Total timing vs initial timing for max HP.

[302man]

read this thread. We are talking mostly about superchargers, but the idea is still the same.

http://www.corral.net/forums/showthr...hreadid=257283

[cleanLX]

You've made some good points.

If the computer gets fuel info from the dist., than that would explain my milage. I've gone from 19mpg city, to 17mpg city. I figured it was the warmer weather and the switch to aerated gas that we are blessed with here in Phoenix durring the warmer months.

To get 60' in the low 1.7's on stock suspension and with stock HP is requiring dumping the clutch at 5000+rpms. If I were running street tires the total timing would make getting out of the hole very difficult with the add'd response/tq down low.
On street tires (not dr's) the car would break the tires loose at the top of second with 15* initial and spout in, but now with spout out and 36*, I can break them loose in second at any time with just a stab of the gas.

I'm not certian, but I 'thought' the computer add as much as 16*, but it was dependant on a host of things not just throttle position, and, depending on what the computer is reading, you may not get the full 16*. I 'thought' that it would add as miuch as 16*, but that it came on in incraments with rpm.

The heat thing is an interesting point as well. On the street the car runs a very small amount warmer, stock guages, so I don't know what the numbers are, just that it's slightly higher now. I've not experienced any detonation on the street or at the track however. I should note, that I don't drive hard on the street, the odd romp, but my street driving would be more akin to Jessie, than Luke or Bo (all of the Duke family).

I think I'll be throwing the spout back in for daily driving duties, and leaving the total timing for the track, see if the temps drop back a little and if my mileage goes back up.

I'm defintaly pulling it at the track... to run 6/100ths off my best time, with worse 60's and worse air conditions, it is definatly a track trick...

That's all.

[cleanLX]

302man...
you type faster than me... both your responses came while I was 2 finger tappin'.

[tmoss]

For those of you who have not seen a EEC timing table, I attached one to this thread. I believe 302man's method of setting up a blown engine with the BTM is a good idea for "spirited" driving. You'll see the table and it's modifiers for driving at less than wide open throttle (WOT) and then at the bottom is the table used for WOT. Keep in mind that this table reflects timing added ABOVE base timing as the computer can only add to the base setting. This is ONE A9L table and if you have one, this may not be your exact table as they do vary from car-to-car and year-to-year.

Notice that timing can actually get well beyond 30* and that is why 302man's suggestion works as well as it does. At WOT the EEC is trying to add timing at the same time the BTM is trying to pull timing. Even in a naturally aspirated car, it's good to pull some timing as rpm increases to maximum and then add it back as rpm falls to keep torque as close to peak as possible.

[302man]

Tmoss, can you send me that info ? That is great stuff and its hard to find. I would like to hold onto it if possible.



BTW, do you know HRSPLAY or Cuda ? They are from over there.

[tmoss]

Anyone can pick up ANY photo from any website by right clicking on the image and selecting "save picture as" on the drop-down menu and saving it to a file on your computer.

[84LX89GT]

This thread peaked my interest, so i did a little researching on the subject of removing the spout. We all know it is the signal to the TFI for when to fire the coil, but i got to thinking...."are there any negative effects to disconnecting the spout?"
This is what i found in an official Ford "PC/ED" - Powertrain Control and Emissions Diagnostic manual.
"The coil ON time, or dwell, for this system is thus entirely controlled by the SPOUT signal. - In the case that the SPOUT signal line opens from the PCM, the ICM will use the PIP signal to fire the coil. This results in a fixed spark angle and fixed dwell."

What this means is that the dwell is fixed....the same amount of time is given to saturate the coil from idle up to 6000 rpm or whatever you feel like revving to. If the coil fails to saturate in the primary, less secondary voltage is induced and spark intensity diminishes rapidly which could even cause a high RPM misfire. I don't think i'll be trying this trick, although it may still work.

[tmoss]

Yep, you got it right from the source you used.

[BilLster]

ok im thinking back to when chevy guys locked out there distributor weights and it worked great at the track but when down shifting created huge problems.

I will agree whole heartedly that this would work as intended at the track but amhaving a little problem with day to day driving requirements. is there a stick versus auto part i missed or N/A versus blown diffrence ?

I am thinking of running total timimg on my N/A set up if i go Apr 25th and will see what changes untill i figure this out i dont have the guts to try it on the turbo set up.

[302man]

Dwell, is the duration of the spark right ? So if you used a MSD ignition, wouldn't it fire 2-3 times anyway up to 2-3000 rpm ? This sounds like a compasitive discharge ignition would more than make up for it.

The spout out method does have its draw backs as has it positives too. I have yet to see ANY drivability issues with an auto or five speed, blower or n/a.

