Quote:
Originally Posted by nothingman
It's an issue which began immediately after I had the PS2 and XDi HPFP installed. It usually occurs around 2,000-2,500 rpm in 6th or 7th gear between 60-80mph when driving the car normally down the road. Having DCT may make it more evident since I'm not manually shifting gears when I'm just cruising. When it happens, the car pulls a ton of timing for a split second.
My PS2 was installed by Frank at TTFS, who is also the exclusive distributor for the XDi HPHP and wrote the fuel maps. I had Frank check and replace the spring in the DV+, check the turbo installation for leaks, replace the plugs twice with both OEM Bosch and NGK 95706, tried different gaps, replaced the O2 sensor, tried both MHD and BM3, tried different tuners... nothing fixed it. That's why I went the path of this big turbo upgrade thinking replacing everything would fix it by process of elimination. Throwing good money after bad... a foolish mistake and never a good idea.
I uploaded a few of my datalogs taken in August but posted to Datazap on 11/20/2020 in case anyone would like to look through them:
https://datazap.me/u/nothingman/
I've talked to at least 10 other people with the same configuration with the same exact problem. Some of those people have the Dorch HPFP, so it's not strictly XDi. I haven't talked to anyone running Spool. This past weekend, I was messaging back and forth with boldy1, who is also having the same problem and we went back and forth with our findings. He even replaced his ignition coils. I was about to order a Precision Raceworks ignition kit to see if that resolved it, and then came across yet another person with the problem that had already tried that. That's when I decided to abandon the project.
The only people I know (count:2) who are running either a Pure Stage 2 turbo or Stage 3 Speedtech kit and aren't having the problem are using different HPFP solutions. One is using an S55 HPFP retrofit, the other port injection.
I've always wanted to own a blistering fast turbo charged car, but I think chose the wrong platform to pursue it with. |
Hey, I came across your thread and find it very interesting.
I have a N55 M135i and had similar issue. My initial goal was to push over 500 HP with only pump gas (98) as I don't want port inject or meth injection kit because I daily drive my car, therefore I want it to be as convenient as possible, just fill gas and GAS!
I followed the "standard route", upgrade HPFP, turbo, intercooler, downpipes etc. But it never worked out. Eversince stage 2, I kept having misfire at around 4000 rpm due to fuel pressure drop. So upgraded to Dorch stage 1 HPFP, ran into the same problem, then people suggesting B58TU pump which they claim it could handle over 500 WHP, easy. Ok fine, bought it, retrofitted it to N55, hoping it would fix the fuel drop problem. But nope, it doesn't. it couldn't even handle 470 HP.
Fueling seems to be the biggest problem for N55s, but nobody really talks about it and many claiming big numbers on dyno (similar setup as mine), therefore, I seriously doubt those numbers.
So now, I am also retrofitting S55 pump on my M135i. There aren't many information about S55 pump retrofit on the forums, so my friend spent countless of hours finding solutions to make it work, activating the 2nd fuel pump, no "extra controller for the 2nd fuel pump or signal splitter or sorts and without any "hardware modification" on the S55 fuel pump.
Luckily, he was able to find solutions for all the problems we were facing, we are now in testing phase. Just test drove the car today, it drives like a charm. Pushing around 530 HP & 700 NM, no more fuel pressure drop (98 fuel). As soon as the car is completely finished, I will share datalogs and dynosheet if you are interested. Cheers.
James