Carbureted LSX forum - CARBED LS C3 at the Track

Well... had some issues all day with 3rd gear. I could never make a full pass. Around 900-1000 ft mark I would hit rev limiter or have to let off because my th400 will not shift into high gear under full throttle. I thought it was because I was about a quart low on tranny fluid now I think it maybe vacuum related.

http://www.youtube.com/watch?v=v6WvkGWjXkY

LOL... listen to the guy on the speaker. Funny stuff.

http://www.youtube.com/watch?v=hf9Icdc5Llw

Damn, knockin on 10s!

Great work man, too bad the trans is being lazy, i am sure my TH400 will have no issues when the 6.0 goes in the TA.

shift it manually

Nice pass' :nod:

Very nice! Congrats. How about more details on the combo

Nice to see you back at it man.

Tranny I believe has a vacuum issue. I was a qt low that day at the track. But for some reason under FULL WIDE open throttle it will not shift. Shifts good into 3rd at normal and part throttle. My Buddy who is a Master tech thinks we are loosing vacuum at the upper RPMs thus we are going to change the vacuum line to a small size. That should fix the problem.

Those runs I was bumping the rev limiter at about 900-1000ft mark. And the run with the Cobra I let off.

I should be getting about 122-124 mph... guessing 10.8-10.7

There is no vacuum at WOT modulator is only for part throttle shifts
car looks great

There is no vacuum at WOT modulator is only for part throttle shifts
car looks great

then what do you think the issue is?

Well.. .I was going to run some 1/8th mile...but looks like rain all weekend!

i dont know much about the old trannys but dosnt that one have a tv cable? maybe it needs some adjustment.

btw I love c3 ls cars I had a blast with my 82 that I swapped a ls1 in, only thing i wished it had was a little more power but i still kept up with new vettes with 340hp to the wheels

NO TV cable... its vacuum and has a modulator. it shift fine in part and normal driving. Difficult to test it on the street. I need to go back to the track... Not a good Idea to test a 10 second street car to see if you can get I high gear at WOT on a public road.

NO TV cable... its vacuum and has a modulator. it shift fine in part and normal driving. Difficult to test it on the street. I need to go back to the track... Not a good Idea to test a 10 second street car to see if you can get I high gear at WOT on a public road.

IMHO its most likely a governor issue.

edit: Did a little search that may be relevent:

http://forums.corvetteforum.com/c3-tech-performance/2271745-79-vette-th400-wot-shift-issues.html

P.S. There's always a manual valve body. :)

IMHO its most likely a governor issue.

edit: Did a little search that may be relevent:

http://forums.corvetteforum.com/c3-tech-performance/2271745-79-vette-th400-wot-shift-issues.html

P.S. There's always a manual valve body. :)

thanks good info...

Good thing I wasn't driving the cobra lol. That was the owners 3rd and 4th pass' in that car. But the vette looks good none the less.

Very nice! Congrats. How about more details on the combo

yes, MORE DETAILS please! I plan on being at Bithlo soon.

Good thing I wasn't driving the cobra lol. That was the owners 3rd and 4th pass' in that car. But the vette looks good none the less.

Thx:nod:

That cobra was slow out the gate... and I hit the limiter 2 times at the top of the track in second gear. MAN if I had a third gear I know I would have gone 10.7-10.8 but he still would have caught me... not sure I have a 10.6 in this ride...

BUT THATS MOVING for...
3000lbs C3 with Th400 - 3.36 gear 3500 stall and LSx motor with a 240/246 cam

Heads? IRS rear? I guess you've tuned it with O2 sensors?

How'd you get a 70s Vette down to 3,000 lbs? I thought they were closer to 3600 - 3700.

btw I love c3 ls cars I had a blast with my 82 that I swapped a ls1 in, only thing i wished it had was a little more power but i still kept up with new vettes with 340hp to the wheels

I always had a soft sport for the 82 Anniversary. Very classy looking car.

Heads? IRS rear? I guess you've tuned it with O2 sensors?

How'd you get a 70s Vette down to 3,000 lbs? I thought they were closer to 3600 - 3700.

IRS factory rear with DRAGVETTE.com 4-link suspension... Catherdel heads stock rockers...no O2...

weight was mostly the LS motor and pulling all A/C stuff a few bumper supports, front sway bar... etc. it weighed 3050 without me on Bithlo scale.

OH wicked CARB and tuning over at BOWTIE AUTO in longwood.

I was going to be happy with my 6.0 combo running 12s!!!!

I guess I need to revise my expectations - 11.99?

My LS power stang runs in the nines on motor !!!

I was going to be happy with my 6.0 combo running 12s!!!!

I guess I need to revise my expectations - 11.99?

My first combo went 12.3-12.0 stall and cam makes a difference

My LS power stang runs in the nines on motor !!!

Nice... I bet it weighs 2700 lbs also with a 4.10 gear and at least 4000 stall

3100 #'s yes it's got a 4.10 and smaller stall 3600. Btw it runs 8.90's on pump gas and a 150 shot..

