# turbo ignition timing



## xray_boy (Jun 22, 2001)

I am wondering about ignitions timing for turbo's in general. Are they different from NA cars? I have a 1.8T in my '90 GTI and when monitoring the ingition timing with the VAG-COM, I only see + numbers. I would think that anything BTDC would be - (is that right?) Do turbo engines have to have timing set ATDC because of the extra pressure in the cylinders?
DAN


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## Agtronic (May 14, 2001)

*Re: turbo ignition timing (xray_boy)*

Take a look over here : http://www.sdsefi.com/emanual.htm
The SDS site has alot of good information. SDS's tech page is also full of info, so be sure to take a peak there too.


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## xray_boy (Jun 22, 2001)

*Re: turbo ignition timing (Agtronic)*

some of that was interesting, but most of it was on how to program their particular unit. anyone else have some insight on this?
DAN


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## need_a_VR6 (May 19, 1999)

*Re: turbo ignition timing (xray_boy)*

Same informative site, but with some example maps:
http://www.sdsefi.com/techign.htm


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## xray_boy (Jun 22, 2001)

*Re: turbo ignition timing (need_a_VR6)*

yeah I read that one too, didnt satisfy my curiosity.


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## need_a_VR6 (May 19, 1999)

*Re: turbo ignition timing (xray_boy)*

Well, then what exactly are you looking for?
Ignition timing starts at a low value, climbs to a "base" setting, dips under boost, and then can return a little when boost stabilizes. Pretty simple actually.


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## Agtronic (May 14, 2001)

*Re: turbo ignition timing (need_a_VR6)*

quote:[HR][/HR]Well, then what exactly are you looking for?
Ignition timing starts at a low value, climbs to a "base" setting, dips under boost, and then can return a little when boost stabilizes. Pretty simple actually.[HR][/HR]​Exactly.


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## xray_boy (Jun 22, 2001)

*Re: turbo ignition timing (Agtronic)*

a low value as in -BTDC, then climbs which way, (into ATDC)?
is advanced BTDC and retarded ATDC? is advanced usually give a negative number and retarded is positive?
When looking at the vag-com I only see + numbers. when I do a run, as the rpms increase, the numbers fall to about 15 at mid rpm and then climb up high to redline, like this.
rpm air in throttle timing
/min g/s % °
2120 17.06 13.3 27.8
2240 18.03 13.7 28.5
2400 34.64 97.3 18.8
2680 50.47 100 19.5
3040 68.44 100 16.5
3400 76.72 100 15.8
3760 81.56 100 16.5
4080 83.78 100 17.3
4440 86.06 100 18.8
4720 89.81 100 19.5
5000 92.5 100 21
5200 94.19 100 21
5440 94.89 100 22.5
5640 97.78 100 22.5
5840 99.42 100 21.8
6000 99.94 100 23.3
6160 99.61 100 24
6280 101.97 100 27
6480 100.58 54.9 24.8
6560 98.83 46.7 24.8

these are the types of basic things I want to know


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## mrkrad (Nov 9, 2000)

*Re: turbo ignition timing (xray_boy)*

instead of throttle, log boost and it will all make sense..
thats what missing out of your log.


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## speed51133 (Feb 18, 2000)

*Re: turbo ignition timing (mrkrad)*

ignition is always advanced. when you say you will back timing off, or retard it, your just advancing it less.
you cant have a negative timing.


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## need_a_VR6 (May 19, 1999)

*Re: turbo ignition timing (speed51133)*

Well you can have negative timing relative to TDC if your advance is considered positive. The stock static igniton timing for all non GTI Rabbits is 3deg ATDC for example. Wierd, but that's the spec.
Here is a sample of what it may look like
RPM**Boost**IgnAdv
1000****0****10
1250****0****15
1500****0****18
1750****0****22
2000****0****25
2250****0****30
2500****0****35
3000****2****34
3500****5****33
4000****7****32
4500****9****31
5000***11****30
5500***13****29
6000***15****28
6500***15****28
Purely hypothetical, but you'll get the idea. Boost in psi, advance in deg BTDC.


