Does anyone know how to...
AudiWorld Super User
Joined: Nov 2000
Posts: 6,270
Likes: 0
What you can do is.....
hook it up with 20G in auto-learn mode, and just do normal driving, and limit the boost to ~10psi or so.
From there, you should be able to extrapolate an extra-rich fuel curve, and then tune it to an appropriate A/F ratio.
However, if the stock MAF is too small, than what good is trying to emulate the stock MAF? If it hits fuel cut when the stock MAF maxes out, then it will do the same thing when the MAP-ECU maxes out.
So basically, you'd have to auto-learn the stock MAF and injectors, then put in the larger injectors, and adjust the MAP-ECU table accordingly.
Or do you have a way to adjust the ECU values as well?
One thing I notice about this unit, is that it is not a true speed-density conversion. It does not take into account air temp, at least not that I can see.
100F vs. 130F has ~5% air mass difference, this could cause problems going from summer/winter
From there, you should be able to extrapolate an extra-rich fuel curve, and then tune it to an appropriate A/F ratio.
However, if the stock MAF is too small, than what good is trying to emulate the stock MAF? If it hits fuel cut when the stock MAF maxes out, then it will do the same thing when the MAP-ECU maxes out.
So basically, you'd have to auto-learn the stock MAF and injectors, then put in the larger injectors, and adjust the MAP-ECU table accordingly.
Or do you have a way to adjust the ECU values as well?
One thing I notice about this unit, is that it is not a true speed-density conversion. It does not take into account air temp, at least not that I can see.
100F vs. 130F has ~5% air mass difference, this could cause problems going from summer/winter
New Member
Joined: Mar 2000
Posts: 176
Likes: 0
$.02
for a large hp increase, looks like a pia unless a near fully populated map is available. speed density tables depend on VE, which can really drop well below na values at high boost/rpm. lots of tunning time.
no temp correction means over-rich or multiple maps needed. no closed loop could be trouble if inspection is req'd.
the gm 3.5" MAF translator looks better, but not sure how well it can be trimmed for much larger inj's, keeping load based timing correct.
no temp correction means over-rich or multiple maps needed. no closed loop could be trouble if inspection is req'd.
the gm 3.5" MAF translator looks better, but not sure how well it can be trimmed for much larger inj's, keeping load based timing correct.
Thread Starter
Junior Member
Joined: Oct 2003
Posts: 538
Likes: 0
ok so...
lets say I build the map from scratch. Autolearn with the stock maf with the smaller injectors and the 14b is useless.
So, now I come to this problem. The diagram that I have to enter vaules into is in Hertz. So lets say I break out all the formuas and such and make a determination what the air mass will be and such and such and prm and what the psi will be and then I can plot a map...BUT I dont know what the damn Hertz are
PS-it does have intake temp
So, now I come to this problem. The diagram that I have to enter vaules into is in Hertz. So lets say I break out all the formuas and such and make a determination what the air mass will be and such and such and prm and what the psi will be and then I can plot a map...BUT I dont know what the damn Hertz are
PS-it does have intake temp
New Member
Joined: Aug 2001
Posts: 254
Likes: 0
here's the problem...
This has already been mentioned, but no matter what you do with the new setup, you won't get rid of fuel cut unless you get an ECU mod. If you need some contact information for that, let me know.
Personally, if I had a 1g, I'd go with a MAFT and a SAFC to finetune the MAFT after I got the ECU mod for fuel cut. It's a very proven combination (550+ HP and well into the 10s), and driveability with the MAFT is like night and day compared to a VPC combination.
It'll give you the adjustability you need to tune whatever you throw at the motor for airflow. There are a bunch of guys in New England that are very well versed in this combo, and if you need some specific info, hit me with an email and I'll put you in contact with them if you want some datalogs or other info.
Personally, if I had a 1g, I'd go with a MAFT and a SAFC to finetune the MAFT after I got the ECU mod for fuel cut. It's a very proven combination (550+ HP and well into the 10s), and driveability with the MAFT is like night and day compared to a VPC combination.
It'll give you the adjustability you need to tune whatever you throw at the motor for airflow. There are a bunch of guys in New England that are very well versed in this combo, and if you need some specific info, hit me with an email and I'll put you in contact with them if you want some datalogs or other info.
AudiWorld Super User
Joined: Nov 2000
Posts: 6,270
Likes: 0
the datalogging might be able to tell you that....
Using temp, RPM, pressure, displacement, and VE, you can tell what the actual mass-flow is.
You'd have to guess on the VE, but the rest you should be able to use and calculate a close guess.
You'd have to guess on the VE, but the rest you should be able to use and calculate a close guess.
Thread Starter
Junior Member
Joined: Oct 2003
Posts: 538
Likes: 0
I know how to get mass air flow from
temp, ve, displacement, and pressure, rpm.
Heres what I run into. Lets say I determine that:
2.0 liter engine (122 CI), 3000rpms, 90% natural capacity/2.15Densiy Ratio, 34.97 g/CF air density. We get a MASS of 9169.1 g/min.
Heres the problem I get:
How many hertz is 9169.0 g/min?
Heres what I run into. Lets say I determine that:
2.0 liter engine (122 CI), 3000rpms, 90% natural capacity/2.15Densiy Ratio, 34.97 g/CF air density. We get a MASS of 9169.1 g/min.
Heres the problem I get:
How many hertz is 9169.0 g/min?
AudiWorld Stories
Bringing Audi to Life for Audi Fans
2027 Audi Q7 and SQ7: Audi Upgraded EVERYTHING!
Michael S. Palmer
Audi Unveils Absurdly Cool New Supercar: 10 Things You Need to Know!
Verdad Gallardo
The Highs & Lows of Every Audi C-Class Generation
Joe Kucinski
Top 10 Most Expensive Audis Ever Sold on Bring-A-Trailer
Brett Foote
10 Audi Features & Options We Miss the Most!
Joe Kucinski
Audi Recreates Crazy-Looking Speed Record Breaker From 1935
Verdad Gallardo
Coachbuilder Recreates the 1995 Audi TTS Concept
Verdad Gallardo
Every Audi V10 Car Ranked!
Joe Kucinski
9 Audi Designs That Aged Like Fine Wine
Verdad Gallardo
New Member
Joined: Mar 2000
Posts: 176
Likes: 0
Re: I know how to get mass air flow from
u can get maf sensors flow calibrated vs volts, I recall vk sensors can also be calibrated for hz vs flow. you then offset that curve for say 50% bigger inj's, scaling all flow values by 1.5x for ea hz value. That is your final chart for mass flow vs hz, with 660 inj's. then fill the map up with boost-speed-temp calc based mass flow points, then switch those to the coresponding hz values.
then richen everything about 5% for a safe start for your extensive wide band testing to follow.
this should delay fuel cut (high flows give lower hz vs stock curve), but may mess up timing curves based on load interpretation.
then richen everything about 5% for a safe start for your extensive wide band testing to follow.
this should delay fuel cut (high flows give lower hz vs stock curve), but may mess up timing curves based on load interpretation.