jgkurz Posted October 9, 2007 Share Posted October 9, 2007 Hi folks, I'm heading out to the drag strip this weekend and am thinking of ways to improve my 60ft time. My car is a 77 280z with a turbocharged L28 and a 5spd manual transmission. It is a street car and will never have slicks or drag radials put on it. My rear tires are Bridgestone RE750's 245/45-16. They are a good high-performance street tires that hold up well for auto-crossing and road racing on track days. The problem is that I can't seem to get better than a 2.0 60ft. I'm usually at 2.1. I've tried launching the car at 2500RPM all the way up to 5000RPM. I've also tried hard side-stepping launches and softer clutch riding launches. I have even made several adjustments my Tokico Illumias but nothing seems to help. Over the summer I trimmed my bump stops so I now have much more suspension travel. I think this will help a bit. I've also thought about heating the tires up a bit. Not a smoky burnout but just enough to get some temperature in the rubber. The air temp will probably be 60deg at race time so a little cold for perfect traction. I'll probably run my tires at 25psi rather than the 51psi rating. Lastly, I've thought about hooking up my auxiliary rev limiter. My EFI allows me to use a secondary rev limiter for a purpose like launching at the drag strip. Would this help build boost even if I'm not able to load a torque converter? I wouldn't think it would but I've seen different schools of thought on this. If anything it would allow me to be consistent on my launch RPM which is still helpful. Thanks in advance for any feedback. Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted October 9, 2007 Share Posted October 9, 2007 I think an aux rev limiter will go a long way to having consistent launches. I really think the issue you have is with lack of suspension travel with the unsectioned struts and the shorter springs. I hope that the trimming you did on the bump stops will alleviate these issues. Does tire pressure play a roll when on street tires? Justin Quote Link to comment Share on other sites More sharing options...
jgkurz Posted October 9, 2007 Author Share Posted October 9, 2007 I think an aux rev limiter will go a long way to having consistent launches. I really think the issue you have is with lack of suspension travel with the unsectioned struts. I hope that the trimming you did on the bump stops will alleviate these issues. Does tire pressure play a roll when on street tires? Justin Yeah, I'm hoping the suspension travel will help. Better weight transfer should give me more bite. Lowering the pressure in street tires will not make a huge traction difference but it should help slightly. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted October 9, 2007 Share Posted October 9, 2007 I've heard not to heat up street tires as that makes them slicker, and only spin them a little if they have a lot of gravel/debris on them. You should be getting better 60' times as with a stock L28ET in my 280z with harder-then-a-rock Kumho tires I manage to consistently hit 2.1 and even once a 2.0. I launch at about 3.5k rpm with some clutch slippage to avoid spinning followed by a hard shift close to 6200 rpm. What are your Illuminas set at? I have mine at 3 in the back. Mario Quote Link to comment Share on other sites More sharing options...
jgkurz Posted October 9, 2007 Author Share Posted October 9, 2007 What are your Illuminas set at? I have mine at 3 in the back.Mario I've tried many combinations but because my suspension travel with the old bump stops was so limited I think it made little difference. My plan for this Sunday is to just set them all at 1 unless someone was adamant about a different arrangement. Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted October 10, 2007 Share Posted October 10, 2007 I can't find Norm's posts on how to do this, but if I remember correctly he ran low 20 psi in the tires, med. setting on the rear struts, soft in the front struts, and a short burn out. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted October 10, 2007 Author Share Posted October 10, 2007 I can't find Norm's posts on how to do this, but if I remember correctly he ran low 20 psi in the tires, med. setting on the rear struts, soft in the front struts, and a short burn out. I found these posts by HybridZ member norm[T12SDSUD] http://forums.hybridz.org/showthread.php?t=76581&highlight=psi http://forums.hybridz.org/showthread.php?t=89986&highlight=psi He says he got a 1.81 60ft on 195/60-14 street ties. Wow!! Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted October 13, 2007 Share Posted October 13, 2007 That's him. I was looking on zcar, where he still posts. He knows is dragging that's for sure, just couldn't play nice. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted October 15, 2007 Author Share Posted October 15, 2007 Thanks to everyone who responded to this post. It helped me a great deal at the the track today. Here's the write-up. http://forums.hybridz.org/showthread.php?p=814680#post814680 Quote Link to comment Share on other sites More sharing options...
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