12psi?

[Dave]

I have an MP computer in my car now, with an APC filter, thats all the mods right now, and I am only seeing 9psi. I swapped another MP comp. in and it ran the same with 9psi. I dont have a manual boost controller on it yet, but I will be putting mine on soon....my question is, is the stock exhaust limiting me? And if so, can I crank the boost up to 12 manually?

-Bryan
89 Spirit

[OmniGuy123]

Quote:

Originally Posted by Dave I have an MP computer in my car now, with an APC filter, thats all the mods right now, and I am only seeing 9psi. I swapped another MP comp. in and it ran the same with 9psi. I dont have a manual boost controller on it yet, but I will be putting mine on soon....my question is, is the stock exhaust limiting me? And if so, can I crank the boost up to 12 manually? -Bryan 89 Spirit

The stock exh. is a downer.

YOu can crank up the boost about all you want, but you will melt your engine.

Read http://www.thedodgegarage.com about 10 times, and then you should be all set. Post again if further clarification is needed. Good luck.

[detobias]

how are you measuring your boost psi ? stock gauges are not always accurate - before you conclude that you are not running what you think you should, invest in a good gauge - then you will know!

if you are still not getting 12 (which is what you think you should with the MP computer?) then start checking the obvious stuff first - leaky / disconnected / improperly connected vacuum lines, functioning wastegate actuator (not stuck), actuator rod connected, etc

does the boost come up to 9 quick ? that would suggest the turbo is at least working decent and hopefully not the problem.

a final troubleshoot step (and more experienced TDers may discourage you from doing this) would be to disconnect & plug the vacuum line to the wastegate, go for a quick 1/2 - 3/4 throttle run - boost should really spike up. if it does immediately let off the gas, and reconnect your vacuum line.. now you know turbo / exhaust is OK and the problem is electronics or vacuum...

[RSTURBO]

I had this problem with my csx...basically my vaccum lines where so old that I re did them all with a block i went from only 17 hg vaccum at idle to 22 and no overboost and a steady 12 psi all the time with a grainger.


Very easy to do took me about 30 min to install.

[Dave]

Ok well Im redoing my vaccuum lines here in about 3 or 4 weeks hopefully. And I have a Phantom boost gauge in my car...30hg/20psi.

And how could I melt my engine by turning the boost up? Would the exhaust just stack up? Sorry, I dont know much about exhausts yet.

[detobias]

Quote:

Originally Posted by cordes Read http://www.thedodgegarage.com about 10 times, and then you should be all set. Post again if further clarification is needed. Good luck.

what he said.

we suggest you spend couple hours reading the above website, and following links to other websites, and reading them, and following links...

you will find that the problem will be: at some point your stock fuel system - pump, injectors, electronics - will not provide enough fuel for the added airflow of high (er) boost. then the engine runs lean (er) , combustion temperatures go way up = holes in piston, maybe burned valves...

[Dave]

Quote:

Originally Posted by detobias what he said. we suggest you spend couple hours reading the above website, and following links to other websites, and reading them, and following links... you will find that the problem will be: at some point your stock fuel system - pump, injectors, electronics - will not provide enough fuel for the added airflow of high (er) boost. then the engine runs lean (er) , combustion temperatures go way up = holes in piston, maybe burned valves...

lol thanks, but Im upgrading to 20% injectors and having Turbos Unleashed calibrate me a comp. to set the boost and manage the fuel.

But for now I just want 12psi, but I guess the exhaust is restricting me.

BTW...read the entire site numerouse times, I havent seen anything about exhaust restriciting boost..just exhaust making boost creep.

Thanks,
-Bryan
89 Spirit

[puppet]

I know what your asking Dave. You don't say what turbo your using .... maybe the wastegate can is too weak.

[Dave]

Stock mitsu. I've considered the thought of the can being to weak...can I put a Garret can on it with no problems? Is the Garret's wastegate arm longer than mine?

Thanks.
-Bryan
89 Spirit

[puppet]

Don't know about switching cans ... if you had it in front of you a guy could probably rig something to make it work.
I'd try wiring the mitz can shut for a run just to test the theory.

[Dave]

Quote:

Originally Posted by puppet Don't know about switching cans ... if you had it in front of you a guy could probably rig something to make it work. I'd try wiring the mitz can shut for a run just to test the theory.

lol I didnt get a word you said.

DO you mean I should unplug the vaccuum line from the can, and then go for a run?

[RSTURBO]

yeah see if you get over 5-7

[puppet]

Wire the wastegate rod shut. Unplugging it won't tell you if it's too weak to hold over 9psi. If it's weak it'll still push open.