Adjusting boost on DSM Internal Wastegate?
 

Hi all,

Anyone know how to adust the bost on a DSM 14B internal wastegate turbo to reduce boost - 10PSI will blow my motor...I was looking for ~ 5 PSI?

I have heard two methods, can anyone verify?

1. Lenthen the actualator rod...shortening it will give you more boost, lengthening it will reduce boost.

2. Cut the spring in the WG by half the length - to reduce to half the boost.

Can anyone validate or suggest other ways?

Thanks in advance for all replies :)

Re:Adjusting boost on DSM Internal Wastegate?
 

Lengthening the acutator rod will decrease boost based on the fact that it will prop the wastegate open a bit. This will "leak" pressure and cause the boost not to cap as high. It also means it will require less boost to completely open the gate.

As far as the spring thing, cutting it in "half" will not reduce to "half" of the boost. Just like lowering your suspension, it's the overall pressure of the spring that creates the tension. So, cutting the spring in half will actually reduce your boost by over half, because of the total loss of compression of the spring.

Re:Adjusting boost on DSM Internal Wastegate?
 

Great! Thanks for the quick response,

What is your suggestion for method?

I could cut the actulator rod into 2 and put a lengther (double female) and thread both ends of the cut rod....Not sure how much I would need to lenthen though per psi drop.

OR

I could cut the spring - not sure how much I would neet to cut it by?

Any suggestions as to the best method and how to more accurately reduce the boost?

Thanks!

Re:Adjusting boost on DSM Internal Wastegate?
 

I would lengthen the rod.. exactly how you described is the way to do it.

Only trial and error.. and your boost gauge will tell.. ;D

Re:Adjusting boost on DSM Internal Wastegate?
 

I would put a spring on it.. ;)

this is how our Z6 14b Turbo civic is controlled, with no wastegate actuator, just a carburator return spring tensioned against the block. Yes its difficult to adjust, but its safe, and you dont sacrifice spool time like if you were to lengthen the rod.

https://www.homemadeturbo.com/misc/spring.jpg

Jeff

Re:Adjusting boost on DSM Internal Wastegate?
 

when you have teh spring on there how doe sit know hen to open and close there is no vac. it will stay closed all te tiem right?????? i'm confused

Re:Adjusting boost on DSM Internal Wastegate?
 

exactly, when tension is against the flapper the gate will always be shut. Then once the turbo starts to spool pressure will eventually over-ride the spring tension and open the wastegate flapper. (thus bleeding off)

It works very well, and I am almost certain this is why our D16z6 hatch had more torque than actually Horsepower.

Jeff

Re:Adjusting boost on DSM Internal Wastegate?
 

so how do you know what spring to get and where do you hock up the otehr end too

Re:Adjusting boost on DSM Internal Wastegate?
 

Loop around the wastegate flapper and just tension the spring anywhere you want. We have used the oil pan bolts, and some spots on the block too. Its trial and error to find the right tension. Just hook it up so its barely its not extremely tight, and go drive it, make adjustments as neccasry. Whats also cool, you can have real low settings like this 1-3psi.. or whatever. It's just a pain in the ass to adjust.

Jeff

here is our dyno graph on a stock z6 with this spring setup
https://www.homemadeturbo.com/adam/adyno.jpg

stock z6 with a custom 14b setup running 10psi. Its very rare to see a honda with more torque than actual horsepower. :o

Re:Adjusting boost on DSM Internal Wastegate?
 

so you just get it to some low boost and then use boost controler? also i have same setup do you remeber what car or spring it was from?