dragstrip tuning...not sure where this should be posted....

[green67cuda]

OK....
I have a few issues that ar eon my mind.  I run high 8.20s/low 8.30s at around 82MPH in the 1/8.  1.80 60'

3200-3250 with me in it
400 (low compression), .509 cam, torker intake, 770cfm Street Avenger, Mallory dizzy and IVa box, 1 3/4 TTIs, 727 with TF-2 shift kit, 3000 B&M Holeshot, S/S springs, 3.91 suregrip and 26" tall tires.

I have a couple of launch videos.
One thing it that I put a snubber on hoping for a little better 60'.  1/2" clearance and put some grease on the top for a tell-tale mark. the snubber doesn't touch when I launch.  seems like it should. 
It seems i'm not getting much torque to the rear wheels, but i'm running a 1.80 60', which should be enough to get good rear suspension reaction, correct?
I launch from idle, because it likes it best.  I have been playing with squirter sizing and currently have a .031 and don't have any any bigger.

advance is 20* all in by 2500.  initial is 18* at idle.

i'm sure I can get some much better numbers from jetting, but that won't fix the 60'. 

any more ideas on getting a harder hit

(and yes, i know the CR is way too low for the cam, but that wasn't my doing)
i'm looking more for chassis tips.  I have and have read the MP chassis book.  I have been told NOT to remove clamps from the rear halves ESPECIALLY for a street car.)

I gotta get to bet because I have to work tonight, but I'll try to finish this up later.

[green67cuda]

oh yeah.....
one thought I was having and was weighing heavily on what i think a big problem is is the torque converter.

is the holeshot 3000 junk?  i bought it as a temp converter because it was cheap and easy.

I have always had manuals, and what few autos I did have were stock-convertered.  this one seems REALLY sloppy to me.  I can be cruising down the road at about 2300-2700 rpm and when I floor it, the engine revs to about 4500.  it scoots really well, but it just seems way too high.  and playing with the throttle at slightly higher speeds feels really mushy.  i can goose it a little on the highway and it has about a 500 rpm play area -above cruise- that's like backlash or something.  just has that area with no response if I feather the throttle while cruising.

[GON_RACIN]

well that 60' is pretty much on with the E.T., my polara use to run that when I had a different combo.  What kind of rear shocks do you have?  As as to why the snubber isnt touching on launch, i dunno    If you arent having traction problems off the line i wouldnt worry about running one personally.  The adjustable snubber helped my polara off the line, but i had tons of traction problems before i put it on.

As the for trans problems, sounds like the converter is to loose.  Thats a problem when you buy one of those one size fits all converters, the stall speed they rate them at is a ball park figure, it will give a different stall speed from engine to engine.  I dunno if those converters are "junk", but the turbo action street converter I had that was priced the same as the holeshot and had about the same stall, was nothing more than a stock style converter that had the fins bent to give more stall.  It came all to pieces not long after it was installed.  Maybe some of the other fellas can give you a little more insight.  Also, how come only 20 degrees total timing 

[Capt Jack]

Have to go with GON_RACIN on this one for sure.  You mentioned launching from idle and not putting the motor against the stall before launch.  with as relatively loose as the converter is @ more or less 3k, I think youre losing a good part of the real push off the light to converter slippage while it catches up.  without that fairly instantaneous torque hitting the rearend the natural 'shock absorbing' nature of a leaf rear will probably absorb most of the 'sweetspot' push off the line.

your drive setup seems to be geared and setup well enough to make torque at a fairly low/mid RPM, but most of that is getting filtered (IMO) thru the converter.

what I'd suggest is try the same 'grease the snubber' telltale, powerbrake/transbrake and bring the motor up to at least close to stall and try a launch.  I'm betting your snubber will contact.  that may or may not get you a better 60' but the more intense initial torque I think might cause the reaction youre looking for.

oh and also, I tend to agree with the 'dont pull the clamps' on a street car.  I did it.  they rattle and tend to shift right and left more than you'd really want on the street.   I also didnt noticed that much benefit from doing it.

mi dos centavos

CJ

PS:  greetings everyone.  this is my first post although I've been hangin' around for a little while.  just thought I'd chime in on one I was familiar with and say hello.   I've read alot of the threads here prepping for the arrival of my latest project ( '73 451" auto/street ride)  and have to send my compliments to you all.  an incredibly knowledgeable bunch on a subject about to become very near and dear to me.

[green67cuda]

distributor advance is 20, so from 18* initial, that'd be 38* total.  it likes it with the low compression.

I have tried launching from 1500, 2000, 2500, 3000.  off-idle still gives the best 60' by almost a tenth.

[joes68340s]

I ran almost the same setup in a 71 challenger 440, 284/484 cam, low compression. 1-7/8 race headers, 391 gears. I really beleive you need more stall with your setup. I ran a turbo action 3500 and it really woke the car up. I still could have used more stall, sixty foots were low 1.6s I ran 9x28 slicks. What tires are you running. My setup ran a best of 11.9 at 115 mph.

