So I wanted to try the tune from 4seconds flat and it was worse. thoughts?

[bigmanjbmopar]

Well gave ole' Don my $10 for is tune to win guide, and it seems to be way over what the motor likes. He says to have a base of 30° with vac connected. 12 initial and 34 total. well when I tried that exact thing it was too high, i did switch the vacuum advance from ported to manifold for full time vac and at first it seemed good smoother idle but after taking the timing to his set points and adjusting the a/f mix it was just way off.

There is a shop a few miles away from me that will give me a tune and dyno time for $400 just going to go there to make sure this motor is at it's full potential.

Background was, it had a low idle and tune, was adequate but was lacking a bit never pinged. Always felt since day one needed to dyno it to get it to a full tune. Thoughts?

 

[kiwigtx]

I put my GTX on a rolling road Dyno last year for a tune-up. A great idea I thought, and it gave some actual numbers to validate the engine possibilities. However, the Dyno man tuned as if it were being raced regularly....which it isn't. Driving around later I discovered the car ran very 'fat' or rich, was increasingly harder to start and idle, but ran awesome when the go pedal was squeezing the carpet.
I ended up de-tuning if you like, and now it starts/runs/idles like a normal car. That's my experience...don't let it put you off. :icon_thumright:

 

[1fastrunner]

With Don's set up, you need the recommended ballast or it will run inconsistently and bad all at the same time.

 

[bigmanjbmopar]

Running all electronic, MSD 6AL with the firecore distributor. Got conflicting info from Don and Mancini Don of course wants me to send it to him for phasing which I don't mind doing but Mancini and the Firecore engineers say that it does't need it as OTB it's set to run in a hot street motor. if more or less is needed just tune the vac or change the springs in the weights.

Really just want to see what the output is and get it tuned for the maximum. I am just unsure of what or how to find the max in my garage. I could just be happy with what I got but why build a 493 if you can't max it out

 

[Hemi Rebel]

Did you talk to him directly or just read the tuning guide? I have the guide and I dont recall reading anywhere in it saying to set a base of 30 degrees. Im trying tp figure what you have going on here. What exactly did you do? Did you set the timing to 30degrees at idle?

 

[bigmanjbmopar]

Vac off dist. capped. timed to 12 initial. 34 total at 3k. took it out for a run and hit passing gear and got a small ping oh and had also had A/F on the front 1-1/2 turns out and secondaries 3/4 out.

Got home, reset to 10 initial and 28 in at 3k and back out on the road no ping. back to a baseline set up until I can get my brain wrapped around whats going on. was thinking a dyno would help with max HP then go from there an need vs want.

 

[747mopar]

I'm in the same boat and am thinking about the dyno as well because I'm quite sure there's allot more to be had out of my 456". My hold up is I want to try a vac adv distributor and a double pumper first to make sure I get it tuned with whichever one I end up liking. I've recently developed a nasty sputter when downshifting and mashing it to the floor as well to get resolved so I'll eventually get there.:banghead:

 

[Hemi Rebel]

Msd distributor?

 

[bigmanjbmopar]

Firecore dual vac & mech

 

[mopar 3 B]

Try this set idle to where it just stays running. With vacuum gauge to manifold vacuum port adjust timing, set to highest available vacuum reading. Use this for base line. Next set a/f to highest rpm and vacuum. I have checked this method with an exhaust sniffer and is real close.
There are to many variables to setting total timing and fuel even in a dyno tune. Temperature, humidity change all the time so if you want it to run its best at the track learn how to do it yourself or finding some one willing to go with and do it for you is best way.