Smoother running Tdi engine

[Daan]

According to this video, someone has tested something:

https://www.youtube.com/watch?v=0MOlYjBNVWA

https://www.youtube.com/watch?v=XUMtruoyOKE

 

[geoffbeaumont]

2 hours ago, Daan said:

According to this video, someone has tested something:

https://www.youtube.com/watch?v=0MOlYjBNVWA

https://www.youtube.com/watch?v=XUMtruoyOKE

 

Sort of... If by tested you mean changed more than one thing at a time and then did some subjective test driving.

That's not a comment on the product itself or whether the manufacturer has done any worthwhile testing - but all we can tell from that is that they felt the car was more drivable (they may or may not be right) as a result of either the injector nozzles, or the inlet manifold - or maybe the combination of the two.

In other words, this is exactly the sort of unscientific testing others have been complaining about.

Obviously, this is two guys bolting stuff on their truck - like the OP it's entirely up to them how they want to approach that. But manufacturers of performance parts should be able to back their claims up with hard figures and the methodology to show they aren't just plucked out the air. If the part actually works, it shouldn't be hard to prove it.

[landroversforever]

11 minutes ago, geoffbeaumont said:

In other words, this is exactly the sort of unscientific testing others have been complaining about.

I've tried asking them on numerous occasions about their testing (usually when I've been moaned at for calling them out on a lack of any proof) and they have never come back with anything worthwhile.

[Snagger]

The only thing I see that manifold and hose system doing is adding to turbo lag.  The turbo output and fuel injection are the same, the head and manifold haven’t been ported, there is no change in valve size or opening.  I just can’t see how any benefit is derived.  I can’t see the smoother bore of the steel pipe really being significant in reducing resistance to the air flow into the manifold as there are more bends for the air flow to navigate.

[Nonimouse]

15 hours ago, Chicken Drumstick said:

 

It’s always the same in the U.K. with performance mods. Complete denial by some that they don’t work. And still wouldn’t believe it, even if presented with infallible proof. 
 

I’ve got nothing to gain if people do or don’t believe. I’m just passing on my findings as a punter who has bought one and fitted. If it didn’t feel like it made any improvement. I’d have either reported that or kept stum about it. I certainly wouldn’t have wasted time posting up lies. 

You miss read what I wrote. I'm not denying it works. I'm asking how it works, because to do so would make all that I understand about airflow into an engine, wrong. I want to know if it does make a difference - you mention a rolling road, excellent idea. 

No one has accused you of lying (except maybe, yourself). I applaud the fact that you were willing to shell out the moolah to try this idea and are willing to risk negative response to a decision.

[Nonimouse]

16 hours ago, oneandtwo said:

They probably are tested.. on a clapped out discovery with lift kit, remould mud tyres, whip aerials, “one life live it” stickers and a chevron wheel cover.

To be fair, they have done just this. But and it's a big but, if you have access to a rolling road and you take a tired old vehicle, then change the oil and filters, run a fuel conditioner through the filter, to improve the injectors and generally take care of it, it will improve a reasonable amount.

 

[geoffbeaumont]

45 minutes ago, Snagger said:

The only thing I see that manifold and hose system doing is adding to turbo lag.  The turbo output and fuel injection are the same, the head and manifold haven’t been ported, there is no change in valve size or opening.  I just can’t see how any benefit is derived.  I can’t see the smoother bore of the steel pipe really being significant in reducing resistance to the air flow into the manifold as there are more bends for the air flow to navigate.

Well, going by the videos @Daan posted, the main claim the manufacturers make is that it makes the engine smoother and more flexible by balancing the air flow between the cylinders - the guys in the videos quoted air flows they'd been given by the manufacturers for the standard manifold and the dual port one, which suggests there may have been some proper testing done (in which case the manufacturers should be able to publish it). I don't think they claim it does anything much to overall air flow*, just that each cylinder gets the same flow. I've no idea either whether they are correct about either the imbalance with the standard manifold or the balance they achieve with theirs - nor whether that has the claimed affect. @Chicken Drumstick and the guys in the video have both reported that subjectively they feel it works - personally I'd still like to see some objectively measured before and after data. I guess flow rates per cylinder would show whether the manifold works the way they claim - measuring vibration at the engine block might be the best way to establish if it's smoother? And I guess rolling road sessions should be able to show the driveability - broader torque curves?

