Timing curve advice

[SoupMan]

Now that I have my hyperspark installed and working it's time to tune the timing. The build is a Pontiac 455 with 6x-8 head. Running an XE274 hydraulic cam with 1.65 ratio roller rockers. 1 3/4 long tubes. If you were to guess what does this combo like for a timing curve?

Prior to the hyperspark I was running 11 degrees at idle with 26 full advance (mechanical only). Was not running vacuum advance.
The hyperspark is currently running 11 degrees at idle and 15 degrees while cranking. All settings are just base tune from the wizard.
At WOT it just runs 29 degrees at all RPMs which seems silly to me but I don't claim to understand.
Cruising (under 88 kpa) it transitions goes from 11 degrees at 2000 to 21 at 2250 and then maxes at 31 at 2500.

[Jeremy]

I'm not familiar with the EFI you are running but I'm sure its pretty similar to my FITECH.

What are the timing inputs you can control on your system?

It should be something like 1100 rpm, 1100 rpm @ 45 MAP reading and 1100 rpm WOT, 3000 rpm, 3000 rpm @ MAP of 45 and 3000 rpm WOT, 6000 rpm, 6000 @ MAP of 45 and 6000 WOT.

[SoupMan]

Yep, it's the sniper EFI (Forgot to mention).

It has a table with MAP and RPM. Each cross point gets a timing value. Everything equal and above 91 is considered WOT. Everything pass 2250 below 91 is considered cruising. These motors cruise well before the 2250 value so I figured it would make sent to move some timing below. Not sure what this motor / combo would like.

[ryeguy2006a]

That is what the tune will spit out when you create using the wizard. What I would do is start reading up on what most Pontiac's like with your similar combo. You have a lot of area's that you can blend and smooth out the transitions on. That's the beauty of running EFI over mechanical/vacuum advances on traditional distributors.

Join the Holley forum and start reading up there. You'll likely find a much better timing table for yourself to start with. Or also check out some of the stock tune files that Holley provides. I'm certain that you will find a better graph in one of those tune files. Basically what you have is a 2D table, that the system extrapolated into the 3D table.

[Jeremy]

You have a lot more data points that you can change compared to my Fitech.  I'm guessing my table will look similar, I just can't change it.

What I run on my 455 is 12 degrees initial.

Idle at 45 MAP which is like running with full vacuum advance is 22, basically 12 degrees initial and 10 degrees vacuum.

3000 at 45 MAP is 44, 32 degrees plus 12 vacuum.

6000 MAP is 32 right now.

1100 rpm is 16 degrees
3000 rpm is 32 degrees
6000 rpm is 32 degrees

From the how to build high performance Pontiacs by Jim Hand, his recommendations are:

10-18 degrees initial with 20-25 more degrees of advance by 2900-3000 rpms with an additional 14 degrees of vacuum advance.

What I did was get my initial curve established first (as if running with no vacuum advance) and am starting to add in the vacuum advance portion to the timing curve.

I recommend keeping good notes and changing as few data points as possible at one time so you can track the changes.  I make one set of adjustments and drive it about a half tank before making any assumptions as to the results until I have seen a variety of driving conditions.

EFI is great, but it takes some time to get it fully optimized.  I've got about 1200 miles on the rebuild and am still finessing the adjustments. 

[SoupMan]

Rye,

Yes, wizard produced that. My problem is knowing what to fill in. I don't know enough about what the motor wants. Also looked at Holley calibrations and although they reference some calibrations in their documentation they do not appear to get installed with the Sniper software anymore...

Jeremy,

That's good info. I didn't remember Jim hand talking about the timing to that extend so I've pulled my Jim Hand book out and am starting to read it again. Now that I have significantly more knowledge than I did when I started I'll be able to make sense of it. I'm a little confused by the 14 degrees of vacuum advance. I'm not sure what range for the KPA that applies to. I probably have to do a bit more reading before diving into this.

[ryeguy2006a]

This is the best graph that I can find, but here's what the base chart that I used for my LS1. Your timing will need to be adjusted, but generally you'll want the curve to look similar to this. What you can do is figure out where the motor is happy at idle, cruise and WOT. Then you can highlight columns or rows between those two points to create a smooth chart. I believe after you highlight the rows/columns there is an option when you right click to fill or blend.

