S/P 400 vs Std 400 with Coan converter

Discussion in 'The "Juice Box"' started by 6D9, Nov 29, 2006.

  1. 6D9

    6D9 Well-Known Member

    Ok....I know this has been beat to death but I think my set up might be a bit different. The vehicle is a 69 Camaro with a 408 sbc. Right now i am running a fixed pitch TH400 with a 3500 stall. The converter will flash 3800. I also just installed a G/V overdrive and have 3.55 gears. The converter in the car now is a BTE 10". How do you think a 10" or 11" Coan converter would do against a S/P 400 overall. Track/street/highway??

    Car specs:

    408 sbc
    AFR 195 heads...10 to 1 comp
    236/242 solid cam..501/510 lift 110 lobe
    RPM air gap
    750 Holley
    1 3/4" long tubes
    2.5" mandrel x pipe 40 series flows
    3.55 gears
    26" tire
    G/V overdrive
     
  2. D-Con

    D-Con Kills Rats and Mice

    The overdrive would likely cause a fixed pitch converter stalled at 3500 to slip alot...unless you plan on driving 140

    I will guess peak torque will be at about 4000 rpm; a tri-shield V/P converter will probably flash to around 3200 in high stall. Maybe lower depending on the torque output of your engine. You will lose some at that track, but gain alot on the street/highway because of reduced slippage. I would say you are a good candidate, but your ET's will suffer some.
     
  3. 6D9

    6D9 Well-Known Member

    Thanks for the reply D-con. The car right now at 60 mph is turning right at 2475 to 2500 at 60 mph. The rpm calculator says without slip I should be at 2150. I talked to Coan today and he felt there 11" prostreet would be quite a bit tighter than the 10" I have now. He said it still should flash right at 3000 rpm. Its a tough choice what to do. One of the main things thats got me worried about the S/P is there are very few experts with these units and none of them are near me in any way. Keep the opinions comimg guys!
     
  4. D-Con

    D-Con Kills Rats and Mice

    Tri Shield is in Minnesota. CKPerformance is in New York area. PAE in Texas. i would talk to at least 2 of them before buying...
     
  5. norbs

    norbs Well-Known Member

    WHen you say 2500 is this on level ground, how about going up a slight grade, no way its gonna be 2500. With those figures your at about 16% slip, that tranny must be running really hot on a highway drive. From what i have read the SP converters should not slip more than 5% under wot conditions. Also if you need more stall, just get a higher sp converter. They can go up to 5000 rpm if needed. Your best to give PAE a call and he can explain to you how his converters work. They are a bit heavier in weight that is a fact.
     
  6. 6D9

    6D9 Well-Known Member

    The 2500 rpm is on flat ground . I have yet to get it on a slight uphill but I am sure it would go up a bit. As far as cooling goes I just got the gauge but its not hooked up yet. I do have a 32K gvw tranny cooler in it as well a aluminum finned deep sump pan. The more I think about it the only real way to fix it is to either go with a real mellow 2200 stall or go S/P. The switch pitch is sounding better and better all the time...... :3gears:
     
  7. norbs

    norbs Well-Known Member

    When mine comes in, i will let you know how it works. :TU:
     
  8. 6D9

    6D9 Well-Known Member


    Cool, Keep me posted ! Did you go with a PAE,TSP or CK?? What converter ?? Thanks!
     
  9. norbs

    norbs Well-Known Member

    PAE as far as i know, they are the only ones making the steel stators for these.
     
  10. 6D9

    6D9 Well-Known Member

    Anyone out there using the CK performance switch pitch Th400??
     
  11. D-Con

    D-Con Kills Rats and Mice

    He (Chris Kokonis) hangs out at the turbobuick.com transmission site, or did anyway. He seems to have a pretty good rep over there last I knew.

    The only onverter that I know has furnace brazed parts is the TSP, it's something to ask about before buying anyway.
     
  12. 6D9

    6D9 Well-Known Member

    I called Jim(TSP) and he said he was out of converter cores. Kinda sucks these things are that hard to find or they dont make "new" ones.
     
  13. D-Con

    D-Con Kills Rats and Mice

    Bummer; I guess I'll be holding tight onto the ones I have left...
     
  14. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"


    The core he needs is the 12" ST300 converter. Search around, bet you can find some. Look in Hemmings. I have one of TSP's converters. I love it. :TU:
     
  15. 6D9

    6D9 Well-Known Member

    Looks like Pro Torque makes the converters for CK so I will give them a call and see what kind of stock if any they have.

    How do you guys think the high quality say 3000 stall(Coan/ATI) will couple at 2300 rpm as compared to the s/p in low stall??
     
  16. norbs

    norbs Well-Known Member

    have you tried to Contact, JIm at PAE? But they still take a while to get. Not sure how your Coan will work? Will they give you an exhcange if you don't like it?
     
  17. 6D9

    6D9 Well-Known Member


    No not yet...I am kinda unsure of if I wanna go with the 4000/1400 that PAE sells. I think 4000 is a bit much for my combo as well as 1400 to tight if I wanna leave it in low stall. The one CK sells is 1800/2800 and TSP's is 1800/3200. Both companys say anything over 3200 in high stall you are just losing to much efficency. I dont have the Coan yet and am still shopping around to see what I want to do. I just put a temp guage in my car today so I plan to get it on the road and see what the temps are like with my current set up.If anyone else has any input I would love to here it!
     
  18. norbs

    norbs Well-Known Member

    Are we talking about efficiency in high stall mode or low stall mode or both?
     
  19. 6D9

    6D9 Well-Known Member

    High stall
     
  20. norbs

    norbs Well-Known Member

    Doing some math, i am coming with a figure of 9% in my s/p setup, in low stall mode. But i'll know better when i get my datalogger hooked up in a few weeks, as it will show mph vs rpm. My gps maybe not be that accurate, and i am trying to maintain 60 mph on a flat grade in OD.
     
    Last edited: Jun 3, 2007

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