MKV TDI intake modification (Modshack prototype)

[mikinoz]

Thanks to Ian from Rennenhaus for working with me to get something to work in the TDI engine bay.

What has resulted is that we are using a Modshack R32 intake as a filter prototype. There was a complete removal of the standard intake before the MAF - and now lives in the shed. The kit that comes with the R32 model filter required only limited adjustment (ie. bench grinding for the bracket and a branch to be tapped before the MAF for the vacuum line).

The bracket is joined at the Earth connection point so the paint on the bracket requires removal.

So down to the nitty gritty;

Deciding the best location for the filter;





After deciding that the best place for airflow was inline with the grille, the following is the result;



Looking through the original air intake area;



Looks very discreet;





Location of plumbing;



Be aware - tight fit - potential rubbing;



Location of the mounting bracket;





The 1000 kilometer review:

Noise: There is a lower tone and some intake drone - nothing like the slurp of a petrol - but notable.

There is slightly more noticeable blow off sound from the waste-gate.

On the highway and around town, not a problem with the noise.

Economy:

At this stage I think there is limited around town economy increase. On the highway, I think that it is saving around .4 - .7 liters per 100 km.

Performance:

Most noticeable is that how much smoother the car is at lower revs. The main problem I had before was the VERY large delay in the lower rev range. This area is smoother and more pleasant than the OEM system.

No great variance on the soot from the rear.

Overall:

I think that as part of the intake, this is a good addition. It will assist with induction of cooler air and more of it undoubtedly.

In a perfect world I would next approach the exhaust on this car, however I am not really willing to invest that amount of money yet.

I would give this solution a thumb up - and as there are not many others out there at this stage, serious consideration if I was contemplating other mods like Chip or Exhaust.

[Greg Roles]

Wow, now that's impressive. Great pics and writeup, especially what you have felt at lower revs. Interesting given most golf sites deem intake mods like yours as having minimal impact. Anything to help the lower rev area in a diesel has to be a good thing. I reckon it's the way to go.

I've just finished an afternoon of playing around with the OEM intake on my TDI, and I'd have to say the airbox entry seems ok, but the exit right up one end at 90 degrees just cries out "bad flow design" to me.

I love the look, and all the free space the lack of the stock airbox opens up.

Nice work!!

[Jaymz]

Well done, good write up. Glad you are getting some results from this mod.

Some would say its not worth it and just leave it alone but at the end of the day its not all about getting more power out of the engine.

If its a mod that helps with the response time of the TDi and makes it smoother in lower revs, its a mod worth doing!

[mikinoz]

I went back to the stock airbox for servicing, and have since noticed that I get more smoke more often through the exhaust.

Maybe there is a better supply of air which is aiding combustion when ModShack is on?

[Transporter]

I went back to the stock airbox for servicing, and have since noticed that I get more smoke more often through the exhaust.

Maybe there is a better supply of air which is aiding combustion when ModShack is on?

Nice mod, what is your fuel economy now (more than year later)?
How many km's have you done on the stock air filter that you removed and how dirty it was? How does the mod shack compare in filtering capability to OEM filter?

[Dyldo]

with Mikinoz's mad tinkering and help, I also fitted a VTDA to my MkV TDI - no point in pics as it looks identical to the ones in this post.

Anyway, I don't know if the car has to get "used to" the mod or if it is a simple matter of the MAF reading the amount of air and adjusting the fuel accordingly, but for some reason i have developed a small stutter at low revs and low speed. really unsure and settling actually, as in it feels like it really is being starved of fuel. feels like when you drive an older car with a bad tune on the carby and it stutters (though not as bad, no fuel smell, no backfiring, and quickly goes away). point is i didn't have this before the mod.

Will do a bit more driving and report back. will also email Steve from modshack and see what happens. agree with all OP's thoughts and observations though, it does seem to spool quicker and seems smoother otherwise.

any immediate thoughts?

