why did i slow down with 4R70w

[dangerzone]

03 cobra with stg4, stock uppr,8#lwr,JLT,BAP,60's, car ran 7.64 best but mostly a 7.7-7.8 car @ 92mph,
i put 4R70w in with baummanater and went 8.08 & 8.02 @ 88mph???
could the tune be off as auto'd have diff. curves than a manual??

 

[dangerzone]

oh yeah, .60ft stayed very, very close. no spinning on either set up
also, im using a mach1 converter as i read some people having g/l with them

 

[TwinTurbo4vGT]

oh yeah, .60ft stayed very, very close. no spinning on either set up
also, im using a mach1 converter as i read some people having g/l with them

u should try using a bigger stall. Mach 1s are lighter than cobras are. Id go with atleast a 2400 stall.

 

[EVLSVTT]

well with autos you lose more power then with a manual .. so im guessing with less power you will not be as fast?

 

[TwinTurbo4vGT]

well with autos you lose more power then with a manual .. so im guessing with less power you will not be as fast?

no. autos are significantly faster than manuals. Even if you do lose 30-50hp you still shave about 1-1.5 seconds off your time.

 

[MVD]

autos are significantly faster than manuals. Even if you do lose 30-50hp you still shave about 1-1.5 seconds off your time.

This is hands down the worst blanket statement I have ever read. For a person who knows how to shift a manual, if they swapped to an auto they will drop no where near 1-1.5 seconds off their ET.

 

[esqeddy]

Its been a while since I was in the drag racing game, but here are my observations and thoughts.

The advantage of an auto is not having the loss of power to the drive train as you shift maunually, which takes longer to do during the course of a run compared to a automatic which shifts quicker and less frequently. Also, for bracket racing, you usually get more consistent run times if you allow the trani to shift itself or have some automated shifting device, since it shifts at the precise same RPM each time.

The disadvantage is that there is a loss of power to the rear wheels compared to a manual trani plus, since it shifts less frequently, you find yourself out of the power band more during the course of a run.

That brings us to your case. I would suggest four things:

First, you check into which valve body your trani has. This controls how fast and how hard your trani shifts. A mushy and/or slow shift can significantly slow you down.

Second, although you say your 60 foot is very very close, why not try to make it better? A little difference in the 60 foot time equals big differences in the ET. A higher stall torque converter will let you leave harder.

Third, where are you shifting and how are you camed? Optimizing where you are shifting and your enginer power vs. RPM, combied with how your torque converter lets your RPMs come up after a shift, can have a significant impact. If your RPM's are dropping too low then you are out of the power band and your power is way down until the car speeds up and the RPMs climb back up. Did I explain this well enough?

Fourth, are you foot breaking? If you can, use a line lock combined with a low side rev limiter, so that you can come up on the RPMs while you wait on the lights. This should reduce your reaction times, make them far more consistent, and allow you to leave a little harder.

Of course, there could still be some other reason your performance isn't better!

Good luck.

P.S. Also look are your gear ratios. Maybe a different rearend gear will help.

 

[mitrls10]

If your stall isn't the right size or matched to the engine it will cause a slower time, might wanna try a diff size stall. Call a auto tranny company or stall converter company like streetfighter or b&m and give them the specs on the car, whats done to it, and tell em you trying to get down your et's and they can suggest the best size and stall speed converter you will need to get your time back down or even faster..

 

[TwinTurbo4vGT]

This is hands down the worst blanket statement I have ever read. For a person who knows how to shift a manual, if they swapped to an auto they will drop no where near 1-1.5 seconds off their ET.

are you a retard? have you ever driven both? Please dont talk when you dont know what your talking about. I have driven with built autos for years, so im pretty sure i know more about the subject than you.

 

[MVD]

are you a retard? Have you ever driven both? Please dont talk when you dont know what your talking about. I have driven with built autos for years, so im pretty sure i know more about the subject than you.

I:lol:ATU

Whatever helps you sleep at night bub.

 

[blowngt]

oh yeah, .60ft stayed very, very close. no spinning on either set up
also, im using a mach1 converter as i read some people having g/l with them

Stupid question, but have you tweaked the Baumennator or did you just run it with the tune they provided??

Reason I ask is because we had to tweak mine quite a bit to get it to shift right.

 

[BADASS03SVT]

my car ran 10.98 @ 125 in October air and swapped in the 4r70w in the spring and it ran 10.95 @ 124 in July weather on its 3 pass of that day. no other changes. its the combo.

if you are one hell of a driver, you wont see much improvement but it certainly wont go slower when setup right.

where is it shifting in each gear?

who's trans is it?

and ditch that Mach 1 tc imo and go to a reputable company like Ultimate Converter, Precision or other.

