Big chamber vs small chamber

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Danny Humphreys, Dec 1, 2004.

  1. Mike Pavia

    Mike Pavia Member

    Joined:
    Feb 12, 2004
    Messages:
    144
    Likes Received:
    1
    Well said Benchracer.
     
    #21
  2. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
    Staff Member

    Joined:
    May 6, 2003
    Messages:
    6,393
    Likes Received:
    64
    gene, theres a million different ways to run these things. fuel/boost/compression/timing all those variables can be adjusted to compensate for the other. we tried 28 degrees once on meyer's car. wasnt pretty. not to say it wont work on another motor.
     
    #22
  3. NITROITCH

    NITROITCH New Member

    Joined:
    Jun 24, 2003
    Messages:
    404
    Likes Received:
    0
    Wow,,,Will did i miss something here?? Seems you were just posting your "expert" advise, with a good attiude and some experiance,,,,but how does it go to a pissin contest???? Hay, it's Christmas almost so let's all enjoy this time off before we start all over again. Man I thought with some time off like holidays and "RETIREMENT" life was a little more mellow. Guest not? Warren :)
     
    #23
  4. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
    Staff Member

    Joined:
    May 6, 2003
    Messages:
    6,393
    Likes Received:
    64
    gene,

    i in no way meant any of my responses as a slant to you. thats why i made my last post, theres a million different ways to run these things. i was just sharing some of what i've seen and thats all. i know if we put 28 degrees in jason's blown car we would hurt parts. thats all. the only point i was trying to make is 28 degrees will not work on every fathead fuel sys/ compression combo. not saying you're wrong, not saying i'm right.

    warren, as far as me being an expert, i'd have to disagree - i'm far from it. i'm still a student of the game. :cool:
     
    #24
  5. FAT HEAD JOE

    FAT HEAD JOE racer

    Joined:
    Apr 29, 2004
    Messages:
    80
    Likes Received:
    0
    i have a brand new 526in brad moter , brad told me to run the lead as low as 27 when i met him in gainsville , also gene terenzio was flying back in the eary 70s at english town and i mean flying! when most of you were still holding your mommys hand lol
     
    #25
  6. Norm Drazy

    Norm Drazy Jr. Dragster

    Joined:
    Nov 6, 2004
    Messages:
    29
    Likes Received:
    0
    The inaccuracy of mag drives is probably the single greatest cause of parts damage in blown alcohol engines. Anyone who answers the mag lead question without first discussing which mag drive is being used is doing the recipient of the answer a huge injustice. It may sound corny, but it is imperative that the spark plugs all fire at exactly the intended number of degrees before top dead center each and every time without unintended random fluctuation.

    My eye opener on this subject happened in 2000 at the Gatornationals. I had been observing random rod bearing hits in Jay Meyer's BA-5 alcohol dragster engine for several races, and had learned that this never seemed to correlate to a particular cylinder's having been lean, so I stopped chasing the problem with the port nozzles. Instead, I replaced the 1/2" diameter shaft in his mag drive with one that was about 13 times as stiff torsionally. Jay had been running 22 degrees of lead because he'd found that running 23 degrees hurt everything. What a difference! The car ran a low 5.50 and the engine parts all looked new. We bumped it to 24 degrees and with no other changes, the ET improved to something like a 5.48 with the same parts still looking new. On the last qualifier, we bumped it to 26 degrees, again with no other changes, and the ET improved to something like a 5.46. Will, were you with Jay then, and if so, how am I doing so far? It's been awhile.

    Anyway, Jay ran a string of 5.46 to 5.47 times, won the race on a holeshot, and never hurt a single engine part. In the end, I found that a 452 cubic inch 10:1 BA-5 with a 2.15:1 overdriven "D" PSI at sea level to 2000 foot elevation in fairly dry air can handle a maximum of 27 degrees of lead. You can get away with 28 degrees maximunm with this same combination in humid conditions. A 526 cubic inch BA-5 at 1.92:1 and a somewhat higher compression ratio can get away with 1 to 2 degrees more lead.

    I haven't found that a crank trigger offers any performance advantage over the internal trigger on a 44-amp MSD provided it is driven by an accurate mag drive. The internally triggered mag drive is, however, more reliable than the crank trigger. If it isn't there, it can't fail.

