rxrotary2_7

i know i can not be the only one who has had a problem staging 550's and 1600's. can anyone please tell what they have done to *help* the situation.
in my personal car, i have no problem with this. the problem is with a friends car i was helping him with. he is still using the stock turbos on his FD. from talking to some other people, they have said that lowering the base fuel pressure will help this out. i have heard as low as 25lb??

vosko

iTrader: (4)

you can move the staging bar under the engine setup page

rxrotary2_7

i understand that.
its the *stumble* once the map reads positive pressure and turns on the secondaries that is the problem, not the pressure or BAR were the staging happens.

rxrotary2_7

maybe it is the bar.... but i was not asking how to move the staging bar. i am asking how to cure the stumble. maybe i was not clear with that.

RETed

Try lowering the bars after the staging bar?&nbsp i.e. leaning out the map points after the secondaries kick in



-Ted

rxrotary2_7

i did that though ted. it it still very noticable. any other suguestions?

RETed

You know if you're leaning out or going too rich?
Is it getting better?&nbsp No change?
How about going the other way?


-Ted

rxrotary2_7

yeah, i know what way to go, and it is leaning out slightly from what the FJO says. i just dont know how low i can go. but even using the PgDn button, not just the arrows, it is still there. i did get it noticable *better* in some ranges, but in the 3500 and 4000 range... damn!!! i cant make a dent in it. have not tried to lower the fuel pressure due to like 3 feet of snow on the ground, but just trying to get some help for when this **** thaws out.
Ted, what do you think about lowering the base fuel pressure? should i? and if i do... should i go back and faten up the bars after the stage and then lean them out again after i try it with lower fuel pressure? thanks for the help.

RETed

To me 25# is way too low for base pressure.&nbsp If you've seen the poll in the Single Turbo(?) section, some ***** are running as high as 55#!&nbsp We usually try to keep it a min of 30# or around 30#-40#.&nbsp Going lower usually degrades idle (unless you're idling over 1,000RPM?) and allows a lot of fuel puddling in the intake.

Oh, and don't worry about the wide-band readings.&nbsp In the beginning, we also tried to tune out the lean-drop on the crossover, but it got us no where.&nbsp After ignoring the lean drop (as bad as it sounds), the crossover was seamless.&nbsp We figured the engine wasn't loaded enough for the lean drop to cause any harm.&nbsp With large staggers such as yours, we run the staging bar really low though - like at least 3 bars UNDER the "0" points.&nbsp Where is the staging bar now?



-Ted

rxrotary2_7

thats what i was thinking. 25LB seemed LOW to me too. right now i have it set for 36LB base. also, the staging bar is at 0-psi. idle is about 850prms.
so you are basicly telling me to stage at a lower bar?

RETed

Get the staging bar away from "0" as much as possible.&nbsp This is one of the tricks for tuning for driveability.&nbsp Having it at "0" causes all kinds of weird problem due to the abrupt transition for turbo'd engines.&nbsp The farther away from "0" you can move the staging bar, the easier it is to tune smoothly.

Big staggers like your set-up, I like to drop the staging bar to the left.



-Ted

vosko

iTrader: (4)

sorry if i wasn't clear that is what i meant. move the bar to the left. i have no stumble when my secondaries come on...

rxrotary2_7

oh ok. i didnt realize you knew all that **** Ted just explained.
like i said... like you, in my single turbo FD i also have no problem with the stumble. its in a friends stock twin car that i installed the haltech in and am trying to set it up is where i am having this problem. thanks for trying to help though jon.

vosko

iTrader: (4)

well i learned the hard way tuning my car... soon i will be retuning my entire map.....

rxrotary2_7

ok.. had a chance to play some more. did what Ted told me. moved the bar into vacume, tried it after boost... either way it did not matter. same thing would happen.

the reason i tried to move it into the boost was becasue i was thinking about AIC's. these come online as the turbo has already reached a pre-determined boost presure, and for the most part, come in seamlessly. i figured that a 550 *should* be able to carry the motor for a few pounds while some air flow is built up, and the huge secondaries will not totaly "dump" into the mix drowning the motor... still nothing. i have the secondaries all the way down to 1.6XX... any lower and from what Ted has told me, they will become unstable.

again this is only hapening in the 3-4K ranges. anything higer and you cant even tell that the transition is there (almost seamless) like if you were to start boosting at 5K rpm... the car is OUT!! but anything in the 3500ish range... it bucks and sputters, and backfires...

can anyone help me? am i doing something wrong? what the hell is going on? anyone? anyone?

another thing i was thinking of doing was adding in some timming were i was staging the injectors... is this a good or bad idea?

vosko

iTrader: (4)

it sounds like you have a timing or ignition problem.....

Manolis_D

iTrader: (2)

Perhaps a dumb question... are you sure the problem isn't turbo-related?

rxrotary2_7

how do you come to that conclusion? would you care to elaborate?
vague answers are not helping.

vosko

iTrader: (4)

you said its hesitating right ? hesitation can be caused by a few things ( you already know) . it can be too lean, too rich, too much timing, ignition misfiring...... i haven't seen the car just trying to give friendly ideas. if someone can diagnose a car problem over the internet 100%, they get a from me

rxrotary2_7

i am not sure of anything. if your question is does the turbo work properly, the answer is YES it does. before the haltech the car ran a 12.9 at 108 with just a homemade intake, a CB and a pettit ecu running 11LB of boost in sequential mode.

the stumble is DIRECTLY related to where i move the staging bar. if you look in the manual in appendix D.3 it states:
"when the ecu begins to stage it begins firing both sets of injectors at once and fires them with the same duration"
this is trhowing me off... what is the SAME duration? is it the last unstaged bar or the first staged bar?
it also says: " if the primary and secondary are of the same flow rate then the first staged bar should theoretically be slightly more than half that of the last unstaged bar."
this statement would lead me to believe that they use tha same duration OF the first STAGED bar??? no?? if this is the case, i can see how Ted was saying to do this in vacume. but even then, if it is coughing under load, then doing this in vacume is not going to be able to ignight/mix air with all this fuel either...???


vosko, you said "well i learned the hard way tuning my car... soon i will be retuning my entire map..... " what is it that you learned? did you learn how to take care of this stumble? if yes, what did you do to cure it? if no, what are you telling me? am i missing something in your reply? also, if you 'tunned' it once, why does it need to be tuned again?? do you mean you were able to get it up and running, and now you are going to have to tune it??? or are you saying you are going to have to re-tune for a different size primary?
sorry if it sounds rude, but i am just wondering. if you actualy do know something that was not mentioned, why would you not help me out?
-Thanks

rxrotary2_7

OIC. thanks for the explination.

rxrotary2_7

talking to Silver7, he has told me that he has NEVER been able to get rid of this stumble. even by emailing his maps to hitman and others to look at. i think there HAS to be something to make it better though.

vosko

iTrader: (4)

i meant the hesitation from too rich or too lean :o. you tried adjusting the bars between the staging bar like ted suggested right

rxrotary2_7

Yup.

fatboy7

Do you have a fuel pressure gauge? If you do, then are there any pressure spikes/dips when you transition? Its possible that you're FPR is having a hard time with the transition. Just a guess....