NZeder Posted November 19, 2007 Share Posted November 19, 2007 Really gutted I couldn't make it, I almost put the car on the trailer and towed her up so you guys could have a look and I could see all your cars. Next time I'll be there with bells on Rob The quickest N/A car was a 240z with a 13.42 and a slipping clutch at 173km/h so should be a mid 12 sec car (car is built for the circuit not drags as 3.9 diff) Fastest 240z was 12.72 - a targa built car with supercharged LS1 with 4lbs boost. The 1000hp Supra dumped all the trans oil up the entire strip = 1 hour later for the clean up. I think it ran a mid 12 before the issue - I was not that interested wrong model of car (it had drag slicks too). Some 300zx Z32 running around the 13's. And 2 289 mustangs doing 15-14's all day long. Looking forward to seeing the car in the future Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted November 19, 2007 Share Posted November 19, 2007 Yep, just looking at the differences in the 60', a .5 in the 60' will equate to approximtely .75 in the 1/4 mile. That'll put you at 9.35 with no other change Lookin solid!! Quote Link to comment Share on other sites More sharing options...
RIPSNZ Posted November 19, 2007 Author Share Posted November 19, 2007 Yep, just looking at the differences in the 60', a .5 in the 60' will equate to approximtely .75 in the 1/4 mile. That'll put you at 9.35 with no other change Lookin solid!! Yeah thats about what I reckon too, Problem is I'm already out of mph at 8500rpm, I'll probably get some 4.56's and get the boost sorted on the line and may add another couple of pound of boost in 2nd and 3rd (was only 20psi on the 146.5mph run) and see if we can't get an 8 without NOS, Once again, thanks for the help:icon14: Quote Link to comment Share on other sites More sharing options...
S15 200sx owner Posted November 19, 2007 Share Posted November 19, 2007 Rob, Just watched your vid again, was that a bit of detonation on the launch? There is a short rattling/knocking noise just as you launch. Quote Link to comment Share on other sites More sharing options...
stony Posted November 19, 2007 Share Posted November 19, 2007 Just playing around with it at the moment as we still have the running in oil etc in there but it made full boost (16psi) by 6000rpm but this may be due to the 6000rpm converter and not having enough load until then.Once we get some good oil in there and wind her up with some advance, higher rpm etc and chuck 30 pound at it who knows??? Rob Now that you have it at the track can you tell what your stall speed is yet? and when your boost comes in. rb30 and rb26 is probably comparing apples and oranges but i figure its gotta be close. Just ordered mine and ATI says it will be in the 4500rpm range. I was thinking this would be too low. BUT i will be able to get it restalled if it is. Thier concern is that if it were too loose that it would have too much slippage in the hi rpm range. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted November 19, 2007 Share Posted November 19, 2007 Rob, Just watched your vid again, was that a bit of detonation on the launch? There is a short rattling/knocking noise just as you launch. I heard that to, but I don't think thats what I heard. I believe its the rev limiter hitting the max as the torque converter is slipping briefly... Thats just my opinion though, as thats what it sounds like to me. Quote Link to comment Share on other sites More sharing options...
BirdmanZ Posted November 19, 2007 Share Posted November 19, 2007 It sounds like the tires scrambling for traction and then finding it to me. Very impressive car. Quote Link to comment Share on other sites More sharing options...
stony Posted November 20, 2007 Share Posted November 20, 2007 Yea thats tire chirp for sure Quote Link to comment Share on other sites More sharing options...
RIPSNZ Posted November 20, 2007 Author Share Posted November 20, 2007 Rob, Just watched your vid again, was that a bit of detonation on the launch? There is a short rattling/knocking noise just as you launch. Definatly can't hear anything like that?? There is 2 or 3 blips of the rev limiter at the end of 1st gear, (just as the car goes past the camera) is that what you mean? Rob Quote Link to comment Share on other sites More sharing options...
RIPSNZ Posted November 20, 2007 Author Share Posted November 20, 2007 Now that you have it at the track can you tell what your stall speed is yet? and when your boost comes in. rb30 and rb26 is probably comparing apples and oranges but i figure its gotta be close. Just ordered mine and ATI says it will be in the 4500rpm range. I was thinking this would be too low. BUT i will be able to get it restalled if it is. Thier concern is that if it were too loose that it would have too much slippage in the hi rpm range. You might be onto something there, 8500rpm with 31in tyres and 4.88 gears should give us 158mph yet we were on the limiter at 146.5mph, maybe we are losing some mph with such a high converter? I just used the converter the car came with and although a little 'slippy' on the street it actually drives quite nice, it sure feels like around 6000 but I havn't had it held on the transbrake yet with any significant boost so can't confirm. The 26 will have far less torque than a 30 and with a large turbo you'll need all the help you can get to get the boost in as early as possible, maybe a sacrifice in top end slip is what you'll need to get away strong, your going to have to try it and see, just as I may have to try a lower stall once we wind up the power and add NOS, Rob Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted November 20, 2007 Share Posted November 20, 2007 Definatly can't hear anything like that??There is 2 or 3 blips of the rev limiter at the end of 1st gear, (just as the car goes past the camera) is that what you mean? Rob Thats what I hear.... Quote Link to comment Share on other sites More sharing options...
