Would appreciate a few MSQs for 3.0 ltr 911

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Targa44
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Would appreciate a few MSQs for 3.0 ltr 911

Post by Targa44 »

Finally got the car started and I could use some Porsche 911 3.0 liter msq. I'm looking for directional ranges for AFRs, VE table and Ignition. As soon as I change the plugs, I'll be trying out VEAL and see what I get, but could really use some ballpark numbers for the old 911. If no response here in a few days, I'll switch to "Gen'l" section.


thanks,

kj
billr
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by billr »

Are you able to drive it on the road now? For those trying to dig out an MSQ for this OP, let me add that it is a simple NA engine.
Targa44
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by Targa44 »

Hello Bill,

I haven't tried to drive it yet. It's been sitting in the same place ever since you dropped by to help many months ago. I went ahead and isolated the sensors and VR wires from the relay board. It took quite a few tries for it to actually catch and idle - with huge plumes of smoke (I'm hoping just from sitting too long)... the smoking diminished quite a bit after it was warmed up. I used the "fixed advance" setting and plugged in 50 on the VE range for idle and the idle settled down. Now I'll switch back to "Use table" and try my best guess on ignition settings - I think I'll be okay range wise, but sure it will need much more attention. I used one of the build-your-own tables that were referenced by someone here and it spit out some ranges I know I can't use with high in the 42 advance area. I can interpolate and massage to fit my needs. I'm sourcing my specific range from a guru (up in Washington) from low of 5 degrees up to the 32 degree area for 91 octane. Many have said I could go up to 36-38 for max advance, but I'll stick to the more conservative as I don't know what anybody has done to their engines.

thanks - I sure appreciate all you do for this community and your willingness to help.

kj
billr
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by billr »

Post the current MSQ that you are using. This is about a '75 engine, single-plug and about 9:1 compression? I wouldn't be worried about running around with the spark advances you mentioned, even on poorer fuel. You will spend little time at-or-near WOT as you do most of the tuning, detonation isn't likely to happen and probably won't do any harm even if it does happen occasionally. I would be happy to come help you, but really can't do you as much good as just running around with VEAL on. Are you still planning on taking it to a dyno for tuning? That is the place to fuss with the spark advance.
Targa44
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by Targa44 »

Good memory - yes, '76 3.0 ltr with about 9.3-9.4 compression which equates to the US 911sc series. Here's the current msq. I've fuzt with the AFR table again and tried to mimic some known quantities from two good sources. I've guessed at the ignition for now.

thanks,
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2017-12-27_No2.msq
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billr
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by billr »

I did a quick online search for "porsche spark curve", there are a lot of charts/tables posted and all seem to end up with 30-40 deg. at WOT. That's kind of what you are hearing from the shop in WA, correct? Again, I would bump your advance up (from the present 24) and listen for any knocking. Or is that Porsche engine type know to be especially dainty?

Trying to tune with no load on the engine is going to be frustrating and quite incomplete. The only modes you can run it in are "idle", with low MAP, and accel/decel transient as you wing the throttle open/shut. Those are tough to do, since compression is low with low MAP and combustion characteristics tend to be poor/erratic. Likewise, transient operation is so, well... transient, and you/VEAL can't even see the data long enough to analyze it well. You need to get this on the road to make much headway. Even then it will be tough to flesh-out the whole table. Pick a gear, any gear, how long do you think you can hold it at near-WOT without getting into troubles around here? That's where the dyno comes in, or you just have to call it "good enough" for pleasure driving.
fast930
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by fast930 »

targa i would say you are fine to veal as bill said. your afr and advance are a decent starting point.
hobieboy
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by hobieboy »

Is your car "stock" 3.0L normally aspirated? For my turbo, with twin plug, I run as high as 30 degree before boost but retard to 17 degree on full boost @ 6500. I think you can run more timing without boost and twin plug. I have no idea how optimal mine is as I have never dyno-ed the car.

Another good way to start is to find out the factory curve for your engine as a starting point.
Targa44
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Re: Would appreciate a few MSQs for 3.0 ltr 911

Post by Targa44 »

Fast930 - I'm slowly starting to piece things together. I've gotten out for a couple of good 30-40 minute runs with VEAL and now the VE table looks like the Rocky Mountains. I'll try to massage the in-betweens that I haven't actually wandered through yet. What I thought was my best 40 minute session was wiped out by a pothole and the laptop shut down on my way home. I have another thread out there about my idle, but I have some ideas to try out for that.

Bill & hobieboy - there are lots of curves out there (via graphs).... mostly straight line with a giant dogleg 2/3s the way through. Trying to determine how applicable they are to my year's engine and distributor (which I no longer have) can be challenging. I have some ballpark numbers and since I'm not going over 32 degree advance at this point, I'll wait for the dyno tuner (w/good MS knowledge) to sort out. I'm not sure if that's impacting me right now as the car seems a little sluggish and not as perky as the CIS was (which was real fat and running in the 10s AFR wise). Then again, my next questions will be around acceleration enrichment once I'm comfortable with VEAL's output. At least I don't think I have time-based AE engaged as the graph shows 100% for TPS - which I also don't have.

thanks very much,

kj
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