KA - In Memory of my Mom (Vincee) and best friend Michael J. Maring
#93
Took the car out today for a little fun. Had a strange thing happen. While accelerating at WOT in fourth gear starting at about 4000 rpm's the car rockets off then starts to "stutter." If I leave it at WOT, it stutter for a couple of seconds and then takes off again. If I reduce WOT too about 75/80% it stops stuttering. The stutter is not unlike a miss. Any Ideas? Other than this, the car runs fine.
Last edited by cjv; 09-07-2003 at 05:37 PM.
#94
Sounds like the TB is shutting down on you again. When the system goes beyond the threshold and it is severe the TB will slap open and close. It is a violent shutter. Only other thing that would induce the same feel would be an over fuel issue. Is your AIC working ok? You would be able to tell this by a black cloud of smoke when it was stuttering.
#95
Stephen,
No black cloud of smoke. There are only two things that are different. First on a acceleration run I banged the the rev limiter pretty hard in first gear one time (really need to extend first). This caused a check engine code to light. I disconnected the battery for a half hour and reconnected. The light went away. I think this may have started the problems. Second, I changed the stock plugs to the Iridium plugs. They are a little shorter, have very thin core electrode and have only one electrode ground instead of two.
I think your first guess is probably it. After the shutter, the boost can go as high as 1.5 bar (the TB is shutting). It is extremely violent at first.
No black cloud of smoke. There are only two things that are different. First on a acceleration run I banged the the rev limiter pretty hard in first gear one time (really need to extend first). This caused a check engine code to light. I disconnected the battery for a half hour and reconnected. The light went away. I think this may have started the problems. Second, I changed the stock plugs to the Iridium plugs. They are a little shorter, have very thin core electrode and have only one electrode ground instead of two.
I think your first guess is probably it. After the shutter, the boost can go as high as 1.5 bar (the TB is shutting). It is extremely violent at first.
Last edited by cjv; 09-07-2003 at 08:59 PM.
#96
It is possible your TB limit was only moved up, not eliminated. In that case you may have caught the turbos on a good day and overshot for a second and clipping the TB limit. Get them to remove it or push it to the moon. When it does happen you think the motor is going to drop on the ground. It does get your attention.
#99
Stephen,
Hey, GIAC didn't want to raise my BAR limits to 1.8 until after the little get together. Thank God for the global economy, I mean tuners.
Greg,
I was hoping my little 232 ci Porsche motor would have the honors.
Hey, GIAC didn't want to raise my BAR limits to 1.8 until after the little get together. Thank God for the global economy, I mean tuners.
Greg,
I was hoping my little 232 ci Porsche motor would have the honors.
Last edited by cjv; 09-07-2003 at 09:00 PM.
#103
How long do you want the motor to last?
Your question is good, but there are a lot of factors to consider
to get an answer. If you mean "How much power can I tune
for, and expect the motor to last as long as stock, for my
typical street driving" then the answer is different than if you
mean "How much power can I tune for so I can win all my nightly
drag races at the strip with my car running slicks, and still tow my
supply trailer to the track?
Stephen of ImagineAuto has a well-pumped 996tt, which he
runs hard and often. He seems confident of the car's durability.
to get an answer. If you mean "How much power can I tune
for, and expect the motor to last as long as stock, for my
typical street driving" then the answer is different than if you
mean "How much power can I tune for so I can win all my nightly
drag races at the strip with my car running slicks, and still tow my
supply trailer to the track?
Stephen of ImagineAuto has a well-pumped 996tt, which he
runs hard and often. He seems confident of the car's durability.
#104
Very true, I am more interested in how much power the internals can take and still have some life. Don't care about dragging the car every weekend. In fact after I do stage 5 it will go to the drapstrip once and then I will be done. I prefer running road courses and that is what the car is made to do.
Thanks!
Thanks!
#105
ok....
It all depends on how much road-coursing you'll do. Track
events are taxing on any car. Even a stock Porsche will
get tired much sooner if it gets run hard on a regular basis.
Brakes will become consumables, and rotors too. Depending
on the power, the clutch may need strengthening. Watch your
tach and temps: keep off the rev-limiter and your motor's lifespan
will be as long as one would expect... I would install an oil cooler
for the transmission for hard track use.
Joe
events are taxing on any car. Even a stock Porsche will
get tired much sooner if it gets run hard on a regular basis.
Brakes will become consumables, and rotors too. Depending
on the power, the clutch may need strengthening. Watch your
tach and temps: keep off the rev-limiter and your motor's lifespan
will be as long as one would expect... I would install an oil cooler
for the transmission for hard track use.
Joe