checking out new exhaust at drag strip

[aafc]

After installing the lt1 exhaust mufflers i made a trip to the drag strip
on fun day sunday ( (April 3,2016). Made three runs,all runs are with the
3" cutout's fully open.
Run #1
60 ft. 1.755 1/8 7.602 mph 94.34 1/4 11.789 mph 118.13
Run #2
60 ft. 1.756 1/8 7.589 mph 94.45 1/4 11.771 mph 118.00
Run#3
60 ft. 1.767 1/8 7.620 mph 94.36 1/4 1180.5 mph 117.11
First 2 runs tires set @ 26 lbs. Air temp 82 to84 deg.
Last run tires set @25 lbs. air temp about 89 deg.
left track had some honey do's to do the rest of the day.

Went back to the track on April 6, 2016. On Sunday i did not have time
to test the exhaust fully closed and open.
Runs #1 and 2 are with exhaust fully closed. tire @ 26 lbs
Runs #3 and 4 are with exhaust fully open. tire @ 26 lbs.

Run #1
60 ft. 1.744 1/8 7.620 mph 93.38 1/4 11.855 mph 116.22
Run #2
60 ft. 1.757 1/8 7.626 mph 93 34 1/4 11.868 mph 114.92
Run #3
60 ft. 1.733 1/8 7.538 mph 94.61 1/4 11724 mph 117.75
Run #4
60 ft. 1.719 1/87.507 mph 94.79 1/4 11.675 mph 118.16

With exhaust fully open gives the best times in 1/4 mile.
But in 1/8 mile almost the same times .
In the last 1/8 is were the ZR-1 comes on strong.
Air temp were in the mid 70's with a chill in the air.
The last run the car felt a little loose ( 8 pm ) . we left the track @ 10 pm
and ran into rain on the way home.

John
1990 white/black #2546
one of a few auto (4l80E ) eq. ZR-1's

[XfireZ51]

Don't be surprised if your ZR can gain 4 car lengths in the last 1/8mph.
It's what happens v a OHV motor.

[Jagdpanzer]

Strong times and trap speeds.
Excellent short times.
What mods and and tire?

[Bob Eyres]

That auto trans is allowing some very consistent short times.

And getting into the 11.6's with only a 118mph. trap speed is a testament to how quick that car is.

That 118mph indicates about 425 crank hp. To turn an 11.6 with that means the auto is getting the job done.

[aafc]

Thank you,
The mods,
SGC 368 with stage one cams, Jeal headers into 2 3/4 in H -pipe into stock
LT1 mufflers with 3 in cutouts. The motor made 418 rwhp on chassis dyno
about 3 years ago.
Transmission 4l80E with 3200 stall FTI conv. gear ratios are 2.75 1st 1.57
2nd , 1.1 3rd and .075 4th. Rear tires are 315/35/17 M.T. drag radials ,
front tires are Hoosier Pro Street on narrowed 1990 17 x 6 in stock rims.
Car weights in @ 3747 with driver and full tank of gas.
I have run as fast as 11.58 @ 120.12. real good air and great bite on track.

John

[QB93Z]

Great times! Thanks for posting your information and analysis.

Jim

[Jagdpanzer]

Do you get into 4th gear before the traps?

[aafc]

Not sure as i leave the transmission in 3rd gear when leaving the line.
The transmission computer is set to shift @ 7000 rpms @ wot, so i have'n
actual looked at the tach (after market PRO COMP ) when going thru the lights.
Darn another trip to the track to check it out ( April 13th or 17th) depends
on work and other factors .

John

[Hog]

Originally Posted by XfireZ51

Don't be surprised if your ZR can gain 4 car lengths in the last 1/8mph.
It's what happens v a OHV motor.

His numbers are showing ET and MPH improvements on both halves of the track, not just the last 1/8th. Unless I am misunderstanding?
xxxxxxxxxxxxxxxxxxxxxxx

Great numbers Jon, your 80e is getting work done. The results of torque multiplication and being able to keep the power applied for the ENTIRE run is evident.

What's your 3200rpm converter stall to if you floor it off the line, or try to hold WOT at a dead stop?