I SPEED

When I make a pass at the track with N20, the truck will shudder up around redline when shifting from 3rd to OD, and the shift is delayed. With no N20 the truck shifts fine.
Watch the video, you can hear the shudder...tell me what you think.

12.3 video

XLR8R

I could only hear the engine stuttering at the 2-3 shift, and it was too dark to get a good read on smoke levels.

I think you should adjust the Hobbs switch for your NO2 initiation threshold.

Are you losing much boost during the shifts?
They sounded a tad slow...

XLR8R

P.S. Great run, BTW!

Mike D

Could it be a timing issue?

mysterync

Contact Olee Poole or Doug Smith! That would be my first recomendation!

rockjeep73

The delay in the 3rd to 4th shift is due to the fact that the shift is electronically controlled and the computer doesnt tell the transmission to shift soon enough for the power level that you are at. You need to wire in a 4th gear toggle switch, just like you have for your lockup.

As for the stutter, I have never heard that before, maybe smarty related? My truck shifts just like your does into OD, but it just lays over at about 3400 without the stutter. Im running a TST/EZ. What RPM is the stutter at?

BTW, when are you locking your converter, assuming you do?

Good looking run though.

I SPEED

The shudder is happening on the 3-4 shift. The Smarty is not in use at the track. I installed a switch for the OD, but the shudder still happens, not sure what the RPM is when it happens as I'm running a BD RAD and it shuts the cluster off.
The N20 system I have is an NX 2 stage with their progessive boost controller. It's totally adjustable, but it happens even when I only run 1 stage with a small jet.

Just for comparison...truck runs 12.21 @ 108.98 on fuel only. The N20 increases MPH but no improvement on ET.

Thanks for the input...keep it coming.

I've updated my sig...

one54ton

Something is up for sure. Everyone I know with a dual stage kit are cutting up to .8 of their E.T.

Jetpilot

I would bet the engine is defueling and too much nitrous at this point. The delayed shift is due to the added HP using nitrous. Install a 3-4 shift switch, this will allow you to manually make the 3-4 shift aound 3200 RPM. My bet is you will see times improve, and the shudder cease.

I SPEED

How would I correct the defueling?

Jetpilot

Put a manula 3-4 shift switch in and manually make the shift around 3200. This keeps the rpms below the 3350 defuel point.

I SPEED

I'll try this next time I'm at the track. Thanks

paulb

I agree with what Rockjeep73 and Jetpilot both said. Remember though, you may have to use the OD switch way before you actually want it to shift into OD. Depends on how your valve body is setup.

If you have the later RAD (two position switch), you can turn it off once you hit 3rd gear, actually I think you can turn it off before then, but I'm way to busy then to try it. It will still defeat the mph limiter. The earlier RAD had a three position switch, and the third position allowed the gauges to work and still defeat the mph limiter.

As far as your E.T.'s not going up, are you using the nitrous all the way down the track? What are your 60' times, and what boost are you launching at?

Paul

I SPEED

I have the early RAD, 3 pos switch. I'm using nitrous all the way down the track, launching at 20-25psi, 1.66-1.69 short time.

CL2000

It is defueling because it shifts to late and the NOS puts the flame out