Question about base distributor timing & total timing

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06-22-2013, 05:32 PM
A.J.

Question about base distributor timing & total timing

I'm looking at sample timing tables for boosted engines and their numbers are my total timing numbers (MPTune) if I subtract the 12* BTDC that I set my distributor at. So my question is: While looking at the total timing tables on MPTune, do I need to subtract 12* to get my "actual" total timing.
06-22-2013, 06:15 PM
tryingbe

Re: Question about base distributor timing & total timing

No. You do not.
06-22-2013, 06:45 PM
turbovanman²

Re: Question about base distributor timing & total timing

Its just a reference point, the timing you see is the timing it is, consider 12 at the dizzy 0.
06-22-2013, 08:05 PM
Ondonti

Re: Question about base distributor timing & total timing

Quote:

Originally Posted by turbovanman²

Its just a reference point, the timing you see is the timing it is, consider 12 at the dizzy 0.

So how exactly does this work in real live when one is set at 12 and another is set at 14. Are you saying the stock computer will then read higher timing numbers by 2 degrees across the board on a scanner? I am not talking about with a timing light.
06-22-2013, 09:20 PM
ShelGame

Re: Question about base distributor timing & total timing

Quote:

Originally Posted by Ondonti

So how exactly does this work in real live when one is set at 12 and another is set at 14. Are you saying the stock computer will then read higher timing numbers by 2 degrees across the board on a scanner? I am not talking about with a timing light.

If you set it at 14, the sync will be off by 2deg (advanced). And the computer will then under report by 2deg the actual total timing.

12 is not "base" timing. Its just the timing the computer uses when you are syncing the distributor to the crank with a timing light. The simple reason for 12deg is that the engine will idle well at 12deg, but not so much at 0.
06-23-2013, 12:24 AM
A.J.

Re: Question about base distributor timing & total timing

Quote:

Originally Posted by ShelGame

If you set it at 14, the sync will be off by 2deg (advanced). And the computer will then under report by 2deg the actual total timing.

12 is not "base" timing. Its just the timing the computer uses when you are syncing the distributor to the crank with a timing light. The simple reason for 12deg is that the engine will idle well at 12deg, but not so much at 0.

I forgot to mention I'm doing this with a 2.4 DOHC. I have the stock Neon-SRT-4 timing tables. I tried using them but it accelerates like a dog. I tried setting base timing at 0* (idles fine) to see if it makes a difference and it didn't. I tried setting it at 0* using my current timing tables and it didn't make a difference in acceleration. I'm trying to figure out the SMEC's "logic" while trying to calculate my timing curve (part throttle/WOT) but with the '04 Neon SRT-4 using a faster processor and DIS and I'm using a SMEC and a distributor, the SRT-4 might work faster and allow for more timing. With mine running as good as it does using Sean's (1fastcsx) "base" timing, and my adjustments for my set up, I think with my set up that's the best I'm going to get and just street tune/dyno tune from there.
06-23-2013, 10:00 AM
Force Fed Mopar

Re: Question about base distributor timing & total timing

If you set it to 0*, then it will be running 12* less timing than the timing tables or the scanner will show, which would explain why it is sluggish. Set it to 12* w/ the CTS unplugged, just like you would a 8v, and then make any timing changes needed in the cal.

The rpm timing table is where you set the base timing. Whatever you have it set to at idle rpm is what your base/initial timing will be. If you want more initial timing, make the timing at 1000 rpm higher.

In basic terms, the AdvanceFromRPM table replaces the mech advance springs of old-style distributors, and the AdvanceFromMap tables replace the vacuum advance.
06-23-2013, 08:25 PM
turbovanman²

Re: Question about base distributor timing & total timing

Quote:

Originally Posted by A.J.

I forgot to mention I'm doing this with a 2.4 DOHC. I have the stock Neon-SRT-4 timing tables. I tried using them but it accelerates like a dog. I tried setting base timing at 0* (idles fine) to see if it makes a difference and it didn't. I tried setting it at 0* using my current timing tables and it didn't make a difference in acceleration. I'm trying to figure out the SMEC's "logic" while trying to calculate my timing curve (part throttle/WOT) but with the '04 Neon SRT-4 using a faster processor and DIS and I'm using a SMEC and a distributor, the SRT-4 might work faster and allow for more timing. With mine running as good as it does using Sean's (1fastcsx) "base" timing, and my adjustments for my set up, I think with my set up that's the best I'm going to get and just street tune/dyno tune from there.

That's probably why your van feels slow, your 12 deg retarded from the get go. You are still using a SMEC and SMEC tables, so the 12 deg has to be factored in.
06-30-2013, 09:10 AM
Ondonti

Re: Question about base distributor timing & total timing

So I am seeing only 24 degrees of timing WOT on a stock 1994 3.0 SBEC II @ 5000 rpms and 2" vacuum using DRB II. This seems really low for a 2 valve head when I see the SRT4 stock map is running about 33 degrees of timing on a 4 valve head. I even see 3000gts (the 24 valve turbo version) running more timing at this load point.
Not sure if this is because of compression ratio but 2 valve heads should run more timing then 4 valves.
06-30-2013, 06:53 PM
Force Fed Mopar

Re: Question about base distributor timing & total timing

Actually I seem to see the opposite, IE my 8v runs way less timing than a 2.4 does. But, it really has more to do w/ the chamber design than the number of valves.