I got a good laugh from Cole's post...

Recently I gave a cute girl a ride in my car and I saw her looking down between the seats for a few seconds at the little red MSD knob I installed on the top of the autoheat box that says, "boost retard".

can't imagine what she was thinking and decided it was best not to say anything. . .

MY Twisted Brother,

I have a ROW 930/60 Engine

Max HP is at 5500 RPM

Max TQ is at 4000 RPM

Your timing is going to be most critical at Max TQ or 4000 RPM through Max HP at
5500 RPM, (Time to shift), Timing needs to be 18*- 22* BTDC at that point.

Now we can put the toys away for the winter and go rob banks or
something. I've been following the Grandpa Bandit on TV and they
haven't caught him yet. He looks like my other brother Earl, I could
do that and buy more parts.

J.

Don't you be driving fast while some cute chick is playing with your Knob.

Cole

Cole,
In regards to what your factory dizzy is doing. I have created a crude graph myself on my 911SC by running the engine at increments of 500rpm from idle on up to 6000rpm and recorded the timing with an adjustable strobe at each set point. I then constructed a graph in excel. this tells you what you got. I then correlated it against the timing charts from the factory manuals superimposing the mechanical advance curves on the vacuum retard curves to see how it compares.
You could try the same thing if you have the factory timing curves for the turbo, where you would need to superimpose an additional timing curve for the boost retard. This is something i wanna try ot do in the future, and will try to post results.
Hey the blood pressure cuff is a good idea for generating boost at various psi while runing the engine without load in the driveway! The question of what safe point to set final timing when advancing timing in search of more performance versus factory data is still subject to individuals interpretation. The factory spent lots of dyno time tuning the engine so I cannot say how far one could deviate from those specs off hand without tuning on a dyno and spending $$$ the same way.

I have the thin black siemens 60's. I talked with a guy today that stated the injectors become "non-linear" under 1.50% duty cycle. Which matches what i've found.

My car does not have a cold start valve anymore, which i'm sure isn't helping matters. But I have been holding the throttle slightly open for a few seconds after cold start to help it stabalize. I may do an on-off valve for cold start, we'll see.

This thread has become so huge that it is easy to get cunfused, I'm so glad to have control of timing fully.

A generic starter motor button is a good way to manually trigger a cold start valve injector.
If you don't have one for a 3.2 manifod, maybe one from an older motronic or L- jetronic 6 cylinder BMW is the same or similar and will cost less.

You don't need no stinking cold start valve with MegaSquirt II. Make sure the IAC is half way open during cranking. Set the ignition timing to 10 BTDC during start-up. Adjust the start-up injection quantity until the car will start, then die after about 2 seconds. Then increase the after-start enrichment until the car stays running. After that, adjust the afterstart decay so that the after start enrichment is all gone after about 2 minutes. The start-up injection quantity is just like the cold start valve. The after start enrichment is just like the warm-up regulator.

Is that 60 lbs/hour for the injectors? If so, that is only 7.6 gm/sec, which is not too big. Over 9 gm/sec is too big. What is the spray pattern. Hopefully not the pencil spray. That is not good for our engines.

No offense but EFInjection stuff is just going to get lost here and be of little use to those that might benefit from it if it were in a thread on an EFI build.

The best. ;)

Hey Fred !!!

Great to hear from you. Hope the new job and location are suiting you well.

Weak minds must wallow in the same gutters because I got the Mtyvac and pressure simulator to do exactly what you have done. With the LM1 and all the feedback I'm going to be collecting I should be able to dial this thing in pretty well.

I got the blood pressure cuff bulb and tire gage idea from a post some place. Wish I could remember so I could properly credit the guy. It's ingeniously simple and dirt cheap. I got the bulb for 4-5 bucks and the tire gage with reset for 10-12 bucks all off evilbay. All I have to do is put a T in the gage line and add the bulb.

I converted my manuals to PDF and I can print pages and take them with me to the garage. Works out well. Keep me posted on your progress and Thanks for the heads up.

Cole

Yeah, back to the timing topics. Why are 930 engines presented here with such weak timing? Why are people taking out so much on such little boost? Seems to me that these motors are setup to take much more advance. Another thing that I noticed is the a lot of people are taking their boost reading from the back of the intercooler where the factory sensor is. So that 1 + bar is bogus. I have a boost switch on my intercooler set up for 1 bar but I take my boost reading from the manifold in front of the throttle body. 1bar in the intercooler is like .8 bar in the manifold. What this says: a lot of false information related to real boost/timing curves.

I thought most took there boost reading from the intake manifold after the throttle plate.

A 930 running 1 bar is about a 11.5/1 effective compression ratio or about the same as a 993 which has twin plugs. On top of that our intake air is preheated even with a decent inter-cooler. We do not have any compensation to pull back timing with changes in environmental conditions nor any knock sensing ability. Thus we should have some level of safety built in.

