texis30O Posted September 7, 2016 Share Posted September 7, 2016 Buy some Vortex generators. I am putting mine on after paint........ you should be able to gain some MPH by changing the airflow over the roof line to the spoiler. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 7, 2016 Author Share Posted September 7, 2016 Maybe next year. One variable at a time so I can learn. I have to put window tabs/straps on this winter, so I want to wait to avoid a placement conflict. Pray for no wind, so the research can have meaning. I want a dead-still race day (wind wise that is). Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 7, 2016 Author Share Posted September 7, 2016 (edited) Driving the Z to work for the rest of the week. Throttle cable snapped in the truck. 10 days to race day...... Edited September 7, 2016 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 9, 2016 Author Share Posted September 9, 2016 The first cable I ordered for the truck came in today-too short! I changed the Z's brakes from my road race kit to my street kit. Played with ride-height some more and changed the oil on both the Z and the truck. The list is getting shorter. Quote Link to comment Share on other sites More sharing options...
jpndave Posted September 9, 2016 Share Posted September 9, 2016 I'm excited to see how she does. Keep us posted! Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 11, 2016 Author Share Posted September 11, 2016 Truck fixed. Airdam carrier installed in truck. Lots of brake work today. Still pulling-it's not the brakes. Gonna try some caster changes tomorrow. Need to scare up some corner weight scales-I'm thinking that a lot of caster could unload a wheel(?). Smaller spoiler in prep for some fiberglass reinforcement, large spoiler solidly attached but awaiting better hardware. All chute parts are in paint now, just need to practice packing it. Death from a million cuts. Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted September 11, 2016 Share Posted September 11, 2016 Caster does have a jacking effect, but only when the steering wheel is turned. When corner balancing the car, you REALLY need to make sure the wheels are pointing straight ahead. If you have 6+ degrees of caster, then turning the wheel will significantly affect the scale readings. If you turn left, the left front wheel and right rear wheel will gain load and the right front and left rear will lose load. On a related note, caster (or more specifically caster trail) produces a torque about the steering axis. If both wheels have equal caster, then when you are driving straight the caster induced torques at the front wheels will be equal but opposite therefore cancelling each other out. If one of the front wheels has significantly more caster than the other, then the car will pull toward the side that has less caster. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 11, 2016 Author Share Posted September 11, 2016 (edited) Perfect advice. I will add some caster on the left since it is going left. Thank you so much for using language I can understand. I was gonna call you if you hadn't replied by the time I got home from church. Thanks for your generosity. Edited September 11, 2016 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted September 12, 2016 Author Share Posted September 12, 2016 More caster (and I mean just a breath more) fixed it. Car goes and stops straight. Full report next week after 1/2-Mile. Target is 150mph. Maybe with a 20mph tailwind! Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 9, 2016 Author Share Posted October 9, 2016 (edited) Car ran great at the GA 1/2-mile but only achieved a best speed of 144mph. Edited October 9, 2016 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 9, 2016 Author Share Posted October 9, 2016 (edited) In prep for the Ohio Mile, I re-glasses the splitter into the airdam. Edited October 9, 2016 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 9, 2016 Author Share Posted October 9, 2016 (edited) Ohio Mile. Ran (5) 170mph runs, a 171mph run, and a 173mph run. Rained entire first day. Got 3 runs on a crowded second day, then 3 runs on 3rd day with a thinning pack and motorcycles being held due to crosswinds. Then rain shut down day 3 early. Don't freak about the proofs-I have purchased these photos, but they are on my laptop. Truck had an idler pulley start squealing on the way home, so we had to do some repairs-seems to be a pattern with me. Had to use the Z to chase parts. The sign in the parking lot says "No car work allowed in parking lot!"-lol. Edited October 9, 2016 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
jpndave Posted October 18, 2016 Share Posted October 18, 2016 Nice! and you're doing that on 400rwhp? Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 18, 2016 Author Share Posted October 18, 2016 Yep! Quote Link to comment Share on other sites More sharing options...
JSM Posted October 18, 2016 Share Posted October 18, 2016 Very nice Keith. So how did the car feel at 173 mph? Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 18, 2016 Author Share Posted October 18, 2016 I'm not an experienced or trained driver, so I don't always know how to translate how the car "feels" into the right words or the right modifications. All I can really say is that the car feels "apprehensive" at about 150 and it is REALLY apprehensive at 170-WITHOUT the tall spoiler (that includes No-spoiler and the short-spoiler). Now, WITH the tall spoiler, the car feels settled and planted-I feel like I'm on my way to Public's to get groceries. The 173 run was done with the short spoiler and it was scary. 170-171 was achieved with or without a spoiler, but without a spoiler the car is kinda scary to me. The final run of the day was done with no spoiler and a big headwind and strong crosswind gusts. The car felt apprehensive (I think this may be the same feeling as "instability") from 150 to 170, getting worse with increasing speed, then after crossing the finish line I lifted the throttle too abruptly and weight shifted off the rear axle-this caused the rear of the car to swerve left HARD requiring me to whip the wheel left pretty fast to keep the car pointed down-track. I realized what was happening and got back on throttle to shift weight back onto rear tires and car settled, then I used all of the remaining runway to stop, being much more gentle as I lifted throttle until the car was going much slower. I think that without the rear spoiler, the rear develops lift. The trip never sought to go faster than 175mph. Rather it was a Test-n-tune trip to test the spoiler options and also to test the effects of radiator opening blocking. With the opening that I put in my fiberglass airdam/splitter, the car gained no degrees of water temp from start to finish line (194-194 degrees). When I substantially blocked the opening, the car went from 198 to 221. When I installed a blocking plate that was somewhere in between, the temp only went form 194 to 210. Mph did not seem to be influicenced by radiator opening size. I will plan to run with my radiator hole open in the future. Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted October 20, 2016 Share Posted October 20, 2016 (edited) Which big spoiler are you using? I am wanting to add a rear spoiler to my car to help with high speed stability and to get a little more confidence in high speed turns (Turn 1, Turn 17, and Bishop at Sebring). I am hitting speeds of 140 - 150 mph headed toward 17 at Sebring. My car NEVER pushes and feels very balanced. I like driving a neutral car at autocross speeds, but would like an aero induced shift toward understeer at higher speeds. Edited October 20, 2016 by 74_5.0L_Z Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 21, 2016 Author Share Posted October 21, 2016 I bought it used off this sight. I will try to find a source that is representative. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 23, 2016 Author Share Posted October 23, 2016 It is either a Retrospec "Downforce" spoiler or a clone. Mike Kelly had one on "Sasha-Gray." It had no mounting system, just a big plug of CF. I put aluminum rivet nuts in it and bolted thru the rear deck skin to mount it. Mine was warped and stands off the passenger fender about an inch while the driver side hits the fender and dings the paint. As a compromise, I made a thick gasket a sheet of 1/4" rubber from the local gasket and o-ring company to space the spoiler off, then put high density foam under the ends to take up the air space. There was a thread earlier this year by a guy who was upset because of poor composite part quality. I'm afraid it is what it is. We can either bitch about it, make parts ourselves, or learn to make aftermarket parts work. Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted October 23, 2016 Share Posted October 23, 2016 Thanks. Every composite part that I have played with needs work to fit right. I'm used to it and accept it. Quote Link to comment Share on other sites More sharing options...
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