dagame27

I currently am running a setup w/ tial 38mm WG, MBC, and vitesse chips. The mbc is as low as it goes. I am reading 10-12 psi in 1st gear and full 15psi in 3rd on my aftermarket boost gauge. However, in 4th, I appear to be pushing 16-17 psi. In 5th, I am slightly higher and it seems to back off when going above 17psi. Any idea's on what's going on? Thanks

Chris

Spidey944

is the MBC a new addition to your setup? Maybe you have it installed backwards, wouldnt be the first one to do it!

dagame27

I'm not sure, I had my mechanic install it. Any pictures of what it should look like? or shouldn't?

Spidey944

by backwards I mean the lines swapped. Where do you have it installed? Engine bay or under-hood?

dagame27

It's under the hood, driver's side, mounted via bracket.

dagame27

On a side note: How much boost is a k26/6 even capable of making? Especially one w/ 150,000 miles on it

Spidey944

It can make plenty of boost, it just can not sustain it for long term at high RPMs It drops off to about 12psi IIRC. I have had mine at 18psi for a few days b4 dialing it back.

Having quality components (Tial, etc) will help it hold boost longer, but it still starts to reach levels where it just wont make more power.

dagame27

OK, that's certainly what I am seeing. A vitesse MAF kit and new turbo are in my future, but I want to make sure that everything is running correctly first. I just had these mods (my 1st engine mods) installed a week or so ago. It's still my daily driver, and has been for 8 years now, so I have to keep it fairly reliable.

porschefig

A 26/6 with ~120k miles can make ~24 psi boost... I'm one of the fools that had the lines swapped on my manual boost controller the first time I took it out.

Is your tial wastegate set up single port or dual port?

dagame27

I'm thinking that may be the case for me. Backwards MBC or Tial. Does anyone have any pics of how it should look? or a diagram? Luckily, I noticed it overboosting, so I am hoping I did not do any damage. ( I am in dual port mode)

dagame27

I've searched this topic and came up w/ some good info. I do, however have a question. Would a tial that is physically installed backwards and lines to the mbc being wrong lead to the same results? such as the symptoms I am having?

Techno Duck

That sounds like boost creep to me. Are you using the wastegate in dual port mode? I was having this issue with my car when running the stock wastegate with the LR black **** boost controller (its a bleeder type). If using the stock wastegate or the Tial in single port mode (i dont know why anyone would even do this) you need to use a ball and spring type boost controller.

Use this diagram to verify if you have the lines hooked up right to both the wastegate and boost controller.

http://www.boostsciences.com/mbcinstall.html

TurboTommy

dagame27;
you didn't say how the boost is with rising RPM.
Boost creep usually manifests itself as rising boost with rising RPM; not really gear based.
Isn't it a bit normal for the higher loads in higher gears to have slightly higher boost?

dagame27

It is normal to have higher boost in the higher gears, but my MBC does not seem to control boost at all. I am still thinking backwards install of the tial or the vacuum lines installed incorrectly. I am going to get w/ my mechanic this week and call Tim at SFR and get things sorted out.

Techno Duck

If your feeling up to it, you can crawl under the car and check the orientation of the wastegate..





This is how it should look when installed correctly.