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tuurbo
Joined: 08 Aug 2007
Posts: 1446
Location: East Windsor, New Jersey
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 Posted: Mon Sep 22, 2008 7:01 am Post subject: |
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Yeah well I didn't mean to move the goalposts - I assumed that the software would make a 'guess' about the safe range and represent those values in a graphical way. They're 'kind of' doing that when they color the various lean ranges in white and the rich in red - but it's not specific to that particular setup. I see. A dyno is going to tell the real story.
I was just thinking - this kind of information could be SO valuable to others on this site - even dyno data. If it could get organized right, it could save a lot of people hours of their own investigation on their cars. It wouldn't be perfect, but it could still be really useful.
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1980 924 turbo, MSD, Meth. Inj, otherwise stock. |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Mon Sep 22, 2008 8:03 am Post subject: |
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well since we've all got (almost) the same cars and engines, it could give some confidence if you see everyone has the same sort of tables and values...
If I could measure speed with MS (is possible) I could figure out some sort of algorithm which compares speed with fuel consumption and tps... but then the algorithm is just adjusting (randomly) and checking if tps is getting less.. if it is, the new found value (afr/ve...) is better than the old.
but that means i've got to update at least once 12x12 = 144 cells... and that means I've got to 'drive' in every cell at least once... that isn't really doable... yeah long term... couple of years for a span.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment  |
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Mon Sep 22, 2008 12:45 pm Post subject: |
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Ignition is very big variable from engine to engine, AFR not so much. Baldwin, I see that your ignition map is way too retarded for normally aspirated 924 engine. It should be around 37-40 advance on full throttle starting from app. 3000 rpm. Did the detonation ocurred during tuning and hence such conservative spark map?
As for AFR table, I have found that 924 engines (without turbos, NA or 931 head) tend to like 13.0-13.5 at WOT. Cruise can go as lean as 15:1.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche |
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RC
Joined: 25 Mar 2007
Posts: 2637
Location: Australia
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| Posted: Mon Sep 22, 2008 1:08 pm Post subject: |
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| baldwin wrote: |
This is my ignition map:
No anomalies I think, no strange dips anywhere.
Ummm... What does MBT mean? |
Personally, I disagree. There is a definite dip in your torque curve at 3.5 - 4K and a resultant dip in HP there too.
Looks like your set up (cam particularly) produces max Tq at 5K. You definitely want your advance all in by there, and likely earlier. More advance at 3.5K should help correct your dip. Stock Euro NA has Max Adv by 3.5K. Doubt whether your cam would need to raise it to 5K. IMHO however you may need more advance than you have with 98RON and even 11:1 CR.
MBT stands for Minimum Best Timing and refers to the MINIMUM advance needed to produce maximum torque at each RPM load site. Has to be established on a dyno, starting conservatively then slowly advancing timing for peak torque. Running the MBT when the torque levels out, definitely before it falls, will give both the greatest safety margin and power.
From your ignition map you are using RPM/TPS. Why?
Does your ECU not support RPM/density (manifold pressure) ? IMHO that is far better in most applications (except ITBs and some extreme racing engines) It is easy to have (near) maximum load (>95KpaMAP) at low TPS, particularly with a single large butterfly. Now that may not be a great improvement at WOT but will be at any conditions below.
From a very quick look at your AFR it appears OK at WOT if its accurate. Could lean it out a fair bit at lower loads but since it is not really "load" but TPS it will only cost you fuel. In no way do I claim to be a tuning expert and hopefully others may also give their opinions. |
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baldwin
Joined: 02 Nov 2002
Posts: 113
Location: The Hague, The Netherlands
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| Posted: Tue Sep 23, 2008 3:06 am Post subject: |
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| Raceboy wrote: | | Perhaps your engine is knock limited, not MBT limited |
Engine is knock limited. I didn't tune it myself, but I know the tuner had to back off the timing until the pinging dissapeared.
| Raceboy wrote: | | I see that your ignition map is way too retarded for normally aspirated 924 engine. It should be around 37-40 advance on full throttle starting from app. 3000 rpm. |
Uhoh. I compared my mapping with a few examples that came with the software, and my values weren't that different, so I thought it was fine.
| RC wrote: | | Looks like your set up (cam particularly) produces max Tq at 5K. You definitely want your advance all in by there, and likely earlier. More advance at 3.5K should help correct your dip. Stock Euro NA has Max Adv by 3.5K. Doubt whether your cam would need to raise it to 5K. IMHO however you may need more advance than you have with 98RON and even 11:1 CR. |
I see.. but wouldn't that decrease maximum power? It is a trackday car, not a daily driver.
| RC wrote: | | From your ignition map you are using RPM/TPS. Why? |
I don't know. It was the tuner's choice.