You also want to make sure that your AFR is happy too. Then you can play with the timing your VE table and see what the learn table looks like.

[Jeremy]

On mine, the "vacuum advance" setting is at 45 kpa.  I'm running between 10 and 12 degrees of vacuum advance right now as I'm easing into adding the vacuum advance.  I'm running pretty lean at low loads as well and I'm anticipating it liking more vacuum advance.

My motor is a 455 with 6x-8 heads, edelbrock performer intake and FITECH fuel injection.  MSD distributor run by the FI.  Cam specs are .560/.560 lift 227/237 @ .050 duration and a 108 centerline.

On your EFI do you have to adjust each point in the table?  On mine, I enter one of 9 data points and it builds the table.

[djustice]

Just about to leave work, but watch this:  https://www.youtube.com/watch?v=jDyA3yTeB5w&t=354s
And build a really good timing map in a few minutes, it helped me a lot.

i would try to about 36 degrees full advance from 3000 rpm and out when your map is about 75-80 kpa and up to 105 kpa

[SoupMan]

Guys, all really good information. Thank you very much. If any of you are in the GTA (Toronto area), let me know, I owe you some beers

So for the weekend I mostly ran with my this tune which is just conservative numbers I threw in that I knew would work. It allowed me to verify my setup is working properly.


Today I applied the knowledge from djustice's video, combined with Jeremy's numbers and I got this. My only concern (comes from a place of ignorance) is the timing at low RPM, low vacuum. It feels like too much timing but again, pleading ignorance.


Rye, you mentioned a graph but I could not see anything. Am I missing something?

Although I understand a large part of the timing does physically, I'm not sure I well enough educated on the why/why not. Is there a resource out there I can read/watch that will help me tune this better?

[ryeguy2006a]

Not sure what happened with the graph, but I just added it now. Probably not super helpful as it looks like you were able to get the table blended properly. Looks much better.

I also believe that you can use your actual KPA readings as an indicator for timing. Play around with the timing at idle and find the lowest KPA and then you can tune the curve based on that. Also, what does your AFR chart look like? Holley tends to make those charts very rich. That can play with your VE and timing.

[SoupMan]

My AFR target is 13.5 at idle and 14 in the cruise area. 12.5 at WOT.

I'll be giving this tune a try tomorrow if time allows.

[ryeguy2006a]

I think I was 14.5 idle and 14.7-15 cruise with my LS motors. Not sure if you can wire in a knock sensor with the Sniper, but if you could do that you could accurately lean it out. Keep leaning it out until you get any rings, then add some back in. I'd say you could comfortably lean it out some at idle and cruise. Better fuel economy and more power. Or better yet if you have a tuner near you, pay them the $500 bucks or so and they will dial it all right in on a dyno.

[Jeremy]

Your low vacuum low rpm numbers look reasonable to me.

Keep in mind, a standard mechanical curve with no vacuum is something along the lines of 12-16 at 1000 rpm, 22 ish at 2000 and 32 at 3000.  Reading your table at WOT you are 13.4, 22, and 28 so to me you are still a little under on your timing.  Low load table looks reasonable but I think you might have room for more advance at low load as you drive it more.

Some engine specs would probably be useful to dial it in.

MY AFR targets are 14.7 at idle, 14.5 at 45 kpa and 12.8 at WOT.

I'd drive it it for a half tank or so and make any notes as to soft spots or pinging before making more adjustments.  I'm guessing your system will take some time to learn after the adjustments as mine does.  Paying attention to the "vacuum" advance side of things can drastically affect fuel economy and driveability.  I've started adding advance at low load and got 3 mpg better on the first half tank and it takes less throttle for all driving situations now.  Second tank isn't doing as good on mileage as I've been having more fun playing with the transitions from low load to higher load!!!

[SoupMan]

Ryeguy, good info which had me look at knock sensing kits. Could not find something that is considered reliable and at reasonable price. I can continue to use my ears as they've been able to detect knock before. Basically sounds like a bad rod bearing.

Jeremy,

Thanks for that info. I've driven it a little with the last tune I posted. Car is definitely better. I unfortunately parked the car for a few days while waiting for parts to solve an issue with my cluster. I'll start playing with the AFR and add a few degree to WOT and low load once I refuel (Ouchy the prices).

