HAZE

i'm back guys, the other thread was getting a bit long. so lets continue here. i'm going to order the 43lb. inj's as soon as i can figure out the whipple/pcm interface. for you guys that are running larger inj's and leaving the whipple computer connected, and unplugging the add on inj's. what is intercepted in your wiring ?. if yours is like mine [ maf, front o2's] i don't see how it can be tuned using o2 readings and l-trims. i've proven to myself through logging with and without the w/computer online, that it does in fact modify the signals. which would seem to make tuning impossible. i know i keep asking the same questions, but noone seems to be able to answer them. if the whipple is sending modified info to the pcm, how can it possibly be expected to make correct a/f calculations ? if it can't see "real" maf and o2 readings it can't compensate with fuel right ?. so again, how are you doing it. guess i'll have to try the tap instead of intercept theory myself since noone else seems to have done it. is it that you guys are using widebands ? and that signal isn't intercepted ? my truck is still coding due to the ridiculously low o2 readings above 60% throttle, maybe my whipple computer is just programmed wrong. ryan, you seem to be tuning with o2's and l-trims and it's working, how is your whipple hooked into your pcm ? and have you experienced the super low o2 readings i'm talking about ?. talk to me guys, i want to get this straightened out. if any of you guys have an in with whipple maybe you can hook me up, they havn't seemed willing to give up much info. thanks, e

BigTex

iTrader: (16)

Exactly. Unless you know what parameters they are trowing out to your PCM, you cant accurately tune for it.

I completely removed my whipple stuff and just ran the compressor, so I can't directly answer your question.

L-EATER

iTrader: (2)

That is why I removed that entire system too. You can't tune it with that thing constantly interfering. Makes the temp gage do funny stuff too. I guess if you had a wideband you could do it but I still dont understand why you would want to keep any of that on there. Just my .02

67SS509

iTrader: (22)

Throw out the whipple computer and wiring, apply 12 volts to the solenoid with a switch. That way at a flip of the switch you have 2lbs of boost or 4.5lbs. Add water injection or something for the detonation. Then tune with a wideband and you are in business.

HAZE

ok, correct me if i'm wrong. the reason's for the bypass are; failsafe for lean condition [ reduces boost, if sytem leans out for whatever reason] and closes under low engine load so your engine acts like a n/a for milage. those are reason enough to keep it, if i can make it do that and only that. if i remove the computer and run a switch, im boosted all the time correct ? and then i have to flip switchs when i want more boost. this truck is a daily driver/tow vehicle, i'd like to keep it as simple to drive as possible. also like to keep the mileage at least as good [ which isn't good] as it is now. also i live in an emission controlled state, they can and do impound your vehicle if you are obviously not compliant [ usually only if they catch you racing]. guess it won't hurt to try my idea, i can always scrap the whipple stuff if it doesn't work. you guys say your running w/o the computer, what problems if any have you run into ? another question i've asked and never got an answer to is; can the stock fuel pump, maf, and map handle boosted applications at/under 5lbs ? if so at what pressure do you have to upgrade to a different maf and or 2-bar map ? does anyone know if any of the previous whipple systems used a tap only wiring system? give me your opinion whether or not you think this could work. if i'm correct the whipple doesn't get any "feedback" from the pcm, it only intercepts sensor signals. and sends modified signals to the pcm. it shouldn't be able to tell if it's intercepting the signal or just reading it. it will still send the modified signal, it just won't be connected to anything. it should still be able to detect maf and o2 signals and control the boost solonoid if it "sees" a lean condition. it will still send a signal to the aux inj's that will be disconnected [ should this be looped?] . this is all just theory about a computer i have no knowledge of how it works. if you know of any reason this won't work let me know. any help is appreciated and i'll keep you guys posted on whether or not it does, in case anyone else is interested in doing this. thanks, e p.s for those who aren't aware, yes i will be using larger inj's.

00z71sierra

Who makes the injectors and are they plug and play? Where can I get them? I have the first gen Whipple on my 5.3 so it uses the mechanical bypass. I have also disconnected the Whipple CPU and aux injectors and it runs 10 times better....but not good enough yet.

HAZE

you disconnected the inj' and computer without using larger inj's ? when i bypassed mine at 2lbs of boost at wot i was at 103% inj. duty cycle. ryan linked me to this place www.azspeed-marine.com/gmtrucks.html haven't dealt with them but called my local shop they said between $60-80 apiece but not for this brand. they are supposed to be plug and play. e

HAZE

me again, guess the question i should be asking is: is there anyway this rewire job could fry my pcm. uh, that would suck.

00z71sierra

Yeah, but I had a local shop tune the PCM to add more fuel to the stock injectors using LS1 edit. It's good now but if I want more I need to add larger injectors. Again, I have the old 2 belt setup so I don't have to deal with their electronic bypass; it only has a mechanical one.

I had so many problems with detonation while using their stock setup that I now wonder why they even set it up this way.

BigTex

iTrader: (16)

The injectors you are talking about from Arizona Speed are GM injectors that were made for the 8.1 liter Marine motor. They flow 42 pounds at our fuel pressure. They can be bought from GM, or other resellers like racetronix and rcengineering. Its a standard Multec II type injector, so it is a direct plug in replacement for the truck injectors. Magnacharger ships these same injectors with their Radix kit, as does Kenne Bell with their GM supercharger kit. Do a search in this section for marine injectors, and you'll find several threads on that subject with part numbers and info.

Contact whipple and see if you can buy the parts for a mechanical bypass. They will probably balk about you removing thier harness and computer and say it will void any warranty, then try and sell you an "upgraded" tune for their system. Just say you aren't interested in their electronics and want a mechanical bypass. Once done, you could just add injectors, remove all their electronics, and have a custom tune for the larger injectors and be all set.