Coan Converter ?

Discussion in 'Race 400/430/455' started by Dubuick, May 20, 2008.

  1. Dubuick

    Dubuick CMDR Racer

    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?:Dou:
     
  2. DaWildcat

    DaWildcat Platinum Level Contributor

  3. Mike Nussell

    Mike Nussell Well-Known Member

    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
     
  4. Great Dane

    Great Dane Member

    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
     
  5. ric

    ric Well-Known Member

    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.
     
  6. Skyhawk

    Skyhawk Well-Known Member

    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.
     
  7. Clark Porter

    Clark Porter Team Headless Chicken

    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!
     
  8. Keith Seymore

    Keith Seymore Well-Known Member

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

    K
     
  9. GRIMM

    GRIMM Well-Known Member

    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. :TU:
     
  10. WE1

    WE1 Well-Known Member

    Steven:

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

    Dubuick CMDR Racer



    Thanks for the feed back I got a 9" 5000 stall on order from Coan so I hope it works out for $1050 :Dou: . Ill have in the car in time to head up to maine on june 5+6 so see ya up there.....:beers2:
     
  12. GRIMM

    GRIMM Well-Known Member

    Good buy, i think youll like it.

    My engine is together, waiting on the AED holley carb, and to install the fuel pump. :TU:
     
  13. stagetwo65

    stagetwo65 Wheelie King

    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. :TU:
     
  14. Jeff Peoples

    Jeff Peoples Platinum Level Contributor

    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.
     
    Gary Bohannon likes this.
  15. Buick

    Buick Ramin Ansari

    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.
     
  16. Tom Rix

    Tom Rix Well-Known Member

    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
     
  17. gymracer01

    gymracer01 Well-Known Member

    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.
     
  18. ric

    ric Well-Known Member

  19. Tom Rix

    Tom Rix Well-Known Member

    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
     
  20. Dubuick

    Dubuick CMDR Racer








    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
     

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