Circle D 3B converter
Circle D 3B converter Hey guys, got a converter question for some experts out there. I have the car in my sig below, its a 9", TH400 setup with a stock heads and cam LS1 with typical bolts ons like headers and lid and cutout and a 150 shot of spray. When I went to the TH400 setup last year I got a Circle D converter from Chris and it was a +4C converter. It was an awesome converter down low and on the spray I was able to go 1.51 60' with it but the problem was up top it was so inefficient that I was blowing through it on the spray and would hit the rev limiter (6200 rpm) in 3rd at 114 mph. The car has trapped 121 before the TH400/circle D converter. So the car was going 11.4 at 114 with a 1.51 60'. Well obviously this did not work since I couldn't get more than 114 mph out of it, so I called chris and he told me to send the converter back to have it restalled so I did. I thought a 3C was going to do the trick but he was still worried that I might have the same problem so he recommend his 3B converter. Now my question is what kind of 60's is this 3B converter going to cut, am I still going to be able to get down into the 1.5's on the spray with it or is that a thing of the past? I always see everybody going with the 3C or 4C converters and not the 3B's so I am curious to see if anybody else has any experience with it and what its going to be like. Thanks in advance.
"All Motor 9 Second club member"
iTrader: (60)
Joined: Nov 2001
Posts: 3,235
Likes: 2
From: On the Bumper!
I am no expert by any means, but I think the 3B will love the juice and the 60fts will be in the 1.5s provided traction is there. That limiter is awefully low IMO. We shift our stock internal cars at that or slightly higher and move the limiter up out of the way safely.
If I am reading this right, you had the TH400 and only changed converters? The TH400 doesn't have the same 1st gear as a 4L60e so there is a slight loss of intial hit from the gear difference if you went from one tranny to the other.
Most of the ET is made up at the first part of the track especially in a low HP car, so the 3B should do very well on the bottle IMO.
FWIW- We pulled mid 1.5s on motor with the 3B and probably weigh more than you and probably don't make the power you do with you on the bottle. Here's a link the thread where we ran it with our baby cam set up on motor.
https://ls1tech.com/forums/dynamomet...results-4.html
If I am reading this right, you had the TH400 and only changed converters? The TH400 doesn't have the same 1st gear as a 4L60e so there is a slight loss of intial hit from the gear difference if you went from one tranny to the other.
Most of the ET is made up at the first part of the track especially in a low HP car, so the 3B should do very well on the bottle IMO.
FWIW- We pulled mid 1.5s on motor with the 3B and probably weigh more than you and probably don't make the power you do with you on the bottle. Here's a link the thread where we ran it with our baby cam set up on motor.
https://ls1tech.com/forums/dynamomet...results-4.html
Yeah you read correctly. I changed just the converter because with the big +4C converter it was just too loose and was slipping too much for the spray. I now have the 3B converter and was just curious what kind of 60's I am looking at, if you were able to cut mid 1.5's then I am hoping my low 1.5 is still achievable since as you said I am making just a little bit more power on the spray probably. The rev limiter is 6200 because I still have stock heads and cam and stock valvetrain so I always thought you shouldn't take a stock valvetrain much higher than that, plus you can really feel the car nose over once you hit 6100-6200 so I figure theres no reason to spin it higher than that.
On a side note I took the car for a drive last night after the 3B install and I have to say it feels very strong. Spins the tires harder than it did before and feels like its puting more power down to the wheels. One odd thing was after I started the car up and was letting it warm up to get the tranny temp up so I could check the fluid level my Check engine light popped on so I pulled the code and it was the dreaded PO300 which is random misfire. Very odd as I haven't had a misfire code ever on this car and I am very vigilant about changing plugs and things. So I cleared the code and continued to let the car run for another 20-30 min then I took it out and drove it around town and the check enging light never came back on. I don't know if the new torque converter maybe threw it off at first or something.
