John Force vs the Slip-tube chassis

Discussion in 'NHRA' started by Hiproger, Jul 31, 2006.

  1. Hiproger

    Hiproger Nitro Member

    On one of the last couple of shows or maybe NHRA2Day, it was said that John is the only driver running at present with a rigid style chassis. That's the first I had heard that. Both Robert & Eric run the slip-tube along with everyone else in the class. With the apparent consistancy/inconsistancy problems he's had of late it kinda made me go "Hmmm, wonder why he won't switch".
    Anybody else have any thoughts or info on that deal? Just curious & I like gettin' into the chassis/techno stuff............"HIP"
  2. DrRocket

    DrRocket Nitro Member

    When Cruz burned his primary car up, they went to the backup car. They mentioned that was the car Cruz won Vegas in, and it was a rigid tube, not a slip tube like the car that burned up.
  3. DLB

    DLB Nitro Member

    That is interesting. I hadn't caught that. I usually just breeze through the NHRA2Day shows though since they are on my DVR when I get home from church. I watched the last 2 weeks episodes today at lunch actually in about 30 minutes...:rolleyes:

    If he is, I am sure he has a reason, but I'd like to know what it is.
    He does seem to have some inconsistency.
  4. T.Smith

    T.Smith Nitro Member

    I know Wilkerson didn't start running a slip tube chassis until Dallas 2005. Sounds like they got a new car at the shop right now, but I'm not sure what type of McKinney chassis it is.

    Last I heard, Medlin & Hight cars were McKinney cars and Force was still racing a Steve Plueger chassis. Someone he has been very loyal to.
  5. Buzzz Miller

    Buzzz Miller Guest

    I had not heard that Force went back to Pleugar stuff. I know a few years ago he switched everything over to McKinney due to lack of Steve building any more cars. I know his tune-up struggled for a while to get stuff switched over. I know he sold lots of his Pleugar stuff off. Did he buy it back?
  6. afx421

    afx421 Nitro Member

    interesting point hip. i didnt catch it on nhra today. wonder why myself. force seems like a guy who hates change.
  7. Horsepower & Heels

    Horsepower & Heels Nitro Member

    Question...

    I've heard of the slip vs. rigid chassis, but am having a hard time picturing how a slip tube chassis works. Anyone have a picture that can point it out for me? thanks, I'm pretty new to the upper echelons...
  8. Hiproger

    Hiproger Nitro Member

    I think Plueger got completely out of the business. He played around with his own car for a while, letting arguably the best F/C driver in the country, Dale Pulde, play along with him.
    Seems I read somewhere that he was now foolin' around with some nostalgia stuff, but I occasionally have what has been diagnosed as brain farts. They ain't no fun I'm tellin' ya.:eek: ..........."HIP"
  9. Usual password less 1

    Usual password less 1 Nitro Member

    When we started the 05 season, we had a brand new Murf slip tube car as well. It was super easy to drive, but every now and then it seemed to take a set and wouldn't drive straight for nothing. Then you would reset the front end and re scale the car ( get the right rear weight right) and it was great again. Like anything that is new there are always some updates. The earlier cars had a tendancy to move all over the place if you pedaled them and the "lifespan" of the front half of the chassis was only about 60-75 runs before it started to sag. Then you would just front half the chassis again. Without giving away any trade secrets the newer style chassis is better...we just updated ours recently and it drives a lot better now. BTW Force still has the Murf "rigid" chassis.
  10. T.Smith

    T.Smith Nitro Member

    Hey Jeff, when did Force quit running Pluegar cars...can't be more than a couple years?

    And thanks for the info.
  11. Hiproger

    Hiproger Nitro Member

    Erica, at Indy last year I asked a crew guy about that & he said come over here & he led me to the front of the car & showed it to me. Very nice fellow but I can't remember what team he was with. (Check the above post). Roughly about a foot & 1/2 back from the front axle the upper frame rail is designed so that one section of the tubing slips inside the accompaning section allowing that rail to expand & contract back & forth so to speak. There are stops welded on each section allowing it to "stretch", or lengthen, but only about an 1/8 inch according to him. Doesn't sound like much but he said it was enough to let the chassis "bow" kinda like a mini version of the T/F chassis. It also allows for a more gentle rise to the front end, smoothing down the reaction of the launch, if you can imagine the words gentle & F/C launch being used in the same sentence.
    There is a drawback though in that it allows the car to dart around more from side to side during the run, which can be especially troublesome if the car drops a cylinder. Hope this helps a little......."HIP"
  12. Hiproger