Regarding engine specs to dial in. In the first post I posted Pontiac 455, 6x-8 heads, 1.65 rocker, XE274 cam (comp 51-224-4) 230/236. 1 3/4 long tubes.  Anything else that needs specifying?

[Jeremy]

What intake are you running?  What trans and rear gear?

Our combo's sound very similar.  Mine is a 455 with 6x-8 heads and a performer intake.  I run the Fitech with a MSD distributor.  3.08 rear  gears with a tremec 3550.

My cam is a Howards with 227/237 duration at .050, 108 centerline and .560/.560 lift.

My AFR at idle is 14.7 and light cruise is 15.0.  WOT is 12.6.  I'll log down my timing specs hopefully tomorrow for you as I think it is about as good as its gonna get.

[SoupMan]

Jeremy,

I did notice we had very similar builds. The rear gear is 2.72 fed by a TH350 and the intake is an edelbrock performer. 

I was out of commission for a few days due to a failed electrical component but I've had a few hundred miles of driving with the last tune I posted. The car behaves very well and fuel mileage went from 11.5 to 13.5.

A few nights ago, my fan stopped running as I was on the highway. Car heated up to 230 and at no point did it appear to knock. That kind of confirms what you said about most of my settings being conservative. Time for a 3rd go at these numbers.

[Jeremy]

Sounds like you are coming right along.  MPG looks good.

I'm consistently 12-13 MPG around town.  Even with heat indexes around 105 this week, temps are staying 195-200 for me, with or without the AC on, so I'm happy there.

I found a problem with my start IAC.  Little did I know that as I was lowering the start value it was lowering the IAC muliplier.  I ended up really choking off the motor and it was real rich on start up.  Now that I have fixed this,  after starts are much smoother with no more flares.  Fires and settles in at 950-1000 as it slows to the set idle speed of 850.

Still have more tuning on the DFCO settings, possibly.  I did get them enabled and working good and picked up a solid 1.2 to 1 mpg per fill up.  Driveability is smoother while shifting with it disabled.

Keep us posted.

[SoupMan]

Jeremy,

That's really exciting. I'd be curious to see your timing table.

Few weeks ago when I drove it after putting a little more timing as shown in my last graph. I noticed that WOT that I was getting an odd sound that sounds like a high pitch ping. This could be something that was always there but I just didn't hear because of the exhaust header leaks which I've since fixed. This got me questioning whether I really know what an engine ping sounds like. I dropped the timing at WOT by 5 degrees and didn't see a difference in sound (I keep a more conservative tune on the SD Card).

Just so I don't go crazy, what does a ping sound like?  Would I feel hesitation in the acceleration or something along those lines?

[ryeguy2006a]

You should be able to use an LS knock sensor. They are very cheap and reliable.

As for the fan quitting on the highway, I'd look into that more. The air moving across the radiator at highway speed should far exceed what a fan can pull, so if anything, the fan running at highway speed would become a restriction in flow. All OEM's disable the cooling fans around 40-45 MPH for that reason. I had mine set to disable at 40 MPH when I built my Camaro and it ran around 183-185* while moving.

[SoupMan]

Rye,

I'm planning on putting a switch to turn off the fan for other reasons but this will be an opportunity to see if this helps on the highway. FYI, running a champion radiator.

With regards to the LS knock sensor, how do you make this work on a Pontiac 455. I did a search and I haven't found anything that was considered reliable to put on car that didn't come with it. Do you have a source?  I'll spend a reasonable amount of money to protect my investment.

[formula jg]

With your EFI systems are you able to view live timing data?

[djustice]

Just did som retuning to my sniper after changing over to Alu heads and a rollercam + singleplane intake, and was shocked to get 15,68 MPG on a 115.5 mile trip to our national Hot agust nigths.
and this is on a .060 over 455 =469 with a TH400 and 3.42 LSD rear end average speed where around 40 mph.
In that  rpm range i targeted 14.7:1 AFR.

[SoupMan]

With your EFI systems are you able to view live timing data?

Yes, I see what the timing it as the RPM/vacuum on the live display. I can also hookup a laptop to get a more comprehensive view of what the computer is doing.

[ryeguy2006a]

Just saw your reply. Here's a good site that explains how to tune with the knock sensors.

https://forums.holley.com/forum/holley-efi/hp-efi/3603-knock-sensor-tuning#post59428