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Discussion Starter · #1 ·
is it possible for those with ignition maps to post them here

this is mine running 1.3bar boost- while at the rr we though we should get more timing than 9deg at max boost max revs - the cossy guys run 15deg or more at 6000rpm!!
CR=9:1, FMIC, DI, GT28rs, 2.3head, 2.1manifold, 2.5" exhaust, autronic sm4.

LOAD(%)\Engine speed(Rpm)=Main Ignition timing(Degrees)
500 1000 1500 1750 2000 2500 3000 4000
20.0 15.0 15.0 15.0 15.0 15.0 20.0 20.0 20.0
30.0 15.0 15.0 15.0 24.0 36.0 36.0 36.0 36.0
50.0 15.0 15.0 20.0 26.0 35.0 36.0 36.0 36.0
65.0 15.0 15.0 22.0 26.0 36.0 36.0 36.0 36.0
85.0 15.0 15.0 26.0 28.0 36.0 36.0 36.0 36.0
100.0 12.0 12.0 26.0 28.0 30.0 30.0 30.0 30.0
135.0 10.0 10.0 22.0 18.0 18.0 20.0 21.0 21.0
170.0 10.0 10.0 10.0 16.0 16.0 16.0 16.5 16.0
200.0 10.0 10.0 10.0 12.0 12.0 12.0 9.5 9.5
235.0 10.0 10.0 10.0 10.0 10.0 10.0 8.0 9.0

5000 6000 7000
20.0 20.0 20.0 20.0
30.0 36.0 36.0 36.0
50.0 36.0 36.0 36.0
65.0 36.0 36.0 36.0
85.0 36.0 36.0 36.0
100.0 30.0 30.0 30.0
135.0 21.0 21.0 21.0
170.0 16.0 16.0 16.0
200.0 9.5 8.0 8.0
235.0 9.0 9.0 6.0
 

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speedysaab said:
is it possible for those with ignition maps to post them here

this is mine running 1.3bar boost- while at the rr we though we should get more timing than 9deg at max boost max revs - the cossy guys run 15deg or more at 6000rpm!!
CR=9:1, FMIC, DI, GT28rs, 2.3head, 2.1manifold, 2.5" exhaust, autronic sm4.

Code:
LOAD(%)\Engine speed(Rpm)=Main Ignition timing(Degrees)
        500     1000    1500    1750    2000    2500    3000    4000    5000    6000    7000    
20.0    15.0    15.0    15.0    15.0    15.0    20.0    20.0    20.0    20.0    20.0    20.0    
30.0    15.0    15.0    15.0    24.0    36.0    36.0    36.0    36.0    36.0    36.0    36.0    
50.0    15.0    15.0    20.0    26.0    35.0    36.0    36.0    36.0    36.0    36.0    36.0    
65.0    15.0    15.0    22.0    26.0    36.0    36.0    36.0    36.0    36.0    36.0    36.0    
85.0    15.0    15.0    26.0    28.0    36.0    36.0    36.0    36.0    36.0    36.0    36.0    
100.0   12.0    12.0    26.0    28.0    30.0    30.0    30.0    30.0    30.0    30.0    30.0    
135.0   10.0    10.0    22.0    18.0    18.0    20.0    21.0    21.0    21.0    21.0    21.0    
170.0   10.0    10.0    10.0    16.0    16.0    16.0    16.5	16.0    16.0    16.0    16.0    
200.0   10.0    10.0    10.0    12.0    12.0    12.0    9.5     9.5     9.5     8.0     8.0     
235.0   10.0    10.0    10.0    10.0    10.0    10.0    8.0     9.0     9.0     9.0     6.0
Needed to tidy it up :)
I'd say 1.3 bar out of a gt28rs is quite a lot of air, I'll post up my map shortly, but its not really a direct comparison, my engine is nearly stock. Having said that, I'm running similar advance to you at .7 bar, and about stock avance at 1 bar ( 11 degrees ). I really thought with your mods that you'd be able to run more advance at 1 bar. All that retard is wasting power. I presume that was the most you could run without knock.
 

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This is my ignition-map on my T8. It needs a bit of a workover, but high-boost is pretty much how I need to have it, without producing knock. I don't quite understand why you need to go to 6 degrees @ 7k rpm, as matthew says, you should be able to increase degrees after peak torque. Some don't even have to drop it where peak torque is...!

Daniel.
 

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This is more complicated than you are making out Matthew. More than likely, the boost will be higher after peak torque, so you now need to retard the ignition to avoid detonation. This has to go up against the need to advance the ignition at higher rpms.
You can see this in my map - at low and medium boost there is some advance past peak torque. But at higher boost, I can't currently run any more advance. Engine mods will hopefully change this.
Theres also the case of running too much advance - its possible that I'm still running a fair bit too much advance in some parts of the map. I think the principle is along the lines of "minimum advance at which maximum torque is achieved". But its hard to know what those numbers should be.

speedysaab: you need to look at all the "15.0" values at low load and low revs. You can get smoother running by advancing it a bit.
 

