Need help/suggestions for dyno tuning my VEC 2

[Shanedog]

I have an 01 GTS with the Roe modified air box, 70mm throttle bodies, B&B headers with no cats and B&B exhaust. It also has a VEC 2.

I took it to a local shop who is known as an excellent tuner (they know their stuff). With the Roe performance tune I made around 435RWHP/450TQ if I remember right. After doing some tweeking we got the car at about 12:1 air/fuel and we made around 445hp/500tq. However, we had a HUGE miss up top (about 4,500 RPM's). We changed the plugs, and it made no difference so I bought some MOPAR 8.5mm performance wires from a forum member and the miss went away. We got it back on the dyno and at 3,500 RPM's it was making about 10 more RWHP and 15 more TQ just with the new wires. However, the dyno was acting up so we couldn't finish tuning the car.

I brought it back a few days ago to finish the tune and for some reason the car is running pig rich again. Following is a copy of the e-mail I got from the tuner:


I came in this morning before it got too hot, let the motor get some heat in it and made a pull and it made 450rwhp and 455rwtq. I still don't know where all the torque went that we made that last time you were in here. Whats weird is that we put the wideband on it and its super rich on fuel. So we started leaning it out a little bit, and a little bit more, and a little bit more until we were telling it to pull a bunch of fuel and it still wasn't actually leaning it out. It still has high 9 / low 10:1 air fuel ratio. There's definitely power and torque to be had if we could get all that fuel out of it.

Does anyone know why its so hard to lean the car out? Do you have any suggestions I could forward on for tuning the VEC 2?

Also, if I am making 450RWHP and 455TQ with a high 9 - 10:1 air fuel, if we get a nice, safe air/fuel ratio around 12:1 or so, where would you expect the HP and TQ to be?

Thanks everyone, I appreciate your help!

-Derek

 

[Jack B]

I have an 01 GTS with the Roe modified air box, 70mm throttle bodies, B&B headers with no cats and B&B exhaust. It also has a VEC 2.

I took it to a local shop who is known as an excellent tuner (they know their stuff). With the Roe performance tune I made around 435RWHP/450TQ if I remember right. After doing some tweeking we got the car at about 12:1 air/fuel and we made around 445hp/500tq. However, we had a HUGE miss up top (about 4,500 RPM's). We changed the plugs, and it made no difference so I bought some MOPAR 8.5mm performance wires from a forum member and the miss went away. We got it back on the dyno and at 3,500 RPM's it was making about 10 more RWHP and 15 more TQ just with the new wires. However, the dyno was acting up so we couldn't finish tuning the car.

I brought it back a few days ago to finish the tune and for some reason the car is running pig rich again. Following is a copy of the e-mail I got from the tuner:


I came in this morning before it got too hot, let the motor get some heat in it and made a pull and it made 450rwhp and 455rwtq. I still don't know where all the torque went that we made that last time you were in here. Whats weird is that we put the wideband on it and its super rich on fuel. So we started leaning it out a little bit, and a little bit more, and a little bit more until we were telling it to pull a bunch of fuel and it still wasn't actually leaning it out. It still has high 9 / low 10:1 air fuel ratio. There's definitely power and torque to be had if we could get all that fuel out of it.

Does anyone know why its so hard to lean the car out? Do you have any suggestions I could forward on for tuning the VEC 2?

Also, if I am making 450RWHP and 455TQ with a high 9 - 10:1 air fuel, if we get a nice, safe air/fuel ratio around 12:1 or so, where would you expect the HP and TQ to be?

Thanks everyone, I appreciate your help!

-Derek

1. Make sure you have the latest VEC firmware. There was a problem with the early firmware, it created a notch like drop in power near peak torque , this could be your miss.

2. The Viper PCM has a habit of adding fuel as it gets hotter - this confuses tuners that have not seen this before. You can expect a full point diff between 70 and 90 degrees.

3. I would ask the tuner to change his O2 sensor.

4. If he is using a tail pipe sniffer it is difficult to get consistent and accurate a/f readings. Have him put the O2 sensor in the oem ****.

 

[Shanedog]

1. Make sure you have the latest VEC firmware. There was a problem with the early firmware, it created a notch like drop in power near peak torque , this could be your miss.

2. The Viper PCM has a habit of adding fuel as it gets hotter - this confuses tuners that have not seen this before. You can expect a full point diff between 70 and 90 degrees.

3. I would ask the tuner to change his O2 sensor.

4. If he is using a tail pipe sniffer it is difficult to get consistent and accurate a/f readings. Have him put the O2 sensor in the oem ****.

Jack, thank you VERY much. That is some excellent information. I will see what firmware I have and forward this info to the tuner. Thanks again

 

[Shanedog]

I just checked the VEC 2 disk (I assume that is how to determine what firmware I am using) and it says its Version 3.5.0 and Dataset ID S106.

Do I need to upgrade the firmware? If so, how do I do that?

Thanks again.

 

[BOTTLEFED]

contact Sean at Roe Racing and tell him what version you have

IIRC, 106 is the old version and 108 is the updated firmware
I don't think you have to send the unit to Roe for the update, but I could be wrong

 

[Shanedog]

contact Sean at Roe Racing and tell him what version you have

IIRC, 106 is the old version and 108 is the updated firmware
I don't think you have to send the unit to Roe for the update, but I could be wrong

Thanks for the heads up, I'll shoot him an e-mail.

 

[KenH]

There is updating instructions and code on his website at Roe Racing: Installers & Dealers

 

[Shanedog]

There is updating instructions and code on his website at Roe Racing: Installers & Dealers

Perfect, thank you very much Ken.