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1979 AMX Stocker update

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gremlin1945 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlin1945 Quote  Post ReplyReply Direct Link To This Post Posted: Dec/17/2016 at 1:08am
Originally posted by Class Guy Class Guy wrote:

Oh, well....

 Dwight, you still working on anything for a 290 combo?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Class Guy Quote  Post ReplyReply Direct Link To This Post Posted: Dec/17/2016 at 7:04am
No. But it's a long story.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote scott Quote  Post ReplyReply Direct Link To This Post Posted: Dec/17/2016 at 8:05am
Link to build thread on classracer.com :  http://classracer.com/classforum/showthread.php?t=60666
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pinballer Quote  Post ReplyReply Direct Link To This Post Posted: Apr/24/2017 at 10:05pm
All right! Finally, some passes down the Coles County Dragway 1/8th mile in mid April's test and tune to get some data.
  Was it slow? You bet!
  Did I learn a few things? Yep.
  Am I satisfied with it's performance? Yes, and no. How's that for vague?

 Here's what we got for now with this 258 2 bbl car at NHRA legal weight, (danged heavy!!), factory manifolds, and essentially a stone stock set-up.

 Pass 1--   Running into direct extreme gusting headwinds of 25-35 mph all day long, first run is at 65 degrees and partly sunny. Car is somewhat cold off the trailer, so we'll call this a shakedown pass. Left it in Drive and let it do it's own thing to get the juices flowing a little, noticed it shifted real early into 2nd. Big time hesitation off the line, and she slimes her way through at 11.65 @ 58mph . OK, we check things for leaks and anything else out of whack back in the pits, nothing found, and we prepare for round 2.
   11.65@ 58 mph .  60' was an eye-popping 2.59, couldn't get the line lock to work, so cleaned the tires off and went on up to the line.

  Pass 2--  Winds remain, we're up to 70 degrees outside now. This time I shifted the car manually from the 1-2 at 4500 rpm. Remember, this is a bone stock engine with 100K on it, so there's no high revving fancy piece here. The third gear shift wasn't forthcoming when I thought it should be, so I let off just a hair to make sure it would come in. It did.
  11.55 @ 58 mph.  60' = 2.48  Track still pretty green and not a great burnout.

  Pass 3--   Time to lean on this car now and see if it can stand it. 75 degrees out, and I let the car get clear up to 180 degrees before the run. I decided to make shifts at 4000 thinking the fall-back into the next gear would keep it more in the stock power band. Wrong move...the transmission revved on up to about 4500 anyway before a shift happened. Learned something here, so I guess we bring the shift point back up a couple hundred rpm again. I could tell the car hooked a lot better on this run, I was trying to get into the stock converter a little more at the line. There's still a hesitation going on.
   11.34 @ 60.24 .  60' = 2.46   Yeah, it was better. Wondering how much this constant wind is holding me back now!

  Pass 4--  Leaving the operating temp at 180 as last run was, 75 degrees out still. Shifting at 4200 to see what happens. Again, noticed it revs to about 4500 before the shift actually happens, so we're going back there on the next run. But the time slip was good, best of the day.
    11.24 @ 61.48   60' back to 2.46. Pretty stable. Guess the car likes the engine hot.  Pulled a plug after the run, they look a little too dark. We'll have to get to that later.

  Pass 5--  Pulled off the air cleaner with it's factory fresh-air ducting to the firewall to see if things would improve or not. Shifting at 4500 again, car at 180 degrees. Run felt pretty positive, but time slip doesn't bear it out. Slowed down some in both areas. Can't get a real good burnout going, the line lock decided not to work today, so we're foot braking it.
    11.36 @ 60.40 .  60'= 2.50.

   Pass 6---  put air cleaner and fresh air ducting back in place. Shifting at 4500 with car at 180 still. Wind continues to howl. Outside temp dropping just a bit to 72. 
     11.28 @ 60.48   60'=2.50.  I'd have to say the air cleaner and ducting gets to stay attached from here on, it obviously helps.

 Crunching the data: if we assume a 60' time of 2.46 as the new norm, the math on the final 4 runs works out pretty good. If the 60' is good, the ET is better in an appropriate amount and if it's off, it affects the ET accordingly.
  In 2016, on the one and only time run I got in the final fall session in October, it 60 footed at 2.42 on a well seasoned track and ran an 11.49 in Drive, so that was it's best 60' that I have records of to work with. In the ancient days, with the engine and trans in a fully street stock 80 Spirit I used to run back in the early 2000's, it's 60' time was in the 2.60 area with the crummy stock gears, so right now the 4.56's are apparently worth about 1.5 tenths off the line, even with the much taller tires compared to the golden days of 14" stock wheels and street tires.

  The baseline is established now, I'd have to say. Car does show a tendency to be pretty stable on the ET's if the 60' time is averaged out on those last 4 runs. She's bracket race ready at this point I'd say, but a LONG ways from the index of 9.04 that I need to run for my class. I'll gradually add in some Stocker pieces over the course of the year and do some tuning and keep posting as to what the improvements are. First order of business is to fix the line lock, and then play with the timing some.
 
