Max Speed Vs. RPM

[blair]

Stock bigport running twin webbers.
S series Diff (3.9's)
running less than 20deg locked advance... thinking of upping to 30 now that ive sorted a bit of cooling (carbs were tuned for 32 a long long time agooooo)

what would you expect in each gear? and at what rpm?

80 is the most i pull in second and thats at just over 6k according to my super sweet jumpyaround stock tacho...

and 3rd just feels like poo above ~120 ( 5k?)

and it honestly feels like it doesnt wanna pull past that/i dont wanna push past that... would this be alot to do with the timing @ those revs?

opions please.

[Rice86]

sounds still like standard

just get a better diff ratio?..

[Sam-Q]

not allowing for my diff ratio compensation at 8000 RPM or so I get the reported following :

1st- 50km/h
2nd- 105km/h
3rd- 150km/h
4th-?? havent found a long enough stretch of road, I have had the needle hit the dash before on a somewhat short stretch though

[doony]

i remember my stock bigport and stock t series would pull similar figures to samQ's

dont think i got that much out of 2nd though maybe 100 or so.

this was at 7,900rpm or whatever the standard redline is for bigports.

[Sam-Q]

yes I must say my tacho I know isnt tottaly acurate, it shows around where 8200RPM should be when I bounce off my 8600rpm limiter.

Now all I need to do is find a very long quiet stretch of road, on private property of course

[RobertoX]

Hey guys,
Here is a spreadsheet I made to caluclate revs and speed. You can change around the gear ratios, final drive etc and see how it might affect your shift point.



edit:
Sorry thats just a pic...
Here is the spreadsheet

[hao.]

^ genius! thanks man.

[Sam-Q]

interesting, that really shows how big a gap there is between 1st and 2nd. This is why a more peaky engine with a high power can be slower without the right ratios to back it up.

Now I wonder what would get a higher top speed for many of us 4th or 5th gear?

[TE27]

thats an awesome spreadsheet man!! good work.

[blair]

ok so i thought 6500 sounded hot with induction...

just took it to 7500 at 95kmish

had a grin on my face for about 5minutes!!!