New Coan Converter

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roccodart440

roccodart440

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So I finally pulled the trigger on a new convertor. After calling at least 4 places I went with a 9.5" billet Coan. Probably the two biggest reasons I went with them were they were the only one that offered me a 4,500 stall. All of the rest offered me a 4,000 stall. The other reason is they offer spragless convertors, which the others didn't. (spragless is race only, I didn't get one of those) They were also WAY more money, which wasn't a good selling point.

Just curious on some of your experiences with Coan, and also how much difference going from a 3500 10" Art Carr to a 4,500 9.5" from Coan will make.
 
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You'll notice the difference for sure. I did going from a 4000 to a 5500. My converter was $2200 in 2009 what are they costing now .
 
Just curious but did the other 3 shops give a reason for the lower stall?
 
Watching as well. I gotta wonder why we are all not actively trading (buying selling trading etc) our converters here. I rarely see one for sale even for SB. Considering this is a tuning element in the drive train is everyone getting it right the first time AND is nobody making engine changes????
 
340inabbody said:
Watching as well. I gotta wonder why we are all not actively trading (buying selling trading etc) our converters here. I rarely see one for sale even for SB. Considering this is a tuning element in the drive train is everyone getting it right the first time AND is nobody making engine changes????
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I think guys are apprehensive about used converters. I was but bought one used a few years back. Paid 425 for it. Last month it cost $516 to restall/rebuild for the new. Not to bad when a new one is $1350 from the guys that reworked it.
 
19DUSTER73 said:
I think guys are apprehensive about used converters. I was but bought one used a few years back. Paid 425 for it. Last month it cost $516 to restall/rebuild for the new. Not to bad when a new one is $1350 from the guys that reworked it.
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Yes thats a good point but this particular part is not as abundant in the adds and being traded as I would expect and I know it’s not because everyone is happy with what they put in initially. So where are all these converters?
 
340inabbody said:
Yes thats a good point but this particular part is not as abundant in the adds and being traded as I would expect and I know it’s not because everyone is happy with what they put in initially. So where are all these converters?
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Yeah I hear ya but don't really have an answer lol. Do any of the converter outfits charge a core? Some may go to a core, some to a scrap pile and others the owner may not know what they are missing.
 
19DUSTER73 said:
Yeah I hear ya but don't really have an answer lol. Do any of the converter outfits charge a core? Some may go to a core, some to a scrap pile and others the owner may not know what they are missing.
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I think a lot of folks are apprehensive about pulling a trans or motor out to access the converter. It is a significant task for many. How many “which cam or which rear gear” threads do you see answered with get a modern higher stall converter and it will be a Big Bang for the buck. But I bet most never do unless it’s out for another reason.
 
This was a 4000 unit of unknown manufacture, in a small block powerglide brake car.

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20180908_091303.jpg

When it did what it did, I replaced it with a custom munsinger (since retired, or....) that stalled at 5200, and picked up .2 and 3mph in the eighth.
Not a direct comparison obviously.
To be honest, look at a dyno sheet, and see how much more power you can make at 4500 compared to 3500. IF it dead hooks, I wouldn't be surprised by a tenth and a half (1/8).
 
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gzig5 said:
I think a lot of folks are apprehensive about pulling a trans or motor out to access the converter. It is a significant task for many. How many “which cam or which rear gear” threads do you see answered with get a modern higher stall converter and it will be a Big Bang for the buck. But I bet most never do unless it’s out for another reason.
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The converter is probably one of the biggest tuning factors you can make other than significant engine modifications. But yeah you have to get at it and that’s not easy but then again nothing really is.
 
19DUSTER73 said:
Just curious but did the other 3 shops give a reason for the lower stall?
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No, they didn't.

My old converter was way too tight at idle and flashed to 3500, the new engine makes peak tq at 4500
 
33IMP said:
To be honest, look at a dyno sheet, and see how much more power you can make at 4500 compared to 3500. IF it dead hooks, I wouldn't be surprised by a tenth and a half (1/8).
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500ft/lb@3500
575@4,500

Seems like a pretty substantial difference
 
340inabbody said:
The converter is probably one of the biggest tuning factors you can make other than significant engine modifications. But yeah you have to get at it and that’s not easy but then again nothing really is.
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No doubt.
If you set yourself up correctly with a few accessories to get the car in the air and manage the trans, dropping the trans is a simple process, even by yourself. Probably doesn't take much longer than to R&R than an intake and carb depending on how your exhaust is configured. I plan on trying two different converters and then converting to manual and trying a couple different versions, so I'm configuring everything under the car for modularity.
 
For me, changing the convertor is an 8h job.

Drain tranny fluid
Unbolt the engine
pull the headers (you can't get to the bellhousing bolts without this step)
Pull radiator
Unhook all cables
Slide engine forward
Change convertor

reverse process
 
roccodart440 said:
For me, changing the convertor is an 8h job.

Drain tranny fluid
Unbolt the engine
pull the headers (you can't get to the bellhousing bolts without this step)
Pull radiator
Unhook all cables
Slide engine forward
Change convertor

reverse process
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You forgot about having coolant drain all over you and your workspace when you pull the header bolts. That part of a big block is MESSY!!
 
Demonx2 said:
You forgot about having coolant drain all over you and your workspace when you pull the header bolts. That part of a big block is MESSY!!
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Actually, the aftermarket head bolts are blind. That isn't the issue. YOu have to pull the radiator to slide the engine forward to get the converter out.
 
roccodart440 said:
Actually, the aftermarket head bolts are blind. That isn't the issue. YOu have to pull the radiator to slide the engine forward to get the converter out.
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Good point. I was recollecting my times pulling headers on my 69 Charger. Always a mess! And likely an 8 hr job as you state.
 
I also don't have a good reference for you. My avatar is a 408 with way less power/torque than your big motor. I have an 8" ATI Treemaster that stalls right at 5000 rpm. I love it and how it idles around like a normal converter but when you stand on it...hang on! Best 60' time is 1.51.
 
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