can anybody tell me why???
need some brains here!
thanks!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote">im not getting it why does 450cc work better than 310 when your not using the extra cc?</TD></TR></TABLE>

Its not about using the extra cc available. Its about sizing the injectors correctly that will allow you to trim sufficient map voltage and ENABLE you run boost without hitting the CEL voltage threshold.

If you read one of the first threads about the hack fully, you would grasp the concept of the hack that would help you in understanding the hack.

 

ok thanks so its like you use 450cc and cut it down 40% you wil get ignition advance and also a lower map voltage. ok now i understand! but if i go with 8psi how big should my fuel cut be, if i don't want to go higher than the maximum map voltage? in other words wats the minimum fuel cut @8psi before i hit a mil?
Wouldn't it help a little if i lowered the rail pressure a little and lower the fuel cut a little? that would make the same quantity of fuel and a little less fuel cut so a little less ignition advance right? or where am i wrong on this???

 

annybody?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote">ok thanks so its like you use 450cc and cut it down 40% you wil get ignition advance and also a lower map voltage. ok now i understand! but if i go with 8psi how big should my fuel cut be, if i don't want to go higher than the maximum map voltage? in other words wats the minimum fuel cut @8psi before i hit a mil?</TD></TR></TABLE>

Its not set in stone what your fuel cut should be as it will differ more or less in every setup. Usually with 450cc and stock fuel pressure you should be OK up to about 11psi. It really depends on the size of your injectors, fuel pressure and how lean or rich you want to run. Ideally you would want to tune your afr with a wideband and not just set it to -40% cut.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote">Wouldn't it help a little if i lowered the rail pressure a little and lower the fuel cut a little? that would make the same quantity of fuel and a little less fuel cut so a little less ignition advance right? or where am i wrong on this???
</TD></TR></TABLE>

Quite the opposite if I figured what your trying to say rightly. Lowering the fuel pressure would mean you that your fuel cut would be less in order to compensate. Ignition advance has nothing to do with fuel cut.....

 

i thought the ignition advance was caused by fuel cut. than why does the ignition advance happen? it isnt there with a vafc on a na engine. can you please explaine it to me than? i thought the more fuel cut the more ign advance so if i'd lower rail presure and lower fuel cut it would be a little less ign. advance
thanks.(ps i dont need the whole 11psi i'll run 8psi)

 

annybody? tell me if im wrong or not!

 

Do you believe that the timing values found on a N/A ECU cooperate just as nicely with 11lbs of boost - or 8lbs as would be your case???

 

Does anyone actually believe this crap J.Davis comes up with?

Transvestike.

 

thanks for the replies!
first: ee-chris i know n/a or stock timing is to much advance for boost, i just dont want the afc to advance even more! i'd rather retard timing @ the dizzy a few degrees than 20degrees! And i can't go stand-alone cause i live in holland!

mad cow:
in what way is j. davis wrong? i believed him cause your the first one than says he is wrong! let me know!
Thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mad Cow &raquo;</TD></TR><TR><TD CLASS="quote">Does anyone actually believe this crap J.Davis comes up with?

Transvestike. </TD></TR></TABLE>

Transvestike!

 

im not sure what you are all bitching about, but can you please tell me if im right or not?
thanks

 

The timing values inside the ROM are static - they are indexed by the MAP & RPM input.

The VAFC isn't advancing the timing - what its doing is placing the 'indexer' on a portion of the timing map that is already too advanced for a boosted application.

 

i understand that part but i thought that if you decrease fuelinjection duration (on the afc) you will ''index'' on a portion that has got more timing advance. so lets say 40%fuel cut would make 20degrees advance(@ a surten point) and 30% fuel cut(with lowered rail pressure) would make 15degrees advance(@ the same point). maybe the mil wil turn on earlier (8psi in stead of 11psi) but if i only need 8psi than i gues it would be nice.
(i am aware that the numbers arent correct)
i hope you annybody understands my story. Tell me if im right or not!
thanks!

 

can't anybody help me? i know my writing isn't to good but it ain't chinese!
thanks!

 

Either way you slice it: Boost + stock timing values = recipe for new topic about WTF went wrong.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote">i know n/a or stock timing is to much advance for boost</TD></TR></TABLE>

Since your only gonna run 8lbs, do you think you'll be able to find some timing values, IN THE STOCK ECU, that are better for 8lbs vs 11lbs by using this method?

 

i understand that i still have to retard the dizzy some degrees. what im trying to say is that if the vafc has even got a werse affect on timing that i would like to minimalize it, and maybe my idea helps a little. so just tell me if im right and if im not then why?

 

What is this 'idea' you speak of?

Do you believe that since the hack was setup to run -40% with 11lbs, that you'll be able to get away with -30% with 8lbs and retarding at the dizzy?

 

il try to explain:
lower fuel cut and lower railpressure to compensate it. lower fuel cut will lower ignition advance. it will also lower the map limit (cause its fooled less) but if im not going for the whole 11psi(max map pressure @40%fuel cut before mil turns on) but only for 8psi than that wont be a problem.

its probably only a little difference

 

Lower MAP voltage = higher ignition timing.

The picture on page 1 clearly shows this.

Put it into perspective: The top side is manifold pressure with the left side being 0v (lets say) and 2.85v on the right side.

You lower the MAP voltage thus bringing the timing into those really high values.

Why not just try it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote"> so lets say 40%fuel cut would make 20degrees advance(@ a surten point) and 30% fuel cut(with lowered rail pressure) would make 15degrees advance(@ the same point). maybe the mil wil turn on earlier (8psi in stead of 11psi) but if i only need 8psi than i gues it would be nice.

so just tell me if im right and if im not then why?</TD></TR></TABLE>

You sir, are correct.

Now your challenge will be to find an appropriately sized injector (at an appropriately cheap price... this is a HACK after all) to fit proportionally with your new AFC settings.

 

yes i could be able to make it with smaller injectors, but i could try to lower the rail pressure. i gues there is nothing wrong with lowering the rail-pressure a little or is it?
also do these figurs seem right to you: max 11psi @40%fuelcut
thanks

 

hello anybody there?

 

We're here... but we don't see any questions not already answered in the writeup.

 

40%fuelcut makes a max of 11psi? is this exact?