Desperately seeking inline 200 help!

[Quincy68]

I have an inline 6 200 bored 30 over with Wisco forged pistons, 10-1 compression, 179/179/108deg clay smith cam, Vintage Inlines head and intake with Holley Sniper EFI.
Took it to a tuner and he could not get the dead stop at take off figured out. Falls on its face either too lean or too rich. Don't know what else to do. Any sugestions???

 

[wicked93gs]

I can't speak to Holley Sniper, but Megasquirt has an acceleration enrichment curve:

MS gives a couple different options on this...you can either use pure TPS, or a sudden change in KPA to kick over to table you need. I would be shocked if Holley does not have something similar. In addition AE, you can also spend more time tuning the section of the VE map that is going to be higher KPA, but low RPM, around the area I have highlighted in blue here:

this area of the map is infamous for getting very little attention, but it is important for sudden acceleration to WOT at idle or low RPM(note: this map has KPA(or rather fuel load since its uses an ITB modifier) values above 100 because its a 3 bar map sensor, this is not a driven tune, just the default values based on injector size and engine size)

I am sure Holley also has some type of auto-tune feature that will help tune that area of the map by target air/fuel ratio.....but to take advantage of it, you need a wideband installed, I don't know the details of your setup, but a narrowband sensor wont allow you to do accurate AFR target tuning(I am sure your tuner used a wideband when he had the car though)

 

[Quincy68]

I must admit I am somewhat clueless on the tuning parameters. The tuner just told me that he went from the lowest to the highest (400) and the car never found its sweet spot that it liked. He thinks that the Holley sniper 4 barrel and the intake is just too much for the cubic inch of the motor and compression of 10-1. I was under the understanding that with EFI you can adjust AF mixtures to the sweet spot? I just need to know if my setup is correct enough to tune or did I go to far? How do I find this out?

 

[wicked93gs]

The whole point of EFI standalone systems is to be able to tune ANY configuration. That being said, I have never used the Holley unit on any EFI conversions simply because throttle body injection in my mind defeats half the point of an EFI conversion to begin with. A lot of people have good luck with Holley Sniper systems though, I just do not know exactly how flexible they are. I would imagine the capability is there...but its one of those things you may have to study up on and do yourself though.

 

[Noobz347]

@a91what

 

[a91what]

He was only adjusting the main fuel table is what it sounds like.
The x-tau, or throttle delta enrichments need to be adjusted.
Do you have a laptop connected to this or just the tuner with the little screen?

 

[Quincy68]

Just the tuner with the little screen.

 

[7991LXnSHO]

He was only adjusting the main fuel table is what it sounds like.
The x-tau, or throttle delta enrichments need to be adjusted.
Do you have a laptop connected to this or just the tuner with the little screen?

The diy tuning stuff makes my head hurt, and I am far from a Luddite. It is probably like talking about different 6L6 tubes, push pull amp circuits and B+ voltages is to most members.
So - it’s great you can help members that dive into this!

 

[a91what]

Only problem is some of the systems like the one the op is using has no way for me to review the tune. Makes it hard to help.