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HybridZ

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4000rpm 2-step clutch dump, 3.54 R200 CLSD with 28X9X15 ET Drag slicks 17psi, stock LS2 400hp/435tq, Z31 axles, Chequered Flag stub axles, single-adjustable Konis with rear rebound set full stiff and fronts set full soft.  Mantic ER2 clutch and pressure plate.  Lots of VHT with beautiful track prep.  Both wheels up during dead-hook, but engine bogged and dropped the wheels back down, almost instantly.  Two more wheelies during the night, but this was by far the best.  Lowered tire pressure to 15psi and reset 2-step to 4500 with plans to keep increasing 2-step till either I got some tire spin or broke something, but the car ahead of me in staging blew his tranny up and dumped all of its oil all over the track and drove right down the groove to half-track before grinding to a halt in the middle of the lane.  I saw 2-hours of track cleanup coming, so I loaded up and headed home.  Car performed below par with 1.60 60' times and consistent 7.30s at 96mph, mostly slowed by dead hooking, even bogging the car on gear changes.  I may be going back to 26s for this track since they put so much VHT down.

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Edited by RebekahsZ
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I always preferred running the 26" drag radials, got my best 60' ft's with them. I went to The Texas Motorplex Friday night and ran 6.71 at 104 in the 1/8th and 10.66 at 125 in the 1/4  on motor only. Never got the opportunity to open the bottle, Those little LS2's are the bomb!!!

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4000rpm 2-step clutch dump, 3.54 R200 CLSD with 28X9X15 ET Drag slicks 17psi, stock LS2 400hp/435tq, Z31 axles, Chequered Flag stub axles, single-adjustable Konis with rear rebound set full stiff and fronts set full soft.  Mantic ER2 clutch and pressure plate.  Lots of VHT with beautiful track prep.  Both wheels up during dead-hook, but engine bogged and dropped the wheels back down, almost instantly.  Two more wheelies during the night, but this was by far the best.  Lowered tire pressure to 15psi and reset 2-step to 4500 with plans to keep increasing 2-step till either I got some tire spin or broke something, but the car ahead of me in staging blew his tranny up and dumped all of its oil all over the track and drove right down the groove to half-track before grinding to a halt in the middle of the lane.  I saw 2-hours of track cleanup coming, so I loaded up and headed home.  Car performed below par with 1.60 60' times and consistent 7.30s at 96mph, mostly slowed by dead hooking, even bogging the car on gear changes.  I may be going back to 26s for this track since they put so much VHT down.

NICE, I wish mine could do that. They only way mine can do that is if I jack up the front end with a floor jack and airbrush the jack out of the picture. :D

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Yes ZG flares. Having trouble getting the video to download because it is in .mov format. And it is turned 90-degrees. The car had the traction to hoist em up, but not enough power to tote em more than about a foot or so. The video looks kind of ridiculous-like I hit a speed bump too hard. Thank goodness I kept my 26" slicks. I think the 28s will have a place on low-traction tracks, but I will definitely be going back to 26s and need to get hp-tuners to bump up my rev-limiter. Everything you said about 60-foot times is true to my experience. It was a good cool low humidity night-the car should have been faster.

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I don't make enough power to put the 28" tires to good use...lol  Your running a stock LS2 correct?  Put a cam, valve springs and push rods in her and go fly!  My LS2 is cam only and still thru the 4L80E made only 418 to the wheels but runs 6.70's consistently. I run a 255/60-15 Mickey Thompson Drag Radial, going to switch to a 275/50-15, which is a 26" tire.

Edited by Zfan1
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With 3.54 gears and your clutch likely locking up at less than .3 seconds in, rpm is going to be pulled down to around 1500 unless you can get some wheelspin or clutch slip. Nitrous can't help when the rpm is pulled down that low, but there are a couple things that you could try to get some wheelspeed...

...more air in the slicks

...if the rear of your car squats on launch, less rear shock

...more stored energy thru either a heavier flywheel or more staging rpm can help break your slicks loose, downside is the added torque spike when that stored energy is released can easily become a parts killer.

...add some clutch lockup delay.

 

Delaying lockup until about 1 second in will result in an rpm dip to around 3000, way better than the current 1500 or so. The added slip allows you to launch at a much lower rpm, so it's not adding as much clutch wear as you might think. If the added rpm nets you enough power to get a little wheelspeed as well, the resulting rpm at lockup of around 4000 will really make your car fly. This route is also much easier on the rest of your drivetrain, as it basically eliminates the torque spike from the flywheel effect of the spinning crankshaft/flywheel assy releasing energy during launch. Also makes it easier to hook up when the track isn't that great.

 

Here's an easy/cheap DIY way to add some lockup delay... http://grannys.tripod.com/clutchtamerdiy.html . I use one to get 1.30 60's from 28" radials, 3.73 gears and a 2.78 1st gear 4 spd, just not possible without it. If you decide to make one for yourself, i'll send you $50 if you report back with results  :)

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My ultimate plan is to build a drag-only Z, 275 drag radial car and put a solid axle and a powerglide in it (funny car style cage, wheelie bars, a trailer hitch and a parachute will be part of the initial build).  I think for this car I'm gonna keep it simple and just drop back to the 26" slicks and raise my rev-limiter to allow me to finish the race without a shift.  I really only went to 28s to try to get the last few feet of the 1/8-mile done in 3rd gear.  Remember, this is my daily driver, my standing-mile car, my autocross car and my road course car-I can't go all the way for drag racing.  I'm walking on the wild side every time I go to the strip and I can't believe I made it home with trailer optional after dead-hooking 5 times in a row and getting light in the front 3 times.  Weedburner-you are totally right.  I've read your stuff and it is super cool, but I don't want a slippy clutch, but I did pay attention to your advice on tires and shocks.  A couple questions:  If I raise my air pressure, will the bias ply slicks be less shock-absorbant (less sidewall wrap?)?  I was thinking that maybe by dropping tire pressure I was reducing the tire diameter at launch so that it would behave more like a shorter slick.  When you say "less rear shock", do you mean less compression resistance or less rebound resistance?  I had the rear shock on full stiff for rebound and the front shock on full soft for rebound.  Compression is non-adjustable.  I run 250# rear springs and 225# fronts.

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Just quit being a sissy and launch harder! I bet you won't bog with a 6k launch! We will fix your broken axle(s) afterwards. Seriously though, pretty awesome. Texis300 needs to hurry up and get his car running, that way I can at least say my parts are pulling the wheels off the ground haha.

 

Looking good though, keep it up.

 

-Will

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