So just add the IS38 and call it a day?

So I keep looking at upgrading the turbo - because I can't stop messing/upgrading the car. Currently have the US Spec A3 2.0T Quattro IS20, but keep eyeing the IS38, but I can't really find much information confirming. Every place that sells it says its just a full bolt-on upgrade. However then I see people with stage 2 tunes which makes sense to get the most out of the bigger turbo. Currently I'm at about Stage 1.5 (dp, exhaust, jb1). So question is:
  1. Can I just get the IS38 and bolt it on to replace the IS20?
  2. Does anyone have an IS38 with JB1 and it works with the stock IS20 ECU?
  3. The biggest issues, I live in California with strong Emissions restrictions. After 6 years of new ownership (2021), then I will need to smog the car - Do most companies try and become CARB certified? I'm not sure if I'll have the car by then, but just in case.
I do understand that tunes will get the most power but just wondering if the IS38 is really, actually, a bolt-on situation. There is a few version of the IS38 too... the IHI one, then the Turbo Tectonics (sp). These I'm assuming are balanced, etc to give better output? Thanks in advance for the info.


Well-Known Member
VCDS Map User
Hello mate, as far as I'm aware (and happy to be wrong) that most turbo upgrades to stage 3 are indeed bolt on BUT once you're already at stage 2 that is with downpipe and intercooler upgrades already installed. Stage 3 ECU software is required and in most cases I suspect a TCU map if you're S-Tronic to increase clutch clamping pressures for the extra torque.


Well-Known Member
VCDS Map User
Ah I may have read this wrong - so you have the A3 2.0 and are looking to bolt on the S3 2.0 turbo ?

I think VW effectively do this with the mk7 Golf GTI when they make the R version. No idea if there are any changes to the internals though. Try posting or looking on a Golf forum there's bound to be someone who's done this.


Registered User
It should be a straight bolt on.

The S3/R engine is essentially the same as the GTI anyway but with a different head with larger, higher sodium capacity exhaust valves, uprated valve springs, IC, radiator and turbo.

The block and bottom end are identical.
Looks like the jb4 might be dropping by the end of the year and seeing if I could use that. George was saying 300+ with an is20.

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Salik Sajid

Registered User
George from burger tuning did swapped IS38 on Golf Gti7 with jb4 produced around 380+whp also he changed injector to Golf check the US Golf Gti forums as there are many Gti guys with IS38s swapped but ofcourse with stage 2 flashed
Yes, just read about George putting the IS38 with the upcoming JB4 and that is something I'd like to do. I think the injectors are required if you are trying to get to the 380+ whp numbers. I'd be happy with just 350 at first... and then get injectors later when I feel like the car is "slow" again lol.