 
NHRA T/SA '79 AMX
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlin1945 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/24/2017 at 11:34pm
Nice to see you out with the car. A few things.Of course these apply when you put the worked motor in. That motor doesn't want to see a lot of heat. I used to do my burnouts at 120 deg. and stage at about 130 deg  You're going to have to shift it at at least 5,000 1st to second and 5,500 second to third.I had 4.44 gears and ran a 26" tall hoosier tires. I used to clear the traps at around 5,700 to 5,800. Hate to say it but the only way to get the weight down is to take off all the AMX gee gaws and run it as a regular spirit. You'll pick up a bit of mph mainly because the AMX fairings cause more drag. And welcome to the world of having a slow stocker and dealing with head winds, tail winds and side winds.Wink

Edited by gremlin1945 - Apr/24/2017 at 11:38pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pinballer Quote  Post ReplyReply Direct Link To This Post Posted: Apr/25/2017 at 1:36am
Hi Ed,
No doubt it will be a whole new world of variables when it actually gets "Stock-ified". We're dealing with a 100 HP worn down smog motor with a stock torque converter for now, so I expect the car to be very slow for quite a while, but I'm a patient man. I also would expect stock rods and rod bolts to grenade in a hurry at repeated 5500 rpm runs, which is where the harmonics of a stock 258 crank go bad, so we're not going there. The graphs of what I now run say there's no power gains to be had up above 4500.
Yet.

Now I gotta argue with you a little. As far as the car's weight is concerned, it is currently at what NHRA tells me it has to be to run T with a driver in the seat-- 3020, and it actually weighs just a touch more. If I were to remove the plastic AMX flares and spoilers, which might weigh 15 lbs max, change out the grille and nothing else about it because I couldn't anyway, and call this thing a '79 Spirit, it would automatically change the natural class of the car into an R car. It would then have to weigh 2870 with me installed in the seat, so yeah, I'd be putting the car back on a diet, and probably me too to make weight. That's a -150 lb change which seems like a real good thing in drag racing. Most people would kill to get 150 lbs out of their race car! But--the index would now quicken from 14.40 in the 1/4 all the way down to 13.95, and the scenery of what's running in R class changes a LOT. Is 150 less lbs and a slight amount of lesser wind drag worth 4 1/2 tenths? I say no. My desktop dyno programs say no, not even close. Can I get enough air through a 300 cfm carb and 270 inches to run against 305 Nova's and other heavyweight small V8 4 bbl cars that are in R? Nope. The only hope I'd ever have of a class win is if nobody else showed up.

Right now, T looks pretty attractive to me as a beginner with limited funds. Might even try U sometime if the situation warrants it, that 14.85 index looks good! The only real scourge of that class is the 302 Mustangs and Mavericks with 2 bbls, and they're fast getting things evened up from the AHFS. There's some hope for the occasional AMC to sneak around in there and surprise people, like a certain '77 Pacer I know of.

Hang in there with me Ed, I'll get there. I do appreciate your concern and experience.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote idrambler Quote  Post ReplyReply Direct Link To This Post Posted: Apr/25/2017 at 12:21pm
Good Show Brian....you will get there....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlin1945 Quote  Post ReplyReply Direct Link To This Post Posted: Apr/25/2017 at 4:46pm
Brian, you still coming to Pa next month? I have a lot more things to run past you about the car.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pinballer Quote  Post ReplyReply Direct Link To This Post Posted: Apr/25/2017 at 6:30pm
  Yes I am still coming out there, it will be on May 6th. Looking forward to a visit with you that evening. You'll have to PM me your address.
 I'll have some news for you too when I see you.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pinballer Quote  Post ReplyReply Direct Link To This Post Posted: May/13/2017 at 11:12pm
   May 12th:  Happy to report we've cracked the 10's baby!  The index is only about 2 seconds away now. (laugh)

   Got the weather to cooperate and went to a Friday evening test session with the car over at the local 8th mile track  Perfect conditions were certainly a plus! Sunny, 70 degrees, and a slight tailwind. The temp gradually went down to 64 by the end of my runs over a three hour period.
  
    The only change I made to the car from last time was to retard the timing a couple degrees, on advice from my mechanic buddy. He thought I might have the car advanced a little too much to be doing it any good. OK, we'll turn it down a couple notches and test that way, it can't hurt. Whether the car's times responded some to that, or to the complete lack of a 30 mph headwind from last time's session is hard to say, but it did turn out real well for me. I could immediately tell the car pulled a little harder.
    The first run of the day on every car I've ever owned and raced is generally a throw-away just to get things livened up. This one is the same. If you recall, the previous session into that big headwind turned out a best of an 11.24.  This time the car went an 11.05 on that first off the trailer pass. Over 3 more runs, we worked that down to a best so far of 10.97.  Yay!  It's knocked off almost 5 tenths from where I began the year and I've spent nothing.
    The 60 foots, although real slow, are still pretty consistent, and the next three runs were like a wind-up clock. 10.985, 10.980, and 10.972 . MPH's were just as consistent: 63.37, 63.36, and 63.36 .  All told, this thing is just itching to go to the bracket wars as-is.  It might be slow, but it's deadly consistent! The driver unfortunately still needs some work, my lights with this slower leaving car than what I'm used to in the past are pitiful. It will take me a while to find the sweet spot again.

   The first major change to it I'm planning now is a torque converter I now have and possibly I'll put a lower geared 998 transmission in at the same time, just because it's convenient to do both at once. My apprehension is I know nothing about the trans, other than "it was rebuilt a long time ago" and never got put in anything.  I guess if it doesn't pan out, we'll freshen up the transmission that's currently in the car and put it back in to keep going. Such is the life of the drag racer...work, work,work--and no promise of a pay-off.

 
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