Need some help to diagnose a problem.
Need some help to diagnose a problem. Hey guys and gals. We took the car to 41 yesterday to test the new transbrake, but were having some problem.
This is the 1st run off the trailer on the footbrake
http://www.youtube.com/watch?v=nuNet5-buz8
That pass the car moves out of the hole and pulls through the 1/4.
60' 1.47
1/8 6.68@102.7
1/4 10.51@128.53
The pass on the transbrake, stalls to about 5k rpm
http://www.youtube.com/watch?v=9NuSu8GaqAw
That pass the car did worse all around.
60' 1.56
1/8 6.95@100.63
1/4 10.837@125.77
For the last run(track was closing) I launched at the 3800chip
http://www.youtube.com/watch?v=oYbNt_-AWfQ
Car felt better than the 1st brake run, but still worse than the 1st footbrake run.
60' 1.55
1/8 6.94@100.46
1/4 10.851@126.05
From people i've spoken with, everyone says that the converter is not able to handle the motor. The car made about 715Tq at 3100rpm. The converter is a 9" Coan 3600stall. My trans guy says its possible that "the suspension is not able to handle the brake, but the MPH loss looks fishy." I'm still leaning towards a converter problem, as the car dead hooks, and the suspension was setup by a good shop and a good guy.
Any ideas?
This is the 1st run off the trailer on the footbrake
http://www.youtube.com/watch?v=nuNet5-buz8
That pass the car moves out of the hole and pulls through the 1/4.
60' 1.47
1/8 6.68@102.7
1/4 10.51@128.53
The pass on the transbrake, stalls to about 5k rpm
http://www.youtube.com/watch?v=9NuSu8GaqAw
That pass the car did worse all around.
60' 1.56
1/8 6.95@100.63
1/4 10.837@125.77
For the last run(track was closing) I launched at the 3800chip
http://www.youtube.com/watch?v=oYbNt_-AWfQ
Car felt better than the 1st brake run, but still worse than the 1st footbrake run.
60' 1.55
1/8 6.94@100.46
1/4 10.851@126.05
From people i've spoken with, everyone says that the converter is not able to handle the motor. The car made about 715Tq at 3100rpm. The converter is a 9" Coan 3600stall. My trans guy says its possible that "the suspension is not able to handle the brake, but the MPH loss looks fishy." I'm still leaning towards a converter problem, as the car dead hooks, and the suspension was setup by a good shop and a good guy.
Any ideas?
not really sure but i would think a 3600 stall on a 540ci BBC is a but on the small side. You should be above 4000rpm stall for sure, maybe even a 10". It also comes down to what trans you are running. I'm guessing a glide or turbo 400 for that much power.
My dad has a 67 caprice with a 468 BBC in it, over 500hp and 500tq, and that motor would eat up convertors. It ate up two TCI street fighters. I think the stall for them was 3200rpms. He called up TCI and they said that the speed shop sold him the wrong convertor. He has a 10" super Street fighter rated at 3600rpms and hs not had a problem since. He has a turbo 400 with only 3.07 gears for now. He will be putting in a set of 4.10's soon.
Try to call White's Pit stop in Lansing at 708-418-8400 or Winner's Circle in Joliet at 815-727-6331. I'm sure one of those places just be able to tell you what you need for the setup you have.
btw nice looking Camaro!
My dad has a 67 caprice with a 468 BBC in it, over 500hp and 500tq, and that motor would eat up convertors. It ate up two TCI street fighters. I think the stall for them was 3200rpms. He called up TCI and they said that the speed shop sold him the wrong convertor. He has a 10" super Street fighter rated at 3600rpms and hs not had a problem since. He has a turbo 400 with only 3.07 gears for now. He will be putting in a set of 4.10's soon.
Try to call White's Pit stop in Lansing at 708-418-8400 or Winner's Circle in Joliet at 815-727-6331. I'm sure one of those places just be able to tell you what you need for the setup you have.
btw nice looking Camaro!
Last edited by scramblerman; May 18, 2009 at 02:54 PM.
go buy a PTC converter for around $1100 
call them with your combo and the dyno graph info and you'll be all set.
also did you try different launch rpms? what are you footbraking the car to? That 60' drop makes me think the slicks were spinning, did you mark the tires with a big white dash mark to see if it starts moving forward or spins a bit?
call them with your combo and the dyno graph info and you'll be all set.
also did you try different launch rpms? what are you footbraking the car to? That 60' drop makes me think the slicks were spinning, did you mark the tires with a big white dash mark to see if it starts moving forward or spins a bit?
trans is a RMVB th-400. Slicks were not spinning(that anyone saw). Take a look at the videos.
I was also running 9-1/2 psi in the rear. The car can only footbrake to about 1900 before the car starts to creep foward.
I was also running 9-1/2 psi in the rear. The car can only footbrake to about 1900 before the car starts to creep foward.
6 & 8 Second Club
Joined: Aug 2006
Posts: 2,284
Likes: 0
From: Illinois, RT 66 dragway area
.
