Coan Converter ?

[Dubuick]

Anyone run Coan Converters? just looking for some feed back on there stuff? looking to buy a converter talk to them today and he sounded like he new about buicks....I was think ing of going to a 9" and that is what Caon suggested ? Running a 8"ati right now but I think it is a little lose for my set up now and they told me that a 9" would just slow the car down and the 8" couldn't get any tighter?

[DaWildcat]

Some good discussion here... http://www.v8buick.com/showthread.php?t=121458

Devon

[Mike Nussell]

I bought a Coan trans and converter from Mike Phillips at AM&P. He built my engine,so he sent them the dyno sheets and specs. Haven't got it together yet,but you might ask him,as he has been runnning them for along time. I am sure everyone has their one opinion. Mike Nussell

[Great Dane]

Mike
Coan does a good job for the Buick guys I know running them,I have an ATI 9" but would like to get a Coan built to try when I get around to it.

Gary Kubisch

[ric]

Expensive...BUT well worth it. Switched to a Coan 9" 5,000 stall from a generic 5,500 stall 9" convertor (I will not mention names as it may get into one of those pissing matches on who's is better). I picked up a SOLID 10th in the 60 foot times on every pass! She dropped from 1.35's to 1.25's. Lost nothing on the top end! Crossed the eyes at 7,000 rpm's, with my Coan, I got the same results on top with my old one crossed the eyes at 7,000 rpm's.

Overall my et was lowered and mph picked up. When I ordered it I faxed over EVERYTHING on my car soup to nuts, head flow data, engine specs etc. Also faxed over the dyno sheets and everything about the car.

Wheels up? You bet ya. My avator was taken at Norwalk on one of the passes after I switched to the Coan.

[Skyhawk]

We have a Coan in the Skyhawk for 8 years now and am very happy. We have been using Ultimate Converters in a few of our others cars and other club members cars and so far so good. Lenny at Ultimate knows his stuff and his shop is right in CT. Give him a try if you like and tell him I said hi. He is on vacation this week though.

[BuickNut455]

Talk to Craig at Coan.....he has worked with many fast Buick guys.
Dominick

[Clark Porter]

First week out with 9" Coan (replaced a 10" ATI treemaster)
Picked up at least a tenth in 60' and et and probably 1 mph.
After I learn how to launch it, I suspect to see more improvement. It seems to work well. See you Mass guys up here later!

[Keith Seymore]

I have always run Coan and am very happy, not only with the performance but with the durability and the customer service.

K

[GRIMM]

Got a coan 10" Maximum Performance converter, 3800-4000 stall.

Havent run it yet, but it sure looks nice, and they are great to deal with.

[WE1]

Steven:

You already have your engine together, running and dyno'd? What were the numbers?

[Dubuick]

Originally Posted by Clark Porter

First week out with 9" Coan (replaced a 10" ATI treemaster)
Picked up at least a tenth in 60' and et and probably 1 mph.
After I learn how to launch it, I suspect to see more improvement. It seems to work well. See you Mass guys up here later!

Thanks for the feed back I got a 9" 5000 stall on order from Coan so I hope it works out for $1050 . Ill have in the car in time to head up to maine on june 5+6 so see ya up there.....

[GRIMM]

Good buy, i think youll like it.

My engine is together, waiting on the AED holley carb, and to install the fuel pump.

[stagetwo65]

I have two Coan convertors, an 8-inch 5600 stall and a 9-inch 5500 stall and I've run them since the mid-nineties. Nothing but good results with either one.

[TORQUED455]

Coan here too. I worked through Mike @ AM&P to get one for my set up.

[Jeff Peoples]

I ran a Coan convertor that I purchased through Automotive Machine & Performance. I was 100% happy with it! I sold it to Shane Dillinger a few years ago, and his car picked up considerably. In fact, I don't think I've ever heard of anyone that was unhappy with a Coan convertor.
Call AM&P.

[Buick]

I run a Coan and love it.

I think Rick Crawford had some issues with them not being able to tighten the convertor up enough for his combo.

[Tom Rix]

If you posted et of 10.05@132 is correct I would say your convertor is more than tight enough, you should be in the high 9.80's in good air with that mph.

You can figure convertor slip with the following formula but you must have an accurate tach (most are off) and know your tire circumference going through the lights. In a BB Buick in the high 9's low 10's slippage should be some where between 8.8-9.5% if combo is optomized for et. Coan makes a great convertor as does ATI. I run tight ATI 8" in my 3 cars and slip is 8.9-9.4%.

