CTS Turbo Intake Fuel Trims

I recently purchased a cts intake for my euro spec gti. Cts have made an intake for the euro tsi that comes with the maf screw holes positioned properly for the euro maf sensor ,but that's where i think the adjustments end.


I had an ITG intake that used to read 260g/s at redline with partial fuel trims of -6% to -8% max in 30 c weather. After switching the the CTS intake in the same weather conditions my g/s readings now reach 300 and my partial trims are -18.2%.

I know about maf housing, turbulence ect would cause this but i thought the intake was specifically designed not to have this issue? Read on CTS Turbos blog about the euro tsi intake when it came out and they mention customers switching to the cts intake because the fuel trims are better than their competitors. This however is not the case with me.


So what to do now? I have emailed them and im awaiting a reply. I went back to the itg intake and trims are normal again. Could they have not taken into account the different euro maf sensor that the CCZA engine uses? Are any of you with cts intakes experiencing weird trims with your us spec gtis? Because a friend here runs a cts intake on his us spec gti and his partial trims is +6.6% which seems quite reasonable. Any input?

Th tubing on that intake is sized incorrectly most likely. Even a slight change from stock 2.6" ID will throw the maf signal off and result in bogus trims. Usually they go lean with a larger ID, but the fact that you are skewing rich means either it is too small (likely based on the G/Sec increase you saw), or the AF location after the bend is giving bad readings. Smaller tubing results in faster airflow and a higher MAF reading (more fuel requested) which seem to be our symptoms. Bottom line? A poorly engineered system. Other possibility...Your Euro MAF outputs higher..Put a US version in and see what happens.

Modshack said:

Th tubing on that intake is sized incorrectly most likely. Even a slight change from stock 2.6" ID will throw the maf signal off and result in bogus trims. Usually they go lean with a larger ID, but the fact that you are skewing rich means either it is too small (likely based on the G/Sec increase you saw), or the AF location after the bend is giving bad readings. Smaller tubing results in faster airflow and a higher MAF reading (more fuel requested) which seem to be our symptoms. Bottom line? A poorly engineered system. Other possibility...Your Euro MAF outputs higher..Put a US version in and see what happens.

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What do you mean by outputs higher?

I had issued with this intake with my euro spec GTI too
I located in Hong Kong, took it off after driving for a week with it.

the car drives super laggy with my K04 setup.

alvinli217 said:

I had issued with this intake with my euro spec GTI too
I located in Hong Kong, took it off after driving for a week with it.

the car drives super laggy with my K04 setup.

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Did you return it for a refund?

Djunited said:

Did you return it for a refund?

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nope, i bought it through a shop locally in hong kong and it runs fine with stock turbo with stage 2 flash cars but not with K04.

so the shop is gonna sell it for me to other customers.

Djunited said:

I know about maf housing, turbulence ect would cause this but i thought the intake was specifically designed not to have this issue?

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In addition to possibly being sized incorrectly the MAF is too close to the 90 degree bend. Turbulence off the bend will contribute to an incorrect g/s reading and poor fuel trims. This is not a good design.

Veracity said:

In addition to possibly being sized incorrectly the MAF is too close to the 90 degree bend. Turbulence off the bend will contribute to an incorrect g/s reading and poor fuel trims. This is not a good design.

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I understand what you are saying but how come many here have purchased this intake and run it and how is cts selling them with a design flaw?

Djunited said:

I understand what you are saying but how come many here have purchased this intake and run it and how is cts selling them with a design flaw?

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Your problem could be worse if the Euro MAF size is different and they didn't adjust for it. Also a lot of people don't check their fuel trims and either don't notice the symptoms (bad gas mileage and drivability problems) or ignore them.

Veracity said:

Your problem could be worse if the Euro MAF size is different and they didn't adjust for it. Also a lot of people don't check their fuel trims and either don't notice the symptoms (bad gas mileage and drivability problems) or ignore them.

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Its frustrating really. They advertised their intake as a EURO tsi intake made for overseas gtis so i assumed it had been r&d'd properly. Could they really have only adjusted for the screw holes of the maf housing? still waiting for an email from them. I doubt they'll respond though and clay seems to be the only one who answers their emails. I guess we'll see but this intake is clearly not designed with the euro tsi in mind.

I've always been curious of the fuel trims on my intake. I have a BSH which cts copied aside from a slightly different maf location. Wonder which is better... or should i say worse. lol although i have no complaints with the way my car drives. I'll just have to log the fuel trims to see i guess. If i get to do that i'll post my findings here as well since the intakes are so similar.

ClapperHighs said:

I've always been curious of the fuel trims on my intake. I have a BSH which cts copied aside from a slightly different maf location. Wonder which is better... or should i say worse. lol although i have no complaints with the way my car drives. I'll just have to log the fuel trims to see i guess. If i get to do that i'll post my findings here as well since the intakes are so similar.

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Be sure to check in with results? Anyone else running this intake please chime in.

Update: no response from CTS to my email. We tried this intake on a euro spec stock scirocco and after driving for a while it went into limp mode with the fault code " 17743/P1335 - engine torque monitor : control limit exceeded".

Looks like im gonna have to sell this on my own. Will not be dealing with cts anymore. I had purchased from them my k04 , tbp and meth kit so i thought id get the cts intake as well. Bad move.

Djunited said:

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Based on that picture, you have the maf backwards, the opening should be towards the filter and the wiring should look like this