Drag Racing Discussions > Front Engine Dragsters

violent shake middle of pass

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LaneM:
wow  all you guys just gave me awhole lot more to think about and look at..I did notice it has loosened one front motor plate bolt..I am fixing to pull the motor and trans out next week and recert a soon to expire flexplate and seatbelts so now I will for certain go over everything to make sure I have no cracks anywhere that thought now is going to cause me some loss of sleep til this is checked out Im still hoping for something tire related to cause the shake but this is a new ride with new bugs and I am new to passing the 10 second mark from my old door car to this..thanks for all the advice everyone.

LaneM:
so now after reading your posts I had to go out and do a quick check for broken parts..well jon you called some issues..what I just found now without getting to  deep into it was a broken weld on cross brace at the nose(where my ballast sits) then both left and right rear engine frame weld tabs are snapped off which also as I can see from the paint marks has let the engine and tranny slide about 1/4 inch forward in the frame..well I certainly have some issues..like I had mentioned this is a new ride that I had gotton from the guy who built her who claimed to have only made 3 passes with her..his best claimed time was 7.29 in quarter in florida..I have made 9 passes but only stayed in throttle the full quarter most of the way 1 time which ran a 8.68  ....my history in car was 2 full quarters out of 6 passes for licensing which I just stayed in throttle hard til 1/8 so as to do the 9.99 for license(ran a 9.40 and 9.20 something)then when I went back I did three full runs..first I had bad shake(oh I had shake durning license full passes also)so I got out of it at 1/8th..2nd pass had a car next to me so I ran him down..it was ok but my attention was on him not the car..3rd pass was solo again and at 1/8 so violent it deployed chute so I of course was out of it then..so..this is a whole new experience..long side from story is the guy I got this from said he belieaves this motor is around 1200 horse..I don't know haven't seen dynos just know it pulls non stop..Im running 32 nossels with a 95 pill still rich and timing at 38.(Was told from mike at alky diggers these nossels were likely what I need here already went from 100 pill to 95..was running 35 nossels and 110 pill with 36 timing..so long and short of this is with this motor(548,dragon slayer crank,jw 14.5 pistons,hellfire rings,dart pro 1 345s milled to 380s,neil chance 5500 stall..running 390gears)came from florida to salt lake city..is this set up going to need awhole lot more support like I am just starting my list of broken parts..lol..wondering what I need to do on the frame and mounts this winter wondering if the rear engine frame tabs were just crappy weld from start and they were easily broke which now in turns lets everything bounce around and cause other things now to start to break. love the ideas,thanks again

JrFuel Hayden:
Well Lane I'm glad you looked for and found some broken stuff. Now the question is what has caused the motor to come loose in the chassis. Maybe just not tighten the bolt enough when installed, but I suspect something else.  Now that you have moved to Salt Lake City, you might want to call Neil & Parks Racecars, in KS, Frank and Scott Parks started in SLC, 785-654-3440. I'm sure they could give you some advice and a contact in SLC to help you get your chassis right.
Now about your racecar set-up, one of the biggest things to keep in mind, is if you raced your car in FL [ about sea level] and then ran the same tune-up in Salt Lake [ 4400' above sea level]. There for allot less air at that elevation, so she'll be rich. BTW, you changing your main pill from .100 to .095 just made it richer. THe pill controls the fuel going back to the tank, ie .095 = more fuel into the motor. If you want more advice on your fuel tune-up you could call Don Enriquez at Hilborn, 949-360-0909, he can help you no matter what fuel system you are running. You could also call Spud Miller at FIE, too.
 We have raced there twice, 2013, 2014 [runner-up] in the JrFuel Heritage, and I put one size smaller nozzles [ #12 from #14 Hilborn], changed the powerglide 1'st gear from 1.68 to 1.76, and the 11" wide wheels instead of the 12", moved the timing to 42° from 32° and maybe the biggest change, a much looser converter. Because of the 6600 DA any motor will make less HP, so that's why the changes I just listed, like 10 mph slower thru the lights than Bakersfield. I would also like to try a 5.14, or 5.34 rear gears too   [instead of my 4.88], because I'm down 300 rpm thru the lights. I'm not sure how much looser the converter is because I never ran the SLC converter at any other track, but my guess is 500-600 rpm. I just called A-1, 360-574-9966, and told them I needed one for 4400 to 6600'. I think I'll go even looser for 2015 SLC. You see the converter is a big deal on performance, you want to have the converter let your motor run in the RPM range it's making good power.
We run a 406ci SBC on injected alky, so I don't know what converter advice to give you on your 548ci. But the best is to run your motor on a dyno so you could send the dyno sheet to A-1. If no dyno sheets, call Allan or Adam at A-1 anyway, see what they recommend, they may also be able to change your current converter. But if you plan on racing any other tracks you may want two converters, one for SLC, and another for the lower elevation tracks. If I could legally run your motor in our 1435 lb car [ with driver], we would be running 6.60-6.70's.
So, have fun, I know you'll have a blast once you get your combo straighten-out.
Say, how about coming to Bakersfield Oct 16-19 for the NHRA Museum Hot Rod Reunion, and look us up, an all orange JrFuel car.
Anyway all this you can work on AFTER you get your chassis program worked out. 
Feel free to call me anytime, 805-444-4489, SoCal
Jon Hansen

LaneM:
thanks jon you have gave me more to think about I will have to give those guys a call and another builder..dave mott from Utah chassisperhaps he has advice.thanks a lot for your input it helps me with other things to look at..since I didn't build the car or know more history then what the former owner had gave me perhaps I just took on someone elses headache..well I will work on it I know it will be a fun ride when bugs are worked out.I'd love to go to Bakersfield but sadly I am dealing with some medical stuff on the 16th but I really hope to make it march.thanks again,Lane

masracingtd1167:
Hi Lane You have gotten some very good suggestions and I have only one thing to add . It sounds like the car has done this from the very beginning and that makes me wonder if something happened on the trip from Florida to Utah ! If the car was not supported very well it could have cracked something on the ride out here . Don't get discouraged and just take your time and check everything 3 times . There are some really good chassis guy's on here who can help you . Bill

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