Newbie question

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Money Shot, Apr 13, 2009.

  1. Money Shot

    Money Shot Member

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    I am very new to Blown Alcohol. I have run nitrous for years and recently made the switch. I have a 565 18 degree Big Chief Headed BBC 13.1 comp with a SSI 14/71 Hi Helix Retro Blower turning only 15% over with a Enderle BAU injector. I have a 110 pump. Spark Plugs are NGK R5671-10, ignition is MSD10 with crank trigger set at 28 degrees total advance. My heads are old nitrous heads that have a massive port volume 500cc and valve area (2.6 int)

    I have made a few passes and always seem to be lean. As soon as I hit the throttle under load its almost like Im against a rev limiter. Motor revs great when not under a load. I am running a .125 main, hat nozzles are 6 44's and 2 46's. Port nozzle pressure is 35lbs jets are 42,42,44,44,46,46. Hi speed is a .075 set at 65lbs. My program says that I should be pig fat but Plugs continue to look lean. Pump has been flowed at 13.1@4000.

    As I stated earlier I am very new to blown alcohol and any help would be greatly appreciated.
     
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  2. Mike Canter

    Mike Canter Top Dragster

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  3. jody stroud

    jody stroud ZOMBIE Top Dragster

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    What stall convertor are you using? Did you have a chip in the two step when you went down on the transbrake? If so what was your two step limit? What do have your k-valve leaking down at? Also 13.1 is alot of compression for a blower motor, it will limit the amount of boost you can make without detonnating. Most of us chevy blower guys run about 11.1 to 1 comp. You may have a bad chip in your two step, just don't be tempted to do the old trick of removing the chip and flatfooting the throttle in low with the tbrake on to find the convertor stall, it may wreck your tranny. It's better to footbrake it and leave at idle and see what it flashes to on your computer to check your stall. A convertor that was tight for a NOS car probably won't be tight enough for a blower motor. Give us some incrementals of one of your better runs and some data from your computer, if you have one. Also some spec's on you car. Jody Stroud
     
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  4. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Forgot to say, Mike Canter's tech tips on reading plugs is top notch!!!! Thanks Mike! Jody Stroud TD9325
     
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  5. Ron C

    Ron C Jr. Dragster

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    10 is a pretty cold plug to start out tunning on. You might switch to 9's and be able to read the plugs better.

    Blessings..........Ron.
     
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  6. Ken Sitko

    Ken Sitko Super Comp

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    Just my opinion, I think the ports might not be opening, or at least they are very restricted. 35 lbs poppet pressure for the ports is way too much, try dropping it down to 11 lbs. Also, blank the high speed (you can always start out with a 50 pill later if you need, and make the main jet an 80. If it was me, I would also change the hat nozzles to 52's. The 110 is being stretched to the limit for the cubic inches you have, at least if you make these changes you might have a chance of having enough fuel in the motor.

    You might be lucky that it is soooooooooo lean; it is not making enough heat to burn anything. I have been there.

    Ken Sitko
    Sitko Family Racing TAFC
     
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  7. Dave Germain

    Dave Germain New Member

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    13 to 1 compression is scarey high. Its probably a good thing it didn't run real good. Could have easily detonated the bearings out of it. Dave
     
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  8. Mike Canter

    Mike Canter Top Dragster

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    He is only at 15% OD. If he keeps fuel in it and doesn't advance the timing he might get away with the high compression. We run 12.5 and up to 12.75:1 with the Promods at the NHRA mandated 20% OD.
     
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  9. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    gap?

    what are you gapping your plugs to? Should be gapping them around .016 or so. excessive plug gap will do what you're describing. if someone else is gapping the plugs, make sure they aren't looser than you think.

    make sure the barrel valve spool is installed correctly. at wot, you should be able to look through the inlet to the outlet.

    i've seen a plug left in the main fuel line seep enough fuel by to idle and rev on the jackstands, but not enough to launch off of or even enough fuel to burn itself up.

    if you have a filter installed, check it to make sure it's not clogged.

    make sure you don't have the main fuel line collapsing or the suction line collapsing somewhere.

    it also may be sucking air somewhere and cavitating.

    maybe the pump is dead?

    don't have much experience with roots, maybe rotors installed incorrectly?

    problem could be on the ignition side, but hard to blame the chalked plugs on that.

    seems to be a major problem in the fuel system....somewhere it has a delivery problem. if it was too lean it would haul ass for a little while until it blew up. i find it hard to believe you got it so lean it won't even launch. i know of one pro mod racer's roots tuneup had a -6 line with a 20 lb check, no jet. it would haul ass until it blew up.

    however cavitation or fuel delivery problems will cause the car to 'surge' rather than act like it's on the chip. if you're running a digital box, i've seen the high voltage side of the tbrake solenoid backfeed through the button causing the ignition box to keep the motor at the two step rpm.
     
