To much power!
 

It's official, I just have to much power, especially with the new TKO-600 and the lower gear ratio's. Even running slicks, if I'm not careful I'll burn 'em all the way through second. It's not the fast way around the track or down the drag strip.

Frustrating, I'm not sure what to do from here. For the drag strip I'm thinking a THIRD set of wheels so I can run true wrinkle wall drag slicks, instead of the road racing slicks I was running today. They work fine for auto cross, all though, I can still enduce throttle oversteer if I go deep on the loud pedal.

At the drag strip tonight, it was pathetic. It took me four passes to figure out how to apply the throttle just to keep the spin to a minimum. Even then 2nd is pretty crazy, part throttle at best until I get to third. The last 1/8th mile rocks though, pulls like a frieght train once I hook up. My ET is a half second slower than I was running with the top loader with a higher gear ratio. Maybe, a high geared close ratio top loader isn't so bad after all for putting the power to the pavement. Surprising results for me, I was so sure I would be faster with a TKO and lower gear ratio's...

So this fellow racer was explaining to me how I need to modify the air cleaners for a smoother flow, for more power. I'm thinking, trust me, power is not the problem here, got plenty of that. :) :)

Excaliber, how much horse power are you running and what is your all-up weight?
Inquiring minds want to know!

I never dynoed it since my last rebuild. It was running 667 horse and George at Gessford Machine did some calculations and estimated I had given up 150 horse to make it more "streetable". I have a hunch I gave up less than that though. The full race engine I had before was just terrible to drive on the street, all go, no slow, no cruise. Now it's more managable but still, a bit problematic, it's still a mean street machine. The car is heavy, about 2,700 pounds, iron block and heads. Let's say I'm running an honest 500 horse, or less if you like, pick a number!

The point is, I'm really begining to wonder WHY there is such a "race" to get more power? I really don't understand WHAT 650 or 700 horse will do for you? WHAT is the point if you can't hook it up? Or maybe, my real problem is torque? It do have some serious torque. :)

Consider these numbers:
With 667 horse, solid roller cam, 12.5 to 1 compression, dual 660 cfm center squirter carbs, "worked" High Riser heads, 7,000 rpm, "bad to the bone" and 6 mpg. I ran the 1/4 at 11.90, couldn't put the power down. OK, rebuild the motor. Drop the compression to 9.6 to 1, flat tappet cam, smaller street friendly vacuum secondary carbs, same heads (and they are still bad to the bone :) ), 13 mpg (MORE than doubled the mpg), 6,200 rpm limit. New 1/4 mile time? 11.99. I mean, whats up with that? You drop a 150 horse and loose only a 100th of a second, double your mpg and can actually drive it on the street? In fact the car FEELS as fast as it EVER was!

...I'm a bit baffled by it all frankly, still figuring it out. One thing is for sure, I need some serious slicks if I'm gonna run the 1/4 mile. Another problem for the 1/4 is the suspension is pretty stiff, for road racing which I do mostly. So, I'm not getting good weight transfer to the rear at the drag strip. Soften the rear shocks maybe, raise the front, ruin the suspension for the road race. You can't win at every thing, you gotta choose your battles.

You shouldn't be baffled, because you've answered your own questions. The "problem" is not too much power. No such thing. The problem is not enough control.

First, you have the wrong tires. You know that. Second, the suspension is not set up for the weight transfer. You know that. And third, the gearing isn't right. You know that, too.

The first thing I would do is try to launch in 2nd gear.

I'v tried drag racing a couple of times. Didn't enjoy it much. Too much waiting in line, and not enough actual track time. But, I had the same issues - couldn't get traction. But I'm not willing the mess with the suspension, since I like to road race. It took me a long time to get the suspension set up right, and I don't want to start over. The best I could do was 12.05, with a lot of tire spin.

What ratio rear gears do you have??:confused:

You might try some taller gears for more control in 1st and 2nd!!:D

As I recall, Bruce Cambern said he dealt with that problem by modifying the throttle to make it less sensitive. I interpreted that to mean he modified the cam action to allow a larger movement of the foot pedal to produce a smaller movement of the throttle. Perhaps that would help you too.

Ernie,
It's about power to weight ratio. It's a lot of tweaking to find it. Try the Power to weight ratio calculator and see how close you are. Getting as close to optimum as possible will get you where you want to be.

Hersh:)

Just pull one or two plug wires.


.

:LOL::LOL::3DSMILE::3DSMILE:

Hersh:)

Gear Ratios:
The Close Ratio top loader was 2.32 first gear with a 3.31 rear gear. That was 65 mph in first, still plenty wheel spin BUT it could be more easily controlled than now.

The TKO-600 has 2.87 (I think thats it) and the 3.31. Wheel spin is hard to control even with the slicks. Wow, I can't imagine having one of those 5 speeds with the 3 something first gear. That would be virtually worthless and impossible to control wheel spin.