_________________
924 parts, http://verkopers.marktplaats.nl/10266983
'98 Volvo 940 LPT Estate |
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Tue Sep 23, 2008 3:13 am Post subject: |
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I have an ignition map pretty much spot on like yours, but on turbocharged stock 924 na (9.3:1 CR and 1 bar of boost).
You should use race fuel and try to tune to MBT and see how much power does it make that way.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Tue Sep 23, 2008 6:20 am Post subject: |
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rpm/tps.... isn't that the type MS says you DON'T want to use? alphaN uses map/rpm...
iirc if you use tps, the map gets calculated by the tps... not accurate in most cases.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment |
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baldwin
Joined: 02 Nov 2002
Posts: 113
Location: The Hague, The Netherlands
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| Posted: Tue Sep 23, 2008 6:31 am Post subject: |
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With the engine being knock limited... does this mean that any attempt to suck in more air is pointless, because timing would have to be backed off
even more (because of increased cylinder pressure)?
_________________
924 parts, http://verkopers.marktplaats.nl/10266983
'98 Volvo 940 LPT Estate |
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flosho
Joined: 01 Jul 2004
Posts: 3160
Location: Eau Claire, Wisconsin
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| Posted: Tue Sep 23, 2008 8:46 am Post subject: |
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Martijnus, you can use TPS for n/a engine, but for a boosted engine, the amount of air isn't linear for the amount of throttle opening..
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Tue Sep 23, 2008 3:31 pm Post subject: |
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Getting more air into engine is always good.
As for knock. What was the intake temp on the dyno and what it is on the road (ambient)?
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Tue Sep 23, 2008 11:43 pm Post subject: |
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| flosho wrote: | | Martijnus, you can use TPS for n/a engine, but for a boosted engine, the amount of air isn't linear for the amount of throttle opening.. |
but do you get a correct air mass/volume estimate with only tps and rpm? isn't map way more accurate?
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment |
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flosho
Joined: 01 Jul 2004
Posts: 3160
Location: Eau Claire, Wisconsin
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| Posted: Wed Sep 24, 2008 2:17 am Post subject: |
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| Martijnus wrote: | | flosho wrote: | | Martijnus, you can use TPS for n/a engine, but for a boosted engine, the amount of air isn't linear for the amount of throttle opening.. |
but do you get a correct air mass/volume estimate with only tps and rpm? isn't map way more accurate? |
Most likely MAP/TPS would be the best way to tune it. Based off the Megamanuals, TPS/RPM tuning is worthless for FI applications, but is useable for N/A applications.
I think MAP would be the best, with help from the TPS.
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baldwin
Joined: 02 Nov 2002
Posts: 113
Location: The Hague, The Netherlands
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| Posted: Wed Sep 24, 2008 3:29 am Post subject: |
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| Raceboy wrote: | | As for knock. What was the intake temp on the dyno and what it is on the road (ambient)? |
The temps will rise when standing still, but if you're moving, it drops to outside temp. When the car was on the dyno, they put a big fan in front of it, but I don't know what the intake temp was though.
Maybe I just overdid the compression a bit... I'm going ahead with the itb's,
and we'll see how it goes. I'll try to beat Martijnus and Rich H to it! 
_________________
924 parts, http://verkopers.marktplaats.nl/10266983
'98 Volvo 940 LPT Estate |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Wed Sep 24, 2008 3:50 am Post subject: |
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| baldwin wrote: | | Raceboy wrote: | | As for knock. What was the intake temp on the dyno and what it is on the road (ambient)? |
The temps will rise when standing still, but if you're moving, it drops to outside temp. When the car was on the dyno, they put a big fan in front of it, but I don't know what the intake temp was though.
Maybe I just overdid the compression a bit... I'm going ahead with the itb's,
and we'll see how it goes. I'll try to beat Martijnus and Rich H to it! |
you'll have to hurry only advantage you have right now is that you've got some sort of base mapping
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment |
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924 FAQ (Technical)
