RebekahsZ

Texas 300-what rear setup are you running again? Glad to hear you are getting some miles on that car. I still have to get under my car and inspect EVERYTHING. I made (2) 174.2 runs on Saturday, which had a tailwind, but it wasn't a huge tailwind. While the car is faster with the airdam, it gave up some stability and became twitchy at speed and damn scary under braking. Talking with johnc and the guys at the track, the downforce of the airdam and splitter pushed down the front and added toe-out. Braking compounded that and scared the shit out of me on record run #2. I was so freaked that I didn't turn that timeslip in and told my brother that we were putting the car on the trailer and leaving in the morning. After watching the meet from a folding chair I got my balls out of my throat and decided to work on the car (honestly, after your first landspeed event, watching other guys go fast is a lot like watching a swim meet, minus the speedos). So we went to Lowes and bought all the tools I had left at home (the tool you didn't bring is ALWAYS the tool that you need) and hacked off the splitter and re-finished the fiberglass (I'm getting decent with glass work and didn't want to have to do it when I got home-I'm tired of itching). Using a set of $2 ceramic floor tiles from Lowes as toe plates and a matched pair of $4 tape measures, we gradually increase toe from my autocross setting of 1/16" out to 1/4" in (total). Staying in 4th gear at about 150mph for 3 runs of TnT, I found that the car was lots safer under braking, but was still very light in the front with the right pedal on the floor. Ripped off (2) 167mph runs into a big-ass headwind to finish the meet. I will return with a whole new front-end alignment and spring rate plan next June. Truck's clutch hydrauilcs shit on me about 20 minutes from home, so I limped in and hit the sack. Cleaning fiberglass dust out of the garage this week, then I start on the truck's clutch and airconditioning. Will be dailying the Z this week, then I make the tranisition for the road course day at ZCON in the middle of July. Pictures and videos when I have time. Down-loaded go-pro videos, but I'm having trouble (newly changed to MAC) getting vids from my video editor (did some serious cropping) to youtube. Unfortunately, I turned the camera off instead of on right before my really scary bump-steer run. That would have been really educational for the forum. Not fun to put on the brakes at 174 and have the car steer almost off the track to the right, then get off and straighten up, only to have it try to drive you off the track to the left. Johnc came to my rescue via an emergency PM and we got that toe adjusted-made all the difference in the world.

Jon, how big is "huge?" That just doesn't sound right.....oh, and I dropped the ass of the car an inch after the first splitter scraping event and kept it down. Observers say it looked a lot more flat. The static rake was intentional but perhaps excessive with an additional 3" of nose down with downforce on the splitter. I tried to video the rear wheel with the flare removed to try to see how i was doing in both travel and clearance. but the camera kept blowing off target. Will see this week if any of that video is beneficial. Next year, I'm hoping forum member Spitznaugle will come again and video the car at the fast end of the track. He was a big help with cutting off the splitter and repairing it, then we had supper together after the pits closed. I had a great pit crew.

I was hoping to do rear spoiler testing next year in May meet. I have a small BRE style spoiler and I hope to buy a Victory spoiler as suggested. I had to get clarification on spoiler/wing rules and I got the clarification I needed. Burton Brown runs in a very restrictive Production Class so he restricted to OEM chassis parts. I'm competing in a Modified Class which is much more permissive. Wings are forbidden but any spoiler is allowed as well as vortex generators. I will work this winter on getting the bolts of each spoiler to line up. From what I've seen, the mounting of the Victory spoiler is kinda chicken shit with just like 4 bolts/scres down the middle. I'm suspicious of that being inadequate, so I will need to doctor it some. I need to reference the existing wind tunnel data to better understand the spoiler situation, but I will do that in the weeks ahead. I sure thought a spoiler would cause a lot more drag..??? Perhaps not.. I'm new to this but I'm eager to learn. Since the front of the car kissed the pavement with and without the splitter, I will be making splitters of varied length that I can attach quickly and TnT. One thing I can't get my head around is how down force affects straight line car behavior. I inderstand why you desire it going around a road course. The negative behavior I experienced was a general twiitchiness and drifting in the lane that started above 100 and got more noticeable with increasing speed, then an uninitiated steering of the car under braking. Toe-in seems to have fixed the steering under braking. I guess I don't really know what car behavior is included in discussions of "stability." And I don't know what levels on perfection and comfort are to be accepted and what degree of pucker factor is just par for the course. While we made big improvements in how the car drove while braking, I don't feel that we really gained anything duri g the accelleration portion of each run.

