Guest Anonymous Posted November 29, 2000 Share Posted November 29, 2000 Does anyone know if a rear sway bar is a help or hinderance in straight line performance with an open rear end. I've disconnected my front sway bar, installed a line lock and bought BFG Drag Radials. I have a date with a disabled bike cop and his Buick Grand National this week. On the street at night. Next trip is to Pomona Fairplex on Dec. 10&11. Just want to know if the sway bar would help tranfer weight too the drivers side tires with the line lock in use. Like a traction bar for IRS. Can anyone explain the theory of rear sway bars on IRS Z's? Does pre-load help or hinder? Thanks,Jeff Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted November 29, 2000 Share Posted November 29, 2000 Haven't run my car at the drags, but if I did, this is one thing I would do. Lateral loads should, of course, be minimal, but having a front bar installed and no rear bar ensures that any lateral load is mostly reacted by differential load between the two front tires, and that load is more evenly matched between the rears, which is essential for traction, particularly on a car with an open diff. With the Z's IRS setup, you don't want ANY kind of sway bar preload, since the torque is reacted in the unibody, and both rear tires are pretty equally loaded under acceleration. Incidentally, I've got a pretty good video of my car doing a great two-wheel burnout back when it had an open diff. Good illustration of the superiority of the IRS setup, at least for modestly-powered Zs. My recommendation: Use the front bar, and remove one of the rear bar links to disconnect it. Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted November 29, 2000 Share Posted November 29, 2000 I have had excellent success drag racing without a rear sway bar. My basic "belief" is that if any side or torsional loading occurs on the back half of the car, the rear sway bar would want to raise the tire that is higher than the other. This is not good for our single slide pigs. I've had more people tell me that what I've done has horribly affected the handling of the car. In all honesty, I hardly even notice thew sway bar is gone, unless I'm REALLY pushing it through a turn. However, keep in mind that without a rear sway bar, the car will tend to understeer (off power, of course) more than before. this is something that I have indeed noticed... but it's minimal. Get rid of that rear sway bar entirely... it's dead weight!!! No sway bar, Line Lock, Drag Radials... Hmmm... sounds a little familiar. Let us know how you run. -Andy P.S. Check out my two wheel single-slide burnout in the readers rides section. Quote Link to comment Share on other sites More sharing options...
Guest pauli Posted November 29, 2000 Share Posted November 29, 2000 not directly relevant, but i was reading about a guy with a solid axle vet who was having wheel hop problems at the track. he hooked up a small video camera in the back somewhere, and discovered the problem: the car would sit there and the wheels would hop alternately. the rear sway bar was doing rather nasty things to his traction. he removed it, and did somewhat better Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted November 29, 2000 Share Posted November 29, 2000 If you get any air what-so-ever underneath those tires, I'm gonna want to see pictures damnit!!! -Andy [This message has been edited by Andrew Bayley (edited November 29, 2000).] Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 29, 2000 Share Posted November 29, 2000 One of these days, soon, James Thagard (240Z Turbo) and I will be racing. He has a 71 with a monster 3.1L turbo, NOS, 4200 stall hybrid automagic and VLSD and thinks he can run with me. That event will be "televised" . Hopefully we can have it available on the web for those who are not bandwidth impaired . ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Guest Frank280z Posted November 30, 2000 Share Posted November 30, 2000 Is it possible to get a tech write up on welding the open R200? I need this info. Frank Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 30, 2000 Share Posted November 30, 2000 Scottie, I can't wait for the broadcast! Seems like before this site was in existance a guy named Jason was emailing me trying to see if I could help him figure how to get his car to hook up. I was no help, but he figured out that 170lb springs in the rear was the trick. I think this is NOSZCAR, not sure though. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 30, 2000 Share Posted November 30, 2000 Jeff, I am with Andy. It took me a long time to finally get the right setup for launching my 240Z hard and quick off the line. I now have both swaybars removed and the Tokico Illuminas (F&R) set to the softest setting. I also do not have an LSD so I welded the open R-200. The result? Consistent low-1.60s 60' with 8psi boost on a transbrake and McCreary 8.5" DOT tires. Like Andy said, you have to be cognizant of your car's setup w/o the swaybars and drive accordingly. In my case, the welded diff adds another dimension. In less than 1hr the bars can be reinstalled, shocks adjusted and I am ready for anything. With this setup, the car has incredible squat which a lot of Z folks think is bad. Bottom line is, nothing else worked for me and I cannot argue with the results. I fully expect to launch even quicker with bigger, stickier tires and with the Z squatting so hard, maybe even put a little air under the front tire . ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 30, 2000 Share Posted November 30, 2000 Frank, IMO, this is not one I would recommend the amateur welder take on. My advice is to spring for about $50 and take it to a driveline[/b shop, not just any welder or machine shop. That is their specialty and you can be assured that the spots to be welded will be properly prepped, all the spots that need to welded will be and a thorough cleanup done. It is more than just a couple of spot welds. What I will tell folks thinking about doing this is that there are pros and cons. It should not be considered a cheap LSD alternative for an everyday street car!!. The obvious pros are that it is low cost, guarantees equal load when launching and if properly done, probably will not break. A primary reason why I did it was because of the gear ratio. I had an LSD that went bad and I am sure I could find another. My problem is that 3.70:1 is a little too stiff for my car and so is the 3.54;1 for that matter. Hitting over 120mph in traps, I have to shift into o/d which is .67:1 and drops the engine to 3900 RPMs . What I actually need is a 3.36:1 R-200. One of the pros, equal load to the wheels, is also the big con because there is no slippage. What you will notice is that the inside tire drags on slow turns and even squeals when making slow U-turns and the car is harder to push when the front wheels are not perfectly straight. There is also an increase in understeering but I cannot tell you how much is attributed to the welded diff as I also have both swaybars removed. As stated earlier, it is a low-cost alternative for a drag racer and if the car is street driven, understand the negatives and drive accordingly. I use my Z primarily for drag racing and I hope we do not start a thread about the Z being a sports car and not a good drag racing car j/k. However, I do not want anyone to think my car is a stripped out drag racing shell. I recently stated in another post on zcar.com, that in an hour I could have the swaybars back on, shocks readjusted, fluids checked and be ready to drive it from Orlando to L.A. w/o concerns (except my aching body) and probably get 26+mpg. Pete, 170lb springs is a good recommendation. I had my rear suspension out and access to set of 280ZX 2+2 springs and decided to do the JTR mod to raise the spring perch. The cutdown ZX springs are supposed to be about 200lbs but they feel no different than the hi-po 240Z springs I took out and work just fine. I magine the soft shocks settings and extreme weight transfer cancels out the extra stiffness. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
John C Posted December 1, 2000 Share Posted December 1, 2000 I have my rear bar off and front bar on and run an open diff. I don't have any wheel hop at all and was told by a guy at the track that the car was pulling both front tires 1 to 2 inches evenly. I haven't had any time to dial my carb or suspension yet ,but I know there's lots of room for improvement. Your best bet Jeff is to make 3 runs with the rear bar hooked up,and three unhooked. Good luck! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 1, 2000 Share Posted December 1, 2000 Thanks for all the info. I have one more question for those running a line lock. Just finished installing mine and it won't even hold the Z at 1200rpms. I can foot brake better than the line lock what's up with that. It's a Moroso unit, my convertor is a B&M Holeshot 2400,700R4 trans worked,3.90 rear gears and a high lift solid cam w/ 253/254 @ .050. Oh yeah the front brakes are stock 240 Z. Which is probably my whole problem. Thaqnks again Jeff. Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted December 1, 2000 Share Posted December 1, 2000 Jeff, How are you setting the line lock? I've tried all sorts of ways, but the only successful method I've found is to "pump" the pedal. I'm 99% sure that the Moroso unit is a one-was solonoid (just like my B & M). Try pumping the $hit out of it and see what happens. I usually have to apply the brakes VERY hard a few times, after I've already engaged the line lock. Unless I do this, the line lock wont do a damn thing. Oh yeah, I'm also running OEM sized front brake (260) as well. -Andy [This message has been edited by Andrew Bayley (edited December 01, 2000).] Quote Link to comment Share on other sites More sharing options...
RickB Posted December 1, 2000 Share Posted December 1, 2000 It sounds to me like you are trying to use the line lock to stage The line lock is really only intended to hold the car stationary during a burnout. I have seen people use line locks front and back to stage but...certainly not the intent of the product. Stage with your foot brake or add a trans "break" (ha ha) to the mix ------------------ RickB 280V8 http://photos.yahoo.com/bornabov Quote Link to comment Share on other sites More sharing options...
Andrew Bayley Posted December 1, 2000 Share Posted December 1, 2000 Who makes a trans "break" (I like that) for the 700R4? -Andy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 1, 2000 Share Posted December 1, 2000 I've made a trans break before. Lone Quote Link to comment Share on other sites More sharing options...
RickB Posted December 1, 2000 Share Posted December 1, 2000 Actually...I don't have a clue as to whether there is a trans broke available for the 700R4?? I've driven a couple of "drive it like ya' stole it" passes with the latest 200R4 trans break though, all I've got to say is ------------------ RickB 280V8 http://photos.yahoo.com/bornabov [This message has been edited by RickB (edited December 01, 2000).] Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 1, 2000 Share Posted December 1, 2000 RickB, are you using the Mallender StageRight unit? ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
RickB Posted December 1, 2000 Share Posted December 1, 2000 Scottie, I ran my Turbo car on the foot brake. But, I have made some 7.40 1/8th mile passes in a friends GN using that trans brake...worked great but it was kinda weird shifting into second to release it. BTW, my last turbo car just went a 11.20@123mph for the new owner on the nitrous at low boost on a street chip. RickB Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 2, 2000 Share Posted December 2, 2000 RickB, yes, it is weird shifting into 2nd to get the car going but it is just as well because the 1-2 upshift happens so fast. MOF, I lock the converter at the line, shift to 2nd to release the t-brake and in one motion, shift to 3rd, then manually shift to 4th at 5200. BTW, 11.2 @ 123 in a GN is a lot of HP. 540 by my estimate. With that MPH it should be in the hi-10s. I could go hi-9s with that engine ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
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