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Macht Schnell
 
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Advance Curves

Hi,
I'm addressing some idle issues on my EFI Tec3r 930. The Porsche workshop manuals are cryptic about what advance should be around 800-1500 RPM. I'm running 93 pump gas. Can I see some screen captures of your advance curves? Here's what I have presenly




Thanx!
Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-04-2008, 11:34 AM
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Les, I believe that idle ignition timing was discussed on Rennlist a little while ago.

I'm sure DonE and Geoffrey posted.
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
Fitting - New service kit.
Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head.

1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods.
Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit.

http://www.danasoft.com/sig/Iamnotanumber.jpg
Old 01-05-2008, 05:32 AM
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Les, keep in mind that Porsche's timing specs at idle are guided in part by the limitations of a mechanical distributor and the timing curve/advance it is going to need over the rev range. With a stand alone, you can break out of those limitations/mindset. For example, I often add a couple degrees more timing at the lowest expected cell, in your case 800rpm, to help stabilize the idle. Exactly what is the idle issue your having?
Old 01-05-2008, 04:48 PM
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Quote:
Originally Posted by 89turbocabmike View Post
Les, keep in mind that Porsche's timing specs at idle are guided in part by the limitations of a mechanical distributor and the timing curve/advance it is going to need over the rev range. With a stand alone, you can break out of those limitations/mindset. For example, I often add a couple degrees more timing at the lowest expected cell, in your case 800rpm, to help stabilize the idle. Exactly what is the idle issue your having?
Hi Mike,
I've got a lot of idle issues! Wandering idle, cold idle, hot idle, blah. blah, blah. I have the workshop manuals and there is no easy way for me to reconcile the mechanical advance curve, vacuum, advance, and vacuum retard curves to get some idea of what the cell timing should be in the "ballpark" of. I'm trying to land on a decent timing setting from 800-1200, so that I can say, that;s reasonable, look elsewhere for your idle issues.

I figure if I can eliminate that variable than I can look at the other variables. That should be the easiest one to eliminate. I might have it now, just would like to see some curves that are well sorted out. I realize all curves under load and higher up in the rpm system will be custom, but even those portions should show trends.

I had a great conversation with DonE recently, and he brought up a very valid point. The reason why a factory EFI car runs so flawlessly is that their R&D depts spend more than a few Dyno hours getting them to run right.

I don't know if anybody with an EFI car has one that is "perfectly" sorted out. But somebody here probably has one that is 99% sorted out. That's the curves I'd like to see. Not to use them, just to look them over for patterns. Mine is going on the Dyno next week where we'll do our own timing curve. I'd like to have some patterns in the back of my mind while I'm doing it. So, I'm not just interested in Idle, but he whole range.

I got some tuning info from a few people, but you wouldn't believe some of the differences, even in the idle areas. I thought the more stuff I could see, some of it may make sense in time. Does that sound like it makes sense?

Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-05-2008, 05:32 PM
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At idle, my timing is 8 degrees, then climbs quickly to 36 degrees around 2500rpm, dropping to 18 degrees at 6500rpm (1 bar). I use a 2D table, so my timing is set by MP and RPM. My timing curve gives me 502 lb ft torque, but more importantly to me, it gives my 8.0:1 CR motor a nice kick at low throttle/rpm.
Old 01-05-2008, 07:25 PM
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Quote:
Originally Posted by DonE View Post
At idle, my timing is 8 degrees, then climbs quickly to 36 degrees around 2500rpm, dropping to 18 degrees at 6500rpm (1 bar). I use a 2D table, so my timing is set by MP and RPM. My timing curve gives me 502 lb ft torque, but more importantly to me, it gives my 8.0:1 CR motor a nice kick at low throttle/rpm.

Hi Don,
Very Interesting. 8:1 CR has got to be nice! Thanx for the info about the idle and the 36 degrees. I guess it's at 36 degrees up to 100 kpa and then retards?

Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-05-2008, 07:37 PM
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Here ya go.
http://forums.rennlist.com/rennforums/showthread.php?t=381693
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
Fitting - New service kit.
Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head.

1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods.
Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit.

http://www.danasoft.com/sig/Iamnotanumber.jpg
Old 01-06-2008, 01:45 AM
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Quote:
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Thanx Nathan,
Interesting read!

Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-06-2008, 06:34 AM
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Quote:
Originally Posted by les_garten View Post
Hi Don,
Very Interesting. 8:1 CR has got to be nice! Thanx for the info about the idle and the 36 degrees. I guess it's at 36 degrees up to 100 kpa and then retards?

Les
You are correct, however my table starts at -80kpa and ends at 100kpa (one bar, even though I have a .8 bar spring loaded).
Old 01-06-2008, 05:13 PM
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Quote:
Originally Posted by DonE View Post
You are correct, however my table starts at -80kpa and ends at 100kpa (one bar, even though I have a .8 bar spring loaded).
Hi Don,
Hmmm, even more interesting. Your car must idle around -60 kpa? And your 36 degrees must be retarding around 0?

Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-06-2008, 05:22 PM
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It idles about -65 kpa and timing is already decreasing to about 28 degrees at 0 kpa.
Old 01-06-2008, 05:54 PM
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Les, at absolute vacuum your engine should be around 34-36. And on the high scale (at cruise) you should usually have around 36-38. Your current map should act lazy especially on response. Try adding timing at absolute vacuum progressively from 1100 to 2500 and be at 36 by 2500.
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Old 01-07-2008, 10:16 AM
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Quote:
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Les, at absolute vacuum your engine should be around 34-36. And on the high scale (at cruise) you should usually have around 36-38. Your current map should act lazy especially on response. Try adding timing at absolute vacuum progressively from 1100 to 2500 and be at 36 by 2500.
I'm not sure what you mean by absolute vacuum? It sound slike I have a pretty conservative curve here though.

Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 01-07-2008, 10:52 AM
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Sorry Les,
100 kPa
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Old 01-07-2008, 05:51 PM
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This should help. Although the cruise figures will be higher but this will get you close.
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Old 01-07-2008, 06:19 PM
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Quote:
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This should help. Although the cruise figures will be higher but this will get you close.
Hi,
WOW, greatly different than mine. I'll look over this quite a bit. You are running on Pump Gas, ehhh?

This Ignition table makes a lot of sense to me now that I see it.
Les
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---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT

Last edited by les_garten; 01-07-2008 at 06:35 PM..
Old 01-07-2008, 06:29 PM
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