Aftermarket Intakes and Fuel Trims.......

[ROH ECHT]

I found this on Vortex MK6 Golf R Section yesterday. Never saw they did this before but it seems worthy to share. They had people post their fuel trims beginning in 2012, first of two years the MK6 was available here in the US. They had people post their LTFT (MB 032 Group 2) off-idle/partial/multiplicative and the intake they had. Once there were ten cars posted with teach intake they posted a range of trims for each. RamAir, REVO, and some others never made the list. So those could be added if you want to add yours and the list can be updated. Obviously, the MK5 GTI and MK6 Golf R are aging now and the range would likely be skewed more. But would still be interesting to add some that aren't on the list. I am certain those with custom tuning will have better trims than those with shelf tunes. My LTFT is at the high end for a Neuspeed P-Flo = +8% with a GIAC H.O. K04 tune. I have recently done smoke testing and loads of fuel related replacements...and I cannot improve the trims. Thinking about trying another intake made from a type of plastic because a few on the list made of the same have the better trims. The point of the Thread on Vortex was to find out how higher trims were affecting boost and power...and they seemed to conclude they saw higher boost and power once they got an intake with lower LTFTs. I didn't read all of it because there's 80 pages. So here it is....you can add if you like and I will attempt to keep it updated. Not sure if miles driven should be added when LTFT is posted. Mine when I clear codes and drive for 30+ miles is usually nearer +5%...then after a long time it climbs to 8%. Thoughts?

[colesey]

I think the revo intake has some decent fuel trims - maybe someone can confirm? Rtech recommend it and their cars typically deliver strong dyno results.

[ROH ECHT]

I've seen many posts stating the same on the TFSI Tuning Group page on facebook(Niki's page I believe).
https://www.facebook.com/groups/529405700525327/permalink/2126516754147539/?comment_id=2126655094133705&reply_comment_id=2128514730614408

Likely because of the scaled-down MAF section on the REVO intake.

[ROH ECHT]

Anyhow, I hope to get 5 to 10 posts for the RamAir, Autotech, and REVO intakes to add to this. So if you have either, or another popular intake, please post so we could get at least five to ten to show a range of their LTFT (MB 032 Group 2)...that would be helpful.

[pudding]

I think the revo intake has some decent fuel trims - maybe someone can confirm? Rtech recommend it and their cars typically deliver strong dyno results.

Nope, trims were around +8% on my ED30.

I did get my VWR intake down to 5% by sleeving it.

Simple fact of the matter - nothing will ever match the OEM intake for close to zero trims.  The ECU will never accurately fuel the engine if the primary load sensor is misreading.

It's not just about sleeving the MAF pipe down until it gets close to zero, it's also about volume, velocity and laminar flow.  All of this VW spend millions on perfecting. Not one single aftermarket intake comes with a laminar flow grid, not one. Most after market tuners say you only need that to smooth out the turbulence of the factory paper filter, which is absolute nonsense. They simply cannot be arsed, or they lack the skill to incorporate a laminar flow grid into their kits.

It's all a moot point anyway since most people who fit intakes are only interested in chooching noises and (small) gains up top.

For people who value low end response, accurate fuelling and quietness - just stick to the factory air box 

[pudding]

The best you can achieve in terms of accurate trims is to 3D print an OEM MAF housing and attach to that a tapered turbo intake pipe from an EA888 engine.  On other end of that, knock yourself out, any old cone will do.

The crucial part is the laminar flow grid to straighten out the vortex created by the compressor wheel, and gradual tapering down of the intake bore.

Or relocate the battery to the trunk and fit the TT-S airbox, pipework and MAF.  You will need a remap though as the TT-S uses a different MAF sensor and bigger MAF bore.....but it's a proper OEM way to increase air flow and air volume into the turbo.

[ROH ECHT]

Some points you made Pudding are why I am considering this intake.

https://volant.com/collections/2007-volkswagen-gti-2-0l-l4/products/closed-box-air-intake-411520

It is on the the list and its range was listed similar to OEM trims. I plan to call them to find out the diameter of the turbo inlet end...so to mate with my DV relocate. I hope it is 2.75" Dia.. I have this DV relocate.

https://www.awe-tuning.com/fsi-diverter-valve-kits

I agree and do not understand when I see comments made of how great an intake is....because of its new sounds.

[pudding]

I've seen that Volant kit before and it looks great.  Well thought out and OEM style, although I've read the build quality isn't great for the money?  We can't get it in the UK, so our American chums such as your good self will have to confirm on our behalf.  If you do buy one, please do share your thoughts 

I would also be interested to understand how they arrived at their chosen MAF bore diameter.  If it was just a basic translation of an ellipse into a circle, it may have the same trim issues as the other intakes.  The problem with MAF is it's logarithmic and not linear like a MAP sensor.  The airflow readings are all over the place as rpm and load changes, so it's not easy to get accurate trims across the board.

