I recently had my P.I. Vigilante converter restalled from 3200 to 3600. I did this because the car did not seem to launch as hard as it did before I put the cam in and I wanted to improve my 60ft since it was the same as it was before the cam. When I went to the track i dropped my 60ft a tenth from 1.75 to 1.65, but my ET slowed down almost a tenth from me averaging 11.95-97 to now it averaging 12.02 to 12.08. Any ideas on why this would happen?

The only other changes i made to the car when I pulled the converter was a Reactor flexplate and a driveshaft loop.

The cam is an EPS 230/234 603/605 lift at 112 the rest of my mods should be in my signature and any help would be great.

 

What was the difference in trap speed?

 

About 1 mph

 

How was the weather on both days? A hot day could easily make that much difference.

 

It wasn't so much a one day to one day to one day comparison. Is more like the 4 times I went last year which the weather varied in would run high 11.90's maybe low 12.00's with a bad launch or hotter days engine temps. The 2 times this year I have yet to be in the 11's and it was cool out the last time i went. Also this year with a bad launch or higher engine temps I am running in the 12.teens.

 

Need to know the DA to compare.

Temp is just one factor in air quality.

It's also possible the looser converter is just losing more HP through inefficiency which is hurting ET and MPH.

 

Maybe your shifts points need to be adjusted since the re stall.

You should of picked up 2 tenths on the big end by loosing 1 on the 60.

 

Post your time slips

 

Do you need before or after converter tome slips? And should i give the best of both or the average?

 

Not that it really matters, but are you leaving at the same RPM that you were before the restall?

 

I tryed leaving at the same rpm and at a higher rpm with the only difference being better 60ft or spinning. I have yet to perfect myblaunch with the new stall.

 

Best before and best after

 

Here's my fastest ET before the stall change and my fastest ET after.

 

your convertor is working better both your 60 foot and 330 improved , by 660 its dropped off slightly and more so by 1320.

You've lost power , surely explainable if the da was worse , more weight , fuel etc.. in the car - its not drastically slower but your saying the weather was cooler last time out so if no other components or tune has changed how about routine maintenance stuff like fuel and air filter , plugs , etc...

 

Air filter is newer and clean, the spark plugs were replaced when I did the cam 2 years ago (maybe 6,000 Mi). The fuel filter is about 5 years old (15,000 miles) I was just thinking about it when I was under the car and it would be a simple and probably needed maintenance I could do.

I know my ET is not off by much, but was hoping for a tenth improvement with the higher stall and I actually ran a tenth slower, but a quicker sixty.

Could I need a re-tune with the the stall increase?

One thing I noticed was my IAT seemed high in between runs, but I never monitored it before so not sure what it should be. I didn't have my scanner, but the Torque app on my phone was saying the IAT was around 178 degrees after the run is this normal? I figured it might be since it sits right above the radiator. I checked the next day before staring the car and it was at ambient temp.

 

I would do the plugs and fuel filter with that much time on them.

Those iat's sound high but if your letting it idle the whole time in the staging lanes and leaving the hood closed sounds about right , pretty much coolant temp. been a while since I regularly raced with a scanner going in a car but I was always within 10* or so of ambient but I had hood open and shut off whenever the car wasn't moving , if your not cycling your starter at least 10 times per pass your not trying hard enough to keep it cool lol

 

I'm going to change the fuel filter, pull the plugs to see what they look like. Will also check the condition of the wires.

If anybody else has other ideas, I would appreciate it.

 

Changed fuel filter, pulled plugs, and measured resistance of wires. The wires were all under 1 ohm and the plugs looked good. Would you still replace the plugs? I wasn't ablt to go to the track this week due to rain hopefully this weekend will be nice.

Also could I need more air in the big end? Would I benefit from a ssra?

 

I think the SSRA can only help a little

 

Car was retuned after the cam?

Are you logging runs? Your shift points I'm sure have had to be raised a noticeable amount. I forget where we shifted stock LS1s, 5800? With that cam you could be 6400-6700?

High IAT temps = pulled timing. Were you idling a long time in the lanes?

I never personally used SSRA or similar but I've read good things about the Chris Johnson ramair that I think Speed Inc. distributes.

But I'd look into the IATs, that could be a few tenths right there.