KNOCKING after cam install!

[final5-0]

Grady,

that just seemed like a lot of base timing...but of course, he's running aluminum heads so I guess that would help out a bit.

Well Clay

it is just not a ........ simple thing as you well know

A dizzy twister can't be compared to a spark table adjuster
cause
Both methods are not on an apples to apples comparison.

SBF's have been making the best WOT power for decades
at 36 total advance ... give or take a few

sooooo

Trying that rule of thumb with the dizzy twisting method of tuning .....
You would need 11 more to add to the 25 in the spark table

Since the pcm can add more spark during light loads
You'll most likely encounter the ping thing
WAY before reaching a dizzy setting of that value

therefore

You can't always go for the optimum total WOT advance value
without
Suffering with values too high during low/mid level load driving conditions

Here is where the big difference lies between the two methods

A fellow with pcm access just has more options.
and
He needs to think differently to take advantage of those options.

Grady

 

[cbarr300]

thanks for the insight.

I was just thinking....that most GT people have that ping problem you're talking about....just twisting the dizzy to 14*

at first glance, it would seem like turning the dizzy to 19* base would cause the car to run somewhat horrible...with a good bit of pinging (especially in the mid-range area as you discussed before.) So while 19* base is good for top end performance, it seems like it would ping like hades during normal driving.

then...I looked at his combo and noticed the alum. heads. I've heard one can run more timing with alum. heads...Me, I'm not to familiar with the timing diff. between alum. heads and cast iron so I can't say anything 100% about that being too much turning at the dizzy.

That's why I was saying maybe he should check the balancer...always a good thing to check anyhow with the stock pieces.

feel free to post up anymore insight on this.

also...this might be hard to follow. I'm way past the point of needing sleep.

take care

 

[Fopar]

Actually ... 19 at the dizzy would only be 34 for a total advance
if
You don't count any adders and are talking WOT only

Of course at mid level loads you could see values
in the mid to high 40's

Grady

how do you figure? You're saying there's only 15* added by the comp? So factory timing of 10* is only 25 total advance @ WOT? I don't think so....

 

[cbarr300]

Yup, what Grady said is 100% true. GTs had 25* for total timing. Cobras had 26* at 5000 and up

 

[final5-0]

how do you figure? You're saying there's only 15* added by the comp? So factory timing of 10* is only 25 total advance @ WOT? I don't think so....

If you care to learn some basics on how the pcm deals with spark

Go to my site you see in the sig and focus on the tuning page

You can see screen shots of spark tables and the like, brief
write ups on issues like shift retard, high speed fuel adders, etc

Grady

 

[95Vert]

Thank you Grady for clearing that up. You saved me some typing.

Why don't you run your timing locked out and be done with it? Eliminate the computer interference.

 

[Methodical]

Yup, what Grady said is 100% true. GTs had 25* for total timing. Cobras had 26* at 5000 and up

Actually, I think the Cobra is 27* but I could be wrong since I have not played with the spark table in awhile. But Grady's correct about WOT timing. It is not as high as you would think.

 

[Stanger007]

It is 26* total on J4J1, but heck who's counting.

I need to go bust open the ZA0 tune and see what the timing curves look like for the Cobra R - got me curious now.

Wes

 

[final5-0]

Thank you Grady for clearing that up. You saved me some typing.

Why don't you run your timing locked out and be done with it? Eliminate the computer interference.

Well ... I guess my answer here would be .....................

Why invest money on self tuning equipment
and
Time with research learning how the pcm operates
if
I'm gonna employ methods such as that

The pcm has the ability to use load, rpm, act/ect temps, and more
to arrive at an optimum spark value

Why would I wanna give up that kind of flexibility and control by using
a method such as that

I don't see the pcm interfering with my objectives
and if you think about it .....
It was I who did the interfering in the first place

The pcm was doing a pretty good job of controlling things when my
car was stock

I interfered with it when I put all those hot rod parts on my car :Word:

Self Tuning is just one making pcm adjustments to compensate for
the hot rod parts

Hope that made sense

Grady

 

[cbarr300]

I think he was talking to the OP when he made the locked out timing comment, lol.

could be wrong though...

so is the problem still gone?

 

[Methodical]

It is 26* total on J4J1, but heck who's counting.

I need to go bust open the ZA0 tune and see what the timing curves look like for the Cobra R - got me curious now.

Wes

Yep it's 26*. Just checked - was curious too.