i think i might be experiencing on or the other. Does fuel/timming cut cause the car to repeatedly "bounce" off of 17 psi? Can you feel it fuel cut? Do you need to be on the dyno to tell if its pulling timing?
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fuel cut feels a lot like the rev limiter. it pulls out fuel to decrease boost. stock and stage 1 pcm's fuel cut at around 17.8-18psi
Stage 1 PCM does not have an overboost cut in it. That's one of the features of it. So, you'll never experiance a fuel/ignition "cut" caused by running too much boost with Stage 1.
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Umm actually you will...the stage 1 ecu will stop throwing spark at around 18psi or so, and the infamous p0108 code will be ever present.
What the computer does is take the spark away completely...if it were to take the fuel away, the boost would remain, but you would run lean..and detonation isnt a good thing..and if you were to overboost...you would know it..it doesnt just bounce off...it feels like you let go of the throttle..a bouncing rpm means you were hitting the rev limiter.
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Umm actually you will...the stage 1 ecu will stop throwing spark at around 18psi or so, and the infamous p0108 code will be ever present.
What the computer does is take the spark away completely...if it were to take the fuel away, the boost would remain, but you would run lean..and detonation isnt a good thing..and if you were to overboost...you would know it..it doesnt just bounce off...it feels like you let go of the throttle..a bouncing rpm means you were hitting the rev limiter.
Nope. I've personally ran 19 psi of boost dropping at 5500 rpm to 16 psi at redline and I've never had anything like you describe happen. I do not have a MAP clamp either. I personally know of several people that have ran more boost than that on Stage 1 with no MAP clamp and they've never hit what you describe either.
Also, at the SRT-4 Nationals, Ethan told us that the fuel/ignition cut is one of the things that the PVO guys removed from the Stage 1 computer.
Now, the car does start to pull timing back when you are running that much boost, but it does not cut it all together. This I am positive of.
Then how exactly did I manage to do that in a stage1 car running 21lbs of boost at redline....
Now, when running 19 or so and keeping the boost under 18 at around 4K up, you have nothing to worry about, but hold 19psi or better up top and see what happens, the P0108 code will magically appear and your car will feel like it hit a brick wall..
Whether or not its supposed to have a limit to it is one thing, all I can say is from my personal experience is that without the safc pulling atleast 4-5% in the upper RPM range while running over 19lbs of boost..the car hit "fuel cut".
Then how exactly did I manage to do that in a stage1 car running 21lbs of boost at redline....
Now, when running 19 or so and keeping the boost under 18 at around 4K up, you have nothing to worry about, but hold 19psi or better up top and see what happens, the P0108 code will magically appear and your car will feel like it hit a brick wall..
Whether or not its supposed to have a limit to it is one thing, all I can say is from my personal experience is that without the safc pulling atleast 4-5% in the upper RPM range while running over 19lbs of boost..the car hit "fuel cut".
Like I said in my previous post, I've ran 19 psi till 5500 rpm, then it dropped off till 16 psi at redline. I never had any code thrown when that happened. Ohh, and how did you manage to run 21 psi at redline? With an aftermarket turbo I assume as the factory turbo is too small to support that much pressure at redline.
Assumptions will get you nowhere...try stock turbo...along with a 75wet shot. In either case, if it were an aftermarket turbo, it still shouldnt matter should it, as you claim the stage1 pcm doesnt have the ability to throw a P0108 code....
when i got my agp wga , i put that badboy in and i went for a drive, in second gear i hit 20lbs boost steady, then in third it went to 20 lbs again . it gave me the overboost performance code wich was like 0234. it didnt stutter at all! ofcourse i adjusted it afterwards to keep it safe. yesterday though i adjusted to get more than 16lbs , i got 17 lbs with just a turn or two but halfway into 3rd gear it started to cut me off. all this is with a stock pcm and stock turbo. I guess some cars just act different!!
We've run more than 19psi with no map clamps on any of our 3 cars, and have never had the computer cut us out! It has always held strong, even when the fuel systems were stock. Now, I will say this, it did throw timing on my car(using 93 octane) when running on the dyno with about 19psi, but it did not cut. Now in the other 2 cars we run race fuel exclusively, weve taken the boost as far as 22 psi without throwing timing on the stock fuel syustems.
Assumptions will get you nowhere...try stock turbo...along with a 75wet shot. In either case, if it were an aftermarket turbo, it still shouldnt matter should it, as you claim the stage1 pcm doesnt have the ability to throw a P0108 code....
Have you ever thought this might be something that just your car is experiancing? Ohh, and running nitrous puts you in a whole differant ball park when tuning, comparing, power, acceleration, and lots of other areas. I'm not dogging it, just saying that running nitrous explains a lot.
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what happens during fuel/timing cut?
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