Finally: on the sealed airdam (fenders still provide access to cold air) vs a small hole cut in it. I ran 167 today in both configurations. However: with an engine water temp of 196 at the starting line, the opened airdam had a temp of 199 at the finish line vs a 230 water temp at the finish line for the sealed configuration. I don't really know how hot is too hot. Stop the car and turn off engine and temp went to 207 for open dam and 244 for closed. The way to cool this sucker is to pull the hood and leave it running with the fans on. So yeah, it matters for temp - didn't matter for speed. I think that's the basics of my trip report. I left with some questions answered, but lots more questions to work out. I still have issues beyond "more power" to work out before I worry about going faster. But a months work with fiberglass (time to start cleaning shop) raised the Lomax Racing ECTA C/GMS record of 161.3 to 167.5 last month then further raising it to 174.2 mph (I will admit to a little tail wind yesterday). Not bad for a tired old Z car built and worked on by a guy who really doesn't know what he's doing. Glad to have all the hybridz help.

Survived and heading home. I do think the splitter contributed to the grounding, but I hit the airdam in the ground today at 167 mph (with 12 mph headwind) so it is either from downforce on the hood or just excessive bump travel. That screwed up my hypothesis of blaming it all on the splitter, cause I cut that shift off! I'm definitely in agreement on the higher spring rate. Thanks for the recommendation - I was thinking at least 400, so you confirmed my suspicions. We are moving into a suspension thread, but lets go with it till somebody makes us move. What about a corresponding rear spring rate change ( currently at 225F/250R)? Keep it soft or up rear rate too? Getting good at adjusting toe, so that bubble has been burst. Car drives better with 1/4" in. Still having to really drive the car (finger tips) from 150 up, and holy shit, don't hit the seam in the midfle of the track -that launched me across the lane at 155 mph. But I'm not swerving from one side of the track and back on braking from 170-ish anymore. I'm also thinking about losing all my front camber (ran at -3 because of upcoming track day) and turning that into more caster if possible. I'm thinking of taking the airdam to Memphis for the track day(I think 150 is doable on the long straight-away) to put some tell-tale zip ties on the struts to see just how much movement I'm getting. Hate to fill the back of my truck with airdam instead of tires.... Tried increasing from compression and car behavior was not affected. Dropped front and rear tire pressure from 55 and 40 to 35 on all corners. Car drove better. Maybe the sidewalls were giving, allowing the suspension to stay more still?

Back for second meet of 2015 with headlight covers and an airdam/splitter. Upped class records to 174.2 mph. But having some handling difficulties at top end. Hard to believe, but 174 is a LOT faster than 167. Talked to johnc after I cut off the splitter (was building enough downforce to lower front end 3 full inches and the splitter scrapped the track!) and we are gonna try to add some toe-in.

Preliminary feedback: The 3" wide splitter 3" off the ground has been cut off. First run-174.2. Car wandered a bit between 150 and 175. Put in impound for a bit because car has no chute. Got to pits and found that airdam had contacted the ground! That means that it built up enough downforce to compress 225# springs 3-inches. Second run-174.2. We had raised the front 3/4" and dropped the rear 3/4" yeilding a splitter height of 5". Car ran great and straight under power but drifted hard right under braking, straightened when brakes lifted, then drifted left when braking resumed. Used full track to stop-was pretty scary. After that, I wasn't going back out in the car. After a while, my courage recovered (I gotta tell ya: 174 is a hell of a lot faster than 150 or even 167, especially when you car isnt going where you point it). We cut the splitter completely off the airdam and re-glasses it in the pits. Put the from ride height back down and checked toe-in. 1/16" out at static. In the morning I'm setting it to about 1/4" in and gonna give it another try. I really want to have it handling well enough to test a couple rear spoilers next year.

