Boost spike to 14psi on bone stock FD, any ideas?
#1
Boost spike to 14psi on bone stock FD, any ideas?
Got a local guy who has a bone stock fd.
His primary turbo boost to 14psi. So his boost pattern is 14-8-10 or something like that. He said his secondary turbo isn't boosting all that strong but the primary spikes to 14psi.
Wondering if anyone had any ideas. Car is completely stock, has precat on it and all that stuff.
Thanks,
Darren
His primary turbo boost to 14psi. So his boost pattern is 14-8-10 or something like that. He said his secondary turbo isn't boosting all that strong but the primary spikes to 14psi.
Wondering if anyone had any ideas. Car is completely stock, has precat on it and all that stuff.
Thanks,
Darren
#4
Full Member
yea just pull the hose from the compressor to the bottom actuator and look through to see if the light is right through the middle or not. oh yea when i took mine off my car the pill slid out pretty easily and i didnt notice and then found it on the floor.
#5
Eh
iTrader: (56)
Just remove the line completely and put on a new empty line to test in a safe manner. If the car is still boosting about 10psi you most likely have a crack or break in a line leading to the wastegate control somewhere earlier in the system. Those stock pills are a PITA to get out of the stock vac line.
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#8
Racecar - Formula 2000
Originally Posted by books
Possible clogged cat or precat.
Dave
#12
Rotary Freak
iTrader: (8)
I realize my response is contrary to the fact that opening the exhaust is more likely to cause a spike. However in my experience when I changed out the cat I went from a 14-8-8 pattern to close to a 10-8-10 pattern. Since his car is stock it may be beneficial just to swap out the cat prior to manipulating the twins.
#14
Recovering Miataholic
My impression is that the turbo pre-control is for the purpose of spinning up the secondary turbo in advance of actually using its output. I thought a failure of that control line would result in the secondary turbo not spinning up, and would cause its slower response to demand. How am I wrong?
#15
If the pre-control failed to open the secondary spool up would suffer, but that "extra" exhaust would flow thru the primary turbine causing an over-boost (before a delayed transition)...
#17
Moderator
iTrader: (7)
Originally Posted by books
I realize my response is contrary to the fact that opening the exhaust is more likely to cause a spike. However in my experience when I changed out the cat I went from a 14-8-8 pattern to close to a 10-8-10 pattern. Since his car is stock it may be beneficial just to swap out the cat prior to manipulating the twins.
Inspecting the cat would be a reasonable first step, rather than replacing it. Failed cats almost always become apparent after a little bit of poking around at it.
Dave
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befarrer
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08-22-15 05:52 PM