3100 #'s yes it's got a 4.10 and smaller stall 3600. Btw it runs 8.90's on pump gas and a 150 shot..

sweet baby jesus... 8.90 on 150 shot. car is working. :D

More on your LSx....what motor is it? 5.3? 5.7? 6.0? 6.2?
Compression? Intake choice? carb size? header size?

Thanks!

LS3 2008 block 4 inch stroke... about 11 to 1, 1-1/34 headers, Vic Jr Intake, 780 AED HOLLEY DP

Heads? IRS rear? I guess you've tuned it with O2 sensors?

How'd you get a 70s Vette down to 3,000 lbs? I thought they were closer to 3600 - 3700.

my 69 vette went 6.71@105 in the 1/8 with 3.25 gears 28 inch tall tires 229 236 cam and 10:1 compression with a 468 and was 3000lbs with out me.

LS3 2008 block 4 inch stroke... about 11 to 1, 1-1/34 headers, Vic Jr Intake, 780 AED HOLLEY DP

so whats that a 414? man thats what i was thinking about doing with my 70nova but thought it would be faster......

LS3 2008 block 4 inch stroke... about 11 to 1, 1-1/34 headers, Vic Jr Intake, 780 AED HOLLEY DP

That setup should be at least in the 10.50 or better range if the LS3 heads are all they are cracked up to be. For your car, I would go to a 4.10 gear, 4500 stall, 1-7/8 headers and get the carb worked by someone who knows what they are doing such as Prosystems.

I hope your transmission issue is as simple as it sounds.

FWIW, my Camaro in the signature is heavier, had much smaller heads and less cam. You should be all over me if you are set up correctly. What kind of 60-foot times did you pull? 1/8 mile times?

My car was Hit... heading to the track a few months back. SUCKED!! rear passenger side.

Just got it out of the body shop... the week before I has hit I made a few 1/8th miles runs. from 7.1 - 6.9 only difference was the launch and how much heat in the tires!

NEW BEST - nothing changed just heated tires more.

60ft 1.65
1/8th ET 6.94
MPH 100.2

Keep in mind I have a 29 inch tall tire with 3.36 gears. And small LS1 205 AFR heads (NOT THE LS3 Heads) also... I dont have 3rd gear at WOT for 1/4 mile... so thats running to the top of 2nd and letting out or bumping rev limiter. NO ROLL BAR either.

Car has 10.8-10.7 in it the way it is...
with LS3 heads... 4000 stall... 3.73 gears I should be good for 10.2-10.0 1/4 or 6.5-6.4 1/8

I am going to get back to the track...but need to get my brake bled. Soft pedal from sitting for 3 months in the body shop

http://i243.photobucket.com/albums/ff79/holley505/IMG_0033.jpg

http://i243.photobucket.com/albums/ff79/holley505/IMG_0028.jpg

http://i243.photobucket.com/albums/ff79/holley505/vetteremixrear.jpg

http://i243.photobucket.com/albums/ff79/holley505/vetteremixoutofbooth.jpg

http://i243.photobucket.com/albums/ff79/holley505/vetteremixhoodpainted.jpg

http://i243.photobucket.com/albums/ff79/holley505/vetteremix.jpg

Pass against a modded Grand sport with drag radials.

http://i243.photobucket.com/albums/ff79/holley505/th_MVI_0026.jpg (http://s243.photobucket.com/albums/ff79/holley505/?action=view&current=MVI_0026.mp4)

Ouch... know the feeling of someone busting up your $hit :bomb:

Glad you're back up and running :cheers:

I was coming home from the track a few years ago when this @ss crossed the double yellow line, went down the side of my truck, up on the borrowed trailer, and caved in the side of my Camaro... RedЯum (http://s10.photobucket.com/albums/a130/Dougs68Camaro/accident/) <-- Pics


http://i10.photobucket.com/albums/a130/Dougs68Camaro/accident/th_DSCF0016.jpg http://i10.photobucket.com/albums/a130/Dougs68Camaro/accident/th_DSCF0014-3.jpg http://i10.photobucket.com/albums/a130/Dougs68Camaro/accident/th_DSCF0004.jpg

Ouch... know the feeling of someone busting up your $hit :bomb:

Glad you're back up and running :cheers:

I was coming home from the track a few years ago when this @ss crossed the double yellow line, went down the side of my truck, up on the borrowed trailer, and caved in the side of my Camaro... RedЯum (http://s10.photobucket.com/albums/a130/Dougs68Camaro/accident/) <-- Pics


http://i10.photobucket.com/albums/a130/Dougs68Camaro/accident/th_DSCF0016.jpg http://i10.photobucket.com/albums/a130/Dougs68Camaro/accident/th_DSCF0014-3.jpg http://i10.photobucket.com/albums/a130/Dougs68Camaro/accident/th_DSCF0004.jpg


OUCH SUX... but car looks good now! Nice ride!