I sure wish the manufacturers would go ahead and drill the damn things. Passing the liability of cracking them off onto the customer is crap. Kinda like me charging a patient for eye surgery, then handing them the knife and saying "ok, I got your money, now do the surgery yourself-ttyl-tata!"

I've got ammo too. In the staging ready to go.

There's 4 more you didn't see. 6 of 7 are LSDs. I want more spare axles. Never accuse me of being in-diff-erent.

The best way is the simplest way. Dead-head into the fuel rail like the factory did. I have 1 fuel line under my hood and it is less than a foot long. Fire risk=damn near zero. Fuel supply problems=zero.

Time to pack a few extra undies and head out!

So would a rod going thru your block!

I will post my results next week in this thread and the aero forum. I hope to do a rear wing comparison next summer-I hope to compare those two wings against each other, and against no wing. So far, down force isn't my priority, rather drag reduction is-the little splitter lip was just a "while I'm at it...". Traction and manners were excellent at 167mph without the airdam. I guess there IS a chance that this could screw that up...this is a prototype, and a 2-piece unit is definite in order. Inhave all the supplies on hand for version two, except motivation, but that will return with sleep.

There is still access to cool airflow for the radiator (no ram air - just fan driven air) and for the air filter via the fenders. That aluminum panel comes off if I still have trouble with cooling, but the old-timers seem to think I will be fine. The idea is to limit air from entering the engine compartment and from going under the car. I plan to warm the engine enough to get the temp gauge in the "normal" range, then to shut off the car until I am directed to start my run. This thing is heavy (60# including the dam, belly pan, and support structure). Together with the headlight covers, I hope to close the gap between my current record of 167mph and the max the cage is certified to: 175mph. I have no idea if this thing will clean the car up even at all! It's just my first whack at getting faster before changing gearing or adding power. If I ever exceed 175, this hobby is going to get (more) expensive, as the safety requirements really sky-rocket.

Ready to go to Ohio Mile!

Way to go!! Love those LS torque curves.

Flat black paint is very forgiving.

More progress. Got new ignition switch done today, and a redundant direct starter switch that bi-passes the ignition switch-don't want to be found wanting again at the start line. Other than a little sanding, the glass work is done. Maybe a little sanding and bondo before flat black paint (Wednesday?). Tomorrow night is trial loading on the trailer and trying to fit airdam in truck. Also, headlight covers. That will leave Wed for painting and Thurs for washing and loading.

Thanks to Andy's advice, the quality of work has improved but there are a lot of early mistakes to live with. Hoping to finish glassing today and get started on headlight covers next. Times a tickin'!

Pics of that when available maybe before tank goes in?? Pretty please? This part might be a winter to-do for me.

What solid structure does the chute pull on? After deployment?

I have closed down the hole in the front 1/2 way-the lower edge was so low that air was just gonna go under the car. I'm hoping to keep the hole closed-it's just there if I have a water temp issue.

Some more airdam photos: Interesting supply cost comparison. Resin: $45 at Autozone, $35 at Home Depot/Lowes, $13 at Walmart. Fiberglass cloth: $7.99 at Autozone, $6.99 at Lowes/HD, $5.47 at Walmart. It's where America shops! Shoes and teeth are optional. I'm hoping to re-do this prototype this winter using only glass cloth (no mat-soaks up way too much resin) using an aluminum belly pan, the steel bracket that I made (with some modifications), and adding closeable brake ducts, radiator ducting, and closeable holes in the belly pan for ratchet straps for attaching to trailer. Then I need a bracket to secure it behind my truck cab. Shouldn't be too bad as my FG skills improve.

Yow! That would have made a mess going thru your fan!