MAXIMUM TIMING FOR RACE MOTOR

[Mike Gaines]

Ok...let's get some opinions so I can digest all of the comments and figure out what is best for MY setup.
MY SETUP:
Your Timing Suggestions for Best ET:
1) 12.2 Compression
2) 75cc heads
3) 283@.050 Comp Solid flat tappet
4) .620 lift including 1/6 rockers
5) Complete MSD Ignition
6) 110 Race Gas
7) Brand new OOTB Holley Dominator 1050 with 5.5 Power Valve, 84 Primary and 94 Secondary (no power valve in secondary)
I have been running 38 degrees total (all in at 2400) for last 2 races...haven't had a test and tune day to compare lower timing. Also haven't had a test and tune day to do jetting comparisons...up or down/ power valve in or out .., etc
Best ET with this setup (with 4000' adj altitude, bad air. Actual track altitude is 676 feet) is 10.581 @ 125.66

 

[dvw]

Depends on chamber shape, piston dome, plug location. Set timing for MPH not ET if you want to be safe. Pulling timing with my Indy motor (15-1 on C-14 running flat tops) from 34 to 30 barley kills .03-.04. Never been over 30. Now a days aluminum heads with good plug location don't need much.
Doug

 

[Tempest 455]

As said above, depends on many factors. However, with your combo, I'm betting 38 is too much.

 

[Dreamcatcher]

A friend of mine that has a machine shop and does all my machine work on my engines told me that 28 degrees total advance is the most he recommends on any engine. Any more than that will gain nothing and can cause premature engine failure. This guy builds a lot of awesome race engines for what it is worth.

 

[Hemirunner]

I've never had an aluminum headed BBM on the dyno that made peak power past 35 degrees. Most are in the 32-34 zone.

 

[Budnicks]

If you need that much more timing your covering up
or it's a Band-Aid for another internal or tuning problem...

Usually no more than 34* BTC total, I've ran engine with 38* too
But pulled timing out down track too, timed or by RPM or gear to be about 30*-32*
after about 3500 or 4500 even 5500 rpm,
but your past that after the launch anyway,
more timing just helped throttle response drivability,
maybe aided in 60ft times {only very slightly ?},
but it will "hurt it" on the big end/w-o-t...
I liked my bigger, higher compression T/S P/S engines to be in the 26*-28*
crossing the stripes, completely different animals thou too...
I did try messing with more timing at altitudes it did help some,
but not worth much N/A-ed...

I've ran BBC's/even some SBC's that liked 38*'s+ & never had any real issues,
especially with long intake runners, or big box/plenums but completely different
types of heads, combustion camber & flame travel too...

With a wedge motor, single 4 bbl on an single plane intake,
relatively short runner, IMO 34* is a good safe total number on straight gas...
Higher octane maybe 36* max, that's pushing it really @ 38*'s...

Look at your plugs is there any alum. spotting or white coloration on them ?
IMO if there is you better back it off...

Depends on your fuel too, not all 105, 110, 115 oct. race gas is the same
some are oxygenated {alcohol blended} Methanol/alky loves more timing,
some of the Better Ethanol blends do too, it's much harder to detonate,
than straight gasoline is, but there's a fine line where, but has some cooling properties
slow burning to stave off some detonation too...
It's better to not be too close to or crossing that line...
Really depends on your build, how/what/where your cam degreed installation
& fuels, valve size, combustion chamber efficiency, ports size/length,
intake design, plug angles, compression, dome or piston shape,
especially ignition spark strength etc., weak ignition will have more problems...

The need for higher ignition timing, generally means there's a tuning issue
cam phasing or usually the carb or needed for running exotic fuels...

 

[Mike Gaines]

Thanks for info so far....I will take the advice

 

[Tex013]

Mike ,
there is no blanket answer . Each motor will be different , the more efficient the less timing needed .
When I run a car on the chassis dyno I will run a timing loop , add and subtract to see what difference there is . But as timing will change so will mixture you must be careful .
This is where a chassis dyno will really help .

Tex

 

[66Satellite47]

Mike , FYI with my new 512 Indy head motor, on the dyno it wanted 34 - 35*. In the old days my iron head motors wanted 38*. The new stuff is different.

 

[383man]

Mine seems to like 37 as thats where it runs the fastest. But I do run 92 pump and use EZ heads. Ron

 

[Dodge 330]

Mine seems to like 37 as thats where it runs the fastest. But I do run 92 pump and use EZ heads. Ron

Very similar here. Mine likes 36° total on pump 91 no ethanol. If I run lower octane I have to pull a little out.

 

[lxmodguy]

My suggestion is don't guess. Find a local place with a LOADED chassis dyno, load in the vehicle weight, put it on the dyno and see what it tells you. Has to be a Mustang Dyno or other dyno that allows you to load down the roller via a brake. Take a bunch on jets with you as well....set it at a know good timing number (call it 30), get the air fuel to about 12.3, put in a degree of timing until the air fuel reaches about 12.7-12.8 and call it a day. Technically you can go until the torque number starts to fall off, but that is up to you if you wanna spend money for more time of the dyno to massage the jets and try a second round.

 

[64 Post]

Very similar here. Mine likes 36° total on pump 91 no ethanol. If I run lower octane I have to pull a little out.

What, you haven't tried running 70º total as one highly regarded racer here has done?

 

[Dodge 330]

What, you haven't tried running 70º total as one highly regarded racer here has done?

Hahaaaa, I wasn't going to mention it, but was thinking it..

 

[mmissile]

All my hemi engines have been somewhere around 32 on the engine dyno. However, my latest pump-gas hemi liked 36. I'll have to chassis-dyno the car, once it's installed.

 

[SUPERSTOCKRACER]

What, you haven't tried running 70º total as one highly regarded racer here has done?

Have you ever been down a drag strip before?

 

[SUPERSTOCKRACER]

Hahaaaa, I wasn't going to mention it, but was thinking it..

You're still over a second and half slower than my pump gas 498. Keep chipping at it, maybe you'll get out of the 11's some day

 

[64 Post]

Have you ever been down a drag strip before?

View attachment 360033 View attachment 360034

You're a moron! You posted a picture of Greg Lane thinking it's me?

Hahahahaha... What a freaking idiot!!!

Go back to running 70º in your engine.

 

[SUPERSTOCKRACER]

You're a moron! You posted a picture of Greg Lane thinking it's me?

Hahahahaha... What a freaking idiot!!!

Go back to running 70º in your engine.

How about a picture of you going down the track at least Greg?

 

[cdr]

I like to run 70.25998 it runns GRRRRRAte LMOL