Primary Turbo boost range on B4

[Chosimba]

Hi,

What rpm should a 99 RSK B4's primary turbo be boosting 2? My car seems to be only boosting on the primary turbo from between 1500rpm to 2500rpm at around 10-12psi. After it gets past 2500rpm the boost drops back to 3-4psi until you reach the secondary turbo.

What could be wrong? I take it this isn't normal

[GravelBen]

That does sound wrong, should be boosting to more like 4500!

[Chosimba]

Any idea what could be causing it to do this? ???

[Guest]

hey could be your blow off valve not holding boost. or a split vacum hose. most boost problems tend to relate to the solinoids needing cleaning.

[Chosimba]

Thanks for the info

I am currently going through the engine bay changing over all the vacuum lines. My car still has the factory BOV installed, but am planning on changing it soon. How would I go about cleaning the solenoids, lol?

[Guest]

im new to this site so not sure but there should be a thread somewhere on hear. try is the search ? if you cant find try www.uklegacy.com they have alot of info. hopefully an admin will see this thread and steer ya in the right direction.

[Guest]

this just sounds like vally of death, try search VOD or V.O.D, its the point in the revs where the secondary comes in

when does your secondary kick in?

-Smurff

[Guest]

After 2500rpm, about 2600? 3500?

[Chosimba]

 akaynlsn said:

im new to this site so not sure but there should be a thread somewhere on hear. try is the search ? if you cant find try www.uklegacy.com they have alot of info. hopefully an admin will see this thread and steer ya in the right direction.

Thanks for that, I'll have a look at it.

[Chosimba]

 smurff said:

this just sounds like vally of death, try search VOD or V.O.D, its the point in the revs where the secondary comes in

when does your secondary kick in?

-Smurff

I've heard about the V.O.D issues with these cars, lol. Currently mine has a huge V.O.D, around 2000-2500rpm. My secondary turbo kicks in at around 4500rpm-5000rpm at around 16-17psi then drops back to 15psi. Car doesn't seem to have a problem when the secondary turbo comes on. Would you know what side of the engine the primary turbo is on? Passenger or drivers side?

Thanks

[Guest]

primary is on the passangers side, if you search VOD, there should be alot of info on here, there are a few things you can try to reduce it, also search zerosport sequential controller

-smurff

[funkytown]

that sounds like real OTT VOD tho... way more than ususal..

[Chosimba]

 WiLd02StI said:

After 2500rpm, about 2600? 3500?

The first turbo runs 10-12psi from bellow 2500rpm then between 2500rpm and 4500rpm-5000rpm it runs 4-5psi, then after 5000rpm or so it runs properly at around 15psi.

[Chosimba]

 smurff said:

primary is on the passangers side, if you search VOD, there should be alot of info on here, there are a few things you can try to reduce it, also search zerosport sequential controller

-smurff

I'll have a look, thanks for the advice

[Chosimba]

 funkytown said:

that sounds like real OTT VOD tho... way more than ususal..

Yea, it gets quite annoying when driving as it literally has no go between 2500rpm and 5000rpm, lol.

[Guest]

4500 rpm is high, could try searching for leaks like mentioned, but is hard on the secondary side, unless you have a compressor?

if you secondary side bov is leaking a little bit i guess thi could be caused, but you will have to do some testing, dont just go changing parts over ( unless there free )

-smurff

[Guest]

 Chosimba']

[quote name='WiLd02StI said:

After 2500rpm, about 2600? 3500?

/quote]

The first turbo runs 10-12psi from bellow 2500rpm then between 2500rpm and 4500rpm-5000rpm it runs 4-5psi, then after 5000rpm or so it runs properly at around 15psi.

oohhh now thats interesting

-smurff

[Chosimba]

 smurff said:

4500 rpm is high, could try searching for leaks like mentioned, but is hard on the secondary side, unless you have a compressor?

if you secondary side bov is leaking a little bit i guess thi could be caused, but you will have to do some testing, dont just go changing parts over ( unless there free )

-smurff

Is my secondary coming in later then it should? I have lots of vacuum line so I could replace all the lines on the secondary side if that would help. I have already done the primary turbo side of the engine, but that didn't help. I thought that the 98-02 B4's and GT-B's had only one B.O.V on the intercooler ???

[Chosimba]

 smurff']

[quote name='WiLd02StI said:

After 2500rpm, about 2600? 3500?

/quote]

The first turbo runs 10-12psi from bellow 2500rpm then between 2500rpm and 4500rpm-5000rpm it runs 4-5psi, then after 5000rpm or so it runs properly at around 15psi.

oohhh now thats interesting

Does that give you any clues as to what it could be?

-smurff

[Guest]

seconday is pretty late,

are all you new lines connected correctly? you should check for leaks, on the new and old lines. also leaks within the black box of doom

on the secondary turbo there is a bov of sort, it releases any excess pressure on the secondary turbo when it is not in use, IIRC.

so if it is leaking, then when the secondary starts to work, the air will just leak back into the intake pipe.

-smurff

[Guest]

It's not pinging is it? If the computer senses bad pinging or detonation, the first thing it does is drop the boost way back.

[Chosimba]

 smurff said:

seconday is pretty late,

are all you new lines connected correctly? you should check for leaks, on the new and old lines. also leaks within the black box of doom

on the secondary turbo there is a bov of sort, it releases any excess pressure on the secondary turbo when it is not in use, IIRC.

so if it is leaking, then when the secondary starts to work, the air will just leak back into the intake pipe.

-smurff

When I replaced the lines I was very careful to cut them to the same length, and made sure that if they had a restrictor in them, that it got put back in the right place. The new lines have been in for around a week, but I will check them again just to be sure.

On the Black Box of Doom I have replaced line 1 and 2 going under the intercooler, but haven't had time to finish off the rest.

Whrn should the secondary turbo be coming in?

[Chosimba]

 SpotMe said:

It's not pinging is it? If the computer senses bad pinging or detonation, the first thing it does is drop the boost way back.

I recently tested the computer for any errors, but it didn't come up with any as the check engine light kept on flashing, and didn't stop on a set code. After testing it, I reset it, just to be on the safe side, and when I was driving it with the two green connectors connected as well as the two black ones, the boost did rise, but kept on dropping back between 2500rpm and 3000rpm. After driving, I disconnected the black and green connectors and it just went back to what it is currently doing. This was when I started replacing some of the vacuum lines.

Should I give resetting the computer another try since I have replaced some of the vacuum lines?