156 2.4 jtd 10v turbo adjustment help - Alfa Romeo Forum
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(Post Link) post #1 of 4 Old 11-05-17 Thread Starter
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156 2.4 jtd 10v turbo adjustment help

Hi i fitted a new mellet turbo chra to my 156 (turbine vanes were damaged). I set the stop screw by comparing it to the old turbo comparing how much the vanes are open when at the stop and measuring. I also fitted a second hand actuator of another 2.4jtd 10v as the old one was rotten.

The problem is i need to set the actuator correctly. I found that it boosts well at low revs but not so good at mid to high. I have access to a scanner so i can monitor boost pressure and revs but i dont have any data to compare it.
Ive heard the vw lads saying it should be set with a vacuum gauge at 3-5 inches mercury to start and about 18 to finish but i dont know if this apply to the 156 2256 turbo. They also say to monitor duty cycle of turbo valve, if its more than 80% at 4000 then it need adjusting.

If anyone can give any details on how to setup the actuator that would be great. I have also extended the rod and this improves mid to high response much better but i would like to get it spot on.

I need details like percentage of turbo valve at so many revs, vacuum pressure adjustment details, maybe a graph of one setup good so i can compare it. Also maybe stop screw adjustment details. Should i do a 3rd gear run and log it (snapon scanner)?

The more info the better. I would really like to get this 156 going well as its such a good engine!

Regards
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(Post Link) post #2 of 4 Old 14-05-17 Thread Starter
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Someone must have some info?
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To adjust it without a calibration tool is very difficult. Only a half turn of the stop screw has big impacts.

Here you can see it

I would send the turbo to a company, who can adjust the vnt.
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(Post Link) post #4 of 4 Old 15-05-17 Thread Starter
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Quote:
Originally Posted by crossshot View Post
To adjust it without a calibration tool is very difficult. Only a half turn of the stop screw has big impacts.

Here you can see it https://www.youtube.com/watch?v=iYTN8ix9SOM

I would send the turbo to a company, who can adjust the vnt.
thanks for the info about the stop screw but does anyone know the best way to set the actuator length?
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