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Discussion Starter · #8 ·
hi guys - thanks for the replys

when tuning flat out ill soon have a drift box to compare times - and this is pretty straight forward- best timing for power without knock
it looks like you can change all the variables to - eg 30-40 time etc so i can tune each part of the map for best power

as soon as i put in 11deg - the power def dropped off using the seat of the pants gauge. (and started to knock on det cans)

when it comes to tuning low down - i dont think the car actually spends that much time on that much vacuum and at so low revs - except for idle and theres a seperate table for that

thanks though

im going to try reducing the boost a bit and running some more ignition to see how it looks

also - whats the max EGT the turbo should see?
 

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I wonder if you'll be able to add back in some advance, and run a little bit richer at the top end to get rid of knock. Maybe water injection would help.
Could you post up your fuel map.
As for reducing boost - yes, try a run at 1 - 1.1 bar max boost and as much advance as you can, it would be interesting.
 

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Out of interest speedysaab what kind of power/tq figures are you making with this setup?
Mine is very similar with SM4, GT2871R .81 A/R @ 1.3bar, though standard head and still using the dizzy to deliver spark. I'd love to hook the laptop up and get the current table for you but my car is out of commission. What clutch do you run????
 

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philb said:
This is more complicated than you are making out Matthew. More than likely, the boost will be higher after peak torque, so you now need to retard the ignition to avoid detonation. This has to go up against the need to advance the ignition at higher rpms.
Disagree.

Peak torque is peak engine load which requires peak retard. Spark can be re-advanced beyond peak torque.

I'm not making any of this up.

Being unable to re-advance timing on your engine is a symptom of a problem. Perhaps the intercooler's saturating or the turbo's out of its efficiency range. I'm not surprised that fully mapped ignition is revealing deficiencies which were concealed by the stock ignition system.

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I don't think you are making any of it up, but it applies straight out to N/A engines.
For turbo engines, you need to retard ignition to avoid detonation. Simple as that. Also, this knock gets more likely at higher rpm. Are you factoring this in?

Yep, the stock c900 is not able to run as much advance as other engines, this is a deficiency.
Did you look at the map that I posted? You will see that at low and medium boost levels, I am indeed advancing the ignition past peak torque.
If I was to implement your theory, I'd need to retard ignition more at peak torque. But its not knocking there, its knocking at high rpm.
I'd be willing to say its just my engine (perhaps fuelling issues at high rpm ), but if you look at speedysaabs table on a highly modified engine , you'll see that the ignition is retarding at high rpm.
Also, high rpm and high boost is exactly where the stock ignition system is at its most efficient, because it actually has the correct advance for this situation, 11 degrees. I've tried running 13 and 14 degrees, it doesn't work.
 

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I'd have to agree with philb - propensity for detonation is directly related to the temperature of the air in the combustion chamber - at higher rpm the turbo is really getting heated up, and the IC is getting more heatsoaked, leading to warmer intake temps.
 

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Nah, thats Matthews point :)
Again, speedysaab is not running with the stock intercooler, or a stock turbo, and the amount of advance is not great, at say 1 bar boost.
I think theres something more fundamental thats forcing people to pull back the ignition timing at high boost and rpm, relative to what people can run on fords, scoobys, nissans, etc.
 

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Discussion Starter · #16 ·
thats my point exactly - and the intake temp is never more than 35deg so cant be that


all i can think is either the squish is a poor design or the exhaust manifold isnt clearing the heat

what timing do the boys with equal headers run?

anyone know where to get those insulating gaskets from?

thanks
Rob
 

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Matthew said:
Disagree.

Peak torque is peak engine load which requires peak retard. Spark can be re-advanced beyond peak torque.

I'm not making any of this up.

Being unable to re-advance timing on your engine is a symptom of a problem. Perhaps the intercooler's saturating or the turbo's out of its efficiency range. I'm not surprised that fully mapped ignition is revealing deficiencies which were concealed by the stock ignition system.
You can read more about comments like Matthew's at places like www.efi101.com/forum/ -- it is not uncommon to add advance after peak torque (peak cyl. pressure) on a turbo car. Or maybe try calling Brad S., whose c900t (for sale, by the way) apparently has centrifugal advance to handle post-peak-torque re-advance.

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Right. I know that the ideal is to be able to advance the ignition with rpm, and I know why that is desirable. I'm just saying that at higher boost levels, I don't seem to be able to re-advance the ignition after peak torque. And on a sub optimal setup, which the stock saab is, the re-advance is limited compared to, lets say, an N/A B202.
If you read my post, you'll see that YES, I was able to do so at lower boost levels. This probably does point to deficiencies with my engine, which is pretty much stock. The turbo is blowing hot air at high boost + high rpm. I have to say, I don't think the intercooler gets heatsoaked as quickly as is made out.

And mods certainly do help. You can see that speedysaab can run a good bit more advance than me at medium boost levels. For example, if I interpolate between sites on the maps, speedysaab can run 5 degrees more timing than I can, at 0.7 bar of boost. And that 0.7 bar out of a gt28rs is much better than 0.7 out of a te05-12b.

Its just interesting that speedysaab, with a much uprated engine, is not able to run a whole lot more advance at high boost levels, compared to other 4 cylinder, dohc, turbocharged engines, with roughly similar sized turbos ( the gt28rs is not uncommon ). I'll stop typing now.
 

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Discussion Starter · #19 · (Edited)
my point - i really cant understand it

forgot to mention ive got piston cooling jets too!

all these are on shell optimax fuel

im going to do some more work - possibly getting the water injection in to run more timing

we shall see...............
 
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