Phantom Posted May 14, 2003 Share Posted May 14, 2003 Car is now in development and finishing stage. Running well enough to know that it squats and then develops some wheel hop when under power. Anyone with suggestions on how to stop that? Also, angle of half-shafts don't seem to be quite right but obviously the R200 is mounted where it belongs. Springs are the european spec nissan springs so they are 1/4" shorter than stock but 15-17% stiffer so height is pretty much normal on that end. They are also only about 5 years old. Thoughts? Strut tower braces were ordered last week and should be here this week. Quote Link to comment Share on other sites More sharing options...
cyrus Posted May 14, 2003 Share Posted May 14, 2003 Hey whats up, I am glad it is running. Get it to a drag strip quick. Dont just guesstimate the results. I want to know what it runs relative to mine. I am considering the LS6 now. I have axel hop too, but at the drags with the tires HOT. It stickes and runs 12.0 @119. My car has huge squat and rolls laterally back and forth under full power! Quote Link to comment Share on other sites More sharing options...
Guest 1SickZ Posted May 14, 2003 Share Posted May 14, 2003 AiR bags.. for the squat and wheel hop.. Airlift part # 60773 about 50 bucks:: http://www.airliftcompany.com/ installed on 88 turbo 300: http://www.geocities.com/spoolinaz/airbaginstall.htm Quote Link to comment Share on other sites More sharing options...
Guest 1SickZ Posted May 14, 2003 Share Posted May 14, 2003 better off to take measurements of your springs let air lift know and they set you up with what you need mgiht be same part # but might not be hope i helped some. Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 14, 2003 Author Share Posted May 14, 2003 Wheel hop could also be a function of the "squat" which will change the tire contact parameters. Moving the differential mount about 1" higher to see how that affects it. Also checking out the airlift site. Newest "ready" date looks like next week. Will have suspension all back together, AC & gauges working. Engine/clutch/tranny are working great! Thanks guys. Quote Link to comment Share on other sites More sharing options...
jeromio Posted May 14, 2003 Share Posted May 14, 2003 This may be redundant and obvious, but if you move the diff mount, make sure you move the whole thing (ie, front and rear). As Pete's site details, maintaining proper ujoint phase is important. I spent a great deal of time trying to ensure proper phase, but I'm worried that I may have some bad drivetrain harmonics anyway (in other words, I didn't do a good enough job). It's hard to tell though since the damn exhaust is SOOOO loud. Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 14, 2003 Author Share Posted May 14, 2003 Jeromio, Thanks for the heads up on the mounts and the u-joint phase. Got it covered. Car is relatively quiet - when the exhaust is attached. Not so quiet today as it's off with the rear end work being done. Cyrus, Probably won't see the dragstrip for at least 3-4 months. Want to make sure it is fully sorted out before I try to break it. Will get it on a chassis dyno and an axle scale fairly quickly though so I'll have some of those numbers. Do you have strut tower braces on the car front and rear? Also - I forget - are you running an LSD or peg leg? Those could affect the side-to-side. Quote Link to comment Share on other sites More sharing options...
cyrus Posted May 14, 2003 Share Posted May 14, 2003 No LSD, one wheel wonder and not bracing. I think the rear arm bend inward under full steam giving the rear to much toe in. Tires are old 215/60/15 on 6.5" I got to get my Viper rear suspension put in! Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 14, 2003 Author Share Posted May 14, 2003 Cyrus, I've got the 3.7:1 R200 LSD. When I get a chance I'me going to try some second gear starts and see how that affects things. Also, I've got the strut tower braces from racetep coming. The front braces back to the firewall and the rear has a second member that comes down on one strut tower to form a triangular brace that should be much stiffer than a normal rear brace. May want to consider that. Quote Link to comment Share on other sites More sharing options...
cyrus Posted May 14, 2003 Share Posted May 14, 2003 Phantom, your funny, that with that 3.70 you will NEVER have traction except with slicks! I am going 3.07, but I think a 3.36 is ideal with good traction. Let me know how it works. 1st rear engine 2.62 * 3.70 * 340ft lbs = 3296 lbs of axle torque LS1 2.62 * 3.07 * 340ft lbs = 2735 lbs of axle torque LS1 2.62 * 3.07 * 400ft lbs = 3217 lbs of axle torque LS6 Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 15, 2003 Author Share Posted May 15, 2003 Cyrus, Yup, your math is correct. Thats why I said I was going to try some second gear starts. 1.78*3.70*340=2239 lb-ft axle torque. May actually be able to come off fairly well. Any way you look at it though, unless the T56 has some special gearing, one of the gears, either 1st or 6th, is going to be basically useless. Now, if I could get a T56 with a custom set of gears, life would be large. I just really don't think that is in my budget, though. 1SickZ, Checked with Airlift. Their application only works with leaf or coil spring set-ups. My '77 has struts in the rear. Thanks for the suggestion but it looks like it's not an option on this car. Quote Link to comment Share on other sites More sharing options...
