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3.2 turbo "ping"

any you guys out there with 3.2 converted to turbo getting any pre ignition? Im getting ping at about 4 psi with 94 octane, but its crappy canadian gas. I run sds efi, played with timing and fuel at boost but still there. Just cant get on the throttle like i want. I am going to try some race fuel next week but dont think i should need it for 5psi.
Old 05-29-2010, 09:34 PM
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You might want to pull some sparkplugs and check them for signs of detonation. I would also take a close look at your fueling and ignition timing. Do you have any way to confirm your AFR's to make sure your not going lean? How are you compensating for fuel at boost, do you have a RRFPR(rising rate fuel pressure regulator) or are you just adding injector pulse width (if so, are your injectors sized appropriately)? I would also confirm that your spark advance is really where you think it is. Do you have an intercooler and what are your intake air temperatures under boost?
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Last edited by sjf911; 05-30-2010 at 07:28 AM..
Old 05-30-2010, 07:20 AM
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7.0:1 > 11.3:1
 
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I can't speak accurately about the 3.2 because it's over 9:1 but on my 930 SDS installation I ran total timing of 29 and started boost retard 2.76psi (-1 degree) and ramped up to -7 degrees at 14.1 psi. I'd think you are going to need more retard (starting sooner) because of your compression versus my 930 which was 7.0:1 but you need to be a little cautious because increased retard also increases exhaust gas temperature rapidly. This is more of an issue with extended open throttle periods like track use. I was able to run 1 bar on 91 octane but again this was with 7.0 cr.

Do you have a wideband o2 meter to tune AFR's?

If you would like my complete sds value table shoot me your email address in a pm.

The project I'm working on right now is an SDS turbo 993 which is 11.3:1. This is going to be a challenge, to say the least.
Old 05-30-2010, 07:48 AM
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hey guys thanks for your thoughts, i use a plx device wide band o2 and and a rising rate fuel pressure reg. I have checked plugs and there is no evidence of detonation. Definitely not lean, double checked timing and played with boost/retard. I am running i/c and temps not a problem, its only 10deg celcius here at the end of may! Just sounds like a can of marbles
Old 05-30-2010, 08:45 AM
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Bad gas with too much timing still? Excessive carbon on valves/pistons? Unbalanced/bad fuel injectors?
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Old 05-30-2010, 09:26 AM
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New problem or just getting car set up?

Euro, US or other compression?

What is your AFR Goal on boost?

How and where are you measuring your boost?

What is your on boost timing goal (SDS controled timing?).

What is the history of the long block?

4psi add's just over one point to your base compression ratio.

Might start at 11/1 AFR and -18 timing on boost.

It is possible to have a solid AFR on a wide band and still have a cylinder go lean with a bad injector but it should show up on the spark plug.
Old 05-30-2010, 12:21 PM
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Might have found prob, timing was at 36deg at rpm so i beleive the retard values under boost were not pulling timing back far enough. Its a US engine with 60k miles, compression good. Not a new problem just havent put many miles on car since turboed. Running 7psi boost dont think i need -18 timing on boost? Need to get on our mustang dyno but theres a huge project sitting in front of it!
Old 05-30-2010, 01:56 PM
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-18 to -20 timing is a conservative starting point.

Start there and work your way up on a dyno and when power gains start falling off pull it back to be safe.

For reference a stock C2Turbo runs about -20 to -23 depending in intake temp and can handle 1 bar on 7/1 CR. That is about an effective compression ration of 11/1.

9.5 and 4 lbs is about like 10.5/1 CR. Stock US Carrera and 5.5 psi is about equal to 11/1 CR.

You might be able to run a bit more boost on good fuel w good tuning and a great intercooler. Some seem to be able to go more aggressive but I do not know if I would.

Not an expert.
Old 05-30-2010, 05:31 PM
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All above is for use with a decent intercooler.

With out the boost should probably be a bit lower I suspect. Though there is a lot less heat created w 5 psi than 1 bar.
Old 05-31-2010, 08:44 AM
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definetly was the timing, pulls hard now no detonation. Now that timing is retarding from 30degrees instead of 36 it works great. thanks
Old 06-01-2010, 07:44 AM
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So timing it is!

Glad to hear you fixed it.

9.5 CR w 7 psi is agressive even with a good intercooler.

I would try pulling timing further and see if you still are making power. -30 on boost is very agressive I suspect.

Just a thought.
Old 06-01-2010, 09:05 AM
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Glad that worked out with something so simple. I run about -16 to -18 at max boost which is .6 bar running 9.5:1.
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Old 06-01-2010, 10:50 AM
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timing is at -30 no load but -22 at boost seems fine maybe will pull it back a little further
Old 06-01-2010, 06:33 PM
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Sorry, that makes more sense.

The best!
Old 06-01-2010, 07:27 PM
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Matter, just a question, but why are you electing to use a rising rate fuel pressure regulator given that you have progammable efi? Are your injectors too small to run without?
Old 06-04-2010, 04:12 PM
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