Careless Posted November 20, 2007 Share Posted November 20, 2007 There's a slight scratchy noise launchin off the line, but it's probably the most minimal amount of tire screech possible, if anything. doesn't sound like it's causing the engine any harm, but then again it's only a video camera. I wouldn't expect it to pick up anything of real concern unless it was super-loud. i don't think it's anything to worry about. To me, it sounds like someone just scratching a screen door or something. Quote Link to comment Share on other sites More sharing options...
stony Posted November 20, 2007 Share Posted November 20, 2007 Yea thats tire chirp for sure The sound is the tires on the edge of traction. the sound comes from well prepped tracks that have lots of traction. heard it many times!!!! Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 21, 2007 Share Posted November 21, 2007 You might be onto something there, 8500rpm with 31in tyres and 4.88 gears should give us 158mph yet we were on the limiter at 146.5mph, maybe we are losing some mph with such a high converter? Yup, you forgot to factor in converter slip in your calculation. If you are getting 146.5mph @ 8500, then my calculation says you have about 10% slip based on 1" of tire growth. 4.56 will get you another 10mph. Seems like something in the 4.30s would be ideal to avoid having to swap again. Quote Link to comment Share on other sites More sharing options...
stony Posted November 21, 2007 Share Posted November 21, 2007 Is there some kind of calculator out there to figure out all this??? I will be running a powerglide with 176 final 31 inch tires with 513 rearend gears. ATI says this will put me in the 150s at around 8500rpm Quote Link to comment Share on other sites More sharing options...
MyLaDyZ Posted November 21, 2007 Share Posted November 21, 2007 RIP.... hey this is a badass car, its CRAZY =), but i was wondering wat rearend you are running and if you can post or send me some pics of the rear setup Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted November 21, 2007 Share Posted November 21, 2007 Is there some kind of calculator out there to figure out all this??? I use this formula I found a gazillion years ago and find it fairly accurate. Multiply the tire diameter by 2.905. When using a slick, you need to add expected growth to the tire diameter. In this case I added 1" of tire growth. You then divide that number by the final drive to get MPH per 1000 RPMs. However, final drive is the diff ratio * gear ratio and if an automatic, you have to add converter slip. In this case final drive is 4.88 and I multiplied that by 1.1 to add in 10% slip. So, a 10% with 4.88s is equivalent to 5.368!!! In your case, you have a 31" tire on a 15" rim and we will assume 1" growth. You also have 5.13s and we will assume 10% slip. My calculation says you will get 140+mph at 8,500. Far be it for me to contradict ATI, but if RIP is seeing 146.5 @ 8,500 with 4.88s, you can bet you will see less as the calculation says. How did ATI come up with 150s? My calculator says 154 with zero slip. Impossible! Quote Link to comment Share on other sites More sharing options...
stony Posted November 21, 2007 Share Posted November 21, 2007 Ripz sorry this is turning into a thread jack but i guess it still kinda applies to your car to. Scottie im new to auto's so im going on what the "PRO'S" tell me. and here is what they said during my last phone call. I said i want to build a converter for my rb26 that will have about a 6000rpm stall. they said "we dont build converters to a certain stall we build the stall according to the build sheet." So i gave them all my specs and he says the stall works out to be around 4000-4500... I say well that will be too low, it will be a slug off the line. He says "well it all depends on what you want. This converter will be locked up in the higher rpms where if i go with a higher stall the converter may be too loose and will have excessive slip on the top end resulting in lower MPH then the converter with a lower stall." So i went with their recommendation they also said if the stall is too low all i have to do is send them all the numbers and the converter and they will restall it one time for free. So some time in april i will have the info. Quote Link to comment Share on other sites More sharing options...
RIPSNZ Posted November 21, 2007 Author Share Posted November 21, 2007 Stoney, even if you have no converter slip there is no way I can see you getting 150+mph from your gears at 8500rpm. With 4.56's and 31 inch tyres I "should see" 172mph, but when you take off converter slip I'm picking more like 160 and I'm sure if I didn't hit the limiter early I would have seen 150 with a 1.9 60ft and very low boost. To gain another 10mph is no easy feet but with race fuel, decent boost and possibly NOS I'd say the 160mph will get chewed up pretty quick. As Scottie says, 411's is too tall (191mph less slip) and I don't have quick access to anything between 411 and 456 so I'll probaly go with the 456, add 2 or 300 rpm if we need it and get a set of 430's on the way for backup. Rob Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted November 21, 2007 Share Posted November 21, 2007 Stony, Are you going to be running nitrous to flash the converter? That is really what you need to do as you don't want a super loose converter to build boost on the line. You will slip a lot on the top end if you use a loose converter that builds boost on the trans brake. Justin Quote Link to comment Share on other sites More sharing options...
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