[Big Yellow]

Dylan,

from looking at Miki's install, have you checked you have all the clamps and hoses fitted on properly?? There might be a leak with your additional plumbing that my R32 didnt need from what it looks like.

When it was in my car, i had no such issues.

[mikinoz]

Hi Dylan - glad it has not fallen off yet.

I am not sure how low you refer to in terms of low revs/speed but I have only ever experienced a hesitation under light load and then demanded more.

Can you explain the stutter further? Maybe the vacuum line has not seated correctly and is slightly blocked (my initial suspicion).

Sounded mean when you left here yesterday though!

[Dyldo]

i am thinking that perhaps we didn't sink the vacuum line enough because of the thicker (read ghetto) sleeve we bought from BRS Racing (Bunnings). think that line is sunk enough thru that rubber?

Was also thinking that the sleeve has too large an internal diameter but am pretty sure we checked it? i dunno. how has yours been? if yours is fine then perhaps it is something else.

am still wondering if it needs a quick dyno tune? am pretty sure i can get one cheap from West End.

Am going on a trip to wollongong tomorrow so will see consistent highway driving and see if it stutters on acceleration.

am pretty sure the hoses are all good. am also pretty sure the sealant was dried by the time we installed the vtda, agree?

as for the stutter, well it happens in 1st and 2nd when you are on sustained low speeds like crawling along in traffic. it feels like the hesitation when losing fuel but you give it some shtick and its ok.

[Greg Roles]

Mine drives similar to stock with the modshack pod, never noticed any stutter. Drives around just fine with no pod at all as well, so I'd have to agree on a vaccuum line or maf plug, or a plug / line in the general area has been upset somehow. Blame the help!

[Dyldo]

thinking logically (yes, it hurts already) am thinking that it most likely won't be a plug/line being upset because the problem goes away when more vacuum is introduced. the rubber sleeve that we bought would be at least 7mm thick i reckon, and we did drill a small-ish hole and poked the spike into it so maybe it doesn't sit deep enough.

We had a small play with some intercooler piping so maybe that DOES need to be fitted?

also, we found an oil (?) house that had been all bent and mangled into a freaky position right near the intake (it was bent before we touched the stock box) and had to untangle it. but i am thinking a freer flowing oil house wouldn't affect this.

we left the screens around the MAF sensor intact too as we did toy with cutting them out. so i assume the MAF is rather unbothered.

the actual filter too was not as dirty as i imagined it would be. had a few scattered bugs that had looked better around the place but thats it.

am thinking a squashed/inefficient vacuum hose through the irrigation spike?

[mikinoz]

Head outside, pull the vacuum line off - and suck on the spike. If you can draw any air through it you are ok, if not, then it needs to be changed.

I have not gone out to check mine, but if I were suspecting that there was an issue with the flange being too thick - that is my first port of call.

[Dyldo]

will go suck on the spike shortly (and thats the last time you'll hear me say those words together in a sentence )

also noticed a second rubbing point. underneath the intake shroud where the seem is, it is leaning directly on the offside cooling fan (the actual whole thing spins so we have a definite rubbing issue when the fan comes on). at what temp does this fan come on?

I have to head out to w'gong and back with some client sites in between. think this will be a show stopper? I can't immediately think of a way to fix this short of getting another bracket and bolting it to one of the leftover holes from the stock airbox.

Edit - sucked on pipe and easily sucked air and bug's legs into my mouth no probs. nearly did your trick and lost the spike, except i was nowhere a street light...)

[Dyldo]

also, Mikinoz, check out your's now with the new flange and also check out your install pics page 1, as your intake stops a few mm short of the bonnet stop whereas mine sits flush underneath it..... i just don't care much for this shroud sitting on a fan casing that is designed to spin

[mikinoz]

I reckon you need to pull the intake back toward the firewall so it is no longer under the cowling and then you should find it will sit up higher and off the fan shroud. Just a bit of fine tuning in your positioning if the pod should see it clear this fouling.

I will drive really slowly and at low idle and see what happens today. Are you driving it to the gong? It should be fine if you have moved it off the fan.