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  10. Mike Canter

    Mike Canter Top Dragster

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    I think you are all jumping the gun as to the car being lean. To an ex-nitrous guy who just switched to a blower reading spark plugs with clean porcelein (no fuel ring) means the car is lean which is not so in a alky blower setup. Sorry but you guys need to slow down and wait until you get some more info.
     
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  11. Money Shot

    Money Shot Member

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    I have read your article and it has been very helpful. My plugs are white down two to three threads. The strap is blue and starting to melt. EGT's at idle are between 500 and 600. 1200 at finish line. Best pass only footbraking has been a 4.79@150. Motor doesnt seem hot though.
     
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  12. Money Shot

    Money Shot Member

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    Wow....Thanks for all the replys. My best pass has been a 4.79@150mph. 1.17 .60ft. Poppin and bangin. EGT's look good at 500 to 600 at idle and 1200 at WOT. Ill replace the chips this weekend and try it again. Ill also fatten this thing up and decrease my port poppet to around 20 to 25. Car is a tube chassis 1986 Vette weighs 2650 with driver. Thanks again.
     
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  13. Bob Meyer

    Bob Meyer Comp Eliminator

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    Mike; give me some more guns and a few canons to jump over........

    I'll go with Ken Sitko as a dead nuts starting point.
    Without my Jetsize here, and an old head to run the numbers in, his info sounds like less than 8.5 gpm. @ 8000. :eek:

    But, I've been wrong before, and of course my standard disclaimer...
    I'm just a welder. (who used to have a signature here)
     
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    Last edited: Apr 13, 2009
  14. Alkydrag

    Alkydrag Sr. Dragster

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    Lean, lean, lean. At 15% over, you have enough pump. But from what I can see right out of the gate, your hat nozzles are too small. That shows in the EGT's. 500-600 is too hot at idle. 400-500 is more like it. We ran the same port nozzle size in our 427 SBC. More compression, bigger motor, more fuel. You need more area in all nozzles. Since your new to BA, I would cap off the high speed. 35 on the port check is a boomer waiting to happen. Ken is right, you could be so lean that the plugs will give you a false reading, I've been there myself.
     
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  15. Money Shot

    Money Shot Member

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    Thanks a ton for all the info. Ill fatten this thing up, change the port poppet and change the hat and port nozzles. I appreciate the info.
     
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  16. Bottlefed

    Bottlefed New to Blowers

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    Just a newbie suggestion here,

    My blower experience is short but I have a fair amount of BBC nitrous experience and with the chief head and this compression and stroke and not being dead on with the tune-up I think you have been lucky so far with not hurting it. When you go through the rest of the suggestions which have all been excellent ( bringing in ports sooner, plug gap 15-16, Blank the high speed and come back to it after your base jetting is correct, egts high at idle) the only other thing that I would add is that the chief heads have a pretty quick burn ( although they are nitrous heads and have probably been softened in the chamber is a big help) I would suggest when you go back to the track you start out with less timing, there will be plenty of time to put it back in when you get it dialed in, and as you ease back in on the timing don't forget to add a little main jet, as unlike a nitrous plug that you clean up and leave alone for the most part, you will need/want to add fuel as you add timing on a blower app.

    Another thing to check is that you have a big unobstructed vent (at least 1/2 id) in the fuel tank as this will affect flow in a blower app.

    R/G
     
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    Last edited: Apr 14, 2009
  17. eli

    eli Banned

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    You wrote port nozzles, 42 42 44 44 46 46 that's only 6 I assumed that you have a progressive nozzle set up so i figured that you have two more nozzles @48, if thats right, you have more than 1/2 the fuel going to the port nozzles,:eek: you should have 70% going true the blower and 30% to the ports, you are pumping hot air into the motor the way you have it, if you tell me what nozzles you have in the last two cyl i will tell you what nozzles you should have, today is the 14th, I'm going on vacation on the 17th if you get back to the post by the 16 I'll get it done for you, if not then after the 27th. Need to know what barrel valve you have. Gene Terenzio Sr.
     
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    Last edited: Apr 14, 2009
  18. Money Shot

    Money Shot Member

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    Port nozzles are 42,42,44,44,44,44,46,46. My engine has a custom sheet metal intake the has the "pie" directly centered in the intake. So the blower is centrally located on the engine. I bought a complete BAU assembly from Good Vibrations that has the Nitro B/V set at 72% leakdown. Thanks again for all the help and advice.
     
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  19. isracing

    isracing New Member

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    Tons of great info here, I will have to start my own thread with my delimas of the outing last week and lack of performace my team experienced once I get all my numbers together...


    But for Will, I started reading your article about plugs, what about for people who run 1/8th mile. I was able to get some good info off my plugs, but am I really getting the full story? Can you provide a little more insight about going 660' rather than the full distance and how that affects your tuneup and plug readings?
     
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  20. Mike Canter

    Mike Canter Top Dragster

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    Will didn't write the article on plugs. I did. We tune the plugs to look the same in a 1/8 mile as we do in a 1/4 mile. You have to have two tuneups. One for each type run.

    Regards,
    Mike Canter
     
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