rate on the standard inlet manifold.
So the dual inlet is rather excellent, because AFAIK you cant tune each cylinder individually, and the standard inlet flows something like 5 or 6 times more air to cyl 3 than to cyl 1, and you cant correct for that. Its also one of the reasons the engine has such rough, unballanced characteristics. Now this doesnt mean that cylinder 3 gets 5 times more air than cyl 1, or that it makes 5 times more power, it means that its a lot harder for the air to get into cylinder 1, so the pressure in the inlet manifold will increase to compensate somewhat for the reduced flow rate. In a normal 4 cylinder engine, the inlet air pressure is normally pretty constant, but I bet if you had a fast enough sensor, the 300tdi would be all over the place.
These are the values for the flow rate of each outport of the standard inlet, taken from the raptorsgarage video, which according to them, came from the manufacturer of the dual port inlet. The values are in in cubic meters per min, for cylinders 1, 2, 3, and 4 respectively. 48 120 289 236 and the dual port inlet delivers 162 to all cylinders, presumably under the same conditions.
I doubt that the standard turbocharger can flow that much air, so these differences might be exaggerated compared to what the engine is actually experiencing, but its definately not a bad upgrade if you plan on fitting a larger turbocharger and running a higher boost pressure!

LetsHopeItFits said:

Have you any guess as to how much power its making in this state of tune? How does it compare to a standard TDI and/or a standard 3.9 V8?

<snip>

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Hi. No I don't, I didn't have any measured data of the engine before I started modding it or after, however, I can tell you it has made a mahoosive (technical term) difference.
The engine feels smoother.
The full width intercooler and the VVT made a big difference with the boost coming on earlier and the increase in cooler air mass giving me a smoother more consistent accelleration.
Sending the FiP off to Diesel Bob helped too.

I do have larger than normal wheels/tyres and a 1.22 ratio transfer box, which along with the turbo, reworked FiP and the larger intercooler give me excellent road manners when i'm up around and over 40mph. The car loves the motorway/dual carriageway, 70 to 75mph is no problem at all but, that's not where i'm at, if I want distance/motorway driving I will use my Hilux.

The next job is to install a 1.41 LT230 which will drop the top speed but will allow the revs to climb quicker offering me a little more power when I am towing a trailer full of wood off the field and up the hills towards home. It should also sweeten the drive in the 20 to 40mph zones with less gear changes and improved smoothness.

miktdish said:

Hi. No I don't, I didn't have any measured data of the engine before I started modding it or after, however, I can tell you it has made a mahoosive (technical term) difference.
The engine feels smoother.
The full width intercooler and the VVT made a big difference with the boost coming on earlier and the increase in cooler air mass giving me a smoother more consistent accelleration.
Sending the FiP off to Diesel Bob helped too.

I do have larger than normal wheels/tyres and a 1.22 ratio transfer box, which along with the turbo, reworked FiP and the larger intercooler give me excellent road manners when i'm up around and over 40mph. The car loves the motorway/dual carriageway, 70 to 75mph is no problem at all but, that's not where i'm at, if I want distance/motorway driving I will use my Hilux.

The next job is to install a 1.41 LT230 which will drop the top speed but will allow the revs to climb quicker offering me a little more power when I am towing a trailer full of wood off the field and up the hills towards home. It should also sweeten the drive in the 20 to 40mph zones with less gear changes and improved smoothness.

Click to expand...

Sounds good, I took a standard 300tdi for a testdrive, coming from a 3.9 V8 manual and it was unbelievably bad, but then having looked into it further, its probably easier to get a 300tdi to make 180hp than it is to get the V8 to do 25mpg!

LetsHopeItFits said:

Sounds good, I took a standard 300tdi for a testdrive, coming from a 3.9 V8 manual and it was unbelievably bad, but then having looked into it further, its probably easier to get a 300tdi to make 180hp than it is to get the V8 to do 25mpg!

Click to expand...

Not surprising really.
The std 300tdi was (new) around 110 horses, which isn't a lot and peaked @ 1700rpm (ish)
I've heard of people getting around 130bhp and mine does feel improved compared to others i've driven but i don't think its in the 130 horses paddock, possibly 120 or just under. To be honest I don't know.
The VVT has increased the power at the lower revs, prior to that it was as flat as a pancake below 2000rpm.
For what I use it for it's enough, the 1.41 ratio will smooth out the lower end.

I do get around 30mpg though ...

miktdish said:

I do get around 30mpg though

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Thats double what I got from the V8.
What breaks on the 300tdi if its pushed too hard? Presumably the headgasket? Or does it run out of fuelpump and run too lean and melt a piston? And how hard has it got to be pushed to do that?