% slip= 100- (mph x rear ratio x 105,600) divided by (rpm x tire circumference)

Good luck!

Tom

[gymracer01]

Tom, thanks for the formula. I run an Autometer Ultimate II tach and according to it I'm at about 12% slipage but this formula has me a 8.8%. I run a 8" ATI that is getting very old. It was a transbrake convertor that Charlie Evans had built back in the mid 90s. I have always ran it footbrake. According to the Tach data it hooks from 4500-4700 depending on transmission fluid temperature. I'm thinking of sending it back for freshening but not sure if I need to change anything. Since I changed to the TA Stage 2 heads my 60' has fallen off .04-.05, I thought I may have lost some bottom end torque and thought of changing the convertor to make it up. I cant' lean on this short block much as it is not strong enough to take much beating. I shift about 6000, and run 6350 across the finish line. Tom you have any ideas? I ran a best of 10.25 @ 129.77 at 3370#s at Bowling Green during the Nationals.
Jim N.

[ric]

Here is a good link with all formulas

http://www.tciauto.com/Products/Tech...culators.asp#4

[Tom Rix]

Ric,

Thanks for the link, makes it easier to calculate. I've always wondered if they take into consideration "tire growth" on the top end or not? My radial slicks don't grow like a bias ply and by just changing the circumference an inch makes a huge difference on slip %.

Thanks,
Tom

[Dubuick]

Originally Posted by Tom Rix

If you posted et of 10.05@132 is correct I would say your convertor is more than tight enough, you should be in the high 9.80's in good air with that mph.

You can figure convertor slip with the following formula but you must have an accurate tach (most are off) and know your tire circumference going through the lights. In a BB Buick in the high 9's low 10's slippage should be some where between 8.8-9.5% if combo is optomized for et. Coan makes a great convertor as does ATI. I run tight ATI 8" in my 3 cars and slip is 8.9-9.4%.

% slip= 100- (mph x rear ratio x 105,600) divided by (rpm x tire circumference)

Good luck!

Tom

If you run my numbers it come out at 13.9% it run 132 in great air last year .last time out it went 10.07 1.36 60' @130MPH

[Dave Mongeon]

Tom I don't think there's any allowance for tire growth , anytime I check mine the calc comes out tighter than I see on datalogger.
Dubuick How much gear do you have in the car?
It may want more . Like Tom suggested, My 69 ran 9.80's at 132
Best 60ft was a 1.29. You may drop et with no mph change by changing gears , Your finish line rpm probably won't change that much either as the converter will become more efficient.
Dave

[Jeff Peoples]

Dave is right. The data logger in my old race car told me the same thing. Convertor slip will change when you change gearing. When my my car was running mid to high 9s, I tried 4.56, 4.30, and 4.11 gears. The finish line rpms did not change as much as the calculators predicted. Although the exact numbers are fading in my memory, I believe the 4.11s gave me about 11% slip, the 4.30s gave about 9%, and the 4.56s gave me about 8% slip. All of this with the same motor and Coan convertor (4600 stall, around 6500 through the traps).
As far as tire growth, I also believe that the formulas don't account for it. A call to your tire manufacturer may help here. Until you really get up there aound 130 mph or more, I doubt if tire growth accounts for much. I would also expect that 32" and 33" tires will grow more than a 28" or 29" would.
As mentioned in an earlier post, the new radial slicks do not really grow at all.

[alvareracing]

I was in line to get a Coan 9" but after a few weeks of waiting the stator they wanted to use for my application they didn't have and Craig was honest to say he could not built it. From that alone I WILL buy my next one from him for true honesty. So I was talked about PTC in Alabama (performance torque converters) I was running a TCI 8" and I had over 18% slippage with best of 1.43 60 footer and 132 mph. I tried PTC 9" and we got down to 1.37 60 ftr and 2.5 mph in the 1/8 and 3 mph in the 1/4 with about 3-400 rpms down. But still have a 10.2% slippage, a best of 9.80's at 136 mph Now I have another custom made PTC 9.5" an half inch bigger and hopefully get the slippage down another 5%. I should crap my pants with these one if it leaves like we think it should. So far I have had good luck with PTC but will see next time out. I guess one day I could try a Coan to really compare. I might just borrows MIke Nussells and see what it likes!!! ps: I'm the converter trying fool I can change them in my sleep, at the track, on the trailer, anywhere, just make them better and faster and I'll try it.