4.5.3 Issues Boost command 6500 rpm and up, No boost after flash and idle cam table causing surging.
Posted: Fri Aug 15, 2025 8:09 am
Please see 8:41 in the time on the log for the first issue below
First issue is FK8 FL5 and DE5 cutting boost to lower value at 6500 rpm to redline log included shows this happening. I have noticed that sometimes different cam timing will alleviate the boost issue but makes the tune sub optimal. I have tried changing every torque value. This happens every time and the fuel systems has plenty left. Stock cars and cars with camshafts will do this when intake cam timing is around OEM area at 6500 rpm.
The log included shows the issue at 8:41 and doesn't happen in 3rd gear. I can only guess at this point it's some sort of torque calculation issue or limit. If I move the intake cam timing to a significantly lower value, it will make more boost but is not optimal. Aircharge was set to 240 all the way to redline and suddenly drops to 222 at 6500. All tables were checked and I rebuilt multiple files.
The second issue is I've had multiple complaints of 4.5.3 on Fk8 somehow effecting boost response and extremely low boost and very laggy feeling. I don't have log from those cars yet. There is no check engine light either.
The last issue I would like to bring up is the idle cam tables being changed causes surging and bounces oscillates the factory settings after flash (30 and -25) and whichever value you set it to.
Thank you sincerely
John Pierro from FK8TD.com
First issue is FK8 FL5 and DE5 cutting boost to lower value at 6500 rpm to redline log included shows this happening. I have noticed that sometimes different cam timing will alleviate the boost issue but makes the tune sub optimal. I have tried changing every torque value. This happens every time and the fuel systems has plenty left. Stock cars and cars with camshafts will do this when intake cam timing is around OEM area at 6500 rpm.
The log included shows the issue at 8:41 and doesn't happen in 3rd gear. I can only guess at this point it's some sort of torque calculation issue or limit. If I move the intake cam timing to a significantly lower value, it will make more boost but is not optimal. Aircharge was set to 240 all the way to redline and suddenly drops to 222 at 6500. All tables were checked and I rebuilt multiple files.
The second issue is I've had multiple complaints of 4.5.3 on Fk8 somehow effecting boost response and extremely low boost and very laggy feeling. I don't have log from those cars yet. There is no check engine light either.
The last issue I would like to bring up is the idle cam tables being changed causes surging and bounces oscillates the factory settings after flash (30 and -25) and whichever value you set it to.
Thank you sincerely
John Pierro from FK8TD.com