Guest 1SickZ Posted May 15, 2003 Share Posted May 15, 2003 O.K. my bad didnt know the strut info. But comon doesnt somone make air bags for a strut ? i know these honduhs are driving around with them on there struts.. and truck i know someone has a universal app you can use. Quote Link to comment Share on other sites More sharing options...
cyrus Posted May 15, 2003 Share Posted May 15, 2003 With a "reasonable" suspension set up I am wondering how much tire is required to make first gear stick on 17's. 275, 315, 335,...? and at some point does it become useless due to the camber change. Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 15, 2003 Author Share Posted May 15, 2003 I have a coworker with a 3400 lb., 345 HP C-5 Corvette. He can squall his tires in second gear if the traction control is off. He is running 275 wide tires. I am far from being expert ont his but I would think that with a 2800 lb car it is going to take 15" drag radials at least that wide to have a chance. To get 275's you'll have to either tub the back end or put some serioous flares on. Maybe some guys that frequent the suspension forum can help out? THe old addage continually proves itself true - more HP = more $$$. Quote Link to comment Share on other sites More sharing options...
maichor Posted May 16, 2003 Share Posted May 16, 2003 How did we get on the tire subject? I was actually looking for the R230 300zxtt diff. to get the 3.7 ratio. Isn't that what they had? The non turbo had a 4.08 R200. I finally went with what I found. R230 from a Q45 (3.54). The reason I wanted the taller gear was because I will have some big tires under there, taller and much wider than before. 6 the gear redline is about 170 mph, first gear redline is 55 mph. Anyway, back to the tires. Since I am cutting the suspension down anyway, I have been trying to decide how much tire is too much. Is there such a thing? :flamedevil: I am shooting for a minimum of 315/35/17's on 11 inch rims. On a 12 in rim I can go up to viper size and beyond (335 or 345 in a 30 series. This would never be possible without my custom suspension and 5" of flare per side from the Velo Rossa Kit. Price goes way up when you get that big, but you know what they say, "wider is better" Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 16, 2003 Share Posted May 16, 2003 Hello Phantom, Cyrus, and all; This may not fit in here too well but it could be candy for Cyrus! One of the first rules for coming out of the hole quickest is to break loose as little as possible (which requires a very tricky foot if you don't set the car up for it). What I am talking about is being able to take your foot and quickly load the full engine power through a properly tuned chassis and gears to the proper tires all without a cloud of smoke and lost time. The choice of trans. is very critical to such performance and if the situation has not been very well thought out some dissappoints are in order. If you had the power and the bite in your "launch gear" you would want the front tires to come off the ground between 8-12 inches to set the chassis angle/weight back on the rear tires for a maximum bite/launch. With a automatic it's the proper choice of convertor "Stall Speed". With the standard it's either steel nerves and a trick throttle foot or a good tuned setup I described or a combination of both. Depending on the year, our Z's are lighter than most of the competition and the power/weight ratio is exellent. But the gears..... ah! the gears must be right! Did I hear someone mention 1.72's coming out of the hole? If the clutch would hold the little extra slippage time after time then I suspect that combo would closely approximate what I suggest (if throttled properly), at least one would have a better chance of moving out insteag of trying to dig a hole in the asphalt. Just don't let it go the other way and bog. If it bogs at all then you lose!..... and have to do something additional like reduce the tire size or raise the rear tire pressureelse. Never settle for a bog! It's tough to set op a stick with a good hole shot gear, good luck there. Next we have second to contend with. If you want to really play the game of drag racing you have to know and use the strongest part of your torque band once you get out of low gear. If you don't know what RPM range this band is in and shift accordingly, then you lose again! It works like this: Lets say your cam grind comes in (according to the manufacturer) at 3500 rpm and makes good torque until 6000 where it really takes a dive; let's say your valve springs are good for 7000 rpm.....then the cam is good for that much but, because the torque is dropping fast, the last 1000rpm is a waste of time as far as your best accelleration time is concerned, so we don't use that part