It'd also be interesting to see how the manifold interacts with various other modifications - is there a benefit on a well maintained stock engine? Is there more or less benefit when increased boost/fuel pressure/injector size/custom IC/etc. are added to the mix?

 

* - in the video there's a comment that'll it'll increase overall air flow, but it doesn't sound like it's a claim from the manufacturer, just the guy holding it going, "Ooh, two pipes instead of one, that'll increase flow" - without thinking about whether there are other restrictions at play.

[Chicken Drumstick]

Just to clarify some things.

 

I've owned this engine for many many years and done tens of 1000's of miles on it. It might be slightly abused, but also looked after I feel. It has always run very well, even before it was tuned.

 

Order of modifications:

1. Injector pump and turbo tuned by Allisport when they fitted their large front mount intercooler. I forget which year this was, but was circa 2005'ish

2. Injector pump fiddled with again probably circa 2006/7. Made more smoke than the Allisport tune, but power definitely up. (all parts of pump played with including cutting the collar off the rear power screw and adjusting)

3. About 10'ish years ago the engine was transplanted into another vehicle. Where it gained a straight through exhaust system, large cone filter and custom ducting from filter to intercooler to manifold

--No other changes for quite a while from this point. It was dyno'd on a rolling road Jan 2019 (I'll dig out the dyno run later) ---

Engine has run great over all this time.

4. A few months ago (June/July 2020) fitted a 'boost ring' to the injector pump. This visibly reduced smoke and made it run even better.

5. A couple of weeks back (Oct 2020) fitted the dual inlet manifold. Biggest difference was significantly smoother running than before or any other Tdi I've driven (have owned 3 myself, my Uncle has one and my brother and have probably driven in the region of 20-30 others over the period of time, in-various sates of tune). However it does also feel a lot more flexible, responsive and better running over just the boost ring addition. This is subjective at this stage, but I'm well versed in modifying vehicles and noting performance differences over the years. And with a number of different cars that have been modded and then dyno proven.

 

The biggest difference with the manifold .is smoothness and refinement of the engine. I have no idea how I can provide anything other than subjective thoughts on this matter. But it is strikingly noticeable.

 

Here are some performance metrics I record in 2019 (i.e. pre boost ring and manifold). I will re-run the same tests on the new setup and compare.

[Snagger]

3 hours ago, geoffbeaumont said:

Well, going by the videos @Daan posted, the main claim the manufacturers make is that it makes the engine smoother and more flexible by balancing the air flow between the cylinders - the guys in the videos quoted air flows they'd been given by the manufacturers for the standard manifold and the dual port one, which suggests there may have been some proper testing done (in which case the manufacturers should be able to publish it). I don't think they claim it does anything much to overall air flow*, just that each cylinder gets the same flow. I've no idea either whether they are correct about either the imbalance with the standard manifold or the balance they achieve with theirs - nor whether that has the claimed affect. @Chicken Drumstick and the guys in the video have both reported that subjectively they feel it works - personally I'd still like to see some objectively measured before and after data. I guess flow rates per cylinder would show whether the manifold works the way they claim - measuring vibration at the engine block might be the best way to establish if it's smoother? And I guess rolling road sessions should be able to show the driveability - broader torque curves?

It'd also be interesting to see how the manifold interacts with various other modifications - is there a benefit on a well maintained stock engine? Is there more or less benefit when increased boost/fuel pressure/injector size/custom IC/etc. are added to the mix?

 

* - in the video there's a comment that'll it'll increase overall air flow, but it doesn't sound like it's a claim from the manufacturer, just the guy holding it going, "Ooh, two pipes instead of one, that'll increase flow" - without thinking about whether there are other restrictions at play.

I think any imbalance in airflow between cylinders would be influenced more by correct porting of the manifold and head ports and setting the tallest accurately.  I can see why having the inlet manifold supply at one end could potentially affect delivery evenness, but I’d be surprised if it really did.  If it does, then a single port in the middle of the manifold would suffice, or a custom branched manifold.  This looks cobbled together and I just can’t see the inside of the original manifold having enough of a restriction to significantly impede airflow to the rear cylinders.

If you want a smoother Tdi, then doing what Mike did on his recent Britrest video and balancing the pistons and each end of each con rod is the way to go about it, and having the injectors and pump checked and adjusted to ensure even delivery and spray pattern across each bore.  It’ll never be smooth as such, but I suspect a lot can be done to make them better.