On a side note I took the car for a drive last night after the 3B install and I have to say it feels very strong. Spins the tires harder than it did before and feels like its puting more power down to the wheels. One odd thing was after I started the car up and was letting it warm up to get the tranny temp up so I could check the fluid level my Check engine light popped on so I pulled the code and it was the dreaded PO300 which is random misfire. Very odd as I haven't had a misfire code ever on this car and I am very vigilant about changing plugs and things. So I cleared the code and continued to let the car run for another 20-30 min then I took it out and drove it around town and the check enging light never came back on. I don't know if the new torque converter maybe threw it off at first or something.
"All Motor 9 Second club member"
iTrader: (60)
Joined: Nov 2001
Posts: 3,235
Likes: 2
From: On the Bumper!
Yeah it could just be from it bigging dizzy if you had the battery disconnected. Usually a dirty MAF or bad plug wire most commonly throws the PO300, but hopefully it'll stay out.
The 3B does hit hard and feels tighter on the street.
Keep us updated!
The 3B does hit hard and feels tighter on the street.
Keep us updated!
Yeah I did have the battery disconnected for the past 3 weeks that the torque converter was at Circle D getting restalled. I will spray the MAF with some electronics cleaner to clean it up since the car has been sitting, maybe I will swap the plugs too just to be sure. I will let you know what it does weekend, headed to the track friday night if the weather cooperates. With the +4C I was going 11.4 at 114 w/ a 1.51 60' hitting the limiter in third at about the 1000' mark so hopefully if I get my mph back with this converter and the car goes 121 it will go 10.8-10.9 somewhere. We will see. Thanks
"All Motor 9 Second club member"
iTrader: (60)
Joined: Nov 2001
Posts: 3,235
Likes: 2
From: On the Bumper!
I would raise the shift points to 6100 rpm and bump the limiter up to 6600rpm so it has a window for over shooting. The spray makes things happen a good bit quicker and I can almost bet you will run better ETs.
G/L at the track!
G/L at the track!
Well I have a RMVB so I do the shifts, I have my shift light set at 5900 right now I think and previously by the time I see the light and do the shift it happens around 6150 but I see what you mean by bumping up the limiter so I don't tap it accidentaly if the shift takes longer.
Trending Topics
"All Motor 9 Second club member"
iTrader: (60)
Joined: Nov 2001
Posts: 3,235
Likes: 2
From: On the Bumper!
Yeah I forgot about you having the TH400. My son and daughters SI Camaros pull strong to 6300 rpm without nosing over. You may have weak valve springs or the AFR might be real rich in the upper rpms (CAT over temp on). Just a thought. We shift that high so we can make it past the 1/8 mile marker in 2nd gear for the bracket races.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
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
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo The weak valve spring is a super possibility, the motor has 136K miles on it. It still runs strong though and doesn't use a drop of oil. Its getting replaced this winter with a 408 nitrous motor so this is its last hurrah. Its going to go 10's if I have to up the jets to a 200 shot. LOL
Update:
Well finally got to the track with the Circle D 3B converter. I went to Richmond Dragway on Friday the 29th of October. Coming out of the hole on a 150 shot using the transbrake it went 1.60 60' and I did not feel any tire spin. I was hoping for a mid to low 1.5. On the second and final pass I got (track was packed) I didn't use the Tbrake and just came up on the normal brakes to about 2K RPM and then stabbed it. The nitrous comes on at 2500 RPM and I cut a 1.59 60' using this method. My question is do you guys think this is the limit of the converter and its not going to get any better or should I try launching it differently? I assumed the Tbrake would be the best but it did launch better without the brake. Any thoughts? I was really hoping i was not going to lose this much on the 60' going to this converter.
The car went a new PB of 11.10 at 122.55 with the 1.60 short time. The MPH is there for a high 10 second pass so now I just need to get that 60 down some. All I want is a 10.99 or better.
Well finally got to the track with the Circle D 3B converter. I went to Richmond Dragway on Friday the 29th of October. Coming out of the hole on a 150 shot using the transbrake it went 1.60 60' and I did not feel any tire spin. I was hoping for a mid to low 1.5. On the second and final pass I got (track was packed) I didn't use the Tbrake and just came up on the normal brakes to about 2K RPM and then stabbed it. The nitrous comes on at 2500 RPM and I cut a 1.59 60' using this method. My question is do you guys think this is the limit of the converter and its not going to get any better or should I try launching it differently? I assumed the Tbrake would be the best but it did launch better without the brake. Any thoughts? I was really hoping i was not going to lose this much on the 60' going to this converter.
