Help!!!! I mod my old SNP to RF and can't get the TEMP UP

Discussion in 'Reverse Flow' started by wild bill, Jun 14, 2014.

  1. wild bill

    wild bill Newbie

    16.5 DIA BY 34 IN cooking chamber with 17in long FB same diam.   Used Feldon's sp? calculator and it says need just under 30 sq in FB to CC opening.  At the other end I have a 6in by 16 in opening.  about 200 degrees is all I can get, Captain. 

    Where have I missed the boat???


    THANKS for your help.

  2. lendecatural

    lendecatural Smoking Fanatic

  3. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Below is a picture of the theory behind the Firebox...... 2 air inlets make it work well...... 30 sq. in. FB/CC opening will work OK... 6 x 16 opening at the end of the RF plate will work.... The exhaust stack should be about 3" ID x 20-30' tall....

    Last edited: Jun 14, 2014
  4. okbill

    okbill Newbie

    can no longer login with original account, so I made a new one to say THANK YOU gentlemen for your reply.  Will try the extended chimney next.

    Thanks again,

    OKBill, I mean WildBill
  5. wild bill

    wild bill Newbie

    got the chimney extended to about 26 inches and gained only 30 degrees.  I made a 'fire' basket to put the fuel in.  Should I try raising the basket???? 

    Making mods to they to even the heat out and losing over 100 degrees in heat is not making my weekend. 

    grate is just shy of 4 inches from the plate. 

    Thanks again for any replies.

    Wild Bill
  6. lendecatural

    lendecatural Smoking Fanatic

    Do you have a football shaped opening from the fire box to the cook chamber under the RF plate? If so, what is the width and height of the opening? Is it possible for you to post a picture of the mods you made?
  7. wild bill

    wild bill Newbie

    3+ by 10    More of a rectangle with two corners rounded off.

    not able to do pix at this time.

    What distance should the grill and the plate be???

    Thanks again
    Last edited: Jun 15, 2014
  8. lendecatural

    lendecatural Smoking Fanatic

    Your 4" above the plate for the grate is fine. I agree with Dave, it seems like your vents are not allowing heat to flow easily into the cooker from the firebox. Add an intake like the one Dave put in the post above and see how that does.
  9. wild bill

    wild bill Newbie

    Added the inlet and the temp rose quickly.  However, it stalled at about 240-250 and burned the fuel in no time.  The way it came,  could get about 250 with about 1/2 to 1 inch inlet opening and the amount of fuel (lump hardwood charcoal) I used in my test today would last a couple of hours.

    Since the set up now requires air inlets to be wide open it stands to reason the fuel would burn a lot quicker.  I do not understand how others who made these mods to this unit do not have the temp problem. 

    May just cut out the chimney and put it back and remove the plate. 

    Any other ideas???  Want to thank DaveOmak and LenDecaturAL for your time and sharing your knowledge with me on this project.

    Thanks again,

    Wild Bill
  10. lendecatural

    lendecatural Smoking Fanatic

    How high above the bottom of the cook chamber is your RF plate, and how big in diameter and tall is your exhaust? Do you have a hard 90 degree angle in the exhaust?
  11. okbill

    okbill Newbie

    Won't let me login as Wild Bill again, so....

    Plate is about 4.5 to 5 in from bottom of CC.  Extended the 3in diameter chimney to 26 in.  It has about a 35 degree bend in it approx 9 in from cooking chamber. 

    Thanks for hanging in there with me.

    Wild Bill

    aka OKBill
  12. dockman

    dockman Smoking Fanatic

    Is there a chance you simply are not using enough charcoal? My Oklahoma Joe will not get good heat unless I load it up with a good amount of charcoal.
  13. lendecatural

    lendecatural Smoking Fanatic

    So the chimney runs horizontal for 9" out of the cook chamber and then turns up? One of the guys had a problem with an exhaust that was running horizontal and had a hard turn, didn't flow well, he ended up putting a box on the end of the fire box end of the cook chamber and running the exhaust straight up, it flowed much better. Here's a link to what I'm talking about.  if the link does not take you to the right post, his exhaust is being built on page five of the thread.

    By any chance did you check your thermometer to make sure it is reading accurately? There are lots of problems with them reading bad and guys chasing their tails when the thermometer was off to the low side. The RF plate position seems to be good and you have a good 30 sq-in where the smoke turns up to the grates so it's starting to smell like a restricted exhaust or a bad thermometer. Does your cook chamber door leak air?
  14. wild bill

    wild bill Newbie

    This is like logging in to this sight... can now login as Wild Bill again.

    using same amount of charcoal as before the mods...air flow seems to be very good, since the fuel burned up so quick.  the chimney is vertical.  it comes off the cc with a slight slant back for about 9 in and then has about a 35 degree bent to vertical.  There are no sharp bends in it.  The heat is just not going into the cc as it did.  can put my hand on  the cc.  it was a lot warmer today. 

    before the mods, I would open the chimney up about half way and use the air intake to control the heat.  could shut it off to 1 in or less and maintain the heat.  225 to 250+ open it up some and 300+ obtained. do not remember opening it up all the way to see how hot it would get.  only thing i can think of is we have the smoker turned 90 degrees from its usual position.  moved it next to the shop instead of moving welder, tools, etc over to the smoker.  Was very windy today and that may have had something to do to the fast burn.  But I have the air intake wide open and added another 2.5 in opening. 

    Thanks for hanging in there with me.  will try another run with the smoker turned 90 degrees to see if that has an effect.  The way it is now, i feel i have no control over the temp.  hope it is not raining or about to rain when I get home tomorrow.

    Wild Bill

    if you think something is impossible to happen, it has probably happened to me.  LOL
  15. wild bill

    wild bill Newbie

    I give up.  think the problem is opening between fb and cc.  raising the chimney to 26 in helped.  raising it to 30 in did not seem to do anything.  adding a 2.5 in dia air inlet to fb helped raise the temp, but not to a satifactory level.  it also came a cost of burning up fuel at a very rapid rate.  (windy day or calm).  raised charcoal basket and this did not seem to do anything.  opening at the opposite end from the fb from 3in to 6 in did not seem to be any difference.  Will get out the welder, grinder, and cutting tool this weekend to change it back.

    Positive take home for me is I found out I do not need a rf smoker to smoke meat after all.  not to say my next smoker buy won't be a rf smoker.  just saying i can wait.

    once again, would like to thank everone who pitched in to help. 

    Wild Bill
  16. lendecatural

    lendecatural Smoking Fanatic

    Is there any easy way to make the FB to CC opening bigger? Glad to try and help a fellow meat lover. Good luck either way you go!
  17. wild bill

    wild bill Newbie


    YES!!! My son and I came to the same conclusion.    We angled the plate that we shut the FB to CC with more and started the bend at about the to of the opening..  opened the other end of plate to 8 in,  6in may work as well.  Had the chimney at about 26 in high and completely closed off the new to air inlet.  BINGO!!!! hit the 300 mark and began to adjust air intake to see if we could lower the temp and hold it.  275 then 250 then 225 and 200,  air inlet opening about what it was for these temps before the mod.  weld on the chimney extention and the 2.5 in inlet I put in and I think we are read for some SMOKIN' Q!!!!!

    Thanks again for the help!!!!!

    Wild Bill   aka OKBill
  18. lendecatural

    lendecatural Smoking Fanatic

    Great Job! I'm glad you found a way to get it opened up, it seemed like it would be less work than taking all the mods back out. Glad to help and anxious to hear how you like it when you finish the first smoke!

Share This Page