1/4 mile times

[MDP727]

Just wanted some input on other times you guys might have. I've been turning a steady 12.5. My car is #211 and has a 408 from custom cars. It has somewhere in the 500hp range. Tranny is a tko 600 with the 3:08 gears. I also have the nitto drag radials.
I'd like to drop into the 11's. Have any of you tried different gears? How about any nitrous applications?
My car is just over a year old with 4500 miles now and it's time to go faster.

[Excaliber]

There are very few Cobras (as a percentage of Cobras out there) that get into the 11's, VERY few. Most, even with BIG horse power generally run 12.1 or 12.2 at best.

Why is that? It remains somewhat of a mystery to me. Small block or big block, low 12's is reality. The major difference between a SB or BB is the trap speed, not so much the ET.

[MDP727]

Here's the rest of the times.
60' 1.9
1/8 8.0
1/4 105.7
It just seems with this motor it should do better.
How does the car feel on the road course? After a year of owning it I think I might give it a go. I race stock cars and always said I wouldn't race my BDR.
Does the front end feel very light to anyone else? There are times on the road I feel the front end slightly veer to one side or the other. Often the opposite direction of a sweeping turn. It's not a push, but almost feels like the front tires are barely making road contact. It easily corrects with little steering input. Also if you are on a road with say semi-truck grooves in the asphalt the car easily wants to track in the grooves.
Does any else have the same handling experiences?

[Excaliber]

Interesting numbers, were about dead even at the 1/8th I'd say. Heres mine.
0-60ft 2.0
1/8 7.9
1/4 11.90 at 121 mph

You can see how the big block just 'keeps pulling' at the end where SB's tend to run out of breath.

Tracking the grooves in the road, or wandering, depends a lot on tires.

[Jerry Clayton]

Speaking to the percentage of cobras out there---I have been out twice with the Windy City Cobra Club to Byron Dragway--
Most of the guys aren't dragracers, some it was first trip to the track since they were in high school--

About half the cars here are either BackDraft or Superperformance, most with 392 to 532 cubic inches--
These lightweight cars with IRS will not accelerate off the starting line, there 0-60 times are best measured with a sun dial
Couple that with most are missing shifts or running hundreds of feet on the rev limiter, doesn't add to good drag times
The unfamiliar feeling they have at the starting line is completely foreign to them compared to the feeling of confidence on the street and there performance shows up in there performance numbers.

So far, the consistently fastest have been RED FF cars with large cube small blocks

Jerry

[Jerry Clayton]

PS
The FF have a solid rear axle and leave the line pretty good

Jerry

[Excaliber]

Good point Jerry, I myself an certainly no 'drag racer'. I was blown away how HARD it is to actually 'get it right'! It took several runs when I first started to figure it out. First few runs were like, "OK, that guy left, I should follow him and see if I can catch up, dam, missed third again!"

...and of course the red ones are always the fastest...

[CHRIS DAMSCH]

Jerry,

What about the little blue small spf with independent rear. 396CI small block
Drag radials

1.5 60'
11.7 @ 114

Many 11.8 and 11.9 runs also.

Sorry, Had to represent the blue cars...........

[Jerry Clayton]

Chris
Didn't I say consistantly?
of course having 8 good holes helps!

And Chris--your little blue car has a line lock? Your experience at the line shows up from the time you sit down, buckle up and----

Did you guys look any further into Wolfies problem?

Jerry

[Jerry Clayton]

Chris--all my Race cars have been blue--of course I raced all my cars, black, red, green, pink&white,silver

Jerry

[CHRIS DAMSCH]

I'm just messing with ya Jerry,

No, we haven't looked into Wolfie's car issues yet. Probably some time this week.

Shoulda tried with 7 good holes...............

[Excaliber]

What? 11.8 and still in the teens on trap speed? I would have expected 120+ Must be a blue car...

Looking at some of the original 289 vs 427 cars shows ET's (around 12, 12.2, 12.3) close to each other, but a significantly higher trap speed for the big blocks.

