Automatic Transmission - low trap speed...

I have a '01 WS6 cam and bolt on car with a 150 shot. Last night it went 11.5 at 114 with a 7.5 1/8th and 1.65 60ft. Im running a fuddle 3800 stall with a moser 12-bolt with 3.73's. What is the cause of the low trap speed? I used to trap in the mid to low 120 range with my 6-speed. Anybody have any input on this?? Im new and ignorant to this automatic thing. :bang:

dunno. but that doesnt sound right. i would think you would be in the 120+ range.

i will be trapping back in the 110 range once cooler weather comes back. something isnt right for you to only trap 4-7 mph faster than me

I was just wondering if you have the tranny rebuilt or is it still the original,cuz I have a cam bolt ons hedders stall and was thinking of adding a fifty shot or higher if the tranny will take it.sorry did not mean to hijack this thread any help or opinions would be appreciated.
thanks
john

i thought autos generally trapped lower for the same mods and ET as a stick car...that being said, most stick cars running that time are in the 120s...


GXPPOWER: funny thing is i'm 2 tenths behind you and i have to let off at the 1/8th or i'll bang the limiter, with a slightly better 60ft than you, whats your 1/8th time?

MIne runs 11.80's at nearly 118 with a 1.66 sixty, your MPH should be closer to 117-120.

A few observations:

Your trap speed does not match your ET.
Your MPH and 60ft times are only good for ~11.75 as best. Did you let off?

Maybe you ran out of N2O

Your transmission is slipping or your TC is bad.


John

A few observations:

Your trap speed does not match your ET.
Your MPH and 60ft times are only good for ~11.75 as best. Did you let off?

Maybe you ran out of N2O

Your transmission is slipping or your TC is bad.


John

Didn't run out of N2O, i checked the bottle when i got to the pits and it was still a bit above 900. Im thinking its my TC or tranny too but i just had my tranny upgraded about a month ago and i havent been having any problems. And my TC lost lockup the other day so im wanting to rule it being the TC.

I agree. Get the TC fixed and see if that corrects your problem.

John

Is it possible for it to only slip in the high end though? Or would it have slipped all the way through?

I was just wondering if you have the tranny rebuilt or is it still the original,cuz I have a cam bolt ons hedders stall and was thinking of adding a fifty shot or higher if the tranny will take it.sorry did not mean to hijack this thread any help or opinions would be appreciated.
thanks
john

Im seeing a rebuild in your future. It will probably hold it for a little bit but definatly probably not too long.

Yeah, an auto is always going to trap lower than a 6 speed, but it does sound like you might be having converter issues.

Bone stock w/stock converter here on a 125 shot trapping @ 116 in crappy weather.

here's what i found with my car. i took it to a dyno day (on a mustang dyno) and they found my 1-2 shift was happening at 6k as opposed to 6.5k where it should of been shifting (like my 2-3). I was shifting before my peak not after, the tuner screwed up on that one. my best ET is in my sig (with a 1.66 60ft) but my trap speed is obviously a little low. The tuner on the mustang dyno told me I should gain some MPH once that bug gets worked out. I'm just waiting to install my heads before i get a retune.

the m6 will have a lower ET but higher mph the auto will have a lower trap speed but a better ET just the physics of the 2 trannies the reason being the converter is nothing more than a liquid torque multiplier (gear ratio) something that a clutch doesnt have so everything being equal driver and car the auto will come off the line faster therefore the lower ET but the mph will suck becuase of the converter

If you look at the delivered energy at end of track (which
is your trap speed) the difference between 120MPH and
114MPH is 10-11%.

I suspect that 3800 converter is not seeing the high side
of 90% efficient until you get up past 5500RPM, maybe
even 6000. So it alone could account for the trap loss.
Especially if you are spraying it and stretching the slip
out even more.

I Personally think its your convertor myself but i could be wrong I have a Fuddle 3600 and my traps are horrible for what power im making. Even if my Ets were bad i think i should at LEAST be trapping 115 or more. Some people have had great success with them, but quite a few people i have spoken too liked the 60 ft times with the Fuddle, but had poor MPH. My car seemed to have lost that topend pull from the minute i installed it(and i know my tranny is fine) I have only ran 111 traps with my H/C car :barf: . Making 418 rwhp "locked" but never dynoed unlocked. I plan on running the car "unlocked" next time in comparison to see

is my trap low? clicky. (http://i95.photobucket.com/albums/l126/s346k/12.jpg)

mods in sig. no times after the tune...yet.

raceweight of 3,750.

s346k, your mods/trap speed seem right on target.

If you know your finish line rpm, trap speed, rear gear, and tire size, you can figure out the amount of slippage in the tc and should help pin piont the problem. But also need to make sure it's not slipping the trans.

I have a '01 WS6 cam and bolt on car with a 150 shot. Last night it went 11.5 at 114 with a 7.5 1/8th and 1.65 60ft. Im running a fuddle 3800 stall with a moser 12-bolt with 3.73's. What is the cause of the low trap speed? I used to trap in the mid to low 120 range with my 6-speed. Anybody have any input on this?? Im new and ignorant to this automatic thing. :bang:

Here's something for ya...At that trap speed you should be gaining 22-23mph from the 1/8 to the 1/4 (assuming correct gearing). If you gain more then yes, I believe your shift points are too low. If your gaining less the say 21mph, your verter is possibly slipping too much at higher rpm's, or your tranny's at fault. For a reference:::My only outing this year and my shift points were off. Instead of 6900 the were 6300 (second to third) causing my shift extension to take me all the way down to 4600 rpm's, and killed my 1/8 mile an hour.

I converted my car over to an auto years ago, and the before and after RWHP loss was 30 wrhp (unlocked, 4000 flash stall), and I lost 3 1/2 miles an hour trap speed.