Do Circle D converters rob top end?
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
Do Circle D converters rob top end? Do Circle D converters rob top end and trap speed more than other brand stalls??
I had a reputable tuner who is sponsor on this board say that the reason my car is trapping so low is because of the Circle D converter I have. He says they are known for robbing top end, which was news to me as everything I ever read about them was absolutely positive and how well it seems to work in my car.
This issue came up after I did a 224 cam swap on my bolt ons 98 ta with a 3200 circle d converter and my trap speed was only 107. I contacted the guy who did my tune and he said I was SOL and that he did everything he could and my car is basically a turd lol.
The car put down 360 hp/373 which seemed reasonable for how small the cam is, but the trap speed seemed really low. So I contacted another tuner and asked what he thought and he seemed to think that the Circle D converter was robbing my top end and that is why my trap speed was so low.
Is that right?
I had a reputable tuner who is sponsor on this board say that the reason my car is trapping so low is because of the Circle D converter I have. He says they are known for robbing top end, which was news to me as everything I ever read about them was absolutely positive and how well it seems to work in my car.
This issue came up after I did a 224 cam swap on my bolt ons 98 ta with a 3200 circle d converter and my trap speed was only 107. I contacted the guy who did my tune and he said I was SOL and that he did everything he could and my car is basically a turd lol.
The car put down 360 hp/373 which seemed reasonable for how small the cam is, but the trap speed seemed really low. So I contacted another tuner and asked what he thought and he seemed to think that the Circle D converter was robbing my top end and that is why my trap speed was so low.
Is that right?
I would like to know more info on this. Especially the tuner, you can PM me the details if you want. You can easily check the converter efficiency by logging TCC slip and compare it to the trap RPM. But also watch out for a false slip number if the 3/4 clutches are slipping. If you want to call to discus this further that is cool. And to answer your question, no - Circle D converters do not rob top end.
Chris
Chris
I would like to know more info on this. Especially the tuner, you can PM me the details if you want. You can easily check the converter efficiency by logging TCC slip and compare it to the trap RPM. But also watch out for a false slip number if the 3/4 clutches are slipping. If you want to call to discus this further that is cool. And to answer your question, no - Circle D converters do not rob top end.
Chris
Chris
We sell our own line of converters but we never steer anyone away from a Circle-D if that is what they want to use.
A looser converter can sometimes be a bit less efficient on the top end, and sometimes converter slip numbers don't tell the whole story (some combos need a sloppy converter) but I would say in my experience, Circle-D units tend to be more efficient and on the tight side.
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
Trending Topics
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
I would like to know more info on this. Especially the tuner, you can PM me the details if you want. You can easily check the converter efficiency by logging TCC slip and compare it to the trap RPM. But also watch out for a false slip number if the 3/4 clutches are slipping. If you want to call to discus this further that is cool. And to answer your question, no - Circle D converters do not rob top end.
Chris
Chris
A couple years ago I upgraded a lot of the components in the tranny. Like the beast sunshell, clutch packs and servos and a shift kit
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
As a rule a higher stall speed converter will slip more
up top (TCC slip RPM). If you go just by the number
it will look pretty bad sometimes (I had a TCI 3000
that was 97% efficient by 5K, have TCI 3500 data
that says 95% but has to get to 6K to get there,
and a TCI 3800 that was south of 90% at 6K).
But what you do not know, is how much of that
slip as %, is going to heat and how much to the
fading tail of torque multiplication. You'd have to
compare locked RWT@MPH to unlocked RWT@MPH,
to gauge that. My low-STR Fuddle is still multiplying
past 5000RPM, going by that kind of comparo. The
little TCI was not.
Look at the ratio of input shaft RPM to output shaft
RPM and compare to nominal in-gear ratio to assess
gearbox friction slip, separately from converter.
up top (TCC slip RPM). If you go just by the number
it will look pretty bad sometimes (I had a TCI 3000
that was 97% efficient by 5K, have TCI 3500 data
that says 95% but has to get to 6K to get there,
and a TCI 3800 that was south of 90% at 6K).
But what you do not know, is how much of that
slip as %, is going to heat and how much to the
fading tail of torque multiplication. You'd have to
compare locked RWT@MPH to unlocked RWT@MPH,
to gauge that. My low-STR Fuddle is still multiplying
past 5000RPM, going by that kind of comparo. The
little TCI was not.