[Ex Member]

17 hours ago, Daan said:

According to this video, someone has tested something:

https://www.youtube.com/watch?v=0MOlYjBNVWA

https://www.youtube.com/watch?v=XUMtruoyOKE

Okay.  I watched the two videos.  What testing was performed?  I did not see any testing.

[Daan]

5 minutes ago, Red90 said:

Okay.  I watched the two videos.  What testing was performed?  I did not see any testing.

They quoted test results of a flow bench test for runners 1,2,3 and 4 of the manifold.

[Eightpot]

On my old Isuzu engine I swapped the tdi plenum type manifold for a banana branched manifold used on a different model car. Can't say it made a lot of difference but looked nicer and had a nice clean flow from intercooler to ports.  

This forked tube thing looks like it evens the airflow across the ports by making it equally bad front & back with a couple of savage bends thrown in.  I can't get my head around how adding volume to the intake won't reduce boost pressure and add lag.  Also how the flow rate will be any different one port to another coming from a pressurised manifold, but would be interesting to see some bench tests or dyno data,   some interesting things can happen.

Not interesting enough to spend 250 quid on though 🤣

[Ex Member]

34 minutes ago, Daan said:

They quoted test results of a flow bench test for runners 1,2,3 and 4 of the manifold.

A test of the manifolds on a flow bench has no meaning.  You need to test it on an engine with a dyno. Engines do not have continuous flow and the way in which the fluid dynamics affects performance can't be determine from a continuous flow test.

Why is it so difficult for these vendors to perform proper testing?  It is a commercial enterprise.

It just confuses me.  I spend much of my working life building and testing apparatus for R&D.  Making design and purchasing decisions without unbiased repeatable data is not logical.

Edited October 21, 2020 by Red90

[missingsid]

My limited understanding of flow testing is to measure the ability of the component to flow volumes of air, if this component is attached to a number of other components in a system then the the ability to flow is restricted by the lowest performer of the remaining items?

Thus twin plenum could flow better unless the other items restrict it i.e the collector size, inlet ports etc. Thus a bench test of the manifold in isolation says nothing.

 

As you have changed the pipework, could you have fixed an air leak? I guess not as it is pressurised so would be blowing?

[geoffbeaumont]

2 hours ago, Snagger said:

This looks cobbled together and I just can’t see the inside of the original manifold having enough of a restriction to significantly impede airflow to the rear cylinders.

The figures they have indicated more flow at the rear inlets (with number 3 having the most - significantly more than number 1 which was worst, I think near double). I can't work out why that would be, and with no methodology we've no way of judging whether the testing in any way replicated the flow within a running engine.

I'd have thought near double the air going into some cylinders relative to others would imagine the engine so much it'd tear itself to bits, but I'm not an engineer. They'd be getting the same amount of fuel, so maybe you just get some cylinders lean, others rich and not that much difference in actual energy released?

[Ed Poore]

2 hours ago, Eightpot said:

I can't get my head around how adding volume to the intake won't reduce boost pressure

Because the wastegate actuator is controlled by boost pressure. Add more volume and it'll simply take longer to build boost but it should still achieve the same pressure. Unless the engine consumes more air than the intake system can deliver.

[landroversforever]

1 hour ago, geoffbeaumont said:

The figures they have indicated more flow at the rear inlets (with number 3 having the most - significantly more than number 1 which was worst, I think near double). I can't work out why that would be, and with no methodology we've no way of judging whether the testing in any way replicated the flow within a running engine.

I'd have thought near double the air going into some cylinders relative to others would imagine the engine so much it'd tear itself to bits, but I'm not an engineer. They'd be getting the same amount of fuel, so maybe you just get some cylinders lean, others rich and not that much difference in actual energy released?

My annoyance is that there’s no benefit to it at all. None of the cylinders take air at the same time as any of the others. So comparing them like that is pointless unless it’s a flow meter in line on a running engine.

[Ex Member]

1 hour ago, geoffbeaumont said:

The figures they have indicated more flow at the rear inlets (with number 3 having the most - significantly more than number 1 which was worst, I think near double). I can't work out why that would be, and with no methodology we've no way of judging whether the testing in any way replicated the flow within a running engine.

I'd have thought near double the air going into some cylinders relative to others would imagine the engine so much it'd tear itself to bits, but I'm not an engineer. They'd be getting the same amount of fuel, so maybe you just get some cylinders lean, others rich and not that much difference in actual energy released?