    I don't have as much experience with other engines, so I don't feel qualified to comment on them.

    Norm Drazy
     
    #26
  7. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
    Staff Member

    Joined:
    May 6, 2003
    Messages:
    6,393
    Likes Received:
    64
    With my limited FC experience, i didn't realize you could get away with more lead. see the student part above...

    like i was saying above, every car likes something different. norm is right on about the meyer story. granted i was cleaning oil pans then, and can take no credit for the idea, one of the great things about when i worked for meyer, i was able to see the tuneup changes and have explained what was going on, ask questions, etc. when norm went with us, i could bounce some of my hairball schemes off him, get told exactly why they would/wouldn't work. not to mention i think norm has enough knowlege you get somewhat smarter just being in the same pit as him, much less having him to explain certain things.

    back to the mag lead deal. on jason's car, we've tried more mag lead, and it just didn't seem to like it. with our first blower it liked about 26.5, with the first update we got, it liked 26, then with the blower we had this year it seemed to like 25. granted we run a touch more compression than 10:1. as i remember part of the meyer gainesville story was he had the lower compression as a result of running the gizmo the race prior. so with less blower/the new mag drive/ more timing made it really happy.

    as far as the fc timing issue goes, i'll have an opportunity to see that in the near future. i planned on starting at 26 and running m bearings, and finding where the point it's happy.
     
    #27
  8. NITROITCH

    NITROITCH New Member

    Joined:
    Jun 24, 2003
    Messages:
    404
    Likes Received:
    0
    Man, I am impressed with you, Will ! I never knew you were learnin all that time you were hangin in the pits??? I would always see you lookin for a meal or something to eat, like my Gumbo or Jambalaya. Even saw you "studying" a box or two of Twinkies,in Calaways trailer. Guess lots of calories can turn into smarts. :) So i'm gonna keep eatin too. All kidding aside I think your a "top student" of the game. WARREN DAUZAT
    P.S. Speakin of "Games" care to bet on "dem tigers of LSU" ???remember last season. lol lol
    You going to D4 banquet. we'll see you there.
     
    #28
  9. Mike Pavia

    Mike Pavia Member

    Joined:
    Feb 12, 2004
    Messages:
    144
    Likes Received:
    1
    How does 5.55@258 sound with a 526, only revving it to 9300 rpm.
     
    #29
  10. Norm Drazy

    Norm Drazy Jr. Dragster

    Joined:
    Nov 6, 2004
    Messages:
    29
    Likes Received:
    0
    Since Duane now runs an A-fuel car, it's probably okay to talk about this.

    He used to run a 4.310 bore X 3.9 stroke engine with very high compression ratios that were in the range of 11.2:1 to 11.6:1. Duane had been hurting a lot of parts until I suggested that he add a couple of degrees of timing in low gear and pull a couple of degrees out of it in high gear. He did the second part, which stopped the parts attrition, but he never got around to stepping on it in low gear. (Who knows whether or not it would have worked.) The lead numbers were interesting: 25 degrees in low and second gear, and 23 degrees in high gear. Yes, he used a torsionally stiff mag drive. His engine developed monstrous torque that demanded a very tall transmission ratio. At Englishtown, where it went 5.26 and 268.85, he ran a 1.56:1 trans with a 4.30 rear and Hoosier tires.


    Obviously, a high compression ratio deprives you of being able to run very much lead. The Grimes/Santos combination is at the other end of the scale in terms of compression ratio. Does anyone out there know how much lead it uses?

    Norm Drazy
     
    #30
  11. BOBBY MARTINDALE

    Joined:
    Dec 4, 2003
    Messages:
    74
    Likes Received:
    0
    MY DAD TOLD ME THAT OPINIONS ARE LIKE HINEY HOLES,EVERYBODY HAVE ONE AND THEY ALL STINK.MERRY CHRISTMAS EVERYONE AND HAPPY NEW YEAR.
     
    #31
  12. Doug

    Doug Member

    Joined:
    Jan 26, 2004
    Messages:
    154
    Likes Received:
    0
    Obviously, a high compression ratio deprives you of being able to run very much lead. The Grimes/Santos combination is at the other end of the scale in terms of compression ratio. Does anyone out there know how much lead it uses?

