To much boost?

[SCCAONE]

How should boost act?
Full throttle any gear or using cruse control boost goes to 24psi back to 10psi back to 14 or 15psi in all gears. Using part throttle I can hold boost to 18psi from 2000rpm all the way to 4200rpm (by modulating the throttle) kinda distracting in the mountains.
03 Golf, Sprint 520 injectors, 97K on the motor and RocketChip coding.
I’ve done all the usual thing, N75, fuel filter air cleaner and no change.

 

[4lowdubs]

It's called a "boost spike", search that topic and you'll find everything you need to know

 

[IndigoBlueWagon]

If you don't have a boost valve the spikes are going to happen. Occasional spikes to 24 aren't fatal, as most boost gauges read a bit high, but you should get a valve in to control them to ensure your turbo's long term survival. And seeing 18 PSI climing into the mountains is fine.

 

[Deevo_3000]

How should boost act?
Full throttle any gear or using cruse control boost goes to 24psi back to 10psi back to 14 or 15psi in all gears. Using part throttle I can hold boost to 18psi from 2000rpm all the way to 4200rpm (by modulating the throttle) kinda distracting in the mountains.
03 Golf, Sprint 520 injectors, 97K on the motor and RocketChip coding.
I’ve done all the usual thing, N75, fuel filter air cleaner and no change.

What about your vnt actuator, or turbo vanes? If the vanes are sticking at all, or the rod isn't moving freely (rusted), the vacuum actuation could be lagging, and then overshooting. If your tune is supposed to be around 16-17psi (RC1?) and you're spiking to 24, something might be wrong. Of course you'll have boost spikes, but I don't think they should be that high. True, your gauge could be reading a bit high... Some logs with vag-com would give you a better idea of whats going on. See if an italian tune-up changes it at all, i had the same thing happening with my old turbo and driving it hot for a while seemed to help. Something to try anyway...

 

[jsrmonster]

vaccume leak can cause overshoot and undershoot. check plastic pipe feeding brake booster, these crack often.

 

[frank p]

ive been getiing spikes on my car and alsowas recommeded i put a boost valve in. are these similar to a blow off valve on gas turbos?? im not to familiar with the part

 

[SBAtdijetta]

This is what you are looking for: http://www.boostvalve.com/volkswagen_2.html

There are other brands, but this is the one I there are a few different options for the TDI. The springs allow different PSI pressures and they are all adjustable within a specific range.

 

[eddie_1]

I found there is no way to really set the boost valve without affecting sustained boost. It'll cut off the boost spikes but it also cuts in to your sustained boost however much you try to tune it. This is because the boost controller is mechanical or vacuum/air pressure driven. I think that kind of precision will require an electrical solution via a sensor. I'm thinking the map sensor could be used to trigger the boost valve that might work better. Such a thing probably already exists in some form - the N75 type of thing.

 

[KROUT]

If you set the boost valve to 20psi it wont affect sustained boost except over 20psi. It will cut the spikes without affecting the power.