bad compression? - bad check valve? - boost leak? - bad boost selinoid?
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bad compression? - bad check valve? - boost leak? - bad boost selinoid?
Hey everyone.
My problem is that with the 99 twins, and boost controlled by the PFC I was tuned to run about .83 to .89 bar. Recetly i can't boost past .79 bar being the max -- most of the time its .69 bar. im not sure what this is due to.
Ive checked and rechecked the IC couplers and I have on order a new set of check valves. When I do a graph on the PFC of boost and RPM the boost graph looks fine just lower than normal.
What is causing this?
could it be bad compression? - bad check valve? - boost leak? - bad boost selinoid? - warmer weather?
I alrealdy searched the threads about this but you all know as well as i do there are thousands of threads containing the words that i need to look up a simmilar problem.
My problem is that with the 99 twins, and boost controlled by the PFC I was tuned to run about .83 to .89 bar. Recetly i can't boost past .79 bar being the max -- most of the time its .69 bar. im not sure what this is due to.
Ive checked and rechecked the IC couplers and I have on order a new set of check valves. When I do a graph on the PFC of boost and RPM the boost graph looks fine just lower than normal.
What is causing this?
could it be bad compression? - bad check valve? - boost leak? - bad boost selinoid? - warmer weather?
I alrealdy searched the threads about this but you all know as well as i do there are thousands of threads containing the words that i need to look up a simmilar problem.
#2
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Not a compression problem, and you've checked for boost leaks. Probably not the solenoids or check valves, since that usually affects things below or above 4500rpm.
The warmer weather can often swing boost by a psi. When was the boost tuned? Does adjusting the PFC restore the .83bar level?
Dave
The warmer weather can often swing boost by a psi. When was the boost tuned? Does adjusting the PFC restore the .83bar level?
Dave
#3
Racecar - Formula 2000
The only things I can think of that would limit the boost to some lower level at ALL RPM's are:
1. Controller setting (boost sensor?)
2. Boost leak
3. Leaky WG or WG actuator stuck partially open
Everything else (clogged cat, collapsing intake hose, leaky check valves, etc.) have more effect in one RPM range than another.
1. Controller setting (boost sensor?)
2. Boost leak
3. Leaky WG or WG actuator stuck partially open
Everything else (clogged cat, collapsing intake hose, leaky check valves, etc.) have more effect in one RPM range than another.
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Does it happen in all gears? I have a similar problem mostly in lower gears intermittently on the secondary turbo. Also on part throttle acceleration just past transition boost jump all over the place. It makes for a very unrefined experience. Leads me to believe its wastegate.
At sea level in FL the 99' will hold .90 all the way to red line on a hot day in 3rd.
All of these bugs have made me strongly consider going non-sequential low-end lag is pretty by modern standards. Even though I can reach .90 boost by 2500 in higher gears it doesn't really have the much down that low.
At sea level in FL the 99' will hold .90 all the way to red line on a hot day in 3rd.
All of these bugs have made me strongly consider going non-sequential low-end lag is pretty by modern standards. Even though I can reach .90 boost by 2500 in higher gears it doesn't really have the much down that low.
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Originally Posted by dgeesaman
Not a compression problem, and you've checked for boost leaks. Probably not the solenoids or check valves, since that usually affects things below or above 4500rpm.
The warmer weather can often swing boost by a psi. When was the boost tuned? Does adjusting the PFC restore the .83bar level?
Dave
The warmer weather can often swing boost by a psi. When was the boost tuned? Does adjusting the PFC restore the .83bar level?
Dave
at most this has helped about about .05 bar maybe from .74 to .79 bar
should i adjust this more?
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Originally Posted by DaveW
The only things I can think of that would limit the boost to some lower level at ALL RPM's are:
1. Controller setting (boost sensor?)
2. Boost leak
3. Leaky WG or WG actuator stuck partially open
Everything else (clogged cat, collapsing intake hose, leaky check valves, etc.) have more effect in one RPM range than another.
1. Controller setting (boost sensor?)
2. Boost leak
3. Leaky WG or WG actuator stuck partially open
Everything else (clogged cat, collapsing intake hose, leaky check valves, etc.) have more effect in one RPM range than another.
Hopefully i will be one of the first testers of boost leak kits on FD's
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Originally Posted by FLA94FD
Does it happen in all gears? I have a similar problem mostly in lower gears intermittently on the secondary turbo. Also on part throttle acceleration just past transition boost jump all over the place. It makes for a very unrefined experience. Leads me to believe its wastegate.
At sea level in FL the 99' will hold .90 all the way to red line on a hot day in 3rd.
All of these bugs have made me strongly consider going non-sequential low-end lag is pretty by modern standards. Even though I can reach .90 boost by 2500 in higher gears it doesn't really have the much down that low.
At sea level in FL the 99' will hold .90 all the way to red line on a hot day in 3rd.
All of these bugs have made me strongly consider going non-sequential low-end lag is pretty by modern standards. Even though I can reach .90 boost by 2500 in higher gears it doesn't really have the much down that low.
Yeah Ive also been thinking about the non sequential mod. I haven't tried this in 4th for any long period of time but in second and third the boost patern is great its just the humps spike at less then .79 bar. Im at sea level and have tepuratures between 70 and 80 degrees F. but i was tunned in 40 degree weather..... about 7 or 8 months ago.
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Originally Posted by dgeesaman
Is there any chance your cat(s) are clogging?
Isn't a cause for clogged cats runing too rich?
I guess Ill have to break out the thermometer and see..... but I did notice that when i start the car it spits black specks from the exhaust pipe and its not oil so I dont know if that means your cats clogged or not ... just a thought.
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