87 930 turbo timing

[Baxter2422]

I am about to set the timing on this car. Got a buddy helping'hardest thing so far is finding a timing light. That a side what do I need to know, 1000 rpm or 6000 rpm advance amount retard amount. I am not much on the terminology. If some one could tell me what I need I can get it done my book only goes to 83.

[mark houghton]

26 degrees BTDC at 4000 rpms. It's that simple, but you need a helper to hold the throttle down at 4K.
Idle speed should be 950. With vacuum hoses connected at the distributor, at idle you should see around 0 degrees advanced. I would have to pull out my book, I don't remember exactly the spec but it might be 2 degrees retarded...which is absolutely stupid from a performance standpoint. Don't get me (us) started on the timing topic....these cars like and can stand more advance than factory setup, but don't mess with it until you understand it.

Anyway, the real test is at 4000 rpms to assure you don't have too much mechanical advance at the top end, which could be detrimental to your engine while on boost (thankfully provisions exist to shave off 8 to 10 degrees of advance when the boost builds).

[Baxter2422]

That should get me there thanks

[smurfbus]

You can reach for the throttle lever to adjust the rpms if you are alone. Mark your TDC line or any other line you aim for with white permanent marker so it will be easier to spot.

[T77911S]

you can do it by yourself.
hold the timing light, then run th engine up until the advance stops advancing. you dont have to hold it. note if the timing needed to be advanced or retarded. then adjust it that amount while at idle and check again.

you DO NOT have to adjust the timing while it is at 4k.

[Bucketlist]

Originally Posted by mark houghton

With vacuum hoses connected at the distributor, at idle you should see around 0 degrees advanced. I would have to pull out my book, I don't remember exactly the spec but it might be 2 degrees retarded...which is absolutely stupid from a performance standpoint. Don't get me (us) started on the timing topic....these cars like and can stand more advance than factory setup, but don't mess with it until you understand it.

So If I understand this correctly, There is advance on cold start (10*BTDC) because vacuum is blocked by the temp switch. Timing then drops back to 2-4* retarded at idle when warm. Centrifugal advance comes in just off idle (1500 rpm) 10* or so to 26-28* at 4000 rpm.
I would like my timing advanced at idle (10*) which I feel would help throttle response.
Would It hurt anything to just pull the vacuum retard line to the pot and plug it?

[JFairman]

"Would It hurt anything to just pull the vacuum retard line to the pot and plug it?"
No it wouldn't hurt anything it'll just run a heck of a lot better and you'll still have more than enough boost retard because the vacuum retard pot and line have absolutely nothing to do with it.

[Bucketlist]

Originally Posted by JFairman

"Would It hurt anything to just pull the vacuum retard line to the pot and plug it?"
No it wouldn't hurt anything it'll just run a heck of a lot better and you'll still have more than enough boost retard because the vacuum retard pot and line have absolutely nothing to do with it.

Thanks Jim, I will give it a try!

[dos531]

On mine when I tried disconnecting the vacuum retard it caused the boost retard to come in way too early. I ended up installing a one way valve in the vacuum retard line so the pot would receive boost but never vacuum. This fixed the problem.

[gsxrken]

We should ask that the exhaustive/definitive thread on timing and vacuum pot behavior becomes a Sticky thread at the top of the forum. I can't even find it right now with the sesrch feature and I know it exists.
Can anyone link to it?

Dos531- how do you know when your boost retard comes in?
(Oh and bravo on the tasty list of toys in that sig)

[mark houghton]

Originally Posted by gsxrken

We should ask that the exhaustive/definitive thread on timing and vacuum pot behavior becomes a Sticky thread at the top of the forum. I can't even find it right now with the sesrch feature and I know it exists.
Can anyone link to it?

Dos531- how do you know when your boost retard comes in?
(Oh and bravo on the tasty list of toys in that sig)

It would be this thread you're referring to I think:
Ultimate 930 Distributor, advance, retard, timing, Turbo lag, MSD, mod, thread.

On the very last post, I attempted to distill it all down as best as words can do - and to the best of my understanding - but undoubtedly someone with more experience will find an error or two (which would be a good thing for me and everyone else).

[dos531]

Originally Posted by gsxrken

We should ask that the exhaustive/definitive thread on timing and vacuum pot behavior becomes a Sticky thread at the top of the forum. I can't even find it right now with the sesrch feature and I know it exists.
Can anyone link to it?

Dos531- how do you know when your boost retard comes in?
(Oh and bravo on the tasty list of toys in that sig)

It was extremely noticeable. As soon as boost hit the car would fall flat on its face. Yes I have a problem with toys...

[JFairman]

Originally Posted by dos531

It was extremely noticeable. As soon as boost hit the car would fall flat on its face. Yes I have a problem with toys...

I'd like to know how you know it's boost retard timing making the motor fall flat on it's face under boost.
As far as I know the only way you would know is if you have EFI with a laptop computer on the passenger seat running the tuning software for the EFI while driving the car or if it's a CIS motor the car would have to be strapped down on a dyno accelerating at full boost while someone is aiming a timing light at the crank pulley.

At the bottom of your post it says you have a J&S safegaurd installed in the car. There's no reason to have one of those on an EFI motor if it has a knock sensor and if the J&S is tuned and working properly it should adjust the timing optimally at all times by listening for detonation or ping and if any is detected the J&S safegaurd computer should delay or retard ignition timing.

[dos531]

When it's pulling the timing that early you don't need a timing light to tell what's happening. It's that noticeable. I disconnected the vacuum retard line and plugged it and soon as it started to get into boost it was like somebody dropped an anchor out the back. Reconnecting the vacuum retard line brought it back to normal. This was all before the j&s by the way.

[gsxrken]

Originally Posted by mark houghton

It would be this thread you're referring to I think:
[url]http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/500986-ultimate-930-distributor-advance-retard-timing-turbo-lag-msd-mod-thread.html[/url

Thanks Mark! That's the one. Bookmarked for future reference
Who is a board admin? I do think it makes for a good Sticky.