[green67cuda]

275/50-15 Drag Radials because it's a street car

[joes68340s]

What pressure are running when racing. Have you tried different pressures. At this point you need to keep a log of where your at know and each single change you make. When I ran my challenger it took months of driving and simple changes to get to the high elevans. It was a street car also,through slicks on at track.

[green67cuda]

found this on TCIs website:

"Too high a stall range torque converter will not benefit the customer. You will see this situation most often when the customer does not have sufficient gear ratio for the converter stall range or the engine is not capable of the appropriate rpm range (too small a duration camshaft, inadequate valve springs, too low compression, etc.) Symptoms include high revs to pull away from stop, marshallow accelerator feel when driving at part throttle, transmission and possibly engine overheating, and a pronounced engine rev when nailing the throttle from a cruising speed."

[green67cuda]

I have changed the pressure between 15 and 35# in 5# increments and it doesn't change the run much, if at all.
So I have been running with 30# because the outside edges of the tires were wearing away, and still had near full tread in the middle.  my fastest ET/MPH occurred with 30# in the tires.

any way I can post my video??

[green67cuda]

let's try this:

http://home.comcast.net/~rodneywendell/videos/dragstrip3_001.MOV

you can pause it and move the button withthe mouse to go slow.  this is a 2000, 2500 or 3000 stall run.  cannot remember which.  I have one of an off-idle launch, but cannot find it.

[joes68340s]

Your car launch doesnt look that bad. But your suspension doesnt seem to react much. What torsion bar are you using and also shock. Do you have a front swaybar. Your front needs to lift more and transfer weight to the rear. Super Stock springs under load will raise the back of car under launch, Thats why the snubber usually dosent make contact. If you are running a mostly street front suspension your launch is about right.

[green67cuda]

"My 440 8.5:1, .509, street dominator, schumacher headers, stock 906's, and an 850dp.  It is set with 3.73 gears, ss springs and 26"slicks.  The best 60' I have seen is 1.70 with good air and on hot days can be around 1.74 and ET the 1/4 12.20-12.40.   I have a snubber setup about 1" below the floor pan. "


I see this and wonder where my car goes wrong.  the main differences are that I have 40 cubes less, TTI headers, 456 heads, 3.91 gears, and my tires aren't slicks

I feel my car should be right on par with this one.

[bentwheel43]

  I think your car runs good for what it is, don't forget it missed the run-for- the money by .003 ,  if it wasn't good you couldn't do that. but get 9x28" hoosier they will work good and I have a good convertor for your parts.      theres more there your cam is mismatched but you know it, so there you are, when you fix it ,with new pistons are a cam      them 9x28" and 3.91 gears, B&M 3000 = fast street car , but for now race that suxer and good luck 

[bentwheel43]

275/50-15 Drag Radials because it's a street car

If I put those tires on my car they won't cut it,you can't here them spinning ? On mine it sounds like you have two hound dogs back there,        I bet your getting away with your mismatch so good its because you are lite if it was 3500# you'll see something 

[green67cuda]

I get no tire spin.  i did the first day I used them, but I figured out their burnout preference.

I spin them up on the line-lock until I can see smoke either in the rearview or out of the corner of my eye, whichever comes first.

I have a video.  This is about the lightest burnout I can get away with.

http://home.comcast.net/~rodneywendell/onlinestorage/dragstrip2_004.MOV

[bentwheel43]

Your car launch doesnt look that bad. But your suspension doesnt seem to react much. What torsion bar are you using and also shock. Do you have a front swaybar. Your front needs to lift more and transfer weight to the rear. Super Stock springs under load will raise the back of car under launch, Thats why the snubber usually dosent make contact. If you are running a mostly street front suspension your launch is about right.

with Joes,what shocks do you have,          I think I got it now    you don't have 90/10 because its a street car    I watch a lot of film my duster as 3in rise in the back and more in the front and holds the front up 1/2 way down the track. sometime I have to limmit it from getting to high         your front  or the back are working right          it don't even look like SS spring.

[green67cuda]

stock shocks in front, 80s/90s truck shocks in rear (for the length)
fronts are new monroe off-the-shelf, and the truck shocks are either the highest priced or second highest priced Gabriels at the parts store.

BUT I think you got me on to something.
I completely rebuilt the front end and i thing the poly strut bushings are limiting a quick travel.  I have .920 T-bars on it, but maybe I need to go to a small-block bar?  When I got the car, I whipped out the catalog and saw that the .920 is for big blocks, so I got them.  I don't want to got to a small-block bar if it's going to be too mushy for the street. 
I'll see about getting some MOOG rubber strut bushings in the near future.

I think the extra uncompressibility of the poly ones is also pushing my lower arms back at the wheel, causing them to bind at the pivot.

[AdamR]

I think your launching and 60fting pretty good.

