85-91 MAP stops responding after 9.25 psi, 92+ after 10.65 psi. What does -40% cut have to do with anything?

 

The stock ECU can only see ~2.85v (atomspheric pressure) before is sets a code.....

The stock MAP sensor can 'see' ~11psi which = ~4.85v....

Trimming the MAP input ~-40% would get you ~2.85v....

Is this what you're getting at dnbruut?

 

I see 3.0 or a tad more before CEL.

Show me a stock Honduh MAP that reads past 10.6 psi, Chris.

 

This little symbol ~, it means 'around'.

So instead of typing out 10.65psi....'tis a little easier to type ~11.

 

I'm super-****. I prefer to approximate to the second decimal place, thusly ~10.65

 

so if mapmax is 10.65psi then why is the max pressure after the 40% hack 1838mbar? cause if you take 1838mbar -1055mbar(negative pressure)=783mbar=11.95psi? this all according to the pictures on the first page!

are there any uberdata or ghettodyne maps that cooperate with a afc, that only change ign. maps?
thanks



Modified by dnbruut at 6:25 PM 7/28/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote">so if mapmax is 10.65psi then why is the max pressure after the 40% hack 1838mbar? cause if you take 1838mbar -1055mbar(negative pressure)=783mbar=11.95psi? this all according to the pictures on the first page!</TD></TR></TABLE>

If the Honduh MAP sensor could return a full 5 volts, which it cannot, it would be equivalent to 1838 mBar/11.8 psia.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote">are there any uberdata or ghettodyne maps that cooperate with a afc, that only change ign. maps? </TD></TR></TABLE>

95% of the MAPhacks I did were on Pre-2.0 Ghettodyne. Ghettodyne has since been supplanted by TurboEdit, Jason took over from Mike when he went 300ZX on us, and the new OBD0 boost code works perfectly... using TurboEdit for a MAPhack defeats it's purpose. Uberdata has always supported boost, using it for a MAPhack defeats it's purpose.

I'm the only person on the face of the planet running a MAPhack, and that's because I'm too damn lazy to do something else with my own car after a day of working on other ppl's. I suck

 

your not the only pesrson believe me! every mechanic has got that problem! theres a saying here in holland: never buy a mechanic's car! ive got a pretty expencive sound system catching dust in my closet for about a year now!

the only reason for the afc is that i cant get the air/fuel right if i have uberdata and no dyno within 70miles. so my plan was to use the afc, set it to rich and drive to the dyno! cause i aint got no money for a wideband.

 

It would not be difficult to drive that distance without ever getting into positive boost territory. In that case, the only reason you may need a "hack" is to get the larger injectors to run right at all. Or you could just leave the stock injectors in, and swap them out when you get to the dyno.

 

yeah ok but i think you cant get uberdata right the first try & and i dont want to drive 70miles 8times! and i cant say: hey let me borrow your dyno and your computer for a while cause i want some free stand-alone! and a afc doesnt need a xtra computer or anything and i think its much faster to make it work!

 

has anyone using the AFC Hack getting a CEL Code 3 (Map Sensor) by putting the output of the AFC more then -40% ?!

what would happen if i set the map output voltage to (lets say) -75%

Greets
Malte.

 

AFC won't go past -50%.

By increasing cut, you move further away from max potential MAP return from the AFC... with how the Honduh MAP can't return the full 5v, you hit -35% to -32% before it's possible to click CEL 3 MAP too high.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">AFC won't go past -50%.

By increasing cut, you move further away from max potential MAP return from the AFC... with how the Honduh MAP can't return the full 5v, you hit -35% to -32% before it's possible to click CEL 3 MAP too high.
</TD></TR></TABLE>

i don't talk about the stock map sensor, what if you scale the map voltage in a way that you get 3volt output at lets say 1 Bar boost (on a 3 Bar map sensor i.e.)

i trierd something like this on a firends car and he get strange cel's (code 3) when i make full throttle runs in 5th gear over the whole rpm band...

in 1st till 3rd gear the problem don't occure...

Has someone an answer for this?

Thanks
Malte.

 

CEL 3 is because the MAP voltage is too high. I'd say you have a little bit of boost creep under sustained WOT. Port your wastegate SSR out to try to sidestep that.

 

read this thread and found it very informative. But I still don't quite follow exactly what happens in the ECU and motor during boost. I asked a question towards the bottom of this thread here https://honda-tech.com/zerothread?id=459335 . I understand why adv timing would make more power under boost, and I understand that timing could be dangerously advanced. But how come knock isn't detected when the HACK gets timing so advanced? Is it just masked by adding more and more fuel until knock isn't there? Sorry for my ignorance but I really want to understand whats happening in the ECU and motor. thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black-LS &raquo;</TD></TR><TR><TD CLASS="quote">But how come knock isn't detected when the HACK gets timing so advanced? </TD></TR></TABLE>

How is knock detected when the ECU isn't looking for it? Those very very few Honduh ECUs that have KS ignore it over 5000 rpm, at near WOT, or quick enough rate of change in MAP to indicate not being at a highway cruise. Honduh KS is for tuning ignition trim at cruise for emissions reasons, not an engine safety device. Worthless! I didn't build my CRX to worry about emissions... and the D15B7 beater gets 38 mpg with 50 degrees of advance at part throttle cruise with no KS. Call me apathetic on the Honda KS.

As for driver detecting knock, the human ear is incapable of hearing detonation that takes place before "audible" detonation. Add into the fact most turbo Hondas are a little noisy, some rides knock detection without a special KS-run-through-headphones type rig or reading plugs is problematic.

 

J.Davis..........boost braniac!

 

so ............... on a bone stock 95 auto LS with a soon to be turbo at about 8psi, what should i do? injectors (450cc), and uberdata? would this be good enough? will this work properly and make the most of my turbo setup?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eymnewdc2 &raquo;</TD></TR><TR><TD CLASS="quote">so ............... on a bone stock 95 auto LS with a soon to be turbo at about 8psi, what should i do? injectors (450cc), and uberdata? would this be good enough? will this work properly and make the most of my turbo setup?</TD></TR></TABLE>

450cc injectors and uberdata will work just fine...stock fuel pump and stock fuel pressure regulator will also be fine for the power you will be making.

 

Ok I just read the post and from what I got on it is that if I use a S-AFC I won't have to retard my timing with 8PSI? I was gonna use the S-AFC till I got my laptop to run Uberdata but I was going ot retard timing 3 degrees is this what I need?

EDIT:::My ? has already been answered thanks.


Modified by dan_w_82 at 12:02 PM 1/17/2005

 

since i'm starting with only 4.5psi i guess it would be smart to use a checkvalve(or zenerdiode) and use the afc without the hack. higher the fuel pressure and only cut out on fuel on partial throtle. and retard a few degrees @ the dizzy.
sounds OK till i can run uber or somthing like it?
any thoughts?
and by howmuch degrees shall i retard the dizzy?

 

annybody?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dnbruut &raquo;</TD></TR><TR><TD CLASS="quote"> i guess it would be smart </TD></TR></TABLE>

to tune it with uberdata or crome? yes, yes it would.

I ran with an AFC for a while, it works. Bigger injectors. However learning is everything and I wouldn't do it again. A chipped ecu is so much better that its not even funny.

I can't believe you brought this thread back from the dead!!

 

sorry for showing you this thread again but its one of the best ever on h-t.

i was comparing afc with stock inj. and higher fuel pressure with afc hack with bigger inj. not afc hack with uber.
it should be pretty safe on 4,5psi right?

i will upgrate to uber later.

 

any opinions from annybody?