Lowered my timing by 3 degrees

And I picked up almost 3 mph but my ET. dropped by 1.5 tenths.

Interesting. I ain't a drag racer but I am assuming ET is the bottom line. Here's a BTT for ya.

That is a big change. Not sure what your ET is but if the car is very fast at all then that is a bunch of horsepower that you picked up.

8.67@154 with 35 degrees timing
8.70@157 with 32 degrees

60 foot is a little off @32 degrees. 1.23
60 foot is 1.18 @ 35 degrees

So it wants timing to get the car moving and retard after. Get a high speed retard. You can probably add another 2-3 degrees at the hit and then pull the timing back out .

I like the mph@32 degrees

.3 quicker with more timing but slower mph.

.03 not .30. And where is the 1.5 tenths in the first post

????

X2

What ignition system do you have. You would be surprised what would happen if you have a way to ad timing down low and take it away up top.

It might not want timing to get the car moving, he might be making more power with less timing and overpowering the tires. I'd keep the timing at the lower number and try to get it too hook.

I have an MSD 6al-2 ,set the timing with a laptop.nThe timing is adjustable every 100 RPM.I have NOT found the sweetspot YET!

Your situation parallels one I witnessed first hand today. Cab was down and made several pulls on a chassis dyno at my friend`s shop. We were trying to get a plug reading on e85 and installed one new spark plug in #7 that was one step colder. The car lost 100whp on a A B B A test. We put the other plug back in and the last "A" pull was right back to normal. 100whp due to one spark plug. That really blew my mind. It is amazing what you can pick up or lose with minute changes. I am impressed that you picked up that much mph with a timing change.

I am thinking he meant .015. One and a half thousandths. Ron

Whats the combo ? Eng , heads , cam and so on ? Ron

It's a 4.200 bore
3.79 stroke with a 6.50 rod in a 48* block.
16:1 compression.
I'm ballz deep in this engine.
Fully CNC ported W9 heads now.
A little to much maintenance to run but this combo screams.

I need a little more gear to spin it harder.
68 Dart that weighs 2955lbs.

I'm getting too old. Grabbed the wrong time slip and slowest pass was 8.82@156.90 with a dead hook with 32 degrees timing.

In my limited experience, very high CR is more sensitive to spark setting. Decades ago, Yamaha road racers set spark to .1mm (.004"), and warned riders that if using WOT below 5,000 RPM the engine would lock up. It did, but it was faster if you're careful.

That's a good running combo for sure but like you said it comes with a cost. High fuel costs, high RPM, original build costs, new and better stuff coming out all the time so we upgrade for a few hundredths, and constant rebuilds. Probably a big reason I'm dragging my feet on my 572. Mines a budget build compared to what the hitters are running and my income is going down faster than it is going up. Heck my Friends are running 4.60's at my local tracks 'heads up" series and drive them often.

Sounds to me like you need a shorter advance curve. If it's an MSD distributor, you can change the button to do that.

t

This was my first thought. Mph is the indication of the power your making, et is just the application of that power. You running a slick, it prob spinning . Work on your suspension now

It's dead hooking, no spinning at all.
I run a bias slick.
So do I leave it at 32* or put at 35* ?
Air fuel is dead on at 12.8 at WOT.

Who’s cylinder heads are on the car did Brett do them

One and a half hundreds = .015 , one and half thousands should be written as .0015, not .015
Dang details anyways

Are those the only choices?

This is just one outing that I'm showing how my ET goes up with the higher timing but mph drops.
This is my new engine going from W8 heads.
Both engines showed the same results.
The less timing equates to more MPH .
The engine dyno made most HP @ 35 degrees.
You cant measure MPH on the dyno.

60 foot is a tad weaker with 32 degrees timing.

As fast said, are those your only choices?

I think you need to test some. Run just 60 foot times and set the timing for your best 60's. Then start backing timing out of it and run the 1/4.

My best guess is, like most N/A cars with decent chassis, your car will like more timing in low gear and want it backed down in high gear, or maybe pull it out in second.

Guys pulling timing and going quicker in 60 feet with N/A combos usually need chassis tuning.

This nonsense that less timing is always better is just that. If it wants more timing in low gear, give it more timing. Look at the plugs and let them tell you if you are wrong or not.

High gear retard is a real thing and is used by those looking to get the last bit of performance. Was being done years ago by class racers, etc. You can do it electronically or put a switch on the shifter and do it with an MSD retard box, depending on your ignition. Or just set the timing where it gives the results you're looking for - go fast, repeat 60s, not run the engine on "kill".

I have a MSD 7531.... Where would I start pulling timing out?

IMO I would ADD some timing in low gear and then begin to pull it back on each gear change. Adding timing at the hit will help burn the fuel that accumulates from being on the two step. Further adding timing will help the engine make more power with the lower load it has in first gear and increase efficiency. If it is a three speed I would pull back a couple degrees in second and in high go back to base or where it makes the best MPH. In the end you will have to experiment to find the ideal place for timing to be. Not unusual for timing to be changed from the dyno for many reasons. Increased altitude, moisture in air or two very common reasons. You need to find a curve that accelerates the car the best. That's generally is more down low then up top.

Fastest ET was at 35*
Fastest MPH is at 32*

Getting my laptop plugged in to my 7531 MSD Box and was wondering if you have ever done this timing curve before?
Not sure when to start pulling timing out.

Add switches to your shifter.

Yes I have been awhile on the 31 box as been using a Grid for a few years. But I am seem to recall the ability to add/subtract timing based on gear changes. It senses the RPM drop on the shift and will trigger the stage, which is a number you may need to tailor to your car. Guess I need to brush up on my 7531 stuff been like 8 years

Now I remember why I switched to the Grid, WAY more user friendly. Anyway here is a video, you would have start with however much advance you want to begin with and enter retards from there. With a grid you just ad to the base on the scree and don't have to touch the distributor/crank trigger. In the 31 you will have to add the timing to the distributor/crank trigger and subtract from there

https://www.youtube.com/watch?v=Er-z-uyW0Us

Yes you are right as I meant one and a half thousandths but did write it wrong as it should be as you put it .0015. Sorry about that. Ron

I remember reading an article in the early 70's where Bill Jenkins retarded his timing in high gear using a dual point dist. I take it he bought the second set of points in when he hit 4th gear as he said it don't need so much advance once the eng is up to speed and the car is rolling along real good. Ron