 

[dangerzone]

still have the stock vavlebody for this stock 4r70w tranny, but plan on upgrading soon.
even though my .60's are close and can be improved,thats not why it slowed down.
yes, i have tweeked the baumannater and shifting @ 6k.
with a bigger converter, wouldnt, it flashed right through the peak torque band???
who is the Lido guy that is so fast, he uses a stock mach converter?
I have just always heard that these cars can pick up alot of ET with an auto swap, and mine slowed down, just scratching my head trying to figure it out?
OH yeah, i still have the stock gears, i plan on changing them as well, any suggestion on ratio's.
it is a DD, so i do not wont to loose 75mph cruise zone. im thinking 3.90

 

[dangerzone]

with the stock V/B thats is in the tranny, 1st to 2nd shift is a bit lazy and i know thats a small factor but surly not the whole prob.
would i need a retune after an auto swap???

 

[BADASS03SVT]

with the stock V/B thats is in the tranny, 1st to 2nd shift is a bit lazy and i know thats a small factor but surly not the whole prob.
would i need a retune after an auto swap???

retune isnt needed. mine was still spot on at least.

where does your car make peak power? 6k rpms seems low...

and what is CLOSE for 60s?

like I said, unless your a really REALLY good shifter, your only going to gain form the auto. its the combination of parts all working together.

 

[94Gt5.0]

Good converter is key. Back when my car had a stock stall in it the car went 12.6@112, with the ArtCarr converter it dropped to a best of 11.82@112 with no other mods.

 

[dangerzone]

retune isnt needed. mine was still spot on at least.

where does your car make peak power? 6k rpms seems low...

and what is CLOSE for 60s?

like I said, unless your a really REALLY good shifter, your only going to gain form the auto. its the combination of parts all working together.

1. car makes power at 6200rpm, i was being a little conservative incase the tune was off a bit.
2. manual 60' = 1.85 / auto 60' = 1.88 on a side note, in most cases, every thousandth on the 60 is 4 thousandths 1/8 mile, so my .85 to .88 is 3 (.003) difference, multiply times 4 = 0.012 wich is one tenth and 2 hundredths. so if the 60
's where equall (1.85 ) my average 8.05 should have been 7.93
3.combo's i was under the impression that whether i have a good combo or not, it still slowed down, no other changes were made. maybe the conbo fit a manual better than an auto???
4. list of mods,(words in prenthithis are being put in).
afco H/E, KB kAP, 60# inj, STG4 steggy,8#lower(changing to a 4# now), stock upper(changing to 2.80 now), C&L meter(changing to stock w/ MAFIA)
JLT CIA, thats about all

 

[dangerzone]

like I said, unless your a really REALLY good shifter, your only going to gain form the auto. its the combination of parts all working together.

not to pull my own rope but i am a really, really, good shifter. i often jump in friends cars for the first time and put down faster ET's then they have with the car since they have owned it. People say i sound like a 5speed C4,,lol

 

[esqeddy]

still have the stock vavlebody for this stock 4r70w tranny, but plan on upgrading soon.
even though my .60's are close and can be improved,thats not why it slowed down.
yes, i have tweeked the baumannater and shifting @ 6k.
with a bigger converter, wouldnt, it flashed right through the peak torque band???
who is the Lido guy that is so fast, he uses a stock mach converter?
I have just always heard that these cars can pick up alot of ET with an auto swap, and mine slowed down, just scratching my head trying to figure it out?
OH yeah, i still have the stock gears, i plan on changing them as well, any suggestion on ratio's.
it is a DD, so i do not wont to loose 75mph cruise zone. im thinking 3.90

Stock valve body?! Dude, that is going to make a much bigger difference than you realize! Also, take your dyno graph and send it to a good torque converter company and let them tell you what is going to be optimal for your car.

 

[BADASS03SVT]

1. car makes power at 6200rpm, i was being a little conservative incase the tune was off a bit.
2. manual 60' = 1.85 / auto 60' = 1.88 on a side note, in most cases, every thousandth on the 60 is 4 thousandths 1/8 mile, so my .85 to .88 is 3 (.003) difference, multiply times 4 = 0.012 wich is one tenth and 2 hundredths. so if the 60
's where equall (1.85 ) my average 8.05 should have been 7.93
3.combo's i was under the impression that whether i have a good combo or not, it still slowed down, no other changes were made. maybe the conbo fit a manual better than an auto???
4. list of mods,(words in prenthithis are being put in).
afco H/E, KB kAP, 60# inj, STG4 steggy,8#lower(changing to a 4# now), stock upper(changing to 2.80 now), C&L meter(changing to stock w/ MAFIA)
JLT CIA, thats about all

if your a really good driver like you say, it wont gain too much imo by just swapping the trans. but when I say combo the motor is out of the equation. Im talking trans/converter/gears/rear tires.

i say ditch the stock valve body and get a real converter and then try to say you slowed down. Like I said, I did the same thing..swapped the trans only and I lost 1mph and gained less than a tenth on my first outing w/ similar 60s. but in similar weather I was up 1 tenth and 1mph. and I was average to above average on shifting i think.

work on the launch too...1.8s is no good at that power level...even on drag radials. you should be able to snag 1.7s easy