My HPS Gen. I/custom SUPERCHARGER experience thread-
Finally got everything installed on the car and got it on the dyno to see where i stand with things prior to putting the car back in storage. I wanted it done now so that i could get a feel for what parts i would need to order etc. before spring so that i'd know what i'd need/have a budget and plan to have to ready to go come May.
current relevent mods-
hps gen I kit
split second psc1-003 in place of the voltage clamp
Car runs very well in some parts of power band, but "breaks" up and hits some kind of an electronic fuel cut or something in others. Any rpm's over 5k or so are likely to trigger this (most likely due to pegging the maf), also often this happens if you aggressively get into it in the mid range (pegging the maf possibly?).
Additionally, it runs lean throughout the entire rpm range (for my taste). It seems that it is likely the ratio which the 02s are trying to regulate it to. Split second makes a scaler which will allow me to adjust this if i want to (now that i know i'll always be in closed loop) and i may want to go that route.
All that said- the car made very respectable power given the issues and i can definitely see some crazy numbers just around the corner...
my plan (please give me feedback)-
add fuel pressure gauge so i can determine if it is truly the 02s limiting my fuel rather than pump or injectors
buy a new maf sensor (i can get jus the sensor right? part #?) and test it with that installed to see if that fixes the driveability. Also, custom build a larger maf housing such that i'm not pegging the meter quite so easily... Another option here might be to buy a larger meter from an w211 e55 or something (do they share the same sensor plug?) as with the scaler i would be able to adjust that to "fit" what the stock ecu expects to see if necessary.
consider adding split seconds lambda scaler- hopefully, based on the results of more dyno time with the maf issue resolved and the fuel pressure gauge installed.
have found no way to directly access ecu tuning software wise...
i installed it myself
I will figure out a way to tune the a/f in closed loop if i need to (there are some options out there) or to basically get it into open loop.
dyno time was at dbperformance- they are my tuners for everything (the wrx and past and friend's projects too)
I really need to figure out if my 'stuttering' type problem is due to my maf or something else a.s.a.p. so that i can then start going down the list of other things- as it is now i can't really start solving the a/f issues, or determine IF i have fuel pump/fuel injector sizes correct.
I would check that your plugs and wires are all in good shape and that you have a clean air filter. You are also going to need to adjust your fuel level for the new found charged air induction to get safe A/F ratios.
i have a rising rate fpr installed on the car (part of hps gen I kit)- everyone i've talked to who have gone down similar paths say that my stock fuel pump and injectors should be good to more power than i'm running now. (so i don't want to just upgrade them because it seems right... i'll wait until i solve some of the other issues and can get a good read on the fuel situation. my car uses the same stock fuel pump as a "600" v12s of the same years and the same injectors and # of injectors as the "55" v8s of the same years---- really seems like both should support 400 crank hp right?)
all plugs and wires are brand new (coppers and magnecores). I talked to my tuner about the possibility that they are in some way the culprit and he said that is very unlikely- that they worked well at high rpm's when the ecu seemed to want them to and that it def. didn't seem to lose spark. That WAS one of my initial possible concerns/issues as to what was going wrong though- and i'll come back to it if need be. The tuner and the guys at split second who i've talked to are both convinced that the A/F problems are strictly due to the o2 maintaining full control (closed loop) even under boost.
i have a brand new air filter as well- however, it's a pos one i got from checker during test fitting.
which are the brands/styles which work well with our mafs? i've heard you just can't run the ones that need oiling (and i'm not).
My thought are that even if the fuel pump and injectors are capable of handeling more HP the cars "tune" needs to tell them to run at a higher rate (more fuel) etc. If the ECU tune has not been adjusted for the increased airflow they will try to run in their stock configuration, of course allowing for some adjustment upward based on MAF readings. The tune and the O2 readings associated with the stock tune when running closed loop are trying to adjust fuel levels based on the stock tune. I'd think your tuner shop would be all over the ECU tune with spark timing, fuel injector duty cycle levels at give throttle and boost levels etc.
All stuff from my Turbo days. Oh check your O2 sensors as well.
Do you know at what RPM the car switches from closed to open loop? Does that correspond with where some of your bucking "break up" is occuring? Car should be on the slightly richer side when in open loop to protect the motor.
Good luck with it and let me know how it progresses.
If you're ever up in the cities throw me a note before hand, I'd love to see your setup.
the issue is that there is NO software available to get into the ecu and actually tune it like a "normal" car
Nor is there information to go full standalone (which would likely be a nightmare anyways to get it to communicate right between all of the control boxes and the transmission).
I'm basically stuck trying to slightly trick the different sensors/modules into making it run right.
This is why i put it together now and don't plan on driving it until summer, lol.
i'll drop you a pm- the car will be in the cities more than it's in Rochester for the next 4 months.
ok, I didn't see all the background on your mods in this post, but a basic tenet is that depending on how much you've increased the airflow of the engine, you need to match it on the fuel side. Your rising rate fpr is a good start, but you'll probably also need to ensure the base rate is higher than the stock fuel pressure to begin with. Not sure on the specifics of MB injectors and such, but you also want to ensure that you're not running them past 85% (IIRC) duty cycle, or you risk them going static = not able to respond fast enough, and unable to deliver enough fuel, usually at a critical time, which = boom!
Ditto for the fuel pump - you'd be surprised how stock fp's usually drop off pretty quickly once they get out of their stock range. Safer to upgrade to a Walbro or something.
Get a fuel pressure gauge before you go any further - fuel starvation is the LAST thing you want in a boosted engine - ask me how I know..
I'd also recommend googling "boost calculator" or variations thereof - you'll find lots of equations to determine injector size, required fuel, etc...
definitely thanks for the advice- and a fuel pressure gauge is among the next phase of things planned (that and modifying/new maf's)
However, i've done a ton of research regarding the stock parts and the hps kit didn't call for larger injectors or pump- so it should have enough fuel for now. I believe i have the same injectors as E55 and the saem pump as sl600...
I def. intend to upgrade if i show any signs of fuel pressure loss OR if i can show the injectors aren't keeping up. At this point i think my closed loop situation is more the issue though.
Linear Mode