Which raises an interesting question:
The original Ford Thunderbolts were running 10's, with POINT type ignition and over the counter parts! Thats a heavier car with a 427 and a top loader, a setup much like you could have seen in a Cobra back then. But it's pretty rare to see 10's for a Cobra, any Cobra, vintage or modern, no matter WHAT engine\horse power there running. Gotta be a traction thing, or, "we" are unwilling to rev them to 7500 or 8000 rpm (which the Thunderbolts did)! So which is it, traction or rpm limited? I know I won't run MINE that high, even though the high riser heads WOULD support that kind of rpm. Scary stuff...

1.5 hole shot is VERY good, WOW! That will rattle the competition enough to cause them to miss a shift (and I know that from experience).

[SkipB]

MDP727,

I've never really figured out what the real rear axle ratio on Backdrafts is for the stock rear end. I've been told 3:10, 3:15 and now you say 3:08. Whatever it is comes from a BMW E36 3 series from the mid 1990s. You might see if you can find a limited slip version that I think runs about a 3:45 - 3:50. There is also a limited slip you can add from Quaife to your existing rear end. I think you may be able to change ratios as well. This may speed things up a bit depending on what gear you are in and where your rpms are at the 1/4 mark. Just to confuse the issue, I have also heard you don't need a limited slip unit for the BMW rear end and that it may be faster without! In any case I would look for a numerically higher rear end ratio.

You guys that have tested various combinations (on the Backdraft only) can weigh in here and help MDP727.

Skip B

[jeffko]

I ran a 12.1 at 116 with an open 3.46. I have since switched to a 3.64 ls diff and have yet to best 12.7 at 109. The open diff was much more forgiving at the launch on radial t/a and the ls is much harder to keep a grip with.

Traction is most definitely the problem. I don't care who you are, putting 460 ft lbs of torque at the wheels with barely 1000 lbs (if that) sitting on it is next to impossible without drag radials or better yet slicks. With a set of street ets and a few practice runs I believe I could sink into the mid 11s relatively easily. Look at Chris's 60' of 1.5. That’s a mid 10 second run with a motor that has more poop. Does he have drag radials? Bet your arse he does.

I would also agree with Jerry on sitting on the rev limiter. I have intentionally done it at the last trap and I am peeking out on rpms somewhere around 100 feet before the 1/4 trap in 3rd gear meaning about 6400. You will have better times if you go ahead and shift. It takes a few tenths to do it, but running flat for 100' does not pay. The other time I do it is most assuredly unintentionally at the line. ~@~^&@!#&*$#^

Yes of course it is experience, but more than that is tires, tires, tires.

Just my two cents....


Hey Jerry, I wished I had thought to have you run my car down the track to see what it would really do.

[CHRIS DAMSCH]

Jeff, Jeff, Jeff........

You know it's not just the tires.......

Look at Wolfies times this weekend.

Oh wait... He didn't make it down the track

Ha

[Jerry Clayton]

Jeff makes a good point--the 364 gear on the rev limiter vs the 346 topping out in third gear--quite possibly where the difference was

The car did launch good very good on the 12.1 pass in the spring tho----only launched so so this weekend.

Jeff--when you get it in the 8's I'll show you how to do 7's

Jerry

[CHRIS DAMSCH]

Jerry, Jerry, Jerry,

Let's not get Jeff so excited about the 8's. He needs to launch that beast into the 11's first.

Probably alot faster than my car is currently.

But just wait until next year......................

10's or bust. Wait... I probably shouldn't use that expression, should I?

By the way Jeff.... There is a fourth gear. You should try it some time.

[Jerry Clayton]

Jeff
I think you could do 10s with what you have--

Jerry

[Dwight]

Buy a pair of good tires, BFG G-Force or anything but the T/A's. They are to hard for a drag tire.
Dwight

[jeffko]

We should have a special trophy for Wolfie breaking the club record with his 12 minute 1/4 mile.

Hey Wolfie, what was that you kept telling me in London when Laura made me break my rearend.

Sucks to be you Wolfie!