Going back to Standard CDti Air Duct

[rovexCDTi]

Well a turbo is blind in that it will just be spun faster by the exhaust gasses until the ECU opens the wastegate or it reaches its capacity to do it.

While i dont necessarily doubt experience id still like to see the figures for reduced air speed due to a non standard intake pipe, especially since the MAF housing has laminar flow channels in it to smooth out flow, making turbulence generated by the intake a moot point. Air still has to go through the same airbox after all.

[Jakg]

I find the attitude of some members on here worrying sometimes...

The standard air intake system is a good design, but woefully undersized (it's designed for 115HP, remember).

Having done the same mod that rovexCDTi describes (junking the whole lot and using a large bore air intake system) I immediately noticed (slightly) better performance.

Yes, having an "open" intake in the engine bay does increase heatsoak, but the air has to go through a turbo first anyway (and get very hot) before then going through an intercooler (and cooling back down) so it doesn't really become a problem, especially as once the car is moving with any real throttle the air intake temps drop to ambient.

EDIT - I've done a rolling road test with the bonnet closed with my current air intake (and very high air intake temps I must confess because a rolling road run is the only time I ever get proper heatsoak) and I've done a test with bonnet open, with the air intake routed up and over the grill in front of a *massive* fan (i.e. having very cold, clean air being FORCED into the engine). 2 hp difference (i.e. nothing).

Also if what your saying is true, what happens when your air filter's airflow is reduced because it hasn't been changed in 30k miles (recommended service interval by MGR). Does your MAF also get confused and cut performance? Of course not...
To all the members that claim air intakes mods, egr bypasses, Synergy's etc do nothing for performance... how come my car has 170HP then?

Originally Posted by BigRuss

Ok here's a question for you all what do you expect that would happen to the airflow figures as measured by the Maf when you remove the air filter or put on a through flow sports air filter?

I would expect the MAF to do it's job as normal, the MAF measures the volume of air passing (effectively). If a freer flowing filter allows more air to go through, and a higher volume of air going through causes the MAF to get confused then it wouldn't be a very good MAF!

EDIT 2 - And I'd also like to point out that not all cars have a ducted air intake from the factory, some just have an open tube style air intake in the engine bay from the factory, near (but not close!) too an area where air can enter the engine bay (example - Seat Leon 1.6 from around the year 2000)... fairly sure Seat have heard of heatsoak before so obviously must know it wouldn't be a problem...

[rovexCDTi]

Unless someone can actually present figures for the MAF readings dropping with our set up I just don't believe it. The physics doesnt add up.

I agree, air speed will be higher through the intake tube with the stock intake, but the airbox and laminar flow channels in the MAF, which dont change, neutralise that effect. The larger intake tube just means air pressure in the air box responds faster to engine demand, 'lag' in equalisation of the pressure is reduced.

[Charizma]

Originally Posted by marinabrian

Modifying the intake serves to bypass the water shedder... period, it does not increase the volume of air by any appreciable amount.

This is a known cause of premature MAF failure, as an aside recommended by the person who has vested interests in selling replacement MAF sensors.
I don't sell MAF sensors, I can only speak from experience in taking real time readings from MAF sensors which have been destroyed by this particular modification.
If I were feeling particularly generous, I would say that a Pierburg MAF was a drop in replacement, however even with MAF signal amplification the result is an output which is far to high at idle and woefully inadequate at 3000 RPM, and as one owner recently found out, was no more robust in terms of water contamination.

Of course this is preferable to a completely out of spec Bosch MAF, however with the price of a genuine Bosch MAF less than half of the original £250, there is no need to compromise any more.

In addition, I have now come across no less than seven cars with HP pump failure, in each case the car was fitted with an HP sensor sensor attenuator tuning module, with the setting on "10".

The DDE4 ECM is a very complex instrument that relies upon the correct data being fed from it's various sensors, and the corruption of a signal from a sensor which is reporting an common rail pressure of 20,000 P.S.I. where the actual pressure is in the region of 24,000 P.S.I. is asking for trouble.

I now await an angry retort from the man who has sold a "million quids worth" of these tuning boxes, but unlike that person, I only care about what is right for our cars, and not simply making money from people.

Brian

Brian,

I have an ECU/fuel/throttle issue, i'm not sure which!

