Coming from a non-CC racing side, I find it odd that you would add timing at a higher RPM.

The weekly motors we deal with are pretty basic, 355 with flat tops, 390-410 stock camshafts up to .550 lift solid lifter, 500 two barrel with a performer. Every engine builder and dizzy builder locks a HEI up making it take total timing out, in the range of 2-5* through the RPM range.

The idea is more timing equals more TQ on the low RPM side and lowers those numbers as RPM comes up and vice versa. Ever try taking timing out as the RPM range comes up?

 

The timing numbers that you see there are my frist try ever on the dyno with me doing the tuning so there will be abit of a learning curve here,

That timing cure is also what i have seen posted on the board and people sayed it was not a bad set up . i no my car is diff and needs are diff just try to see what people do how fast they bring in the timing, max timing and so on

yes i thing i need less timing going back soon

 

Your timing map looks backwards to me also. I have maximum timing in by 3000 and retard it two to three degrees on the top end.
You will probably find a lot more response if you put more timing in on the bottom end. If the car is making good HP on the top end I would leave that part of the map alone.

Daren

 

Gump,
so youre timimg would be ie:

0-3000 36* and start taking out 1-2* so on up to 7000rpm

rpm/kap-timing your timing
400-22 36
600-22 -
800-22 -
1000-23
1200-24
1400-26.5
1600-27
1800-28
2000-29.5
2200-31.5
2400-32
2800-35 36
3200-35 -
3600-35
4000-35
4000extended spark adv table-36.5
4500-36.5
5000-36.5 34
5500-36.5 34
6000-36.5 34
6500-36.5 33
7000-36.5 33
like this

 

It all depends on how well your car ran with the timing set at 36 deg at 7000. It also depends on what gas you are running and you if your A/F ratio is good (A little too rich is better than a little too lean).
My application is drag race only, so I run VP fuel exclusively.
I have my timing at 41 deg about 500 rpm below where I stall my converter (@ 3000 rpm). I begin to take timing out at about 5000 rpm. By 6000 rpm my timing is at 38 deg.
If your car ran well at 36 degrees why take out timing?

Hope this helps,

Daren

 

This is just in the wot part of the timing table 85kpa-100kpa
or are you saying to do the hole timing table from 0-100kpa

thx for the help

do you have tuner cat and if so could i see youre file on the timing
thx

 

As I said, my application is race only. I run my opti spark like it is a conventional distributor(x timing at x rpm). It is much easier for me to work with and I am not interested in emissions and other daily driver type issues. Both of my cars have Accel DFI.


Daren

 

So my under standing with timing is

(all this done on the dyno)

-Eng temp allways the same 170-190 range

-bring in timing as fast as you can and have full timing in by 3000rpm, take that through the rpm range taking out 1-3* timing to peak rpm.

(Why do you want to take timing out as rpm go's up)

WOT timing starts in the 85kpa-100kpa & the is the same from 85 -100kpa (my car is a na set up)

Afr in the 13-13.3 range with +1-2* timing and -1-2* timing to find what the car likes.

What is bad air? this is mid Oct sould you leave full timing in or take out 1-2* timing because of the air. then what will happen in mid summer when air temp is bad will this hurt the car or will the
iat/map/eng temp/ pull timing out
thx

 

I warm up my oil first and then cool my motor back to about 100 deg. I try to never stage above 140 deg (we normally push the car down the staging lane).
More timing will get you out of the hole better. When you take out a little timing you will pick up mph.
I do not adjust my timing for bad air, only my fuel. You can run more fuel when the air is denser.

Daren

 

Should youre timing cure stay with youre tq cure

i.e

my tq peaked at 5500rpm so should i have full timing untill5500rpm then start to drop it off as the rpm go's up to 7000rpm

 

Timing is usually taken out at higher rpms because the unburned air/fuel mixture is more turbulent (in the chamber) as rpms go up. The more turbulent mixture burns faster, requiring less advance.

Something else worth mentioning... The other factor is that the engine is less likely to have detonation at higher rpms. Since there's less time to complete the burn cycle, there's also less time for the unburned mix to be pre-heated by the flame front moving towards it. Lower temps= further from pre-ignition, which means more timing *can* (not must) be run without knock.

 

I think these cars need a good bit more timing on the low end, especially after adding exhaust. Low rpm timing will improve torque, which is why they say it will leave better. If you've ever seen a mustang do the locked distributor without the spout connector and run faster, you can do the same thing in principle. It just requires us to change the maps in the computer instead of twisting a distributor. I've seen a car pick up 5 mph in the 1/4 from this. Granted, it was a h/c car, but it works. Mustang boys say its worth 2 - 3 mph. A benefit to doing it in the ecu as opposed to the distributor, is our cars will still be easy to start. Just don't change the map down that low. The more timing and compression, the harder it is to start. I have yet to do back to back testing on my car at the track with that, but will be shortly. I'll let you know. Drivability definitely improved after I added some timing down around 1500 - 3000. I kept the topend the same since I don't have a cam or heads, yet.

 

At what point do you stop the advance of the timing, should the timing cure and Tq be the same
ie: if my Tq cure stops at 5500rpm is that the point where hp takes over and i should start taking out timing