Author Topic: low boost after turbo upgrade  (Read 2662 times)

May 17, 2013, 04:07:29 pm

tdotdub

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low boost after turbo upgrade
« on: May 17, 2013, 04:07:29 pm »
hey guys. so I have been runing 18-24 psi on my tiny old turbo for 15k later it popped no surprise. Finally got the T3 on my 1.9td azz. the reason boost was so high previous was due to the giles pump and I did not want to mess with it to turn it down. Now with the new turbo t3 I can only get 10-12 psi. Nothing was changed other than small turbo to big.
Not sure why such a huge difference. We used the old manifold so no blow off valve is on it from the 1.6td manifold.
Any clues why it so low?
looking to get it to around 16-18psi, but the waste gate hose is to tiny to add a boost valve in there, what is another way? boost valve in the line from the fuel pump to the manifold?
|thanks.
87 Audi 5000S Quattro Turbo Diesel (the car I want to light on fire everyday)
99 Beetle TDI (the beater)
99.5 Cabrio  (the innocent one)

Reply #1May 17, 2013, 04:30:57 pm

8v-of-fury

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Re: low boost after turbo upgrade
« Reply #1 on: May 17, 2013, 04:30:57 pm »
Boost valve in the manifold to pump line will achieve nothing.

The T3 line is not to small to plumb in a T for a boost valve connection. I have a T3 here that will probably make its way on to my brothers AAZ as well.

You likely have much lower boost because the T3 is substantially bigger than the k03 you had.

Reply #2May 17, 2013, 06:55:22 pm

RabbitJockey

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Re: low boost after turbo upgrade
« Reply #2 on: May 17, 2013, 06:55:22 pm »
Boost valve in the manifold to pump line will achieve nothing.

The T3 line is not to small to plumb in a T for a boost valve connection. I have a T3 here that will probably make its way on to my brothers AAZ as well.

You likely have much lower boost because the T3 is substantially bigger than the k03 you had.

i think that is some of it, and i think he just needs to install a boost valve/mbc  how is the line too small???  did your old turbo have a stuck wastegate?
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Reply #3May 18, 2013, 03:55:17 am

Patrick

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Re: low boost after turbo upgrade
« Reply #3 on: May 18, 2013, 03:55:17 am »
Just plug the line. the AAZ will handle 30 pounds.... Do a test drive and see if it stays under that with teh line plugged.

Reply #4May 18, 2013, 06:41:01 am

8v-of-fury

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Re: low boost after turbo upgrade
« Reply #4 on: May 18, 2013, 06:41:01 am »
Do not listen to that man.

Yes the engine will handle 30 pounds, but the turbo will be done in 10k or less. That is WAY outside the efficiency range of a 35 trim T3 turbo charger. Not to mention.. without a HUGE air-to-water, 30 pounds would be so hot you'd likely have less power than before at stock boost.

Reply #5May 18, 2013, 02:03:43 pm

tdotdub

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Re: low boost after turbo upgrade
« Reply #5 on: May 18, 2013, 02:03:43 pm »
i was able to limit the boost trough having the mbc in the line from the pump to the intake manifold.

i dont want more than 16-18 because its not intercooled. It looked like the wastegate hose is much thicker and shorter, I dont want to splice it in case my fittings wont work so I will try to find the proper hose and fitings to make it work.

the k03 was always boosting high and got higher with warm weather. The t3 is for sure WAY laggier but smooth power and doesnt sound like a weed wacker. Smoke at low rpm is more but clears up better  at full boost with only 12psi vs previous 20psi+
87 Audi 5000S Quattro Turbo Diesel (the car I want to light on fire everyday)
99 Beetle TDI (the beater)
99.5 Cabrio  (the innocent one)

Reply #6May 18, 2013, 02:06:51 pm

8v-of-fury

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Re: low boost after turbo upgrade
« Reply #6 on: May 18, 2013, 02:06:51 pm »
You limited boost with your MBC there because you physically were limiting the amount of boost the pump saw, and therefore were injecting less fuel. Meaning less boost right?

There are two simple fitting in the compressor, one in the compressor housing and the other in the wastegate. thread them out find the thread and put in barbed fittings so you can replace with rubber boost hose like from the pump to the manifold.