    Norm Drazy Yes
     
    #32
  13. Norm Drazy

    Norm Drazy Jr. Dragster

    Joined:
    Nov 6, 2004
    Messages:
    29
    Likes Received:
    0
    Gene, You'd think that all you would have to do is look to the TAFC class for the answer, but once again it's not so simple.

    The TAFC performance really never took much of a hit, as the Gasparelli family proved at the Pomona season opener right after the rules change. What I believe really happened is that prior to the 1.92 rule, virtually everyone was running transmission ratios that were WAY too agressive, ranging from 1.64 to 1.76. The rear gears were generally 4.56, with 36" Goodyear tires, and shake they did! In contrast, the alcohol dragsters were having good success with transmission ratios in the 1.56 to 1.67 range with 4.56 rear gears and 36" Goodyear tires. This was despite the fact that the alcohol dragsters were running 450 to 472 cubic inch engines with the blowers at 2.15:1 versus 500 to 526 cubic inch engines with the blowers at 2.25:1 for the TAFCs. By pure luck (or maybe the NHRA had this in mind all along ;) ), the reduced overdrive dropped the power curve right into the sweet spot it needed.

    Since I think the alcohol dragsters are by and large running the correct trans ratios today, reducing the blower overdrive to 1.92:1 would probably slow them down by a tenth of a second or so.

    Norm
     
    #33
  14. Serge TAD 182

    Serge TAD 182 New Member

    Joined:
    Jun 4, 2003
    Messages:
    61
    Likes Received:
    0
    Bonjour Norm Drazy.... (sorry , this is french speaking but Norm does speak french pretty good )

    Just to clarify Norm , Duane's 5.263 ET at 268.71 MPH in 2002 in Englishtown has been run with a 1.60 Trans Ratio , the corrected altitude was -169 at that time. The run before , they ran a 5.280 ET at 269.13 MPH . That s enough about those secret !!!!! It take a awesome track condition and a shakeproof driver to do those number ( I Think ). We will try to improve our LEARNING curve again next season , Very interesting to see your comments on this site and again I am sorry for my poor english.

    Serge TAD-182

    [ December 11, 2004, 06:55 AM: Message edited by: Serge TAD 182 ]
     
    #34
  15. Danny Humphreys

    Joined:
    Aug 4, 2003
    Messages:
    489
    Likes Received:
    0
    Thanks for the input guys, i'll file this in my cranium for later use.
     
    #35
  16. NITROITCH

    NITROITCH New Member

    Joined:
    Jun 24, 2003
    Messages:
    404
    Likes Received:
    0
    HAY SERGE, did you mean learning curve? "leaning curve" is very small radius before "kaboom time". lol lol :) Warren "cajun french speaking" Dauzat, Baton Rouge, La.
    p.s. I too enjoy reading and learning from Drazy's post. Hay Norm too bad you have enough time on your hands to post daily because you can't sell new screw chargers. Keep posting and developing great products.
     
    #36
  17. Serge TAD 182

    Serge TAD 182 New Member

    Joined:
    Jun 4, 2003
    Messages:
    61
    Likes Received:
    0
    Hay Nitrotich , that s why I always apoligise for my english , but that time it was a keyboard error . ''Learning''was the right word , and about ''leaning'' ask Norm , you dont have to do much of this on a PSI set-up. SORRY FOR MY POOR ENGLISH....

    Serge TAD-182
     
    #37
  18. Serge TAD 182

    Serge TAD 182 New Member

    Joined:
    Jun 4, 2003
    Messages:
    61
    Likes Received:
    0
    OH MAN !!!!

    Another misspelling '' NITROTICH '' sorry ''NITROITCH''

    Serge
     
    #38
  19. NITROITCH

    NITROITCH New Member

    Joined:
    Jun 24, 2003
    Messages:
    404
    Likes Received:
    0
    "fee pa sa" :)
    that's suppose to mean "don't do that" but I can't spell anything in french.......and almost nothing in english... lol lol
    Warren Dauzat
     
    #39

Share This Page