A 993 only runs about -16 deg at TQ peak (where a motor is most sensitive to timing) which is about what we run on boost.

The 993 also has the ability to bend the timing curve which we do not.

Thus, it seems we are running about as much advance as we can get away with safely under varying conditions.

http://forums.pelicanparts.com/uploa...1259900288.gif

Stolen from 911chips.com

Z,

Would be interested in what your non weak timing is. What advantage is there to more advance on a 930, and what does a real boost/ timing curve look like.

THANKS !!!!
Cole

Hi Cole. I see a lot of 930's with their boost readings taken from the intercooler, thus all this 1bar+ running is not the case and everything is not factual related to real time pressure events in the cylinders - timing, too. When I got my car, I could easily swing the boost gauge past 1bar with marginal power results. I fooled around with the timing and actually got it running pretty strong with 26-27 with an old HPV1 twin pac. When I inspected the motor compartment, I switched the line to the manifold and the boost stabilized at .8bar yet I still kept the timing. Anything lower with timing and the motor turned sluggish. I've since rebuilt the motor with all the go-fast goodies along with modern ignition controls. The stock motor showed not a single sign of detonation. Anyhow, a lot of post here about timing and boost is misrepresented based on this pressure loss. I see aggressive timing reductions starting at .5 bar, like -2 per pound or 16 all the way up. Just seems weak to me, that's all. I start pulling closer to peak boost and leave the lower levels alone. The car blazes. I've also heard that the older crazy fast cars with single pots had no boost retard at all but I think some of this was covered here on this post but I don't recall it actually being verified.

zcoker- my mechanic told me (back when i had the stock dizzy) to just unplug the vacuum lines and run the dizzy locked at 25* BUT make sure to run good fuel. Told me the car would fly, and i believe him. Now I have full ignition control and will start to gradually ramp total timing up from my base of 16*in 2* increments on the dyno to see what effect it has on power. I see 200kpa at the intake manifold with a 1 bar spring in the gate. (my wastegate also gets it's signal from the intake manifold as apposed to the inlet side of the intercooler)

FYI
I belive Vac-advance is about 9-10 deg w/o boost it would come in at about -16 to -17.

cont.

-25 setting is what Bruce Anderson recomends in his book for a modified 930. However he keeps the boost retard function. He is only pulling the timing back a deg to alow for running .9 to 1 bar boost.

drmatera,

Yes, setting it up on the dyno is the only way to come to a proper conclusion. The apx. -16 that we believe the factory puts timing at on boost may be a little conservative of a lot depending on the build and ambient temp's.

The best "educated guess" I could get was from Steve W of 911 chips and he thought we might be able to take up to somthing in the 18-20 deg range on boost. Remember his chips do pull timing back with higher ambients.

Again, a weakness of CIS is the lack of safe gards and often less than ideal AFR's that may also call for a margin.

Thus a well tuned 930 w effecent turbo and intercooler might preform well near -20 on boost if well maintained and somthing like a dirty injector dose not make for one cylinder to run lean.

see, now this is where it gets confusing

"""-25 setting is what Bruce Anderson recomends in his book for a modified 930. However he keeps the boost retard function"""

that statement confuses itself. to save tons of confusion why can't somebody just say what the total advance at WOT (which i might add means full boost) is, period.

The max timing you should see at WOT and 1 bar on a basically stock 930 is............... ?

A bassically stock 930 should probably not be running 1 bar. I have seen what that can do.

-16 on boost is bassically what the stock setting comes to and has worked well for a lot running 1 bar. -15 at 1 bar would be in line with BA's recommendation once you boil it down.

That is derived from the factory recommended -26 deg total advance with no load at or above 4000rpm with apx -9 to -10 deg of boost retard for a net of -16 or so.

Anything more aggressive is a modification and one would be well served to be validated on a well maintained motor (balanced injector flow and proper AFR) with proper testing on a dyno. Just my opinion.

Not sure if this is what you are asking.

that statement is exactly what I am after. When I said "basically stock" i ment engine. Headers, turbo upgrade and possibly even larger intercooler are almost givens for the average 930 guy these days. or me atleast :)

That's what us MSD BTM junkies are trying to do...advance the crap out of the timing and shave it all off by the time full boost is reached in order to retain the "stock" 16 (or maybe18) degrees at full boost.

The unknown question is at which point in the boost curve will additional advance become dangerous. That's why you see us starting to retard away the additional timing we added starting at around .3 bar (5psi) so that all the extra timing is gone sometime before full boost is reached. That's why a stock distributor timing curve relative to boost levels would be nice to have, so we can set the MSD to drop off the timing to somewhat match the stock distributor curve. Make sense?