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Discussion Starter #1
I see turbos being advertised for the alh engines, what are the choices for the ahu? It seems like there is a direct replacement on tdiparts.com and upgrades for alh turbos but no larger turbos for the ahu.
 

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Yes,I will add some more info to the performance page under 1000q. tdiparts doens't sell turbo upgrades for the early cars, check kermatdi.

If you want to get fancy, you can adapt the alh turbos to fit your block. The biggest issue is control of the VNT vs the wastegate. It requires changing the n75 valve, the valve that controls the wastegate/vnt actuator and the ecu has to be a custom chip.
 

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Discussion Starter #3
How do they change the n75 valve? The alh turbo has the vnt. How do they adapt, will it bolt up? Do the exhaust ports line up?
 

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NO! Be very careful if you are dealing with used turbos. K03 refers to the housing size only. K04 is a housing size. Garrett 15 is a housing size. Garrett recently changed their naming system so now it would be something like G1517 or G2520 instead of GT-25. A gasser's k03 is not the same as a tdi k03, the housing may be similar but the turbo wheels are different sizes. This is because their spool up is for a different amount of gas and higher in the rpm band and is designed for less boost. A TDI turbo is designed for lower rpms and higher boost at lower rpms.

If you want to swap in a VNT turbo, it'll bolt up but the mounting is a little different, you need a new downpipe, maf, n75, ecu, and I think a motor mount.
 

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Yeah, that too.

All the 4 cy Vw exhaust manifolds have the same shape ports and I think they should fit. The issue is that they may not fit in the engine bay and may not fit with the turbo hanging off it. I do believe that all the 4 cyl TDI manifolds are bolt on. This is why you can mix turbos with other TDIs.

Also keep in mind that you should get a chip+nozzles before you go to a new turbo. unless your old one is not making boost or is leaking oil, the turbo is a more advanced performance mod. The actual labor is relatively easy but the issue is choosing the right turbo. I would check kermatdi's turbo and not go to the hassle of extensive mods before choosing to go with a VNT turbo.
 

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Discussion Starter #7
Okay, so the VNT is out of the question, how much power does the larger hybrid turbo give? How smooth is the power?
 

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What is your goal? Are you modding for economy or power? Remember that you want to match your turbo to your power goal, bigger is not better. A bigger turbo mainly lets you run more boost which makes more power, if you don't plan on spending a lot of time at heavy boost, then a smaller turbo is a better fit. It's important to be honest when looking at your own goals, not looking at other people's dyno chart and getting stars in your eyes. Money is a factor for most people too. You can get big top end power and keep your low end power, but how much do you have to spend?

A larger hybrid turbo for that generation lets you run about 3-4 psi extra, this equals less smoke and more power at higher rpms.
 

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Discussion Starter #9
It looks like a stage 3 hybrid turbo for the jetta makes about 15 hp, 30 torque if you have other supporting mods. Kind of expensive for all that trouble and money.
 
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