vega Posted March 3, 2010 Share Posted March 3, 2010 So I was fooling around the other day with the z and had it going at about 130 mph to test what it is like with the steel bumpers off. The shaking it once had is now gone. BUT now I found that I have another issue; the car starts to have a floaty feel coming from the front of the car. It felt as if I were to turn it it would flip. This is something I would like to fix. I read a little bit about the windtunnel stuff to be honest most of the stuff you guys were saying was and or is way above my head. So that being said. What can I do to make the car more stable and planted as I get it to those higher speeds? Picture examples would be great. I am planning on doing body work very soon so if there is stuff like wings and splitters or a particular body kit that is better than others for aerodynamics, I would much appreciate the information so I can have it setup better before I repaint it. The car as is a 1978 280z 5 speed stock front lower valance and has the steel park bench bumpers removed. the radiator is fully exposed at this point big open mouth. The suspension right now is all stock struts shocks etc. all 1978 factory. thanx vega- Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted March 3, 2010 Share Posted March 3, 2010 One word: downforce. P.S. Is it possible removing the park benches makes it sit higher? Did it have that problem before you removed the bumpers? Either way, it seems like the front end could be a little high for the car's weight/configuration. Lowering the front end slightly could naturally give it a better stance without having to add a wing or anything that drastic. Quote Link to comment Share on other sites More sharing options...
jt1 Posted March 3, 2010 Share Posted March 3, 2010 Add an air dam to the front, seal the airdam back to the radiator support, and if you have any adjustment add some caster to it. jt Quote Link to comment Share on other sites More sharing options...
vega Posted March 3, 2010 Author Share Posted March 3, 2010 Add an air dam to the front, seal the airdam back to the radiator support, and if you have any adjustment add some caster to it. jt do you have any pictures for examples to what your talking about as far as the air damn goes? I understand the caster idea I've thought of changing the alignment a bit seeing that its going to change at higher speeds. I did forget to mention that I have staggered tires as far as height goes.n I have taller tires in the rear to bring the front end down- not DRAMATIC really but, 185 65 front 195 70 rear. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 3, 2010 Share Posted March 3, 2010 (edited)  By removing the front bumper, you have allowed a lot more air into the open nose.  That air is getting into the engine bay and pushing up against the underside of your hood.  Simply blocking off a good portion of the grill will get you where you were, or better. This is all covered in the aero thread section. You want the air to go around or over the car, not into the engine bay or under the valence, generally speaking Edited March 3, 2010 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted March 3, 2010 Share Posted March 3, 2010 *getting on old man pants* There is no reason for you to be getting up to those speeds on public roads. Keep it safe. /rant When I first got my 78 and took it on the interstate, at 85 MPH [Yes, I was speeding] it felt very 'floaty.' I attributed it mainly to those huge bumpers, but when I took mine off, I also put on the MSA Type 1 Air Dam. The car feels very planted at those higher speeds now [Never been up to 130 MPH though]. I would suggest getting a type one, I *assume* the brake ducts help, but I have no experience with the non-ducted airdam, so that's purely conjecture. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 3, 2010 Share Posted March 3, 2010 *getting on old man pants* There is no reason for you to be getting up to those speeds on public roads. Keep it safe. /rant When I first got my 78 and took it on the interstate, at 85 MPH [Yes, I was speeding] it felt very 'floaty.' I attributed it mainly to those huge bumpers, but when I took mine off, I also put on the MSA Type 1 Air Dam. The car feels very planted at those higher speeds now [Never been up to 130 MPH though]. I would suggest getting a type one, I *assume* the brake ducts help, but I have no experience with the non-ducted airdam, so that's purely conjecture. I was going to say that, but in his defense, he never mentioned anything about public roads... Quote Link to comment Share on other sites More sharing options...
vega Posted March 3, 2010 Author Share Posted March 3, 2010 I have access to closed off forest roads- I will also be taking the car to brainard race way soon. So is the type 1 ducted better than the BRE style? Or vise vera? For at least what I am doing. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted March 3, 2010 Share Posted March 3, 2010 Wow, 130mph. That must be speedo-indicated. I hit 135 indicated, (redline in 4th, 125mph actual) at 9500' elevation (years ago, old man!) with no front end lightness. Thanks to the air dam I have. Quote Link to comment Share on other sites More sharing options...
jt1 Posted March 3, 2010 Share Posted March 3, 2010 do you have any pictures for examples to what your talking about as far as the air damn goes No pictures, but if I wanted to use a 240Z chrome bumper I would use something like a MSA 1401, which doesn't have the useless brake duct holes. If I didn't want the 240Z bumper, I would use the MSA type 3, and block off the brake holes before I painted it. jt Quote Link to comment Share on other sites More sharing options...
vega Posted March 4, 2010 Author Share Posted March 4, 2010 so the brake duct holes are useless? Quote Link to comment Share on other sites More sharing options...
jt1 Posted March 4, 2010 Share Posted March 4, 2010 Yes, unless you're road racing and have the air ducted to to cool the brakes. Otherwise they just let unwanted air under the car. jt Quote Link to comment Share on other sites More sharing options...
vega Posted March 4, 2010 Author Share Posted March 4, 2010 Ok well I will keep that in mind. Thank you very much. Quote Link to comment Share on other sites More sharing options...
SHO-Z Posted March 4, 2010 Share Posted March 4, 2010 The aerodynamics of the Z is not set up for 130 mph. I drove a Lamborghini Mirria 202 back in the 60s and at about that same speed it was a real hand full. Very few car have the aerodynamics be stable at that speed. Remember these cars were sold on looks not aerodynamics and gas was cheap. Go to the race track and check out all of the Zs and look at their modifications. There are some manufactures of body kits made for racing that should improve stability but you still need to do your homework and find out what they do with the under carriage. Quote Link to comment Share on other sites More sharing options...
vega Posted March 5, 2010 Author Share Posted March 5, 2010 I'm in MN not too many people use these cars for that. If you are aware of what people are doing or links to body kits that actually would help, that would be much appreciated. Quote Link to comment Share on other sites More sharing options...
Mayolives Posted March 6, 2010 Share Posted March 6, 2010 QUOTE: The car as is a 1978 280z 5 speed stock front lower valance and has the steel park bench bumpers removed. the radiator is fully exposed at this point big open mouth. The suspension right now is all stock struts shocks etc. all 1978 factory. Congratulations. You sir, have the fastest stock 1978 280 Z car on the face of the Earth.(Sorry, I couldn't let this one go) Quote Link to comment Share on other sites More sharing options...
vega Posted March 6, 2010 Author Share Posted March 6, 2010 (edited) I'm just going by the speedo bub. I've also had the speedo tested- by radar, I'm not 100 percent sure if its 130 that i have not had done by radar. I have at 90 for sure. So I am sure its close. Your not helping so unless you would like to help keep the flaming and the random opinions to yourself or NICO. On a side note: I do enjoy your quote in your sig. Edited March 6, 2010 by vega Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 6, 2010 Share Posted March 6, 2010 The stock Z can do 120 pretty readily....130 with calibration error is not that far off. Quote Link to comment Share on other sites More sharing options...
vega Posted March 7, 2010 Author Share Posted March 7, 2010 The one thing that may affect it is that I may not be using what the stock tires are supposed to be. I am not sure on that. Does anyone have any skid plate designs for higher speeds at all? Quote Link to comment Share on other sites More sharing options...
yetterben Posted March 7, 2010 Share Posted March 7, 2010 I will be at Braianrd raceway in the spring/summer. Come on down to Road America Quote Link to comment Share on other sites More sharing options...
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