    Hiproger Nitro Member

    Sorry Jeff, I was writing my response the same time you were writing yours. While I've got your ear in a manner of speaking, when are we going to see you out there again. The sooner the better for me & I'm sure you probably feel the same way................"HIP"
  13. speedster

    speedster Nitro Member

    erica picture a pipe 1 1/2" diam and inside that pipe another pipe 1 1/4"diam and in that pipe another pipe 1"diam and non of these pipes are welded to each other? the bottom rails are solid all the way up the top rails are the slip tube rails. so when ya hit the throttle the chasis raises up and the top tube pulls apart from each other just a little bit! i hope that kinda helps with a picture of what a slip tube is! even my sons jr. dragster uses this technology and it's pretty cool;)
  14. Horsepower & Heels

    Horsepower & Heels Nitro Member

    Thanks, guys! I'll see if I can get a closer look at one in Indy now that I know what to look for.
  15. Nitrohaulic

    Nitrohaulic Nitro Member

    I'd say the vast majority of dragsters sold today that don't have rear suspension have slip joints in the top rails in front of the driver's compartment. They're very common in faster dragster classes.
  16. DrRocket

    DrRocket Nitro Member

    I'm thinking every time one of these chassis makes a run, the slip tubes are subjected to a bending stress. Eventually the tubes start bending, take a set, and start binding against each other internally at the joint, it would seem to me. Then it's time for new pipe. That's about 60-75 runs according to Jeff's post. Hopefully, that's causing replacement of tubing before metal fatigue at the slip joints sets in and prevents any catastrophic failure like we've seen in the rails.

    I'll bet that F/C crew chiefs were looking at the T/F cars as they arched their way down the strip and thought "Wow, I wonder how we could get OUR cars to do that?" and viola!! The slip tube F/C chassis!! At one time, the coupes used coil over suspensions, but that was with solid front and rear axles. Now Roger, you said the amount of travel was 1/8 inch. I wonder if anyone's thought about going back to a non solid suspension??? How about active suspensions like we see in Pro Stock? Oh boy!! Another timing system to keep track of!!!
    Last edited: Aug 1, 2006
  17. Nitrohaulic

    Nitrohaulic Nitro Member

    Anything that takes shock from the tires allowing them to apply more clutch and lower ETs, they're going to be interested in. I wonder if John's chassis choices are more up to him or Austin?
  18. Buzzz Miller

    Buzzz Miller Guest

    NO!
    The NHRA will not allow any suspension systems in funny car. Scotty Cannon had some amazing set-ups to keep the chassis rigid, but allow a touch of travel in the front wheels. They would not even look at his working prototype. They were quite opposed to any idea there. Safe or not. He also had ideas of changing the back half of the chassis. Again. Safe or not, no chance. (I think the actual quote was "Don't you dare bring that junk to one of our race tracks.")
    Unless something drastic happens, or one of NHRA's super buddy buddy list comes up with the same exact thing, it will not happen.
  19. Hiproger

    Hiproger Nitro Member

    David, I have thought the same thing. With the knowledge we now possess with shock absorbers it seems that you could have be an indefinite number of settings to work with. I don't think that a suspension would work on the rear axle though as there is just way too much horsepower for anything to work. However with the front suspension the only problem I could see would be the weight factor. These guys spent an awful lot of money just to shave off a couple of pounds & a spring/shock package would certainly be heavier.
    Anyone remember the elaborate front suspension set-ups on some of the old Buttera F/C chassis. The "Snake" & Don Schumacher cars are a couple that come to mind. Sure wish the "Shoe" was still posting here. I'm sure he would have some insight on this subject.
    Don, come on back. Your many, many fans miss you..............."HIP"
  20. Pablocruise

    Pablocruise Nitro Member

    Maybe they will start to install sensors in the F/C chassis tubes to measure how much load is present. Same as the T/F chassis?
    I notice they are now using sensors in the wheelie bars.

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