1/8 mile to 1/4 conversion...

[cjshaker]

I have zero experience with 1/8 mile numbers, so I was trying to get an idea of what my car did at the FE R&R. According to a couple guys I talked to at the reunion, my 7.55-7.60 times equate to 13 second et's. I was kinda bummed to hear that, but it didn't make sense to me because my 60' times were .3-.45 better than I had ever done previously, and I had run a 12.2 then, and the car just felt much better on the launches and all the way through 1st gear.

I checked some on-line calculators and they pretty much all agree that those times equate to 11.7-11.8 second ET's. My usual 1/8 mile speeds were in the 96-97 range, but at the Reunion I was more like 92-93, which is understandable considering the headwinds. Again, on-line calculators say that those 92-93 1/8 mile speeds convert to 115 mph trap speeds, which is exactly what my car previously ran, and very consistently.

I know some experienced racers here are good at knowing 1/8 mile times, so I'm just wondering, what would my 7.55-7.60 times have worked out to in the 1/4? I was really hoping to hit the 11's this year, so I was a little bummed about the 1/8 mile limit, but I understood why they were.

[blykins]

You're right, around the 11.70-11.80 mark.

[Stangman]

Look up Wallace calculator Doug. You can play around on that thing for a while.
11.86. Awesome Doug and it will be even faster without headwind

[Drew Pojedinec]

I dunno how you can really equate one to the other.
If you built the car for the 1/8 wouldn't it be geared for such?

I might be showing my racing ignorance here.....

[cjshaker]

Drew, most guys that run 1/4 mile are pretty good at knowing what that would show in the 1/8. Yes, a car built specifically for 1/8 would be geared differently, or just use 3 gears instead of 4, but experienced racers can tell you what an 1/8 mile run would be in the 1/4, or at least very close. Most experienced racers can also tell you what ET you should be running just based on trap speed...if the car was set up properly.

[jayb]

Doug, you are definitely well into the 11s at 7.55 in the eighth mile.  Just for a point of reference, when I got my Mach 1 to the track back in 2005 for the first time, it ran 7.05 in the eighth on a Friday night, and the next day ran 10.90 in the quarter at a different track, but basically the same weather conditions.  I think you have an 11.50 car there with some tuning and further launch technique. 

[cjshaker]

Thanks for the responses. I had a hard time believing I could have knocked that much time off my 60' and went slower than I had at Drag Week , even given the headwind and uphill track. I'm just glad to be making progress.

[Barry_R]

I agree with the high 11s number

My car ran 6.98 at 101 on its best pass
Last year it ran ....6.98 at 101, and a 10.94 at 126 (if I recall correctly)

Even though my 60 foot was improved (still not good, but better) the car did not pick up anything - I attribute that to the headwind.  On one of the three time shots I took you could feel the car move to the side pretty well and I fumbled the 2-3 shift while correcting.

[Falcon67]

Don't bother with calculators, this chart is close enough.  7.55 is about 11.78, same as my Falcon with the 351C.  Dragster clocks 5.8~5.40 @ 125, thats good enough for Super Comp, 5.40 is about 8.49, over 150 MPH. 

http://cochise.uia.net/pkelley2/eight-to-quarter.htm

[Jim Comet]

My Comet ran 7.75's in the 1/8th and 12.15 to 12.25 in the quarter. Definately 11's. Jim

[rcodecj]

My 67 ran 7.65 1/8, and 12.01 1/4

[cjshaker]

It's nice to know I definitely made some major improvements. My 60' times were killing me before. After I watched my in-car videos, I still made quite a few mistakes, so I've still got a lot to learn and improve on.

[BattlestarGalactic]

I typically run in the 96-97 mph in the 1/8.  That is going 11.0 at 119-120 mph in the 1/4.  On good days, 10.90's at 122 mph.

A slow 60ft will kill ET(especially 1/8 mile), but the MPH will tell the HP tale.  Even my black car will blaze the tires to a 15.0 1/4 mile, but go 111 mph.  That equates to 12.0 ET if I put tires on it.

As you work on chassis/clutch the ET will start to drop drastically.

[Falcon67]

Battlestar has it.  ET is affected by 60', phase of the moon, your foot, that guy in the diesel truck tracking water to the line, some girl winking at you in the staging lanes, etc.  MPH is a measure of HP.  It takes X power to move the mass of the car to some MPH.  I ran a half pass to test the dragster, lifted a little after the 330' block, 5.88 @ 97 MPH LOL.  A better example - footbraking the dragster at about 1800 RPM got the best of 1.35 60', 5.57 @125.5 MPH.  Put it flat on the floor loading the converter on the 2 step at 3100 - 1.20 60', 5.40 @ 125.5.  That's also an example of what the right converter can do for a package.  And flip it over, the wrong converter for the combination can kill the hell out of your performance. 

[cjshaker]

I knew my 60' was killing me. Larry's speeds are very close to what I run, typically 96-97 in the 1/8, very consistent 114-115 in the 1/4. Of course he's trapping faster because he has more horsepower, but I could never get my 60' under 2 seconds. Not even close really. This time I got it down in the low 1.8 range. Still lots of room for improvement. Larry's times, compared to mine, show what a properly set up car does.

My stock 3.78 stroke means I have to wind it a bit more off the line; I just don't have the torque that stroker engines have. That's where the 3.19 first really came into play...and helped a bunch! I'll be changing to a Sof-Lok clutch this year or next, so that will help also, after getting it sorted out of course.

This stuff is all very interesting to me as I learn more and get more experience in. Having some knowledge about it really helps show me where I need to make improvements. You guys are a big help, and I really appreciate that.