I am currently running the standard HAHN stage II turbo system on my 2003 ecotec cavi and am looking into new fuel management since I am going to be increasing boost to about 13-15psi. Right now I am using the cartech FMU that comes with the kit. I read on here that if I am running over 12psi and using HPT that I will need to keep my FMU for the increased fuel at full boost. I have been doing a lot of research and have been looking into the Portfueler and the AEM f/ic but the portfueler is pricey and the f/ic hasn't been used on the ecotec cavi as to my knowledge. My friend is running the f/ic on his cobalt 2.2 s/c and it works great but the cobalt is set up different than the cavi so idk if it would work. The portfueler seems to be the best option but it is very pricey as I had said before. I am planning on using HPT but is this true about needing to keep the FMU as well? Also right now I am running 32lb injectors, what size injectors should I be running at 13-15psi?
I would first venture to say that 32 lb/hr are not going to be sufficient for more boost. I'm running 30 lb/hr on an n/a eco if thats any reference. 15psi out of the 16g i'd say go with at least 42lb/hr injectors to be safe. 60lb/hr if you think you may again want to up the boost or upgrade in the future.
As far as if you need the FMU, a good way to judge is to first attempt to tune it with HPT. Get your new injectors and get the injector constant right. Start tuning. You will likely find you need to adjust your VE offset to get the fuel you need up top. If you find you can't adjust the offset high enough without sacrificing the low rpm/idle drivablity, then its time for an FMU.
Or you could always skip that step and just use the FMU, dyno tune and call it a day.
The portfueler is your most expensive option, but it's the best. If you do it, put your stock injectors back in and get rid of that FMU stuff. Your car will act 100% stock and drive perfectly and the portfueler will take care of fuel in boost.
Otherwise, go with some 50# or 60# injectors.
Stock motor? 15 psi might be too much.
The motor will have rods and pistons within the next few weeks. The more I think about it the portfueler is sounding better and better. Thanks for the quick responses.
The portfueler is your most reliable option. Or the equivalent type of extra injector controller.
-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party
pistons and rods... its time for 25 psi baby!!!!!!!!!!!!!!!
I tuned a car to run 11.01 1/4 mile w/ fmu/hpt setup with a very steady afr, in the 11.5-11.8 range. It's possible and there have been a couple threads discussing it.
HPT and a FMU
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4 Cams...32 Valves...5 Liters...This Could Get Fun!
i got mine at 11.8 on 25 16 g. i can't squeeze any more gas outa it. Im phat said there should be plenty more but i gave up. i want the port fueler.