for drags. But then neither do we use the lower part of say from 3500 on up to say 4000 rpm (except in first gear). This leaves us a torque range/power band of 2000 rpm (4-6000) to shift within, keeping the rev's up and staying within the most powerful 2000 rpm part of the entire "Power Band" all the way! My Richmond 4+1 (5 speed) drops back about 1700 rpm's each time I shift. Staying in my power band's strongest part keeps my accelleration at the max for what power I have. This is what you want and, it's exactly what the front runners have going for them. 2nd gear, 3rd, 4th? .....all the same. Your shift point would always be 6000 rpm. You would want to also try to finish the quarter just as you peak at 6000 in 4th, or as close to it as possible without having to run it past 6000 where time is lost or shift where even more time is lost. Of course for the car to be able to perform like this at the end will reflectsome on the holeshot gearwise, you just have to sort that out like everybody else. Use the ring and pinion and tire size to help you do that. Now the tires. For the maximum performance it's true.....the wider the better (of course), but ubfortunately as has been mentioned in here, that can be a problen because of extensive mods and cost. Well, what can I say?.....Get the widest you can and build your trap run around those. This is not good if you want to later go for the biggies because that will alter your whole run and you'll likely have to tune the chassis all over again. But that's life.....LOL In such a short post I hardly have time to mention driver skills. I will mention only one cardinal rule for winners. Practice this reverently: Once at the line, you can neither see or hear the other car, it is not there, you are racing alone against time. You can see the lights, hear your engine and see the strip, that's all! If you can't learn to be professional and hold this concentration then the other guy is going to give you the razzle-dazzle and jump you at the light, (he may jump you anyway but you and the car did your best). And who knows.....whocares?.....he may "Red Light" for all his fooling around! See you there!..... And I'll be looking underneath to see if you at least got ladder bars! Quote Link to comment Share on other sites More sharing options...
Phantom Posted May 16, 2003 Author Share Posted May 16, 2003 Thanks for the words of wisdom spiirit. My combination of tires, tranny & differential gives the following speeds at 6,000 RPM: 3.70:1 Other option of 3.07:1? 1st = 45 54 2nd = 67 81 3rd = 92 111 4th = 120 145 5th = 162 195 6th = 240 289 I was thinking that a second gear launch, assuming the clutch holds, would get me through the quarter with just two shifts and I'd be at redline in 4th as I crossed the line. The weak link in my accelleration is the tires so this is going to take a lot of skill - which I don't have at this point - but it will improve with practice. The 3.07 rear end would require a 1st gear launch and three shifts through the quarter with the engine lower in the power band at the end. Quote Link to comment Share on other sites More sharing options...
cyrus Posted May 16, 2003 Share Posted May 16, 2003 Well actually all this stuff is interdepentant... The differential determine the torque being put down. The tires have to handle that. Then the fenders have to accomidate the tires. And the real stinker is under stock fenders a 235 is all that will go under the front so you probable do not want to exceed 285 on the rear. Now with your flares that that is not an issue. With my viper suspension I could run 335 but that would dwarf the front and make its handling suck. Some times I can't win! ps I do not see any way to make the rears wheels match the front with the 6 lug rears! Quote Link to comment Share on other sites More sharing options...
maichor Posted May 16, 2003 Share Posted May 16, 2003 I am lucky, because the VR kit gives me 2" of flare up front so thats an extra 50 mm per side so you are talking 285 up front, that is why I will go with 315's or 325, in the rear. Blueovalz has 315's all around but he has huge flares front and rear. It is all just a dream at this point. But, my goal is to have it driving, not complet in December. So, between now and then, floor pans, subframes, rear suspension, rest of wiring and plumbing and mount the kit. No paint or finish interior by that date. Wish me luck. Quote Link to comment Share on other sites More sharing options...
cyrus Posted May 16, 2003 Share Posted May 16, 2003 Phantom I see 120mph in 4th on your car. I am already there. I think it should be 130mph so you have room to grow. 5 gear is unacceptable. Quote Link to comment Share on other sites More sharing options...
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