You do not get a flow imbalance in an engine like you would in a continuous flow test. In a four cylinder engine only one cylinder is intaking air at any one time. The firing order causes the flow to go back and forth from one pair of intakes to the other.  This prevents any real pressure imbalance within the plenum.  The air stops and starts at the far end allowing time for the pressure to equalize.

If they were serious and actually wanted to do testing and support their design hypothesis, they would add individual EGT sensors to each cylinder.  This provides the easiest way to determine how well balanced is the flow of air through the cylinders.  It is a low cost and simple way to provide science behind their statements.

Edited October 21, 2020 by Red90

[Eightpot]

15 minutes ago, Ed Poore said:

Because the wastegate actuator is controlled by boost pressure. Add more volume and it'll simply take longer to build boost but it should still achieve the same pressure. Unless the engine consumes more air than the intake system can deliver.

Yes having a minor brain fade there, but from off-boost it will take longer to build boost as there's another litre or so to pressurise.

[Snagger]

2 hours ago, geoffbeaumont said:

The figures they have indicated more flow at the rear inlets (with number 3 having the most - significantly more than number 1 which was worst, I think near double). I can't work out why that would be, and with no methodology we've no way of judging whether the testing in any way replicated the flow within a running engine.

I'd have thought near double the air going into some cylinders relative to others would imagine the engine so much it'd tear itself to bits, but I'm not an engineer. They'd be getting the same amount of fuel, so maybe you just get some cylinders lean, others rich and not that much difference in actual energy released?

With unrestricted ports giving a continuous flow out of the manifold, yes, there would be a difference in flow rate and mass from each port; path of least resistance and all that... But on a running engine, with only one valve open at a time, there is nowhere else for the airflow to go.  I don’t think there would be any measurable difference between the ports.

[Snagger]

2 hours ago, Red90 said:

 

Why is it so difficult for these vendors to perform proper testing?  It is a commercial enterprise.

It just confuses me.  I spend much of my working life building and testing apparatus for R&D.  Making design and purchasing decisions without unbiased repeatable data is not logical.

Because proper testing produces quantifiable data that undermines placebo effect and BS sales claims!

[Tanuki]

I'd be pondering whether any beneficial effect was derived from increasing the plenum-volume (the total volume between the outlet of the turbo and the inlet-valves) which may improve engine performance because there's a bigger volume of turbo-pressurised-air waiting and available to be gulped when an inlet-valve opens.

Some would say that the downside of increasing total plenum-volume would be increased turbo-lag when building boost - but we all know that the answer here is 'change down early'. I never want to be significantly-loading an engine at low RPM - doing so knocks-out crankshaft bearings.

[FridgeFreezer]

Now, not to judge whether this thing is helping or hindering or doing nothing, but my 2p's worth;

It's fairly well known that humans are terrible at judging performance upgrades like this - often you can make changes that hurt performance but actually make the thing feel (or sound) "better" or sportier and people will be absolutely convinced it's made an improvement.

Loud exhausts are the classic, a lot of them hurt performance as many of them are just thrown together to look shiny and sound sporty and it's a huge factor in how drivers perceive the performance.

I've seen it 1st hand and done some moderately non-scientific experiments many moons ago working at a kart track - with 50+ identical karts all with computer timing transponders being driven almost constantly by a huge mix of drivers you could pick out particular karts that, due to age/wear/damage would be faster or slower than the fleet, but they were often the ones that subjectively felt the opposite.

The common example was karts with a cracked chassis felt faster because they hugged the corners better (flex!) but were demonstrably slower, while karts with a damaged exhaust felt faster because they were louder but actually ran slower.

Personally I can believe that a change to the induction system that softens the cacophony of clattering from under a 200TDi bonnet would make the vehicle feel a lot smoother and could result in a subtle driving style change that ends up being reflected on the GPS-dyno.

[Retroanaconda]

The mind is good at playing tricks for sure. A few years ago I oiled up my throttle cable as it was getting a bit stiff. The car immediately felt more responsive and powerful, the reality being I just needed less force with my right foot to achieve it!

[Chicken Drumstick]

3 hours ago, Eightpot said:

Yes having a minor brain fade there, but from off-boost it will take longer to build boost as there's another litre or so to pressurise.

You could say the same about bigger inter coolers. Or a Defender 200Tdi vs a 300Tdi (200 is further back with longer pipes to the IC). 
 

Im not sure anyone ever really complains about more lag in these circumstances. 
 

And I can attest, it doesn’t feel more laggy now. If anything less, but as it is smoother it does also pull better off boost too.