Starting in 2nd has been shown, for some folks around here, to make for a better ET, but it's also very hard on the clutch. So that is not a viable option for me, the occasional not really serious drag racer.

Bobcowan is right about the suspension, I've spent a lot of time getting it right for road racing and don't want to change it now! :)

Of course "we" are always traction challenged, but with the new lower 1st and 2nd gear ratio's I'm just now learning what most folks have always known. It's tough to hook up! 1st gear ratio on a wide ratio top loader is nearly the same as the road racing TKO like the one I have now. So, 90% of you guys already know this stuff. I'm the "newbie". :)

I don't think many of us are running a Close Ratio with a 3.31 rear gear. In general I find manufacturers don't recommend that setup. BUT, I'm kind of re-thinking that now, it's not a bad over all choice. Counter intuitive though, drag racers are always looking for a lower gear. 4.11 and such. The 289 Drag Cobras were running something like 5.13's, extremely low. So, lower ratio's like I have now, would seem to be moving in the right direction, but there's more to it than just gear ratio's obviously.

My dual carbs are setup for 1 to 1 ratio, not progressive. A change there, to progressive type linkage, might be a good call. Like that "cam" thing for more pedal travel, less carb. The "light beer" approach. :)

As you know a road race tire has a narrow heat range for optimum traction. A drag radial would be a better choice, softer compound to begin with, and a wider heat range. All I ever run at the track are MT street radial and have 60's in the 1.38-1.39 range consistantly, and probably have around 800 horse. Also I don't have a drag race suspension, it's more for road racing, huge bars and shocks and springs and everything heim jointed, and I don't change anything when I go to the track....I just break stuff.

Since I may be buying a dedicated drag race tire, would you recommend the MT street radial over, say, a full blown drag race tire?

Or, as you suggest, perhaps it's better to have some slip than break stuff!!

That's a very impressive 60 ft time for the MT, sounds like that may be enough tire.

Ex a guy over on the FFR board is building a 700 plus HP FF. He has a throttle linkage that is two stepped to limit the throttle. Just thought I would throw that out.

It's all in your setup, Ernie. It sounds like you've got some fine tuning to do (though I am not sure how long your axles are going to last with slicks on the car).

Here's a 427 small-block Roush-powered SPF running high 10s (video of Greg Schroeder in his SPF).

http://www.youtube.com/watch?v=XmDd14eITU0

Keep in mind the drag cars with the low gears (numerically high) are generally running a very tall tire which effectively makes final gearing taller than a low profile tire.
My 2 cents.

I'd say, unless you know how much torque your rear can handle, go with the MT street radial. It doesn't wrinkle, so it will slip some, so you can minimize breakage. I've got a transbrake and usually leave somewhere between 3000 and 3500. 26.1 diameter tire and 3.54 gears. 0-60 under 2 seconds and 0-100 in 5 seconds. Running right at 6 seconds at 1/8 mile and between 118-120 Mph. Mid 9's in the quarter at 135+

Now that's hauling a$$!:eek::)

I too, went through the same frustration,with 500+ hp.Until one day talking to a long time Super Modified racer.He asked: has the car ever been scaled? No.So we went to his shop and did just that,also adjusted the rear control arms to a more positive angle for better launches.Now this car with slicks, launches hard and straight,at the same time is a corner carver.

Ernie;

With your present set-up it's all about thorttle control now and it'll take some practise to get it down...
Had the same problem with my Fastback running street tires at the strip, went twice for some "test/tune" days and pratised launching at varouis rpms till I could get it down the track with minimal tire spin....

I'd come off the line at idle and roll into the throttle till 3,000rpms, then I could put it to the floor, I'd let off the gas bewteen shifts, especially 1st to 2cd, get back in the gas in 2cd with slow steady pedal pressure till wide open and hammer down in 3rd/4th gear.....

I too think drag radials will be your best bet....

Practise/practise/practise..............

David

ernie, i went thru the same thing couple years ago, i'm still tweeking it.
what i have done to launch so far....

mickey thompson drag radials, running 13 psi and do a good burnout first.
added morosso purple coil springs in the rear, i still run street shocks.
i run an automatic with manual valve body, i cannot jack the converter (3500 stall) leave the light like your pulling out in traffic when i'm rolling then whack it, my lights suck but my et is nice. keep timing back it will help with the tire spin, you won't loose enough power to make a difference.
i think a progressive linkage may help you, the short wheel base and the weight is the problem, its hard to transfer witha short wheel base without the suspension to go with it.

i remember the first launch i tried, jacked converter to 3 grand and let go, i did 3 180's and finally got out of it to save the car. i weigh in at 3200 lbs and still feel like i'm on ice. my next step is an adjustable rear shock to dial in street and dragstrip. i need to get her to squat more, then i will have to keep the front end down......