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## SILVERADO (May 16, 2002)

*Re: turbo ignition timing (need_a_VR6)*

Damon at Turboperformance says"On a turbo car advance the timing 2 degrees from stock settings,for all of you with distributors that can advance timing manually that is.If you have a adjustable cam,2-4 degrees of cam advance is what was recommended.I'm gonna try it and hope I don't blow a third piston!


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## need_a_VR6 (May 19, 1999)

*Re: turbo ignition timing (SILVERADO)*

Is that for a stock turboed car with stock boost, or for an NA car running more boost? If it's the latter, I would be worried if he was working on my car


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## speed51133 (Feb 18, 2000)

*Re: turbo ignition timing (need_a_VR6)*

i think hes confusing cam timing with ignition timing


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## 2kjettaguy (Dec 24, 2000)

*Re: turbo ignition timing (speed51133)*

My engine is not very happy with me according to that article. Supercharger + heat + too much boost = knock > timing retard of like 20 degrees








I need an intercooled setup


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## need_a_VR6 (May 19, 1999)

*Re: turbo ignition timing (2kjettaguy)*

Speed, that would make sense.
2kjettaguy, yeah, 20deg retard is alot. You really don't want more than 5-10 as your EGT's go up quickly. I know EGT isn't as critical because you don't have to deal with a wastegete, but 20deg is alot of timing pull. Did you log this?
The roots SC is hard to intercool as well, unless you dropped the whole Neuspeed casting for a stand alone blower with an air to water IC sitting above the valve cover. Whatever you could come up with would work well, but I'm sure it's alot cheaper (and more powerful) to just do a full on turbo setup at that point. Water injection would be a decent idea, but you'd have to be careful!


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## Rabbid Rabbit (May 1, 2000)

*Re: turbo ignition timing (need_a_VR6)*

hmmmm......On my Turbo Bunny using CIS Im using a vacuum retard unit on my distributor. Its actually from a Saab 9000 Turbo. Im thinking that the one from the Saab might be retarding my timing way too much cause my car seems to lose a bit of steam as the revs increase. The a/f ratio stays perfect all the way upto redline, but I dont have an EGT guage to see what happeneing on the hotside. Anyone have any experience with my situation?


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## need_a_VR6 (May 19, 1999)

*Re: turbo ignition timing (Rabbid Rabbit)*

You might be able to check it with one of those little hand vaccum pumps. Run the car and get it good and warm. Disconnect the vac advance hose and plug it (no leak). Now connect the vacuum pump so that you can put positive pressure on your dist advance port. With a timing light check your base timing. Start pumping till you get to 1psi. Check timing again for retard. Put 2lbs on it, repeat. From this you can roughly guesstimate what your retard/lb is. If you're pulling out more than 1deg/lb it's probably too much if you're well intercooled.


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## JettaRed (Aug 14, 2000)

*Re: turbo ignition timing (xray_boy)*

quote:[HR][/HR]a low value as in -BTDC, then climbs which way, (into ATDC)?
is advanced BTDC and retarded ATDC? is advanced usually give a negative number and retarded is positive?
When looking at the vag-com I only see + numbers. when I do a run, as the rpms increase, the numbers fall to about 15 at mid rpm and then climb up high to redline, like this.
rpm air in throttle timing
/min g/s % °
2120 17.06 13.3 27.8
2240 18.03 13.7 28.5
2400 34.64 97.3 18.8
2680 50.47 100 19.5
3040 68.44 100 16.5
3400 76.72 100 15.8
3760 81.56 100 16.5
4080 83.78 100 17.3
4440 86.06 100 18.8
4720 89.81 100 19.5
5000 92.5 100 21
5200 94.19 100 21
5440 94.89 100 22.5
5640 97.78 100 22.5
5840 99.42 100 21.8
6000 99.94 100 23.3
6160 99.61 100 24
6280 101.97 100 27
6480 100.58 54.9 24.8
6560 98.83 46.7 24.8

these are the types of basic things I want to know[HR][/HR]​The plus numbers represent BTDC or timing advance, which is good, especially with the high g/s numbers. Cruising is usually upper 20s to 30, so your numbers are good. Mine drop as low as 8 degrees under full boost.


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## samrabbit (Feb 18, 2002)

*Re: turbo ignition timing (JettaRed)*

it would have been sooooooooooooo much easier to design an in-manifold liquid cooler when they designed the expensive casing for the eaton guts......................but that would have been way too easy.


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