To me, the negatives are : not emmissions legal, gas mileage might be down 1-2mpg, (some cases it has increased,) when used with a power adder(blower), you need additional equipment to opimize your set up.

Positives : no longer haveing the EEC pull out timing due to varying conditions = gaining consistancy, when using a power adder, a BTM can be used with this method to pull back timing, consistancy at the race track: my car would run at +/- .02 every time. (usually driver shifting error) no hard starting when hot - I used 30 degrees base, tends to clear up a rich running engine at idle, for power adder (blower) guys : part throttle detination is almost always eliminatedand best of all, its free....if it don't work for you, no harm no foul, just change it back.

This idea of removing the spout out, was used by guys like Lideo at Alternative Auto and Jimmy Larocca. The problem was : when using a blower, part throttle detination existed as well as detination just off full throttle. This method fixed the the detination problem as well as gained a few HP due to the increased timing at lower RPM.

Why do I feel so strong that this is a good exceptable way to go ? Easy : it worked for me and I had basicly nothing that made my car run a 10.13@135 . I had a S trim- everybody and their brother has one of these .... (at least it seems like it) edelbrock 6037 heads, GT-40 intake-lower ported, 1 5/8 lt headers, C4 and 3:55 gears. Nothing fancy here. But it worked and when I went over to this type of tuning, my performance kept going and going until I leveled off af at my 10.13 . Again, this way might not work for you, if it don't work , just change it back.

[tmoss]

Originally posted by 302man
Why do I feel so strong that this is a good exceptable way to go ? Easy : it worked for me ........

There's more than one way to skin a cat, you found another way that works well - good for you, that's what hot roddin's all about.

[84LX89GT]

dwell is the coil on time (primary side) when the processor gives it power before breaking it. The dwell is how long the coil is "on" saturated, before the circuit is opened inducing the secondary spark to fire the plugs. Less dwell time (primary on time) creates less of a magnetic field in the primary coil, which will induce a smaller voltage in the secondary. If you have MSD ignition and coil, though, you don't really need as much dwell time because the system is designed for multiple spark discharge which has small dwell time anyway. On stock engines, though, removing the spout may not work because it's designed to have a certain dwell at a certain engine speed/load, it's worth a try because there's no harm in the consequences. I just didn't hear any negatives to the spout theory, thought i'd be the party pooper

[TONYD]

Ok,

My .02.. I have the timing locked with the spout out on my 95 gt (see sig) .. I picked up a ton of low end with this mod (before removing spout with the sucky timing curve on the 94-95 processor it would ping with more than 10 degrees intitial when it would go into drive.. now i run 34 total and with the high torque stater that comes on 92 and newer mustangs it carnks fine AND it picked up 3 FULL TENTHS NA and 2 tenths on bottle

My car is DRIVEN DAILY and has been nothing but better with this change..

And whoever it was that stated it would take away low end has their wires crossed it HELPS torque and low end..

All A9L and A9P processors add 20 degrees to base timing.. They add it at differing times (the p is a auto computer and the L is a 5 spd processor) But idealy on a Performance car you want your total in as early as possible this promotes torque, throttle response , etc..

As for the misfire problem with the reduced dwell time it might be a problem with a stock ignition car BUT with a MSD it is not nor do i see it to ever be .. (i have heard of some stock cars with the timing locked via spout removal having a top end bang)

Ever car will be different in the amount of timing they like. It depends on the head, cam, etc.. Most motors will make best et and mph at anywhere from 30-38 degrees of total timing.. Some stock headed cars may like slightly more due to a more INefficient combustion chamber requireing more ignition lead to get a good burn..

I never run anything but pump gas so just because you lock timing does NOT mean you need race gas

I have done this to MANY blower setups on fox body cars with good results by being able to have more initial and use a btm to pull out timing as the boost hits.. Thereby making the car have more throttle response and low end before the boost hits under light throttle..

Just my .02

[tmoss]

Originally posted by TONYD

All A9L and A9P processors add 20 degrees to base timing.. They add it at differing times (the p is a auto computer and the L is a 5 spd processor) But idealy on a Performance car you want your total in as early as possible this promotes torque, throttle response , etc..

For those of you who might want to see an A9L spark map, it in this thread

"Total timing vs initial timing for max HP"

This site won't let me post it again. They ought to link it up and show the link at least!!!!!!!!!!!!

[bigred90gt]

Back to the original idea in the thread, I pulled my spout and set my bast to 30 something deg and ran it without the spout, and hit my best time of a 14.2 (I know, still slow). Just for comparitive values, I re-set the timing to 26 deg base, and put the spout back in, and ran the same et on the next run. I am not sure about the mph on each run, but I'm sure they were close. But that is just my expiernces, all cars run a little different.

Caymon