Traction

**Firebirdjones** · 03-04-2014, 10:03 AM

Originally Posted by dethinboots

Wouldn't want to destroy my drive shaft... Yeesh. I have been looking at the drag bags for quite awhile, I'm just not really too sure about them. I know it will keep the wheels from hopping. But does that translate to traction when they are in contact with the road. And is the driveshaft snapping a very common concern? Should that be upgraded before I look at DR's?

The wheel hopping (if it's a problem) is something that should be controlled first and foremost. That breaks parts in a hurry.

Your half shafts are a weak link for sure, but since you're an automatic it's not as much of a concern as it would be if you had a manual trans popping the clutch and banging gears.

Wheel hopping may not be much of a problem with the auto either since you aren't shocking the drivetrain violently. Just something you'll have to mess around with and see how the car acts.

**dethinboots** · 03-04-2014, 10:50 AM

Oh okay. Thanks for the clarification

**dethinboots** · 03-16-2014, 11:43 AM

So with my 245 bike tires I still managed a 12.8 this past Friday. I'm pretty happy either that so far.

**pajeff02** · 03-16-2014, 01:39 PM

Nice! What was your 60' time and top end mph?

**Firebirdjones** · 03-17-2014, 04:55 AM

Haha, 245 isn't exactly a pizza cutter, you have about 9" of contact patch there

Shouldn't be too bad to hook on a prepped track.

Need more info on the rest of the pass....DA numbers that day??

**dethinboots** · 03-17-2014, 11:39 AM

2.2 60ft 110 trap speed

**Firebirdjones** · 03-17-2014, 11:56 AM

Hmm, I'd say that was a VERY happy dyno. With 420 RWHP that thing should be trapping 115+. I only made 370 RWHP with my wifes car and it routinely traps 112+ in the AZ heat with a 3,840 race weight.

Are you at nose bleed altitude or was the DA just that bad? Is the car extremely heavy?

That ET/trap speed/60 foot is pretty typical as a whole and what I would expect on street tires, so nothing unusual about that run.

**dethinboots** · 03-17-2014, 12:54 PM

Well in my defense I don't actually hook till I'm a quarter of the way down the track and I don't launch.

- - - Updated - - -

DA? And I believe the goat is around 3800

**dethinboots** · 03-17-2014, 12:56 PM

The way that I was spinning and failing to grab leads me to believe I could put down much better numbers with the proper set up.

***SMWS6TA*** · 03-17-2014, 01:42 PM

Originally Posted by dethinboots

Well in my defense I don't actually hook till I'm a quarter of the way down the track and I don't launch.

- - - Updated - - -

DA? And I believe the goat is around 3800

Density Altitude. Good tracks have that info. Reason why - at sea level your engine will perform differently then at say CO where they are a mile in altitude with thinner air.

More dense the air the more the engine can burn, just like the colder the air = more dense. Thus the reason cold air kits and even Nitrous/Methane systems.

Hotter days the cars seem to slow down.

**Firebirdjones** · 03-17-2014, 02:39 PM

Originally Posted by dethinboots

The way that I was spinning and failing to grab leads me to believe I could put down much better numbers with the proper set up.

Spinning won't affect the MPH all that much, and MPH is what I'm really paying attention to here. That's a very typical ET for the trap speed you ran. 110 mph will yield high 12's if you can 60 foot in the 2.0-2.2 range, which you did. So I'm not seeing a whole lot of wheel spin or anything else unusual about that pass.
Matter of fact, I ran a string of 110 MPH passes in my wifes car with 60 foot times just like yours on street tires and it would ET 12.80-13.0's with very mild wheel spin.

However nothing wrong with that pass at all, and 110 mph is plenty fun to drive. That trap speed indicates a car that is capable of very low 12 second passes with the right 60 foot time. To get there you'll need a converter. Sticky tires at this point won't yield all that much, maybe a tenth or two. Throw a converter in there however and I see that car going 12.20's and 30's at that trap speed.

**pajeff02** · 03-17-2014, 05:54 PM

DA makes a huge difference on how our car runs -- in good air it'll lay down a 12.5 pass easy. On a hot, humid day I'm lucky if I can get below a 12.9.

**Firebirdjones** · 03-18-2014, 04:34 AM

Not sure where he's from other than his description saying Fort Hood, which could be about anyplace. This time of year I can't imagine the DA being all that bad unless he lives a mile up or something. Has to be out my way somewhere because with all the nasty weather you guys have been getting Jeff, I don't imagine any dragstrips open out there right now.

**pajeff02** · 03-18-2014, 08:26 AM

Our track was supposed to open March 22th... but I don't see that happening.

**35th-ANV-SS** · 03-18-2014, 10:20 AM

Maybe it's opening for bobsled and snowmobile racing.

***SMWS6TA*** · 03-18-2014, 10:30 AM

Ft Hood is in Central TX, city out the gate is called Killeen. Hour south of Waco, hr north of Austin, and 35 mins west of Temple.

Don't know which track he was at. Closest one I remember was around Temple.

**pajeff02** · 03-18-2014, 02:54 PM

Here's a site I visit during the track season -- all good info!

DA Calculator - Density Altitude Calculator - DragTimes.com

**Firebirdjones** · 03-18-2014, 03:41 PM

Originally Posted by 35th-ANV-SS

Maybe it's opening for bobsled and snowmobile racing.

**dethinboots** · 03-26-2014, 05:20 AM

I was at the little river drag way in academy Tx. I would really like to hook as much power as possible to the ground, and the tires and convertor are def the answers. I was just a little but hurt about the knock on my dyno results. Being in the 12's however makes me giddy like a school girl.

**Firebirdjones** · 03-26-2014, 05:47 AM

Not knocking the results, just something to keep in the back of your mind if you need to dyno the car again in the future. They are just tuning tools and nothing more, but people use them for chest pounding. They are a good indication of power and potential but you have to use the same dyno and same operator to gauge that accurately.

Most dyno's (not all) that show a car with 400 RWHP, if the car is in the 3500 lbs race weight range give or take, will run in the high 11's at 114-115 mph with decent air and 60 foot times. So my best guess is the dyno used in this case may have been a little on the happy side, especially for the moderate camshaft, based off the ET and MPH you ran. Goats are a little heavier, so that might attribute to 2-3 tenths, but that's still off the mark.

Once a converter is in the car and 60 foot times improve, that will be the real test. However I agree a 12 second car is still a fun street car to drive. Even a 13 second car is fun. Something that will trap 110 mph is nothing to sneeze at, it will still get you in trouble