car bogging off the line

[Paxton Dan]

Hello, newbie and my first post other than the hello is a tech question, not good!:-D

I just put my car back together with a new set up.
stock torque stock car gt40 aluminum turboswirl x heads gt40 upper and lower tubular intake 70mm throttle body 4.10 gears
the car bogs really bad til 2000rpm than on slicks it will almost if not break loose at the track!
what would cause such a bog? to big of a t/b?

any help would be appreciated!

[bojo68]

"stock torque converter". Bog isn't always bad. there are some that use it to keep from doing nothing but burnout. In a stick, you can find the rev level necessary let bog just enough to keep from going up in smoke, back out and catch it, then floor it again and supposedly get the best times, so I've been told. Something similar may be possible with an auto also.

[Paxton Dan]

but I thought with a stock cam a stock torque would be okay.
do I need an upgrade?

[slowstang]

Seriously, get rid of the stock torque converter. Think about what would happen if you launch a stick car at 1500rpm while on slicks.

[Paxton Dan]

yeah your right.
my other car has a 2800 stall torque in it, I put it in when I upgraded the aod. I just thought this car would work without a stall torque for awhile.

but i don't think thats my initial problem it feels just like about 30 feet out the nitrous hits. it's that feeling.

[RdRunnr]

Where is your base timing set?

[Paxton Dan]

14 degrees initially.
let me ask you this.
if it was lets say a notch out of time it wouldn't start hot and sure wouldn't have went in the 13's right? because thats kinda what it feels like.

[bojo68]

14 degrees initially.
let me ask you this.
if it was lets say a notch out of time it wouldn't start hot and sure wouldn't have went in the 13's right? because thats kinda what it feels like.

Got your cam specs?? Pop a valve cover and check intake opening...

[Paxton Dan]

no cam specs, stock cam though.
I kept thinking there has to be a vacuum leak somewhere so I jerked the upper off of it and checked everything. nothing....
dunno,

[lone sailor]

Coming out of the hole on a stock converter gives you basically no torque multiplication, because these converters suck balls. You can't stall them at all without the tires trying to break loose. Are you matting the pedal off the line or easing into it? What size tire are you running? Is this GT40 lower intake ported? If not ported, you're probably choking the shit out of those X heads as well since the stock cam has much lower lift.

Do you have any times? Full time slip might help a bit.

[bojo68]

yeah your right.
my other car has a 2800 stall torque in it, I put it in when I upgraded the aod. I just thought this car would work without a stall torque for awhile.

but i don't think thats my initial problem it feels just like about 30 feet out the nitrous hits. it's that feeling.

What you call "that feeling" I call getting ass ended by a train. If you've got something that drastic going on, that's non linear to say the least. That suggests other things...

[Paxton Dan]

my intake (lower) was cnc'd to match the port of the heads.
well, I footbrake and I did bring the rpm's up.
they tell me to flat foot it leave at an idle.
I will pop a timeslip late tonight.
My terrible 60' will tell you that I can't get off the line.
2.14 was my best 60' I got 2.18 last year running a second slower!

I want to say right now, thanks everyone for helping me!
I have sunk a lot of $$ in my car and want more than im getting.

[bojo68]

Is it ALL BOG, or are there traction problems?

[lone sailor]

What brand and size TB, CAI, & MAF are you running guy?

[DirtyD0g]

I think you have way too much air coming in for the fuel at idle. I'm sure a converter would help, but I doubt that is the real problem.
Alan

[Paxton Dan]

Im running a 26x10 Mickey's so traction is good. I did have some traction issues about 20 feet out but none that will cause this.

my Throttle body is a Summit (i know) 70 MM I have a BBK CAI and no mass air, (Speed density)
The plugs will be snow white one minute the next dirty.
Fuel pressure is set at 46lbs the TPS is set at .070 volts
the IAC was cleaned properly
02 sensors are connected and working.

best run of the night.

R.T .050
60' 2.144
330' 5.783
1/8 8.798
mph 80.9
1/4 13.57
mph 101.6

the car is so lazy off the line a high 14 second gen 1 lightning had me covered until about the 60'

[frdfandc]

Fuel pressure looks high. Set it to 42 psi with the vac line off. Your TPS voltage is too low. It should be .96 volts. Also a 70mm T-body is WAY to large for your combo. A 65mm would fit the bill better.

I wouldn't run a 70mm until I was pushing over 400hp.

[lone sailor]

You say traction isn't an issue, but you're only cutting a 2.144 60' on Mickey's. That's a street tire 60'.

I also agree with frdfandc. TPS is way too low, you're not getting good WOT voltage. Anywhere from .93-.98 is acceptable and 5.00v @ WOT. 40-42psi fuel pressure with vacuum line DISCONNECTED.

Also keep in mind that the speed density computers don't repsond as well to modifications as mass air meter'd computers. Not saying you can't make it run good with speed density, but it will be much more time consuming.

[Paxton Dan]

I'll drop the fp asap!
and bump the volts up!
the car wasn't spining, thats how lazy the car was! atleast im pretty sure the car wasn't spinning.

Im gonna put a new fuel filter on lower the fuel pressure, fresh plugs and bump the volts up some and flash the converter this time.
Tire pressure is between 12.5 and 13.5 last time out.

I need to get my 60' back, it was quicker last year running a second + slower!!!!!

(Thanks for everyones help, maybe I can get a vid and let you guys see and hear it off the line.)

[1147]

any updates

[Paxton Dan]

Im actually bringing the rpms up to about 900-1000 rpm and leaving like that ( I can cut a light that way)
I run a 26x10 M/T Et Drag
the GT 40 is ported some
The best pass the car made. (Which isn't very good at all for what the car is)

R/T .005
60' 2.144 HAD A 2.18 STOCK W/GEARS STREET TIRES
330' 5.783
1/8 8.798
mph 80.9
1/4 13.57
MPH 101.6

A STOCK 5.0 MURDERS ME FOR ABOUT 30 FEET THEN THE CAR COMES ON STUPID STRONG!

[Paxton Dan]

well took it back to the track friday night this is after the shift kit.
60' 2.154
didn't get to run all out before the rain came.
i had to lift that pass because the car i was running got over in my lane so i lifted.
it didn't feel impressive and still bogged like crazy?
oh well.
need more seat time, try it again this friday night. this time last year i already won 2 foot brake races!

[lone sailor]

Upgrade that converter and get some stall in that thing. Then tell us how the sixty foot times are.

[Paxton Dan]

Upgrade that converter and get some stall in that thing. Then tell us how the sixty foot times are.


my next "project"

[Paxton Dan]

well, went back to the track again friday,
it's like I can't get enough timing in the car. it likes it....
here's a video not really of my car, im the guy in the left lane. my freind is in the right. however you can see and hear my convertible.

you can hear my car boooooogggg then take off.
I think I just need a stall....

http://www.youtube.com/watch?v=IKKamI5tAZo

[Paxton Dan]

took it to another track this weekend 1/8th mile.

here's the specs..

60' 2.082
330' 5.777
1/8th 8.815
MPH 80.79

[paul nieto]

Sounds like you should get a 2 step so you can rev and luanch consistently, lower your fuel pressure a bit to lean it out. If the tires are slicks they could be biting too much if your only leaving at 1500 to 200 rpm. i understand you have a stock converter so you can't go to 3000 but ideally that would fix the bog if you can hit the tires harder with higher rpm. The reason why your boggong is the tires hook up and slow the motor down so you can also try to raise the tire pressure so it would spin alittle and bring the rpm's up a bit. Good luck.