My ZT-T CDTi 135 has a Synergy2a with a pierburgh MAF (about a 16 months now) I carried out the air intake mod. about 4 months ago it started to present issues rarely but, these have almost now become the norm.
It will not accelerate straight away all the time but eventually picks up and pulls away. It has started getting worse and sometimes stutters on accelerating.
It will sit and cruise at speed quite happily until a demand is placed then sometimes it will respond as stated above.

I would like to come over, i'm in west Cumbria, and have you look at the issue if you can? I can take a day off and drive over if that is ok?

Regards Richard

[HarryM1BYT]

Originally Posted by rich17865

The egr bypass stops the inlet manifold clogging up with carbon deposits. Seems like a benefit to me.

Look at it logically - the worse restriction in the intake, is the inlet valves. Anything wider than those will form little restriction to the flow.

A seriously clogged up EGR will restrict the air flow, but I doubt the EGR valve or lack of would make much difference. The difference between bypassed and not bypassed is that bypassed you will never need to clean the EGR out again.

Cleaning the entire system out when fitting a bypass will certainly do no harm, but probably cleaning out the cylinder head inlets will have by far the greater effect.

All IMHO..

[HarryM1BYT]

Originally Posted by Charizma

Brian,

I have an ECU/fuel/throttle issue, i'm not sure which!

My ZT-T CDTi 135 has a Synergy2a with a pierburgh MAF (about a 16 months now) I carried out the air intake mod. about 4 months ago it started to present issues rarely but, these have almost now become the norm.
It will not accelerate straight away all the time but eventually picks up and pulls away. It has started getting worse and sometimes stutters on accelerating.
It will sit and cruise at speed quite happily until a demand is placed then sometimes it will respond as stated above.

I would like to come over, i'm in west Cumbria, and have you look at the issue if you can? I can take a day off and drive over if that is ok?

Regards Richard

By way of a quick test, try unplugging your MAF then see how it performs.

[rovexCDTi]

Originally Posted by HarryM1BYT

Look at it logically - the worse restriction in the intake, is the inlet valves. Anything wider than those will form little restriction to the flow.

A seriously clogged up EGR will restrict the air flow, but I doubt the EGR valve or lack of would make much difference. The difference between bypassed and not bypassed is that bypassed you will never need to clean the EGR out again.

Cleaning the entire system out when fitting a bypass will certainly do no harm, but probably cleaning out the cylinder head inlets will have by far the greater effect.

All IMHO..

It doesnt really matter on a turbo anyway. Of course you want more air in faster, and a bigger inlet helps that. Having said that if our inlets downstream of the turbo were too big there would be more lag, but our turbo is up to the job.

I think it depends on your driving style, if you drive harder and on boost more, the bypass makes more positive difference.

[HarryM1BYT]

Originally Posted by Jakg

Yes, having an "open" intake in the engine bay does increase heatsoak, but the air has to go through a turbo first anyway (and get very hot) before then going through an intercooler (and cooling back down) so it doesn't really become a problem, especially as once the...

The cooler the air entering the turbo, the cooler the air exiting the turbo and the more effective the turbo can be in compressing the denser air.

The intercooler will dispose of more heat, the hotter the air flow through it, but if it goes in hotter, it will come out hotter too - rather like it does in a domestic heating radiator.

I agree the MAF should be able to cope, irrespective of how the airflow is achieved, providing it is within its design limits.

[James.uk]

Rolling road tests vary so much from garage to garage and the many diff types of methods and machines used, plus the skills, of the operator, plus the "loading" applied at each garage. etc etc all go to make a RR test a complete lottery..

A single vehicle on its own can be the "victim" of favorable, or otherwise, loading by the RR operators...

The good thing about a group going for a test together is you do at least get a comparison to work with...

In my case, the more I read about RR tests the more confuzzled I got, there are so many many many variables I just gave up trying to understand it all in the end...

I think the best/only way to test a cars power is to get in and have go------
...

[Charizma]

Originally Posted by HarryM1BYT

By way of a quick test, try unplugging your MAF then see how it performs.

After a nice long chat with Marinabrian, i did just that, with the Synergy 2 unit disconnected too.

I went for a drive and it seems the problem has gone away!!

New Bosch MAF ordered

Replacement Cold Air Intake on its way

Then a trip to Newcastle to see Marinabrian at his convenience.

Regards Richard