The car went a new PB of 11.10 at 122.55 with the 1.60 short time. The MPH is there for a high 10 second pass so now I just need to get that 60 down some. All I want is a 10.99 or better.
Last edited by tording99Z28; Nov 1, 2010 at 08:11 PM.
"All Motor 9 Second club member"
iTrader: (60)
Joined: Nov 2001
Posts: 3,235
Likes: 2
From: On the Bumper!
Man that's a tough one. I really expected the 3B to 60ft better than that with all else being equal. I almost have to suspect slight tire spin if the air quality was comparable. Can you have the nitrous come in any earlier?
FWIW- Our cars have always 60fted the same off the footbrake as it did off the TB. It feels totally different, but the time slips are the same.
FWIW- Our cars have always 60fted the same off the footbrake as it did off the TB. It feels totally different, but the time slips are the same.
It is possible there is some slight wheel spin, I just didn't feel any but if its only turning them over a time or two then theres a good chance I wouldn't feel it. I can bring the nitrous in earlier but off the Tbrake it was stalling to 3500 and the nitrous comes in at 2500 so as soon as my foot hits the floor and the WOT switch is activated the nitrous is spraying so off the brake I don't know that bringing the nitrous in earlier will help, however foot braking it bringing the nitrous in earlier might help. It is a wet kit so I don't want to bring it in too low as I fear there could be some pooling and a BOOM!! You think 2000 RPM is too low for a wet kit? I am going to a different track this coming friday night that is genrally considered a better track so if it was spinning hopefully that won't happen this coming Friday. I also lightened the car today by about 60 lbs and planning on getting rid of another 40 lbs or so before Friday so the car should be about 100 lbs lighter so hopefully that will give me a tenth as well. Any other suggestions from anybody on launching technique?
From what I remember when I watched your run, you had some spin, most everyone there was getting spin that night, and with the track prep they had to do 3 times from breakdowns, the track was cooling fast, and I bet the prep wasnt that good back at the light. I think with the TCR mods you are doing, you will catch that 60 back down, and may get your 10 your looking for. Too bad I cant go to VMP with ya and watch, getting ready for this stupid mission I have to go on for the Army, but good luck man on the run.
Well it may have been spinning then I guess so hopefully thats it. You are right about the two idiots that oiled the track down so that didn't help any. I am also working on rewiring my nitrous and trans brake setup so that when I am on the line and I have my transbrake engaged I can go to the floor with the throttle and it won't spray nitrous but as soon as I let go of the Tbrake switch it disengages the brake and reengages the nitrous and off I go. Right now the way its wired I can't go the floor with the throttle on the brake because the nitrous will spray so I only go about 75% throttle then as I let go of the Tbrake button I put it to the floor so theres a split second in there that the car is not full throttle and i am sure that is costing me at least a few hundredths of a second so hopefully that will help too.
"All Motor 9 Second club member"
iTrader: (60)
Joined: Nov 2001
Posts: 3,235
Likes: 2
From: On the Bumper!
I'd bet you were spinning and that is what had me baffled since I was pulling 1.5s at full weight with that same converter on motor. Of course I have the lower 1st gear, but I'm running 3.23s out back where as you have the 3.70s. You probably make more power than I do on the bottle also even though I'm getting all of mine out to the tires at the hit.
I'm only trapping 118mph so I'd bet you'll see better 60fts and ETs on the outting.
G/L
I'm only trapping 118mph so I'd bet you'll see better 60fts and ETs on the outting.
G/L
10 Second Club
Joined: Jan 2010
Posts: 195
Likes: 0
From: Houston Tx
I had the same problem with my 4C+ it was pushing throught the converter at the big end. I lost 23mph from locked on the dyno to the rev limiter in 3rd gear on the street. I just picked mine up from Chris today. He went from the 4C+ to a 2C. I hope I don't lose anything down low. I think the only reason my car ran good on motor was because it was able to spin the motor up to around 3800 off the footbrake. Hopefully I will be able to get it back in and make a trip to the track this weekend for some new results.