Look at the ratio of input shaft RPM to output shaft
RPM and compare to nominal in-gear ratio to assess
gearbox friction slip, separately from converter.
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
As a rule a higher stall speed converter will slip more
up top (TCC slip RPM). If you go just by the number
it will look pretty bad sometimes (I had a TCI 3000
that was 97% efficient by 5K, have TCI 3500 data
that says 95% but has to get to 6K to get there,
and a TCI 3800 that was south of 90% at 6K).
But what you do not know, is how much of that
slip as %, is going to heat and how much to the
fading tail of torque multiplication. You'd have to
compare locked RWT@MPH to unlocked RWT@MPH,
to gauge that. My low-STR Fuddle is still multiplying
past 5000RPM, going by that kind of comparo. The
little TCI was not.
Look at the ratio of input shaft RPM to output shaft
RPM and compare to nominal in-gear ratio to assess
gearbox friction slip, separately from converter.
up top (TCC slip RPM). If you go just by the number
it will look pretty bad sometimes (I had a TCI 3000
that was 97% efficient by 5K, have TCI 3500 data
that says 95% but has to get to 6K to get there,
and a TCI 3800 that was south of 90% at 6K).
But what you do not know, is how much of that
slip as %, is going to heat and how much to the
fading tail of torque multiplication. You'd have to
compare locked RWT@MPH to unlocked RWT@MPH,
to gauge that. My low-STR Fuddle is still multiplying
past 5000RPM, going by that kind of comparo. The
little TCI was not.
Look at the ratio of input shaft RPM to output shaft
RPM and compare to nominal in-gear ratio to assess
gearbox friction slip, separately from converter.
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
I've driven a Circle D car at the track. It performed as expected. So I'd say no I don't agree with your tuner. However, I'm curious what size converter you have? Not stall speed but what actual size is the converter? 11, 10.5, 9.5 inch etc...
I just put a circle D 3600 3c in a friends bolt on camaro. It has pacesetter long tubes, TSP off rd Y, SLP LId, ported stock t/b, magnaflow exhaust, and it trapped 108-109 consistently full weight with 225lbs driver in +1100 da. So I don' think that it hurt trap speed at all. Like was said in another thread you started , you have a problem with motor, tune , or could be tranny slipping more than likely is one of your problems.
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
I just put a circle D 3600 3c in a friends bolt on camaro. It has pacesetter long tubes, TSP off rd Y, SLP LId, ported stock t/b, magnaflow exhaust, and it trapped 108-109 consistently full weight with 225lbs driver in +1100 da. So I don' think that it hurt trap speed at all. Like was said in another thread you started , you have a problem with motor, tune , or could be tranny slipping more than likely is one of your problems.
TECH Apprentice
Joined: Dec 2011
Posts: 323
Likes: 0
From: ny
well when my buddys grandfather get someone in the shop that is saying their tranny might be slipping he takes about 5 oz of lucas tranny fix puts it in then tells them to take it for a ride to see if its any better. (i think thats the only reason he keeps a bottle around haha) and he says its usually a pretty good determination the tranny is slipping. the guy is 78 and can build a 4l60 with his eyes closed in his sleep so it cant be to bad advice. i havent tried it yet tho 
btw wanna race? another v8 under the belt wouldnt hurt, haha jking
btw wanna race? another v8 under the belt wouldnt hurt, haha jking
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
I used my timing tuner and added about 4 degrees of timing and it seems to pull harder on top end. Im thinking the tuner left timing out cuz he wrote me a no2 tune.
Thread Starter
11 Second Club
iTrader: (3)
Joined: Jan 2007
Posts: 914
Likes: 0
From: wentzville, MO
well when my buddys grandfather get someone in the shop that is saying their tranny might be slipping he takes about 5 oz of lucas tranny fix puts it in then tells them to take it for a ride to see if its any better. (i think thats the only reason he keeps a bottle around haha) and he says its usually a pretty good determination the tranny is slipping. the guy is 78 and can build a 4l60 with his eyes closed in his sleep so it cant be to bad advice. i havent tried it yet tho
btw wanna race? another v8 under the belt wouldnt hurt, haha jking
btw wanna race? another v8 under the belt wouldnt hurt, haha jking
