Any with experience running an 1/8th then 1/4 and seeing how accurate the charts are. A friends Chevelle with a 496 and my 383 chevelle are traction limited with radials with 2.3 60' times. We each ran a 9.1 in the 1/8th with mine @77mph and his 496 at 83mph. We both commented that these new engines do not seem to get really hooked and going til mid way down the track. With practice the 60 ft could improve obviously. Does any one have experience showing the cars running stronger 1/4's than the charts predict with street radial cars?

383 is 425hp/460ft lbs estimated 3500lbs with driver
496 is 475hp/550ft lbs estimated 3900 w driver

Thanks

Originally posted by gurdy:
Any with experience running an 1/8th then 1/4 and seeing how accurate the charts are. A friends Chevelle with a 496 and my 383 chevelle are traction limited with radials with 2.3 60' times. We each ran a 9.1 in the 1/8th with mine @77mph and his 496 at 83mph. We both commented that these new engines do not seem to get really hooked and going til mid way down the track. With practice the 60 ft could improve obviously. Does any one have experience showing the cars running stronger 1/4's than the charts predict with street radial cars?

383 is 425hp/460ft lbs estimated 3500lbs with driver
496 is 475hp/550ft lbs estimated 3900 w driver

Thanks =
Some are some aren't.
Just use .64 for ET & .80 for MPH & you will find it about as close as anything out there in most cases.
Divide your 1/8 stuff & multiply your 1/4 stuff ;)

IE: 9.1/.64 = 14.22
83MPH/.80 = 103.75

Again, these are ESTIMATES but you will usually find them fairly close.

NHRA multiplies the 1/8 mile ET by 1.6 for the 1/4 mile ET. I went through my time slips and found that for me 1.56 is more accurate. There is a chart, using 1.56, linked in my sig. A buddy of mine, using his time slips, found 1.58 more accurate for him.

Originally posted by Pat Kelley:
NHRA multiplies the 1/8 mile ET by 1.6 for the 1/4 mile ET. I went through my time slips and found that for me 1.56 is more accurate. There is a chart, using 1.56, linked in my sig. A buddy of mine, using his time slips, found 1.58 more accurate for him. =
Hi Pat,
I like 1.56 as it is the reciprocal (is that the right word??) of .64 graemlins/thumbsup.gif

guys arent these conversions correct assuming you are getting traction?

could a car thats not getting traction in the 1/8th turn a faster time in the 1/4 than those calculators predict due to tire spin?

The reason they are saying it is pretty accurate, despite tire spin/traction issues, is because the mph is true no matter what. 60', 0-60 times, etc, will always change, but the mph stays true.

Originally posted by Wolfplace:
</font><blockquote>quote:</font><hr />Originally posted by Pat Kelley:
NHRA multiplies the 1/8 mile ET by 1.6 for the 1/4 mile ET. I went through my time slips and found that for me 1.56 is more accurate. There is a chart, using 1.56, linked in my sig. A buddy of mine, using his time slips, found 1.58 more accurate for him. =
Hi Pat,
I like 1.56 as it is the reciprocal (is that the right word??) of .64 graemlins/thumbsup.gif </font>[/QUOTE]It sure is. I hadn't noticed that.

Originally posted by LXS:
The reason they are saying it is pretty accurate, despite tire spin/traction issues, is because the mph is true no matter what. 60', 0-60 times, etc, will always change, but the mph stays true. i understand about the mph aspect of this. but my question and what i believe to be gurdy's question is whether a car that is spinning well into the eighth mile will run a quicker 1/4 mile time than the conversion predicts.

actually, MPH is not always true, especially so with a car that has a 10" converter.

If i Spin the Tire, i pick up MPH.

It's not very likely that cars running from 77-83 MPH speeds at the eight mile are having severe traction problems. My old 375 H.P. "396" Chevelle was hooked up prety well after going through 1st gear and ran 88 MPH at the end of an 1/8 mile and 107.7 at the quarter. A car in this power range probably isn't going to be spinning downtrack after the first 100 feet or so.

anybody notice the word "ESTIMATE" in this thread anywhere :D

Estimate, Approximate, About,
The numbers will be close but I don't think it would be the best plan to use em as a dial in graemlins/sad.gif

Just as Brian stated, the MPH will almost always be CLOSE within a few MPH between a good & bad run just as the numbers from the formulas will be close for an (here's that word again) Estimate

Originally posted by Wolfplace:
anybody notice the word "ESTIMATE" in this thread anywhere :D

Estimate, Approximate, About,
The numbers will be close but I don't think it would be the best plan to use em as a dial in graemlins/sad.gif

Just as Brian stated, the MPH will almost always be CLOSE within a few MPH between a good & bad run just as the numbers from the formulas will be close for an (here's that word again) Estimate i read that and i understand what the word estimate means, and i have no intentions of using this estimate as a dial in. what im trying to ascertain here is how wide a margin of error there is for this correction factor.

is it possible that a car running traction limited 9.1s in the eighth could run 13.80s - 13.90s in the 1/4?

Originally posted by RatONaStick:


i read that and i understand what the word estimate means, and i have no intentions of using this estimate as a dial in. what im trying to ascertain here is how wide a margin of error there is for this correction factor.

is it possible that a car running traction limited 9.1s in the eighth could run 13.80s - 13.90s in the 1/4? =
Is it possible,, of course it is, highly doubtful but possible & as has been touched upon above, I highly doubt you are going to have a traction problem to the 1/8 mile in a 14 second car :D
My GUESS is a 14.0-14.1 would be about the limit but it usually goes the other way to like 14.3

In the two cars in the first post the 83MPH one obviously has the ability to run a better ET when sorted out judging by the MPH posted, it just had more of a traction problem than the 77 MPH car.

Originally posted by RatONaStick:
is it possible that a car running traction limited 9.1s in the eighth could run 13.80s - 13.90s in the 1/4? I'd say yes, very easily. I run between 8.8 and 9.1 in the 1/8th at 83 mph. My quarter times are 13.54 best 13.6 avg, @102-104mph. 2.00 to 2.20 60fts.

When it was a little slower, like 13.80-14.00 it was still 9.0-9.2 in the 1/8th.

I believe my 1/8 and 1/4 times are slower than they should be given the mph. I know I have traction problems, 4-speed and radial t/a's, along with an overcammed SB. For me that means hook and bog, or wheelspin. I've gotten better at controlling the spinning though... smile.gif just enough is ok, but way too much and you slow way down.

chris

the conversion chart doesnt work for my combo.........my 1/8 mile is at best 8.97 with a 2.18 60 ft time........but i rely on hp to pull me on the top end with 13.68 @ 105.454 mph......with having 1-2 shift in the whole 1/4 mile in a sense my motor is just comming on hard just after the 60 ft mark......

the 496 is more then likely pulling high 13's out of its hide at about 104 mph and the 383 is in the lower 14's at 98 mph.......