Ok im not too hot with the search button i know so sorry if this has been asked but i couldnt find it.
Im after the max speeds (at 7000RPM) in each gear on a S14 manual with standard diff. The reason i ask is due to the fact that i am right on the change point between 3rd and 4th while drag racing so im considering a different closer diff to get me into 4th earlier.
Would the S15 diff acheive this as i dont know the ratios or would i be looking at a auto diff?
Cheers
The reason you probably can't find anything on it is because it would come under careless driving habits etc....
Its not a good idea to post saying "I got 130mph in 4th in my 200!!" as it just promotes people to go out and try it or better it.....
May be worth asking the question in motorsport section rather than the general section...
surely the question of the speeds is irrelevant. if you are just about to hit 4th at the qtr mile you have to change something.Originally Posted by redlinezak
either up the power, so you will hit 4th earlier on the strip, or use the auto diff which is lower.
I'm in the same boat mate.
You want an S14 auto diff or a skyline GTS-T diff (shorter than the auto) or a GTS-T auto diff (even shorter again).
That or fit tiny rear wheels and tyres
Hence my question as to what speeds i can expect in each gear. If changing to an Auto diff will get me into 4that say 90 mph then ok but if it only lowers it by a couple of MPH i might need to think of a different unit as i would lose more time changing gear than i would gain. currently i can touch 109mph on the strip but thats with grabbing an early 4th.
Im guessing the S15 diff will lower the ratios a fair bit from standard so thats looking favorite at the moment but i could do with someone to confirm.
Also it doesnt need to be proven as im sure someone cleverer than me knows how to calculate it (i know tyre size will change it somewhat) but even on standard rims it would be a help.
Cheers
You could use smaller diameter tyres to lower the gearing a bit.
Don't know how much of a difference it would make though.
There is a calculation to work out the speed, but you need to know the ratios of the gears, and the final drive.
I used to know it, but can't remember now. It's got something with the amount of revolutions the wheel does per mile in it somewhere though
Edit: must type faster !
Last edited by Daniel H; 27-11-2008 at 17:57. Reason: missed last reply typing too slowly
all i know is....
smaller wheels = more acceleration
bigger wheels = higher top end
longer gear ratio = higher top end
closer gear ratio = more acceleration
most people on strips go for a closer ratio (grabbing more gear changes) and a lower final drive as this means faster acceleration but lower top end.
i could be talking crap but thats what i know....lol
Yeah thats the general theory although in high end racing the ratios are very closely calculated. Obvioulsy im not going that extreme but would be nice to make a more educated decision
The auto diff ratio would solve your problem. You can fit the workings of a S15 diff and have the ratio of another, the 2 parts are seperate.
If you ask Sprout on here about it, he can talk you through it, having put a S15 diff into his S14a diff casing, so had it all apart as well
dammit just asked the question to which youhave just provided the answer in another thread i found whilst searchingSo effectively i can have the helical S15 diff with an auto's ratio........ I think you need to take up drifting in that S15 of yours Ben and of course for drifting you will need a 2 way diff
Think i have sorted out now what i need cheers. I will have MT street's on the back so not really the option of going any smaller.
Cheers guys
That last message makes no sense to meManual transmission streets?
Drifting is not my bag... why dont you take up drifting, then you wont be bothered about ratios
S14 box with manual diff (3.692)
1 - 41
2 - 71
3 - 103
4 - 135
5 - 161
S14 box with auto diff (3.920)
1 - 38
2 - 66
3 - 96
4 - 126
5 - 151
Basic calculation of actual speed, not speedo speeds
I was pretty sure I got 110 out of third on Bruntingthorpe runway with plenty of revs to spare before redline in a standard S14a, might recollect it wrong though.
On the standard speedo?
Mickey Thompson Streets - drag tyresThat last message makes no sense to me
110 on the speedo is more like 103 anyway
MT = Mickey ThompsonThat last message makes no sense to me
Drifting is not my bag... why dont you take up drifting, then you wont be bothered about ratiosStreet legal drag tyres. And no im not into the drifting either. Guess i will just have to find someone else with an S15 to harass .
Im liking the sound of that drifter. What skyline is that from?S14 box with manual diff (3.692)
1 - 41
2 - 71
3 - 103
4 - 135
5 - 161
S14 box with auto diff (3.920)
1 - 38
2 - 66
3 - 96
4 - 126
5 - 151
Basic calculation of actual speed, not speedo speeds
MPH
205/50/R16 tyres
3.692 S14 manual diff
+-----+-----+-----+-----+-----+-----+-----+
| RPM | 1 | 2 | 3 | 4 | 5 | 6 |
+-----+-----+-----+-----+-----+-----+-----+
| 500| 2.9| 5.1| 7.4| 9.7| 11.6| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 750| 4.4| 7.6| 11.2| 14.5| 17.4| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 1000| 5.8| 10.2| 14.9| 19.4| 23.1| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 1250| 7.3| 12.7| 18.6| 24.2| 28.9| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 1500| 8.8| 15.3| 22.3| 29.1| 34.7| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 1750| 10.2| 17.8| 26.1| 33.9| 40.5| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 2000| 11.7| 20.4| 29.8| 38.8| 46.3| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 2250| 13.1| 22.9| 33.5| 43.6| 52.1| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 2500| 14.6| 25.5| 37.2| 48.5| 57.9| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 2750| 16.1| 28| 41| 53.3| 63.7| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 3000| 17.5| 30.6| 44.7| 58.2| 69.4| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 3250| 19| 33.1| 48.4| 63| 75.2| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 3500| 20.4| 35.7| 52.1| 67.9| 81| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 3750| 21.9| 38.2| 55.9| 72.7| 86.8| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 4000| 23.4| 40.8| 59.6| 77.6| 92.6| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 4250| 24.8| 43.3| 63.3| 82.4| 98.4| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 4500| 26.3| 45.9| 67| 87.3|104.2| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 4750| 27.7| 48.4| 70.8| 92.1|109.9| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 5000| 29.2| 51| 74.5| 97|115.7| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 5250| 30.7| 53.5| 78.2|101.8|121.5| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 5500| 32.1| 56.1| 81.9|106.7|127.3| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 5750| 33.6| 58.6| 85.7|111.5|133.1| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 6000| 35| 61.2| 89.4|116.4|138.9| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 6250| 36.5| 63.7| 93.1|121.2|144.7| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 6500| 38| 66.3| 96.8|126.1|150.4| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 6750| 39.4| 68.8|100.6|130.9|156.2| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 7000| 40.9| 71.4|104.3|135.8| 162| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 7250| 42.3| 73.9| 108|140.6|167.8| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 7500| 43.8| 76.5|111.7|145.5|173.6| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 7750| 45.3| 79|115.5|150.3|179.4| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 8000| 46.7| 81.6|119.2|155.2|185.2| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 8250| 48.2| 84.1|122.9| 160| 191| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 8500| 49.6| 86.7|126.6|164.9|196.7| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 8750| 51.1| 89.2|130.4|169.7|202.5| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 9000| 52.6| 91.8|134.1|174.6|208.3| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 9250| 54| 94.3|137.8|179.4|214.1| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 9500| 55.5| 96.9|141.5|184.3|219.9| 0|
+-----+-----+-----+-----+-----+-----+-----+
| 9750| 56.9| 99.4|145.2|189.1|225.7| 0|
+-----+-----+-----+-----+-----+-----+-----+
|10000| 58.4| 102| 149| 194|231.5| 0|
+-----+-----+-----+-----+-----+-----+-----+
R34 GT (non-turbo model) auto.
You can get a 4.111 from a GTST manaul, or a 4.3 from an auto
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