Whittie Posted December 6, 2008 Share Posted December 6, 2008 The dotted lines are from the last tune, the only difference this time was the exhaust!! Went from a stock header 2.25" system to mandrel 6-2-1 tuned length extractors and a 2.5" highflow exhaust Power is not that massive but the torque is HUGE, pulls like nothing else! Here is a bit of a write up about the car now its finished, including spec list and some pics: http://forums.hybridz.org/showthread.php?t=141631 **EDIT** Just for clarification, this is wheel numbers, not flywheel as i know the graph says Quote Link to comment Share on other sites More sharing options...
ktm Posted December 6, 2008 Share Posted December 6, 2008 How can the new torque and HP numbers cross at one RPM and the old numbers cross at a different RPM? They both should cross at the same RPM. Quote Link to comment Share on other sites More sharing options...
Whittie Posted December 6, 2008 Author Share Posted December 6, 2008 Should they? Why is that? Quote Link to comment Share on other sites More sharing options...
ktm Posted December 6, 2008 Share Posted December 6, 2008 Unless I am missing something, torque and horsepower when plotted on the same vertical scale must cross at 5250. Things get a little odd when torque is on one scale and horsepower another. Saying that, your original curves are plotted on the same vertical scales as your revised curves. Torque and horsepower for both runs should cross at the same RPM if the scales are the same. Notice that on your latest run the curves cross damn close to 5250. Converting Nm to ft-lbs indicates that your torque and hp are on the same scale. On your latest run, the curves cross at 5250, at ~167 hp and ~ 167 ft-lbs (227 Nm). Quote Link to comment Share on other sites More sharing options...
JIM73240Z Posted December 6, 2008 Share Posted December 6, 2008 yep. something is amiss. torque and hp ALWAYS cross at 5250. it is a math thing. jimbo Quote Link to comment Share on other sites More sharing options...
ozconnection Posted December 6, 2008 Share Posted December 6, 2008 I'm happy for you that you found increases in midrange torque. That really makes the car 'fun to drive' and really responsive to your right foot. Well done on your upgrade. Those torque curves look a little erratic IMO. I had graphs that looked like that when there was wheelspin on the chassis dyno. It's just so difficult to interpret curves that look like that and what to tune/correct with engine calibration to 'smooth' things out a little. Post some sounds from your tailpipe here so we can have a listen please. Better still, strap a small one to the arse of the car and take it for a spin so we can listen to it properly 'winding up under load' Cheers mate. Quote Link to comment Share on other sites More sharing options...
datsun723 Posted December 6, 2008 Share Posted December 6, 2008 is your L28 stock otherwise? Quote Link to comment Share on other sites More sharing options...
Whittie Posted December 6, 2008 Author Share Posted December 6, 2008 here is an incar vid of last weekend. So obviously before the tune, but still with the new exhaust. After the tune it sounds much deeper but otherwise very similar. and no the zed is not stock L28, 60 thou over bore, flat top pistons, shaved deck and head, head port, triple 45 webers etc etc. read the link i posted to my write up and just scroll down for the full list http://au.youtube.com/watch?v=CJn4M5SktwY Quote Link to comment Share on other sites More sharing options...
PalmettoZ Posted December 6, 2008 Share Posted December 6, 2008 here is an incar vid of last weekend. So obviously before the tune, but still with the new exhaust. After the tune it sounds much deeper but otherwise very similar. and no the zed is not stock L28, 60 thou over bore, flat top pistons, shaved deck and head, head port, triple 45 webers etc etc. read the link i posted to my write up and just scroll down for the full list http://au.youtube.com/watch?v=CJn4M5SktwY Hey Whittie- Good driving skills, you worked your way right to the front there. How did you end up ? Car sounds really good too. Quote Link to comment Share on other sites More sharing options...
TimZ Posted December 6, 2008 Share Posted December 6, 2008 Unless I am missing something, torque and horsepower when plotted on the same vertical scale must cross at 5250. Things get a little odd when torque is on one scale and horsepower another. Saying that, your original curves are plotted on the same vertical scales as your revised curves. Torque and horsepower for both runs should cross at the same RPM if the scales are the same. Notice that on your latest run the curves cross damn close to 5250. Converting Nm to ft-lbs indicates that your torque and hp are on the same scale. On your latest run, the curves cross at 5250, at ~167 hp and ~ 167 ft-lbs (227 Nm). You're almost there - the 5250 thing is a conversion specifically for torque in lb-ft and horsepower. If you convert both torque plots to lb-ft then you will find that they do have the same value for hp and torque (in lb-ft) at 5250. Quote Link to comment Share on other sites More sharing options...
ktm Posted December 6, 2008 Share Posted December 6, 2008 Duh. The 5250 is specific to torque in ft-lbs and power in horsepower. Thanks Tim. Quote Link to comment Share on other sites More sharing options...
Whittie Posted December 7, 2008 Author Share Posted December 7, 2008 Hey Whittie-Good driving skills, you worked your way right to the front there. How did you end up ? Car sounds really good too. Cheers Well the event was regularity. The aim of the game is to post a time and then repeatedly do that time over and over. You score 1 point for every 1/100th of a second you are away from that time, lowest points at the end of the day wins. So, in terms of regularity, I lost But in terms of what counts: Fastest Z (of 8 on the day) and 3rd fastest in the field behind an evo 9 and my old mans TT supra Quote Link to comment Share on other sites More sharing options...
Globerunner513 Posted December 10, 2008 Share Posted December 10, 2008 That sounds like a endurance racer i talked with. He told his team that who ever posted the fastest lap time of the day had to buy dinner for the whole crew. Basically ensuring that they endured, first and foremost. Interesting concept. Quote Link to comment Share on other sites More sharing options...
Whittie Posted December 12, 2008 Author Share Posted December 12, 2008 Globerunner, that is exactly what regularity is about. However, within our field of about 8 z's we have a tendancy to take things a little serious basically its the only way to race in a pack without a full race licence and log-booked car. So for me and the other zed boys we take it as a chance to just have a bit of fun and none of us take it too seriously in terms of regularity or fastest time, just as a good way to race with people we respect as drivers. When i want to go fast i go to sprint days. Infact i have a sprint event tomorrow so it might be a chance to see if i can go one better than last time. I will be sharing drives with my dad and we will be swapping cars so i wont get a super fast time in 1 run. I will however be able to truely guage how much faster the car is now than it was Quote Link to comment Share on other sites More sharing options...
zxtman Posted December 12, 2008 Share Posted December 12, 2008 FYI ... just so that we all know, the exact number is 5252 Quote Link to comment Share on other sites More sharing options...
Sideways Posted December 16, 2008 Share Posted December 16, 2008 How can the new torque and HP numbers cross at one RPM and the old numbers cross at a different RPM? They both should cross at the same RPM. I know im late on this and maybe its been answered by now (though i did see a couple others asking), but check the scales. Hp is on the left, torque is on the right. They are set to different scales. Quote Link to comment Share on other sites More sharing options...
katman Posted December 18, 2008 Share Posted December 18, 2008 Uh, 30+ ft-lbs increase with just an exhaust system change? That don't pass the giggle test. You have a 'tater stuck in the pipes of the old system? Quote Link to comment Share on other sites More sharing options...
Sideways Posted December 18, 2008 Share Posted December 18, 2008 I see a 20 pound increase, fwiw. Quote Link to comment Share on other sites More sharing options...
fhptom Posted December 18, 2008 Share Posted December 18, 2008 When I do my DE events consistent lap times are the only thing to gauge whether or not you are hitting your marks every time. I like the concept alot and it gives you a goal when you are out there with cars of much greater HP and cannot keep up in there pack. Tom Good video of some nice Z cars also. Quote Link to comment Share on other sites More sharing options...
TimZ Posted December 18, 2008 Share Posted December 18, 2008 Uh, 30+ ft-lbs increase with just an exhaust system change? That don't pass the giggle test. You have a 'tater stuck in the pipes of the old system? Look again - the graph is in Newton-Meters, not lb-ft. 20Nm is about 14.7 lb-ft. Quote Link to comment Share on other sites More sharing options...
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