Quarter mile times vs. engine type and power output?

[saturnkk]

This thread is fun to read!!!

[rpatton3]

167 mph top end and and 10.5 second 1/4 mile times! Wow!

I have a Roush 427 with 515 HP and similar torque TKO five speed and 3.46 rear axle ratio.

My car is not gonna be that fast on either end but it is nice to know your car is.

Best wishes for 2013.

Russell

[Roush #1]

Russ,
Your comment comes up frequently, and the only answer I have is the gear ratio differences between the T56 and the TKO along with my lower rear gear ratio. Compare the T56 to the TKO and you will see a little lower ratio (normally) in the T56 vs the TKO in the first three gears and a closer ratio (normally) between 4th and fifth in the T56 vs the TKO which all contribute to a little quicker acceleration through the first 5 gears.
If we were both running the same overall gear ratio, I doubt there would be much difference in acceleration with both of our engines coming off the same dyno making very similar horsepower and torque numbers.
This information is what I believe the initial thread question was about. I hope we have helped answer the question.....although my combination works for our horsepower and torque curves it probably wouldn't work as well with another engine.

[xb-60]

Originally Posted by olddog

...You may want to ask what type of tires are used at the track. How much power you can hook to the ground has to do with tires...

Yes, tyres are a significant factor. I suggested specifying whether 15" or 17" wheels
Cheers,
Glen

[olddog]

Originally Posted by xb-60

Yes, tyres are a significant factor. I suggested specifying whether 15" or 17" wheels
Cheers,
Glen

The OD of the tire is part of the gear ratio calculation.

Wheel OD doesn't matter much in a drag race. At least I cannot think of why it would.

What I was actually talking about is how sticky the tires are. Street tires are hard designed for long wear. Drag slicks are very sticky. A huge difference in traction.

Then the drag strip puts a tacky surface down. They do use different stuff for different competitions. The tack will pull your shoes off, if you don't have them tied tight. So from one track to another, even the same track on a different day, there can be quite a bit of difference.

Horse power at a dyno is corrected to what the engine would have produced at sea level at a specific temp and other weather conditions. In theory, this allows an apples to apples comparison regardless are where the dyno is located and what the weather is. The point is that no matter what the dyno said the Hp is for an engine, the elevation of the track and the weather conditions will impact the true power that the engine is making.

[olddog]

Originally Posted by Hotfingrs

That's the reason I feel I could be in the 8's with a solid rear end. I run a C4 Corvette set up now and am limited by half shaft breakage.

At London I expect you have street tires on. The front tires stay on the ground.

Getting to 9's at the track, I expect you have some type of a drag slick. Are you lifting the front wheels at the track? I expect a straight axle would allow much better weight transfer to the back wheels, in addition to not breaking. I agree you could go faster.

[Hotfingrs]

Originally Posted by olddog

At London I expect you have street tires on. The front tires stay on the ground.

Getting to 9's at the track, I expect you have some type of a drag slick. Are you lifting the front wheels at the track? I expect a straight axle would allow much better weight transfer to the back wheels, in addition to not breaking. I agree you could go faster.

I run the same tires at LCS as I do at the track. M/T Street ET's Radial. 275/50/15

[rpatton3]

Originally Posted by Roush #1

Russ,
Your comment comes up frequently, and the only answer I have is the gear ratio differences between the T56 and the TKO along with my lower rear gear ratio. Compare the T56 to the TKO and you will see a little lower ratio (normally) in the T56 vs the TKO in the first three gears and a closer ratio (normally) between 4th and fifth in the T56 vs the TKO which all contribute to a little quicker acceleration through the first 5 gears.
If we were both running the same overall gear ratio, I doubt there would be much difference in acceleration with both of our engines coming off the same dyno making very similar horsepower and torque numbers.
This information is what I believe the initial thread question was about. I hope we have helped answer the question.....although my combination works for our horsepower and torque curves it probably wouldn't work as well with another engine.

Thanks for the enlightenment . I have volumes to learn and I bought a new turnkey car on birthday 58 and promptlly spent a year in and out of hospital and home IV's.

Seriously, I don't think I would ever have the stones for 167 MPH in passenger's seat with a professional driver at the wheel. The BMW rear axle is not up to drag racing, either. You have done your homework well.

Right now, I am getting big mufflers to pass "tennis ball" test.' Spirited street driving is all my car will ever see. The road race/rally in Big Bend and Silver State? would be at top of my "Bucket List."

Have a great 2013. Thanks again.

Russell

[Roush #1]

The only difference I can think of - other than overall diameter of the tire - when wheel OD is important in a drag race is the availability of tires. I am not aware of anything but drag radials available for 17" wheels. There is a lot of difference in a drag radial and a conventional "slick" ...mainly in the flexibility of the sidewalls which help on initial shock, growing in size as speed increases and more (softer) choices of rubber compounds for the "slicks".

[xb-60]

What about you SBF (347 and under) guys? I know there are some very impressive performers - daily drivers - out there.
Cheers,
Glen

[olddog]

Originally Posted by Hotfingrs

I run the same tires at LCS as I do at the track. M/T Street ET's Radial. 275/50/15

Impressive. They hook good enough to break parts. Are they stickier than the Avon that get very high marks around here? How many miles can you get out of them?

[QWIK 1]

Quarter mile times vs. engine type and power output?

My best time with my sbf (306ci) normally asperated. 15" slicks 4:30 gears
Aprox 380ish rwhp.





https://www.youtube.com/watch?v=-whV_8NhNXk

[Roush #1]

Gobra update:
Over 30,000 miles
One more weekend of 10.50's @ 130+ mph in the quarter mile
One more 118 mile long Big Bend Open Road Race completed (104.7 mph avg. speed)
Valve covers still have not been removed

[Jaydee]

I have posted this before. But if you removed the weight, and God forbid, put in a turbo charged worked rotary in a Cobra, would it beat a V8?
JD

[Roush #1]

Qwik 1....those are quite impressive numbers. The best I have seen for a 306. Please tell us more about your car. Thanks !
Jody

[olddog]

Originally Posted by Jaydee

I have posted this before. But if you removed the weight, and God forbid, put in a turbo charged worked rotary in a Cobra, would it beat a V8?
JD

Jaydee I do not mean to be rude. I doubt many people on this site know much about the rotary engine.

So how could someone with no knowledge, of what you ask, answer?

If you want an answer, give some information. Do you mean a Mazda? What does that engine weigh? How much torque at what rpm? Peak Hp at what rpm? Better yet a chart of torque verses rpm over the entire rpm range. Then how much boost will you add with the turbo? If you know this you pretty much know the answer.

Oh yea and which V8?

Frankly most would consider putting a turbo charged rice burning rotary into a replica of the ultimate muscle car, as distasteful as pissing on a picture of the virgin Mary.

If it will make you feel better, I'm sure that a highly modified rotary could beat a bone stock 210 Hp 5.0 Ford small block, but what would it prove?

[Jaydee]

No offence taken. I don't know a lot about the power output of a rotisserie, just that they don't have a lot of torque, but rev high and are good in low weight cars. Yes, I would never consider putting one in a cobra, I'm just chucking an idea out there, in case someone does know.
JD

[twin turbo]

Originally Posted by Jaydee

I have posted this before. But if you removed the weight, and God forbid, put in a turbo charged worked rotary in a Cobra, would it beat a V8?
JD

Jaydee, there is nothing magic about a turbo rotary, which is why so many have switched to the Chev LS conversion on their Rx7's. Very little weight difference in that case. Cheers.