Those poly bushings really slow down front end rise though. Ive replaced all mine with rubber except in the upper control arms and those are next. A high quality converter may help also. I bet that B@M slips a bunch up top.

What size is your exhaust ? It looks pretty small in the video .

[green67cuda]

What size is your exhaust ? It looks pretty small in the video .

those are 2".  I've been wanting 2 1/2, but haven't gotten around to it yet.

[Chris_Holliday]

 your car is right for what you have in it.  The weight transfer is a problem just like you think.  The combination of the big torsion bar, stock front shock and battery location can be helped but don't change the parts if you like the way the car drives on the street.  The small exhaust and vac secondary carb is hurting performance also.  I am sure through changes in carb and exhaust you can go faster than my swinger.  My car only sees the street 5 times a year at the most and I have to tolerate the 90/10 shocks and /6 torsion bars to get the numbers you are trying to compare. 

[383man]

Well I can tell you this.  My sons Dart is a  400 with the .557 cam and bone stock untouched Eddy heads.  It has the Dynamic 9.5 convertor that flashes about 4200 and drives like a stock convertor on the street.   We use 3.91's and when we had stock front shocks and M/T 28 x 9 slicks the best ever 60 was a 1.62 but it would jump around alot like 1.67 then a 1.65 and 1.68.  We put a 6 point roll bar in to make sure my son was always safe and added the 90/10 front shocks.  Then we switched to Hoosier QTP 26 x 9 tires.   We have raced it twice like this and have put 13 passes on it.  Every single pass has been a 1.61 or 1.62  60 ft times.   Not alot faster but man is it ever consistent now and it hooks great on the Hoosier QTP tires.  His best is a 7.33 at 93 in the 1/8 and 11.55 @ 116 in the 1/4 and his 400 is 10.2 comp.   I would think your Cuda should run deep in the 12's and 60 in the mid 1.70's.   I have to wander how good that convertor is as I also think your car should mph a bit better.   My old 383 was a 9.5 eng and used the .484 cam.  It had the same Performer RPM intake and 750 DP we use on the 400 and the same 3.91's.  It used a TA 10" tight 3000 convertor and it ran a best of 7.87 @ 87 in the 1/8 and 12.31 @ 110 in the 1/4.  I know your comp is not alot but I feel your car has more in it.  The convertor could hurt mph if its slips in high gear.  I really like your car and hope you get running where you want.   I think your car has more mph in it and we need to help you find it and the more power will drop your 60's.   Ron

[green67cuda]

Well I can tell you this.  My sons Dart is a  400 with the .557 cam and bone stock untouched Eddy heads.  It has the Dynamic 9.5 convertor that flashes about 4200 and drives like a stock convertor on the street.   We use 3.91's and when we had stock front shocks and M/T 28 x 9 slicks the best ever 60 was a 1.62 but it would jump around alot like 1.67 then a 1.65 and 1.68.  We put a 6 point roll bar in to make sure my son was always safe and added the 90/10 front shocks.  Then we switched to Hoosier QTP 26 x 9 tires.   We have raced it twice like this and have put 13 passes on it.  Every single pass has been a 1.61 or 1.62  60 ft times.   Not alot faster but man is it ever consistent now and it hooks great on the Hoosier QTP tires.  His best is a 7.33 at 93 in the 1/8 and 11.55 @ 116 in the 1/4 and his 400 is 10.2 comp.   I would think your Cuda should run deep in the 12's and 60 in the mid 1.70's.   I have to wander how good that convertor is as I also think your car should mph a bit better.   My old 383 was a 9.5 eng and used the .484 cam.  It had the same Performer RPM intake and 750 DP we use on the 400 and the same 3.91's.  It used a TA 10" tight 3000 convertor and it ran a best of 7.87 @ 87 in the 1/8 and 12.31 @ 110 in the 1/4.  I know your comp is not alot but I feel your car has more in it.  The convertor could hurt mph if its slips in high gear.  I really like your car and hope you get running where you want.   I think your car has more mph in it and we need to help you find it and the more power will drop your 60's.   Ron

thank you.  i always wondered more about the car.  I always saw that he runs such better times with a somewhat simuilar combination.  i'm going to build a new tranny and get a better converter an see what happens.  i was on the road the other day at about 3700, and when I punched it, it immediately revved to 4300 as it accelerated.
i definitely think there's some slippage there.

[74duster383]

My 2 cents on the converter. I'm running a 73 charger, 4000+ lbs.  383, 484-284 cam, 11-1 trw's, 906 heads.   Last year I had a fairbanks 3500 stall.  60ft of 2.05 or so.  1/8 mile ET 9.08 77 mph, switched to a dynamic 9 1/2 converter.  The only change I made was the converter, now I'm running 8.50's with a best of 8.43 at 81 mph.  60ft now is 1.88, 1.89 best of 1.86.  I was absolutly amazed.  The new converter stalls to 4200 and I'm still playing with to see where I get the best launch.  Best 700 bucks I've spent.  Dynamic has got my vote.