No I have not experienced that with my sled but I have the stock intercooler...for now....Any of you guys hitting the boost cut out at half throttle acceleration? Right around 23 psi boost.

No I have not experienced that with my sled but I have the stock intercooler...for now....Any of you guys hitting the boost cut out at half throttle acceleration? Right around 23 psi boost.
PEFI Stage 4 is a 4 bar tune. FP = 58/59 psi key on engine not running. Makes up for injectors probably being too small at 43.5 psi fp.You have to remember that 998 guys are a greedy bunch, and they are running hardware beyond what the tune was developed on. I dont care what brand tune a guy runs, when you put on bigger mufflers, ram air intakes, bigger intercoolers and other hardware that the tune wasn't developed for, they are going to go lean and change with the wind. You should see how lean some of these things run, and then people decide not to use closed loop and data log...
The stock injectors are out of fuel using "300 HP" tunes with good hardware. I know some guys running 3" mufflers and intakes on 280 PEFI sleds and they are extreme lean. They get by with it by throwing in some race fuel to keep them alive. The PEFI setups are not supposed to be using any intakes or mufflers larger than their own 2.5" trail muffler that does not flow much. The little turbo is out of air right along with the injectors being out of fuel in the so called "upper 280-300 HP" levels. I'm not sure there is a true 300 pump gas setup out there on a real engine dyno myself with stock injectors and turbo, (Tommcat had 297 real engine HP I believe on a stage 4 PEFI setup he dynoed, and I think he even had cams in that engine, they are claimed to be 320HP on pump gas stock engine from PEFI).
These ECU's are not much to write home about for consistency day to day either. They are severely lacking in different areas compared to good automotive stuff out there. Basically the ECU is a POS in comparison. We chase them day to day with the changes and there no consistency in them. They are all over the board and no two sleds are the same.
What kind of boost are you running with the header ect?PEFI Stage 4 is a 4 bar tune. FP = 58/59 psi key on engine not running. Makes up for injectors probably being too small at 43.5 psi fp.
I have cluster flash too so all 5 tunes are now 58 lb tunes.
They still want you to run their 2.5" restrictive "performance" trail muffler. I run 3" Sandale, a bigger intercooler, so my fp is higher than 58 to make up for it.
I don't get boost cut at all. Our baby turbo is all done about 280. When I ran on track dyno, on what PEFI calls "Full Race map" w C16 and waste gate locked (at .015") max hp was way down at about 7800. Turbo can't pump any more.
Boost levels off at 17-18. AFR 11.8-12.0. Based on my AEM AFR gage w Bosch LSU 4.9 O2 sensor.What kind of boost are you running with the header ect?
It would be interesting to see your AFRs at that kind of fuel pressure.
How much boost do you see with waste gate at .015 ?PEFI Stage 4 is a 4 bar tune. FP = 58/59 psi key on engine not running. Makes up for injectors probably being too small at 43.5 psi fp.
I have cluster flash too so all 5 tunes are now 58 lb tunes.
They still want you to run their 2.5" restrictive "performance" trail muffler. I run 3" Sandale, a bigger intercooler, so my fp is higher than 58 to make up for it.
I don't get boost cut at all. Our baby turbo is all done about 280. When I ran on track dyno, on what PEFI calls "Full Race map" w C16 and waste gate locked (at .015") max hp was way down at about 7800. Turbo can't pump any more.
Couldn't get past about 22. Turbo too tiny.How much boost do you see with waste gate at .015 ?
I have noticed this Tim. I will consistently show higher boost numbers at around 50 to 60 % throttle and lose it under acceleration because i think the header just blows the wastegate open under hard acceleration. I'm done chasing my tale with this set up and will correct before the snow flies next season. I'll have to deal with higher AIT's, but it nothing that can't be overcome.Not wide open, half throttle mine hits boost cutoff on acceleration.
I have noticed this Tim. I will consistently show higher boost numbers at around 50 to 60 % throttle and lose it under acceleration because i think the header just blows the wastegate open under hard acceleration. I'm done chasing my tale with this set up and will correct before the snow flies next season. I'll have to deal with higher AIT's, but it nothing that can't be overcome.
Mike very valid point in fuel and i think even though closed loop is adding fuel it struggles with lower octane on cold days and just can't keep up. Even by adding 3.5 oz of Boostane per tank, mine would be hitting 110% and without a huge demand on the throttle. I would rarely see it pull fuel under "normal" riding conditions at 53 lbs.
What muffler?This has been an interesting subject and read for me. I didn't realize that I wasn't the only one having to raise the FP on my sled to 50+psi. My sled has a stock wastegate yet will build upwards towards 20 psi boost at WFO and I know that is not typical with a header so I thought that my FP requirements for safe AFRs was an anomaly. Looks like these Hurricane Header tuned 998s are really needing the fuel and we all know you need fuel for horsepower.
I really like the adjustable FPR as it is so easy to quickly adjust which I have used to gain fuel economy by reducing FP for slow trail riding where the closed loop is not always active and I know I am not going to be wide open on the 300 tune.
Again...for me...closed loop and data logging is essential on my sled and I would not tune above a stock muffler 240 tune sled without it.
I was actually thinking about running a 3/8" return line Tim because symptoms are similar to a pinched return line. I'll most likely add this, but definitely going another route next year in regards to the stock wastegate. Honestly would have already gone this route but got sidetracked the last couple years under the circumstances.I think it happens at the last reduction in boost to bring down to the "300" level.
Header and 3" muffler is what tune is designed for so i don't get it. Up front i have the stock intercooler with the secondary intercooler under hood which is supposed to deliver more even air to all 3 cylinders. Turbo is all stock.
Found my fuel return line was getting pinched when seat flexes down just ahead of pump and messing with fuel pressure.
Might have to run an internal fuel line inside tank from original return location to the fuel pump slipper.