Need some suggestions on 60' times 73 RR

[BlooDSMeaR]

My 73 roadrunner has a 360 based 408 stoker, 500hp 530 tq engine. Im running a 727 to 4.10 rear gears. 29x10.5w tires. The best ET I have ran was 12.2 @116 MPH. That was off the 6K limiter into the traps. Since that one good run. I have only been able to get a best of a 12.5 @ 112
Several times I have been told by other races at the strip that my 60' times are struggling. What can I check, look at or change to get my 60' times down?

Another thing to note, When I took off the slicks for winter season, on one wheel, it looks like the tire is wearing heavily on the inside half. Could this be from a bent axle housing? I can also note that when turning left in the car it likes to chatter a whole lot more than if I was turning right in it.

I am open for any ideas.

 

[Jerry Hall]

Check your wheel bearing, change your rear axle fluid and add fresh sure grip additive.

 

[biomedtechguy]

What can I check, look at or change to get my 60' times down?

What are your 60' times?

 

[PRHeads]

You haven’t said what the 60’ times are..... so we can’t say if they are soft or not.

What is the rpm through the lights when it’s going 112? Is it still bouncing off the limiter?

Didn’t you put a solid cam in the motor?
If so...... just turn the limiter up.
6000 is a pretty low limit for a solid lifter performance cam.

116mph is plenty of speed to run well into the 11’s.
You’d likely need to be mid-1.60’s or better though to do it.

If it’s not bogging or spinning off the line, it’s “usually”(or at least “often”) the converter doesn’t have enough flash stall.

Cam/carb/converter....... those need to be on the same page.

 

[BSB67]

Looks like a 1.95 60 ft. or so now
I wonder where the 4 mph went? If you don't have a good explanation for that, check cylinder pressures, and valves for possible bad lobe.

I would think you have enough gear. Your tire seems a bit too big. Maybe more converter. What do you have now?

 

[PRHeads]

Looks like a 1.95 60 ft.

Is that posted somewhere and I’m not seeing it?
Or it’s calculated from other data?

If the actual 60’ time is anywhere near that.......I feel like I’d hope it was spinning.
If not..... there is def an issue with “something”.

 

[BSB67]

Is that posted somewhere and I’m not seeing it?
Or it’s calculated from other data?

If the actual 60’ time is anywhere near that.......I feel like I’d hope it was spinning.
If not..... there is def an issue with “something”.

Just numbers rolling around in my head. But they are probably close unless something is going on mid-track.

If my estimate is close, and with that much tire (I.e. likely not spinning) it's missing a lot of something off the line. The 1.95 is P-235 BFG territory.

 

[33 IMP]

Yep, I'll bet the op won't be happy with what Wallace says it should run at 116. Or 112 either.
We need more info. Is the sixty foot soft, spinning,bogging, wheel hopping , or what? What converter? Is the trans fresh, or going away? Where did the 4mph go?
Op: post the 112 and 116 timeslips if you can.

 

[dvw]

Converter
Doug

 

[33 IMP]

Also, with that rear gear you should be in high gear well before the 1/8 mile marker, so you have a whole 1/8 mile to monitor the finish line rpm.
What is finish line rpm and fuel pressure ? Less pressure or rpm since it slowed down, or the same?
And by the way, Doug is absolutely right, if the 60 is just soft, a converter can make a world of difference.

 

[BlooDSMeaR]

Sorry guys forgot to post the pertinent info.
I have a Hughes HD-24-35 3500 stall converter with a fresh TCI 727 trans. And am running a hyd roller cam.
I have been leaving the light at 2500 RPM, My 60' times are all in the 2.2 to 2.5 seconds.

 

[33 IMP]

Are you completely blowing off the tires? If not that is WAY slow. No insult intended ,im sure you know thats not good. Wallace calculators says a perfect pass with 112mph should be high 1.60s 60ft, and 11.90 or so. Perfect is REAL hard to obtain with a street car, but your 60 should be lots better than that with an 11" (10.5w) slick. It sounds to me like your converter isn't working, at all.



Or maybe your runner is 7000lbs?

 

[biomedtechguy]

My 60' times are all in the 2.2 to 2.5 seconds.

Welcome to my world... Lack of traction hell...
My planned solutions that are not relative to my manual 3 pedal transmission are:
Assassin traction bars and a COMPLETE Calvert rear suspension system with Viking double adjustable rear shocks.
Install the line lock I've had for 2 years.
Cut better 60 ft times and start having fun again at the race track.
My times have been around 13.3 at 106 to 13.6 at 105. My 60 ft times are so bad, and I KNOW I've got a "12 second engine" and the proof is my lousy 60 ft times.
Take a 13.3, go from 2.2 to 1.6 60 ft and the math says I'll be running at least a 12.7 sec quarter mile.

 

[PRHeads]

Have someone video the car leaving the line.
With those 60’ times, it would almost have to be blowing the tires off.

If not....... something is really...... really..... not working.

 

[BlooDSMeaR]

You haven’t said what the 60’ times are..... so we can’t say if they are soft or not.

What is the rpm through the lights when it’s going 112? Is it still bouncing off the limiter?

Didn’t you put a solid cam in the motor?
If so...... just turn the limiter up.
6000 is a pretty low limit for a solid lifter performance cam.

116mph is plenty of speed to run well into the 11’s.
You’d likely need to be mid-1.60’s or better though to do it.

If it’s not bogging or spinning off the line, it’s “usually”(or at least “often”) the converter doesn’t have enough flash stall.

Cam/carb/converter....... those need to be on the same page.

RPM through the lights is close to 6k but have not hit the limiter set at 6k. My first few runs just as I was passing the traps it would hit the limiter exactly at the trap. But I have lost speed.
The converter is a good one , its a Hughes performance HD-24 35. When I bought it I had initially bought the HD24-25 but when the first TCI trans failed, I sent it in to save the warranty on the TCI trans. I asked them to loosen it up to 3500.

 

[PRHeads]

Imo, a 3500 stall speed street/strip converter shouldnt be showing 10% slippage, as yours is.

However, that aspect of your converter isn’t the cause of your poor 60’ times.

 

[biomedtechguy]

You can hear my problem with wheelspin when I try to launch at any RPMs over idle.
It sounds like a 7 speed...

 

[dvw]

If it doesn't bog. If it doesn't spin. It's the converter. maybe not broke but incorrect. My street car had run 11.70@117. With a new cam it ran 11.70@122. A converter swap 2 weeks later, 11.05@123. The converter may be fine, just wrong for your combo.
Doug

 

[33 IMP]

Word on the street is that the initials stand for Total Crap Inside.

 

[PRHeads]

If it doesn't bog. If it doesn't spin. It's the converter. maybe not broke but incorrect.

I look at it just a little different.
If it doesn’t bog, and isn’t spinning...... since it’s supposedly not some super tight stock replacement converter....... it would almost have to be junk.

One big question mark for me is......where did the 4mph go?
Could also easily be a converter issue.

No one likes to think their converter is the problem cuz they’re not cheap or any fun to change....... but are very often the culprit when sub-par performance is being seen.

For me....... I’d really want to see some video of several launches before going any further.

As was mentioned previously....... it wouldn’t hurt to check on the health of the motor too....... in trying to find where the 4mph went.

If it’s blowing the tires off....... then it makes sense the 60’ is so bad.