Honestly, I wish their was an affordable aftermarket DI ECU solution to bin off the stupid MAF, but only Syvecs offer a plug-n-play solution......at $4000!!

I just don't understand the fascination of 4 cylinder choochs, pops, bangs and Darth Vaders. Subaru Boxer, V6 and V8 turbo noises, hell yeah, something to get excited about as they have actual charisma and pleasing tones....but a noisy, droney, raspy, chuffing 4 cylinder just sounds lame - imo 

For proper scorched earth VW turbo power, strap a turbo to an R32.  Nothing VAG comes even close for noise and power, not even the RS3/TTRS.

Forgive me, but what's the purpose of that DV relocation kit over the OEM K04 solution?

[ROH ECHT]

I've seen that Volant kit before and it looks great.  Well thought out and OEM style, although I've read the build quality isn't great for the money?  We can't get it in the UK, so our American chums such as your good self will have to confirm on our behalf.  If you do buy one, please do share your thoughts  I have been calling them because I want to know if the opening at the turbo inlet end is 2.75". They aren't answering so far, so I plan to phone ECS Tuning to see if someone there can measure it.

I would also be interested to understand how they arrived at their chosen MAF bore diameter.  If it was just a basic translation of an ellipse into a circle, it may have the same trim issues as the other intakes.  The problem with MAF is it's logarithmic and not linear like a MAP sensor.  The airflow readings are all over the place as rpm and load changes, so it's not easy to get accurate trims across the board.

Honestly, I wish their was an affordable aftermarket DI ECU solution to bin off the stupid MAF, but only Syvecs offer a plug-n-play solution......at $4000!! OUCH!

I just don't understand the fascination of 4 cylinder choochs, pops, bangs and Darth Vaders. Subaru Boxer, V6 and V8 turbo noises, hell yeah, something to get excited about as they have actual charisma and pleasing tones....but a noisy, droney, raspy, chuffing 4 cylinder just sounds lame - imo  I agree.

For proper scorched earth VW turbo power, strap a turbo to an R32.  Nothing VAG comes even close for noise and power, not even the RS3/TTRS.

Forgive me, but what's the purpose of that DV relocation kit over the OEM K04 solution?

Here...U.S., we didn't have an OEM solution as there were no models(VW or Audi) with a K04 or DV located at the front of the engine bay until the 2012 Golf R. So, prior to then we had DV relocation options. Mine was from AWE Tuning. It utilizes the "sound pipe" we have on the MK5 GTI (N. America Region) and places a K04 DV at the intake to turbo coupler. This was one reason why all tuners here required aftermarket intakes for K04 tunes.



I spent nearly an hour talking with GIAC yesterday. Trying to figure out why mass air differs. Because I was asked by a stage 2+ ED30 guy why my mass air data is 272 g/s(4th gear) to 280 g/s(3rd gear) when his is 240 g/s.  Andrew (GIAC) says many things have to do with why the MAF sensor data changes. They were involved with development of an intake for our MK5 and the first version would cause a cut-out under high load and due to disturbed air flow. When testing it...they went to and up a hill....it would just nearly die part way up the hill under heavy load. Anyhow, he says air must be traveling very undisturbed at the MAF...which I already know. So I then asked Andrew to look at the REVO intake. The same intake of the person who asked me what my mass air was. He pulled it up online and immediately said he doesn't like the reduction just upstream of the MAF. So I said look at the RAMAIR next...he said it has the same issue. He added, he isn't sure how those reduction sections just before the MAF will affect air flow, but it will. He said he wouldn't be surprised if the LTFT's for those intakes would be farther from zero than the oem airbox. Also, intakes with multiple connections can have high LTFT additive. He didn't have time to look at the Volant, but given the results of 0% to 5%...I'd say it works well. But quality?....I don't know.

It would be nice to see some LTFT posted for both the RAMAIR and REVO intakes.

[pudding]

OK, makes sense.  North America always misses out on the decent spec Euro cars.  And what Euro cars you do get, are strangled by California emissions controls!  You guys have some seriously anal and frankly silly vehicle regulations and laws   

What I don't get is why after all the silly rules and massively strict emissions and safety regs you have, red turn signals are allowed    They are seriously dangerous.  Should be amber like the rest of the world 

Interesting.  240gs equates to roughly 300hp, and you're seeing 350hp.  300hp is a mild boost 'stage 1' over here on the K04.  Stage 2+ usually sees similar to your numbers.  What map did this ED30 guy have?