Did the humidity & temp go up every pass?? 2 1/2 mph is not that big of a deal.
If something was hurt I would expect more loss. Did you check plugs every pass?
Could the tune be off & you're running with wet plugs?? Blow out the air bleeds??
Do all the little things before sending converter back for check up.
Some cars make best pass 1st, when block is cold??
I don't know your specs, but that's not enough HP to over power most 9" converters.
I know a lot of guys with more HP using a 8".
If you were blowing off the tires, the 60" & ET would suffer, but not MPH, so as you said, probably hooks fine.
Unfortunately most of the time it's trial & error until you find each problem one at a time.
?? for you, why a 9" converter & why so tight. Please don't call anyone but Coan.
They know what they're doing, you can't trust what counter guy will answer at a local shop.
Good luck Spencer.
.
Did the humidity & temp go up every pass?? 2 1/2 mph is not that big of a deal.
If something was hurt I would expect more loss. Did you check plugs every pass?
Could the tune be off & you're running with wet plugs?? Blow out the air bleeds??
Do all the little things before sending converter back for check up.
Some cars make best pass 1st, when block is cold??
I don't know your specs, but that's not enough HP to over power most 9" converters.
I know a lot of guys with more HP using a 8".
If you were blowing off the tires, the 60" & ET would suffer, but not MPH, so as you said, probably hooks fine.
Unfortunately most of the time it's trial & error until you find each problem one at a time.
?? for you, why a 9" converter & why so tight. Please don't call anyone but Coan.
They know what they're doing, you can't trust what counter guy will answer at a local shop.
Good luck Spencer.
.
.
Did the humidity & temp go up every pass?? 2 1/2 mph is not that big of a deal.
If something was hurt I would expect more loss. Did you check plugs every pass?
Could the tune be off & you're running with wet plugs?? Blow out the air bleeds??
Do all the little things before sending converter back for check up.
Some cars make best pass 1st, when block is cold??
I don't know your specs, but that's not enough HP to over power most 9" converters.
I know a lot of guys with more HP using a 8".
If you were blowing off the tires, the 60" & ET would suffer, but not MPH, so as you said, probably hooks fine.
Unfortunately most of the time it's trial & error until you find each problem one at a time.
?? for you, why a 9" converter & why so tight. Please don't call anyone but Coan.
They know what they're doing, you can't trust what counter guy will answer at a local shop.
Good luck Spencer.
.
Did the humidity & temp go up every pass?? 2 1/2 mph is not that big of a deal.
If something was hurt I would expect more loss. Did you check plugs every pass?
Could the tune be off & you're running with wet plugs?? Blow out the air bleeds??
Do all the little things before sending converter back for check up.
Some cars make best pass 1st, when block is cold??
I don't know your specs, but that's not enough HP to over power most 9" converters.
I know a lot of guys with more HP using a 8".
If you were blowing off the tires, the 60" & ET would suffer, but not MPH, so as you said, probably hooks fine.
Unfortunately most of the time it's trial & error until you find each problem one at a time.
?? for you, why a 9" converter & why so tight. Please don't call anyone but Coan.
They know what they're doing, you can't trust what counter guy will answer at a local shop.
Good luck Spencer.
.
As for the converter, i'll give Coan a call to see what they think. Our trans guy said that was a good choice for our setup.
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6 & 8 Second Club
Joined: Aug 2006
Posts: 2,284
Likes: 0
From: Illinois, RT 66 dragway area
.
If you want to borrow for testing or your's is bad. I have 3-4 converters on my shelf.
I believe I have 1 for 800, 900 & 1050 HP. You can test before wasting money??
.
If you want to borrow for testing or your's is bad. I have 3-4 converters on my shelf.
I believe I have 1 for 800, 900 & 1050 HP. You can test before wasting money??
.
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I grabbed the dynosheet for exact#'s
704.3@3249RPM
Thanks for the offer john, I'll let you know.
Yeah that's true.
704.3@3249RPM
Yeah that's true.
Well this is becoming intresting. I found the numbers off the converter and called coan back. That converter was originally setup for a 468BBC(our old motor)
10" 750hp, 3800-4000 stall Part #20328
10" 750hp, 3800-4000 stall Part #20328
6 & 8 Second Club
Joined: Aug 2006
Posts: 2,284
Likes: 0
From: Illinois, RT 66 dragway area
.
I know I've been gone several month's & don't know your combination.
Why are you using such a tight stall. Sounds like your choking down an engine that will probably like 52-5400??
Are you trying to drive this thing on the highway??
I checked my shelf, the 800 HP piece is blown up. I still have 2-3 more laying around if you want to test something else.
.
I know I've been gone several month's & don't know your combination.
Why are you using such a tight stall. Sounds like your choking down an engine that will probably like 52-5400??
Are you trying to drive this thing on the highway??
I checked my shelf, the 800 HP piece is blown up. I still have 2-3 more laying around if you want to test something else.
.