TR2/3/3A 1/4 mile fast time driving technique

[TFB]

I haven't tried to time my basically stock TR3 for off the line performance but I am curious about best technique,particurally how a factory test driver would get the best time,usually reported around 18 seconds for a 1/4 mile.
What would be the ideal rpm shift points etc.,
Thanks
Tom

 

[PeterK]

Practice, practice, practice.

 

[Geo Hahn]

I would suppose with an unmodified engine you would shift at redline unless you had reason to believe that you could safely go higher (or didn't much care which is possibly how a factory driver would treat the car).

 

[glemon]

Dump the clutch from about 3000 rpm to start, and shift at the redline full throttle as quickly as possible. I had a chance to do quarter mile times in my TR250 a couple years ago and was able to get pretty consistent times (don't know if they were best possible, but they were consistent!)

 

[TomMull]

Putting a stock TR3 on the dragstrip reminds me of the time a farmer I once knew hitched up a pair of milking cows for the ox pulling contest at the town Fair.
Tom

 

[CJD]

Putting a stock TR3 on the dragstrip reminds me of the time a farmer I once knew hitched up a pair of milking cows for the ox pulling contest at the town Fair.
Tom

Yep...shift whenever you like, cause the Prius you're racing is going to win unless his battery goes flat.

 

[TFB]

Yep...shift whenever you like, cause the Prius you're racing is going to win unless his battery goes flat.

Thanks for the responses and humor.I have no intention of drag racing,but the factory obviously tested the cars in the 1/4 mile drag format.
I actually think that winding up to redline in all gears is not the fastest,but was curious what expertise might be out there.
Thanks
tom

 

[Lukens]

This might fall under the heading of "destructive testing". Why flog a 50 year old motor?

 

[HealeyRick]

If you look at the graph and charts from this Sports Car Illustrated article it seems they shifted at the red line in 1st and 2nd and stayed in 3rd until they finished the 1/4. They cut .6 sec off their 0-60 time by shifting from 2nd to 2nd overdrive instead of making the 2-3 shift. They probably played around with different launch rpms to see what gave them the best times: https://drive.google.com/file/d/0B5xnnKbPEWx5Z2h5V2JiTmF2Wkk/edit

 

[TFB]

Thanks Rick.That is just the kind of of info I was curious about.Lots of good stuff in the article,thanks again
Tom

 

[glemon]

Why flog a 50 year old motor?

A. It is fun
B. It is kind of what they were made for
C. Triumph TR 4 Cylinders are pretty tough old beasts, I flogged the **** out of my 4A as only a 20 year old can and never broke anything in the motor (of course it was only about 15 years old then)

 

[Darrell_Walker]

C. Triumph TR 4 Cylinders are pretty tough old beasts, I flogged the **** out of my 4A as only a 20 year old can and never broke anything in the motor (of course it was only about 15 years old then)

Me, too. Though I did break the front suspension mount (but it was previously broken anyway).

 

[glemon]

Me too, front suspension mount, actually popped as I carefully was backing up to parallel park, hit the brakes and it snapped. Am am sure prior abuse and metal fatigue had nothing to do with it.....

 

[Simon TR4a]

I would imagine you want to keep the engine between peak torque and peak horsepower rpm. But going a bit past the peak to redline would give the benefit of lower gearing for a better multiplier effect, which would more than compensate for a small drop in power past the peak. I found in racing that it is possible to change gears with only a dip of the clutch, not fully disengaging as you would do in normal driving. This would reduce the brief time interval when the engine is not driving the car forward.
A close ratio second would be a really big help, but that's another matter!

 

[CJD]

Take out the clutch spring for a few more milliseconds on the shift...or adjust the linkage to 0 play.

 

[HealeyRick]

I would imagine you want to keep the engine between peak torque and peak horsepower rpm. But going a bit past the peak to redline would give the benefit of lower gearing for a better multiplier effect, which would more than compensate for a small drop in power past the peak. I found in racing that it is possible to change gears with only a dip of the clutch, not fully disengaging as you would do in normal driving. This would reduce the brief time interval when the engine is not driving the car forward.
A close ratio second would be a really big help, but that's another matter!

Now we're getting into the area of shaving tenths, aka "destructive testing", aka "It's not my car, what the ****?" Tach up the motor and "sidestep the clutch" (allowing your left foot to slide off the side of the clutch pedal and let the clutch lever bang up to the top for immediate clutch engagement. Preload the shift lever for the 1-2 shift and when you're near the shift point, dab the clutch and yank the lever back into 2nd, then to 3rd, etc. This is literally known as "banging gears." (aka speed shifting).Sometimes these shifts are made without dipping the clutch. Disclaimer: My familiarity with these procedures should in no way be considered an acknowledgement of unsanctioned contests of speed. :angel: