Slammed68 Posted October 17, 2009 Share Posted October 17, 2009 Depends how far out he is having traction issues. I have trapped anywhere from 111-114 just based off of where my car will actually hook, which is pretty damn far out.. My buddies gto traps 125-126 and we hang right beside each other on the street now that my heads are on.. So you're telling me when my car traps 114 and will drive right beside a 125 car, that its not correct? We will see when my rear gets built and I get a tire on the thing. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted October 17, 2009 Share Posted October 17, 2009 Depends how far out he is having traction issues. I have trapped anywhere from 111-114 just based off of where my car will actually hook, which is pretty damn far out.. My buddies gto traps 125-126 and we hang right beside each other on the street now that my heads are on.. So you're telling me when my car traps 114 and will drive right beside a 125 car, that its not correct? We will see when my rear gets built and I get a tire on the thing. I made no comments on your car running beside your buddies car. I'm referring to your comment that trap speeds mean nothing, when it is a good indicater of how much power the car has. The et on the hand is influenced greatly by the setup of the car. That is what I was trying to point out. Quote Link to comment Share on other sites More sharing options...
Whittie Posted October 17, 2009 Share Posted October 17, 2009 In my N/A 2.9L l28 i have raced 3.5, 3.9 and 4.4 Diffs. Honestly, if i were building a turbo, regardless of what gear and rpm i wanted to be in at the end of the quarter mile (honestly, probably 4th at about 6500 or less, no more, not enough torque) I would run the 3.5 For cruising, racing, strip, whateva, it is just a good compromise. The 3.5 will also let you launch at decent rpm, get some small slip (wheel and clutch) and still have good legs when you hit boost so you're not changing gear all the time. Quote Link to comment Share on other sites More sharing options...
240zdan Posted October 17, 2009 Author Share Posted October 17, 2009 Depends how far out he is having traction issues. I have trapped anywhere from 111-114 just based off of where my car will actually hook, which is pretty damn far out.. My buddies gto traps 125-126 and we hang right beside each other on the street now that my heads are on.. So you're telling me when my car traps 114 and will drive right beside a 125 car, that its not correct? My traps were always within 1mph. A car that traps 10mph more than yours in a 1/4 mile is FASTER than yours. Trap speed tell you your power to weight. 1/4 mile tells you traction and setup like mentioned before by Bernardd. I really dont know where this is going. I like to have intelligent discussions on this forum but seems alot of the time Im arguing (or other people are arguing) about statements that make no sense. I dont care what you say, you may hang with your buddies GTO street racing for a few seconds but when it comes down to it he is going faster at the end of the 1/4 mile, therefore he accelerates faster than YOU. Simple isnt it? Whittie: a 3.5 isnt too far off from what I have now. I understand the concept of using lower gears with a boosted car but remeber I am still running a standard bore rb26 with very little bottom end grunt. I think a 3.7 would be ideal but id like to try the 4.11 and see what it feels like. If I dont like it I can always replace it with a different shortnose with different gearing.. Quote Link to comment Share on other sites More sharing options...
bradyzq Posted October 17, 2009 Share Posted October 17, 2009 Hi, Neat car! Couple of things you might want to consider: You mention that you have no traction in 1st and 2nd. This means your setup cannot get the torque to the ground. By going with a 4.11 over a 3.36 rear end, you are adding 22% more torque to the wheels. They will still be overloaded and spin even more! You say that your car is sluggish down low with little grunt. Not matter what your diff is, when you shift to 3rd, your revs will drop by the same amount, so staying up high in the revs is a transmission ratio issue, not a diff issue. Of course, your biggest change will be the addition of the LSD. Hopefully you hook so well with it that you shoot out of the hole like crazy. Good luck with the car! Quote Link to comment Share on other sites More sharing options...
240zdan Posted October 18, 2009 Author Share Posted October 18, 2009 drag radials shoudl solve the no traction issue, i am just afraid to run them right now with the oem 240z stubs and halfshafts. converting to cvs and billet stubs to solve that Quote Link to comment Share on other sites More sharing options...
Canadianz Posted October 19, 2009 Share Posted October 19, 2009 I know what you mean Dan about 3.3's being too tall. Alot of people forget that the 300zx /GTst transmissions already has taller gears in it. I have yet to take my RB to the track however I switched from a 3.3 to a 3.9 or 3.7. (I think it was the 3.9 and it really woke the car up, I no longer felt like I was driving a 3 speed with two over drives ! I was doing about 75 mph in 5th at just about 2k, which was amazing for fuel economy but dropping 2 gears to pull on a highway was a bit silly. Any how awesome numbers, sounds like your in for some fun, and faster times too! Quote Link to comment Share on other sites More sharing options...
Mike Rowe Posted October 21, 2009 Share Posted October 21, 2009 I have just got my RB26 260Z running. I have a 3.9 diff I think, I have an Apexi D Jetro, but not yet dynoed or properly tuned. I have the RB25 GTS 5 speed, and whilst the motor is forged everything, it is standard, other than bigger turbos. So far I have found that the gearing is far too tall, and I will be changing to a 4.1 as well. I also have an R32 GTR (390hp at rear wheels - cam & apexi & N1 Turbos) and the gearing is far lower (4.1 diff) and the car is much better, and the gearing not too low. Once I am run in and I have fitted the 4.1 & Quaiffe LSD I will tell you how it goes, but I agree with needing the 4.1 regards Mike Quote Link to comment Share on other sites More sharing options...
240zdan Posted October 22, 2009 Author Share Posted October 22, 2009 I know what you mean Dan about 3.3's being too tall. Alot of people forget that the 300zx /GTst transmissions already has taller gears in it. I have yet to take my RB to the track however I switched from a 3.3 to a 3.9 or 3.7. (I think it was the 3.9 and it really woke the car up, I no longer felt like I was driving a 3 speed with two over drives ! I was doing about 75 mph in 5th at just about 2k, which was amazing for fuel economy but dropping 2 gears to pull on a highway was a bit silly. Any how awesome numbers, sounds like your in for some fun, and faster times too! I know exactly what you are talking about. When I do a 3rd gear pull on the highway and top out the revs, I realize Im already doing twice the posted speed limit, and I havent even got to shift once! Right now my 87 toyota 4x4 daily beater is more fun to drive around town since I actually shift gears and dont have the sluggishness the 3.3 provide. The 4.11 will be awesome! And I really think the 4.11 with a proper LSD, 15 psi of boost on stock turbos, a new exhaust system with properely designed downpipe and maybe a set of drag radials shoudl put this thing well into the 11s. Right now I cranked up the boost to 15 psi for the hell of it with the open 3.3 and its not even fun. I am laying one wheel patches everywhere, even when on the highway. Just drop it to 2nd and stomp on it. 2nd probably goes up to 90mph. haha Quote Link to comment Share on other sites More sharing options...
Careless Posted October 23, 2009 Share Posted October 23, 2009 Have you any idea what your engine speed would be at say... 70mph in 5th gear? I'm contemplating changing my final drive... not quite sure if it would be a good idea yet. I have just got my RB26 260Z running. I have a 3.9 diff I think, I have an Apexi D Jetro, but not yet dynoed or properly tuned. I have the RB25 GTS 5 speed, and whilst the motor is forged everything, it is standard, other than bigger turbos. So far I have found that the gearing is far too tall, and I will be changing to a 4.1 as well. I also have an R32 GTR (390hp at rear wheels - cam & apexi & N1 Turbos) and the gearing is far lower (4.1 diff) and the car is much better, and the gearing not too low.Once I am run in and I have fitted the 4.1 & Quaiffe LSD I will tell you how it goes, but I agree with needing the 4.1 regards Mike Quote Link to comment Share on other sites More sharing options...
Mike Rowe Posted October 23, 2009 Share Posted October 23, 2009 I cant tell you as yet as the tacho isnt working, but I am having that sorted shortly Quote Link to comment Share on other sites More sharing options...
Challenger Posted October 23, 2009 Share Posted October 23, 2009 I dont care what you say, you may hang with your buddies GTO street racing for a few seconds but when it comes down to it he is going faster at the end of the 1/4 mile, therefore he accelerates faster than YOU. Simple isnt it? This isnt neccesarily true. Accelerating at a somewhat constant rate will give you about the same top speed at the quarter as a slow launch (spinning the tires) with the rest being balls to the wall. Also as mentioned, If your complaining about having wheel spin in 2nd wont the 4.11 amplify that a lot? I love long gears, constantly shifting takes away from the speed in my opinion. But 90 in second would be pretty awesome. Quote Link to comment Share on other sites More sharing options...
GrayZee Posted October 23, 2009 Share Posted October 23, 2009 For a L28et I would say the 3.54 gear is the right choice as that engine has alot of torque but only about 6k rpm to work with. For a Rb, a 4.11 might work well seeing that you have alot more rpms available between gear shifts. As long as you don't put yourself in a position where you find yourself shifting into 5th at the end of the quarter. Quote Link to comment Share on other sites More sharing options...
stony Posted October 23, 2009 Share Posted October 23, 2009 I can tell you that a 4:88 will put you in the top of 5 th gear. It will also throw enough torque at the rearend it will shear z 31 stubs like they are solder. If you are go down the how do I go fast in the1/4 mile road i would have to say go with the ttt rearend with a gtr diff and built rb 25 tranny. The only other way to get down the 1/4 mile is a backhalf. Quote Link to comment Share on other sites More sharing options...
Slammed68 Posted October 23, 2009 Share Posted October 23, 2009 This isnt neccesarily true. Accelerating at a somewhat constant rate will give you about the same top speed at the quarter as a slow launch (spinning the tires) with the rest being balls to the wall. Also as mentioned, If your complaining about having wheel spin in 2nd wont the 4.11 amplify that a lot? I love long gears, constantly shifting takes away from the speed in my opinion. But 90 in second would be pretty awesome. Thats what I am trying to relay to them, they might be trapping within 1mph of each run when hooking.. Im saying, trapped 84mph BEST ONE NIGHT, 92mph BEST A DIFFERENT NIGHT, same setup, in the 1/8th, just by where i start hooking, 92 obviously being a very VERY light launch with no throttle variation in 1st and easing through 2nd.. BUT - I agree, from a dead hook or having little traction problems you WILL trap very close on each run. Right now my best trap in the 1/4 is a 114... sad right? But my car IS faster than my buddies 125-126 trap GTO, and it is faster from down low to up top, anywhere in the range.. SO - unless you're dead hooking, or not having huge traction issues, dont worry about your trap. Ban me if you don't like the truth, pro's. Quote Link to comment Share on other sites More sharing options...
240zdan Posted October 24, 2009 Author Share Posted October 24, 2009 Im saying, trapped 84mph BEST ONE NIGHT, 92mph BEST A DIFFERENT NIGHT, same setup, in the 1/8th, just by where i start hooking, 92 obviously being a very VERY light launch with no throttle variation in 1st and easing through 2nd.. BUT - I agree, from a dead hook or having little traction problems you WILL trap very close on each run. Im sorry I dont understand your language. No one can convince me that your car is as fast as a car that can trap 10mph more than yours in a 1/4 mile. A car that traps 10mph more than yours in a 1/4 mile is FASTER than you, I dont CARE what it runs in the 1/4 mile or what you run, I am talking about racing on the highway, from a 80mph roll, to 140mph. You will get walked on. As far as 4.11 introducing wheelspin, I am having wheelspin issues due to the fact I am running a OPEN r200 with worn street tires. I would obviously run radials and the 4.11 woudl have an LSD. I think I mentioned this a few times already. Off I go to install my 4.11 and watch my times get better Quote Link to comment Share on other sites More sharing options...
GrayZee Posted October 24, 2009 Share Posted October 24, 2009 Off I go to install my 4.11 and watch my times get better Good luck, and let us know how it works out. btw, I don't understand how a car can get 10 to 20 mph differences in trap speed regardless of 60fts. Unless you are letting off the throttle mid way down the track or something. Last time I went to the track I had BRUTAL traction issues, I ran a 13.4@117.5mph. Now if I was able to get some textbook starts I would likely run mid 11's but I certainly would not expect a 125+ mph trap unless I did something to increase HP as well. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 24, 2009 Share Posted October 24, 2009 SO - unless you're dead hooking, or not having huge traction issues, dont worry about your trap. It might take much longer to cover the first few feet, but the car is still accelerating just as hard for the other ~1300 feet. I've run(in my f-body) 15.3 at 106 because the track was cold and I didn't get the tires hot, waited a bit and did a better burnout, 13.0 at 108, got a bigger stall converter and slicks and went 12.3 at 109. That's a 3mph variance over 3sec. Quote Link to comment Share on other sites More sharing options...
Slammed68 Posted October 25, 2009 Share Posted October 25, 2009 I'll get some footage, my PB trap is 114, have done it twice. From a 50 roll where he hooks on the street, I walk him. Very slightly, BUT, I walk him.. I mean, look at the video of me and him going from a 50 roll BEFORE my heads were on, I barely got ran on, and after a LOT of tuning with the new heads, it pulls like a train compared to before. We've ran, I walked him. I mean, seriously guys, just because you haven't done it, doesn't mean someone else hasn't Going from 9.2:1 comp to 11:1 comp, better flow, and going from 130% inj duty at 6K to 81% inj duty at 6K... and 10.7:1 AFR to 12.7:1 AFR.. tell me that my car with that much of an improvement would not pick up what is lost in the above run.. Quote Link to comment Share on other sites More sharing options...
GrayZee Posted October 25, 2009 Share Posted October 25, 2009 Here is some good reads: http://www.stangnet.com/mustang-forums/567417-trap-speed-vs-et-explained-here.html http://www.turbobricks.org/resources.php?content=quartermiledyno Quote Link to comment Share on other sites More sharing options...
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