The Revo intake is crap.  I bought one and after an hour's drive I saw +8% trim    I removed it and sold it as that's unacceptable.

So let's say the Revo under read 8-10% on this gentleman's ED30, his MAF reading could actually have been 253gs.  Remember what intake kits claim - MORE airflow, not less    Classic example of how a poorly designed intake can cost you power, rather than adding it.  If the ECU is only seeing 230gs, it's certainly not going to add fuel for 253gs, so you simply won't get 253gs worth of hp, which is approx 316hp.

It would therefore be interesting to see what MAF reading he gets with the standard intake.

Ambient temperature and elevation can also affect MAF readings.

Yeah you don't see big reductions in pipe diameter right next to the MAF on OEM intakes!  GIAC are on the ball.

[ROH ECHT]

OK, makes sense.  North America always misses out on the decent spec Euro cars. Right...LOL...it took until mid-2006 to get the MK5 here. VW had to make reductions to it for the lower VWofA price point.

Interesting.  240gs equates to roughly 300hp, and you're seeing 350hp.  300hp is a mild boost 'stage 1' over here on the K04.  Stage 2+ usually sees similar to your numbers.  What map did this ED30 guy have? I'm not certain what tune it has. He messaged me from the "TFSI Tuning" fb page...and my fb messages have been deleted.

So let's say the Revo under read 8-10% on this gentleman's ED30, his MAF reading could actually have been 253gs.  Remember what intake kits claim - MORE airflow, not less    Classic example of how a poorly designed intake can cost you power, rather than adding it.  If the ECU is only seeing 230gs, it's certainly not going to add fuel for 253gs, so you simply won't get 253gs worth of hp, which is approx 316hp. The irony of those claims...LOL.

It would therefore be interesting to see what MAF reading he gets with the standard intake. Yes, I mentioned he do this if he still has the stock air box just to see the air volume with it...and to consider the REVO intake has its design flaws.

Ambient temperature and elevation can also affect MAF readings. Funny...his last message said he is back up the mountain and the trims rose to +11%

Yeah you don't see big reductions in pipe diameter right next to the MAF on OEM intakes!  GIAC are on the ball.

Recently I thought of asking on a local fb page if anyone has the complete "air inlet to turbo", and engine cover, bits from a MK6 Golf R they may be willing to sell me. Wouldn't mind testing this all myself.

[pudding]

MK6 R intake parts are exactly the same as K03 GTI, except the panel filter.  For some bizarre reason, K04 engines have a slightly thinner filter than K03.  Different part number.

In the UK, many tuners have found the standard intake components (inc paper filter) is good for 330 crank hp.  Curiously enough, this is exactly the maximum hp Borg Warner themselves quote for the K04.

Higher numbers have been seen with aftermarket intakes for sure, 350 is about all you get, completely strung out.  The 380-400hp figures seen on the internet can be ignored as the turbo simply cannot flow enough for that amount of horses.

The airbox to try is the MK2 TT-S with the CDL engine.  It has a massive volume compared to the GTI, and a bigger MAF.  The battery will need relocating though.

[ROH ECHT]

MK6 R intake parts are exactly the same as K03 GTI, except the panel filter.

Not the same here due to the DV location. The tube differs between the air-box and turbo inlet. K03 DV is mounted on the K03...and the K04 DV of the MK6 Golf R is mounted forward near the throttle inlet pipe. I no longer have any of it so I would need it all but with the K04 tube between air-box and turbo.

[pyle]

Can't one just build an intake around the stock MAF so as to keep the fuel trim as close to 0? What would be an acceptable trim change since on my old car had a range of +10 to -10 which VAGCOM pointed as acceptable. What are the actual restrictions in the stock airbox/tubes?

[pudding]

We used to be able to, using this part - https://www.ecstuning.com/b-42-draft-designs-parts/fsi-maf-housing/1315297~42d/

But sadly it looks like it's no longer available.

The critical thing even that MAF housing doesn't have is the laminar air flow grid.  It's critical the air pulled through the MAF is straightened, otherwise you get massive trim errors.

It's something that could easily be 3D printed though, and incorporate a steel mesh. It's time and resources though.

The air coming into the engine, and the burnt gases being shat out of the exhaust are all finely optimised at the factory - end to end.  Changing any of the components has an adverse affect on the engine response, be it at the low end or the top end.  That's why most people always go back to the factory intake because they either can't stand the noise of an aftermarket system, or the altered throttle response.

If it was easy to build the perfect compromise at an affordable price, it would have been done already 

+/- 10% is a very wild deviation.  A healthy running engine should be around 1% on the trims.