Diameter snorkel, pressure of VNT and lack of power

[henk]

Question regarding my 110 TD5 with VNT:

I have a snorkel on my 110, one that goes through the top of the wing with internal diameter 2,5 inch.

From the snorkel to the airbox I have a flexible hose reinforced with metal so all the original plastic stuff is gone.

But I have the feeling that the engine is not pulling as it could, Measured the pressure between turbo and intercooler and get max 1 - 1.1kg with full throttle in 3rd.

Questions I have:

- is ID of 2,5 inch enough for a TD5?

- what about modifying the internal of the airbox?

- increase the pressure of the VNT?

[mad_pete]

Can you not disconnect the snorkel and run it and see at happens ?

[henk]

Mmm, the hose is a bit smaller than the entrance at the airbox so I fixed it with silicone but it is indeed a good and easy option option. Will try

[Tim2809]

Snorkel needs to be bigger than air filter inlet bore size as the longer the pipework on the snorkel the more friction is created and reduces flow. Sounds odd but its the same with water pipes too

[dangerous doug]

Snorkel needs to be bigger than air filter inlet bore size as the longer the pipework on the snorkel the more friction is created and reduces flow. Sounds odd but its the same with water pipes too

Actually up to a point the longer your intake is the more torque you have at the bottom end. I'm sure an engine that revs to 4K wont be effected. I'm not sure friction has anything to do with it either, small piping and turbulence within the inlet tract is the enemy. I put a 3" system on my v8 and it made a vast difference over the Mantec system previously fitted. The 3" system was longer too

Henk

There is also a small amount of porting that can be done to the td5 air box to increase flow. Google td5 airbox mod to see what people have done

[=jon=]

I put a 3" system on my v8 and it made a vast difference over the Mantec system previously fitted. The 3" system was longer too

Sorry for the hijack - where did you get the 3" Snorkel from? I've got a 2 1/2" or so one on mine and it strangles my v8, so it's disconnected...

[dangerous doug]

=jon=

I had the same problem as you with the v8 so I made one

[=jon=]

Thanks - looks like I may have to find someone with a pipe bender then!

[landroversforever]

Doug, the torque increase is only regarding the intake runners. Prior to that any extra length is a restriction, so you going up to a 3" pipe will be what helped, not the extra length.

Most snorkels out there restrict the engine. Its all about the pressure drop along the length.... the longer the pipe the bigger the drop as the air is trying to 'fill it back in'. Henk you will probably find a massive difference with the snorkel disconnected.

[V8 Freak]

I currently have my TD5 using the standard side wing port.

The Land Rover pipe is 2.5 inches diameter or less from memory and it's not strangling my engine.

IRB fitted intercooler, VNT, map and boost box.

It's going very well still after over 30k in this configuration, so much that I feel I need another gear and the T/box is already 1.2 ratio.

Have you checked all the obvious first and plugged in some diagnostics?

Air filter, Fuel Filter, hoses, intercooler, (Leaks) waste gate moving freely, MAF & MAP functioning etc.

Have a friend who was complaining about his TD5 performance.. He drove mine and couldn't believe what they can do.

He had the ECU wires for MAF & air temp pulled out of the ECU plug without knowing so even though he change MAF he drove it for 5 years thinking this was all it could do.....

Now it's normal

Neil

[landroversforever]

I think you would see a difference with the snorkel disconnected Neil!

[V8 Freak]

Believe me I've driven with and without Ross and no difference.

Point to note is I don't have a snorkel / raised air intake, merely using the Land Rover side vent....

[landroversforever]

Ah that will be why then . I'd read it as you talking about a snorkel and not the normal intake pipes.

[henk]

My setup: Allisport intercooler, VNT and remap from Pete (BAS), boost box not yet connected

All hoses are silicone, all filters new, new MAF, connector of MAF tested and gets current

Manometer connected after the VNT and it reads 15 PSI max (+/- 1 bar),

So tonight I will try removing the snorkel and also see if waste gate works/moves

[henk]

Removed the snorkel completely: so just have the short pipe on the airbox: not much difference,

Removed then the hi-clone thing inside the airbox also without result

The waste gate actuator is rather difficult the move and adjusting the screw did not work as I do not have an allen key long enough

Trying another remapped ecu did not work either as my old nanocom started creating problems

Very unsatisfied of my evening...

[BennehBoy]

Did the TD5 110's ever get the cat down pipes? Just asking as many a D2 has lost power due to the cat clogging...

[mad_pete]

My v8 doesn't like the snorkel but it's not strangled. Find the pick up and full throttle slower with it on but it's not strangled if performance is really bad I would expect it's something else.

[henk]

Modified the interior of the airbox and now (still without snorkel) I have the feeling it pulls better

Tomorrow test with snorkel

[Maverik]

My 200tdi is presently disconnected from the snorkel as it suffocates it, when I've got a spare minute I'll be increasing the diameter of the steel tubing.

[RedLineMike]

had a 3" snorkel on my tedius 5 with the vnt & allisport ali intake pipework went ok with that without any restrictions

[mad_pete]

Because of science and stuff the cross surface area of 3 inch vs 2.5 is a lot. I think that half inch is 30% more area

[Ex Member]

44%. (3 x 3) / (2.5 x 2.5) = 1.44

[simonr]

In terms of resistance to flow, it's actually a lot better than that. It's proportional to the 4th power of the diameter (because the resistance occurs at the interface between the pipe walls and the fluid. The cross sectional area increases much faster than the area of the bore of the pipe).

So the increase is 3^4 / 2.5^4 = 81 / 39.06 = 2.07

Thus the increase from 2.5 to 3" bore gives over 100% increase in flow.

Si

[henk]

@Simon: would a flat wall like a silicone hose improve the flow compared to one with a metal spiral in (that is normally not flat inside) or do we talk about minimal differences?

Anyway problem solved: I was using the original MAP sensor together with an ecu adapted for a VNT. Another sensor together with a little bit more turbo pressure makes it a different car

[Snagger]

44%. (3 x 3) / (2.5 x 2.5) = 1.44

That's for a square. pie x the square of the radius gives a circular sectional area. But yes, the point is that the area increases as a function of the square, so the gains are more significant than initially imagined.

Simon is absolutely right that circular pipe has less drag than any other section, especially those with corners - corners cause interference drag, which is why aircraft have radiused fairings where their fins and wings meet the fuselage. So, all the fancy new cars with funky shaped exhaust pipes suffer reduced performance just because of the aesthetics of that exhaust pipe.

As for putting vortex generators into the induction pipes (like Hyclone), they create even more drag. They are snake oil products that misrepresent aerodynamic principles to deceive buyers. The smoother the bore and gentler the bends, the better.