How much boost? Mk4

**vdubdrum** · 09-21-2011, 10:15 AM

So I kno I've posted a lot of things but I have a 20ae GTI with a 3 inch turbo back forge dv APR intake and stage 2 APR ecu. I think I may have a boost leak or somethin. But my question is about what psi of boost should I be spiking and holding? Seems like Its running sluggish

**Euro** · 09-21-2011 10:15 AM

**Agent Orange** · 09-21-2011, 12:19 PM

Let's start with this. What pressure are you seeing? What's it spiking at and what's it holding at? All cars are different even with the same tune, but mine would spike at 19-21 depending on weather and would hold a solid 15-17 through most of the torque band...

**vdubdrum** · 09-21-2011, 12:31 PM

K sems right then. Mines spiking at 19-20 and holding 15 maybe 16. But it seems sometimes it will spike and hold but looses boost with out me doing anything. Like letting off the gas. I need to check my plumbing and look for cracks and what not. Just curious to see if this sounded right

**jeovas19** · 09-21-2011, 12:54 PM

That does seem kinda low for holding boost was getting that with apr stage 1 check your intercooler piping one section is really close to the front passenger tire and could easily get hit from something coming up from the tire

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**vdubdrum** · 09-21-2011, 12:56 PM

K I'll Check it out

**bugzy** · 09-21-2011, 01:13 PM

My old setup on my B6 A4 1.8t would hit 18-19 lb then taper off to around 15 psi also.

**vdubdrum** · 09-21-2011, 01:14 PM

With stage 1 or 2 ecu?

**1965truckrod** · 09-21-2011, 02:02 PM

The stage really doesn't matter for boost, stage matters for additional bolt on's to be compensated in the fuel map. All Non Big Turbo's no matter the tune will spike to 20+ and taper to 15. Some companies tune their maps for torque, some tune for Horse power gains over torque it depends on the company.
Unless you have other modifications such as a jacked waste gate, modified N75 valve, or some extensive ecu mapping you will always taper to 15psi more or less. The only ones you will see with higher boost are Big Turbo fuel maps that negate the stock waste gate control because of external waste gates or much later waste gates then the stock K03, K03s or K04 in some cases.
There are exceptions to this rule of course as there are some companies that have gone past the recommended boost settings and that of course requires additional modifications.

Just to clear that up.

Jesse

**DCxMagus** · 09-21-2011, 02:19 PM

3rd gear pull I spike to 22.5 slowly fade to about 15 at 5k then fade to around 12.3 at 7K but I have maestro so I tell my car what I want to do =P

the new map I'm throwing in that I will test on my way back from school should hold a bit more boost =P

**vdubdrum** · 09-21-2011, 02:56 PM

K that explains it. Thanks Jesse

**1965truckrod** · 09-21-2011, 04:44 PM

If you have any other MK IV related questions feel free to ask.

Jesse

**tvelev92** · 09-21-2011, 05:00 PM

Originally Posted by 1965truckrod

If you have any other MK IV related questions feel free to ask.

Jesse

the stock ko3s which you should have, loses boost at high rpm. You did a good job choosing a 3 inch exhaust and the stage 2 tune because you would be going down to 10 psi close to redline if you had a stock downpipe.