S2-3456789-K

yes, that's the one. i just put ap1 gears in with 225/50-16's, and the top speed it gave me is 167.3 mph. i thought the ap1 was geared for slightly over 170 mph? i've seen that on some other threads, and my simulation shows 172.xx mph. can anyone comment on this?

RED MX5

Tire slip and deformation make the actual top speed somewhat lower than the calculated or indicated top speed. I know my car (CTSC and 4.30 gears) will pull redline in sixth (with the top down ), but I'm not sure exactly how fast I'm going at that point. It's somewhere over 150, but ...

S2-3456789-K

thanks for the info red; i guess i should note that for my sims. i want to run a sim using a dyno from an sc'ed S

RED MX5

Simulating losses due to slip and deformation independently might be tough. I'm sure the two interact, so the functions are not likely to be trivial. It might be easier to use lumped values based on actual measurements. You could use a GPS or RADAR gun to measure actual speed vs RPM and calculate the difference between that and the theoretical speed for a given RPM. Put the loss data in a table and index into it by rounding the calculated velocity. Trivial hashing.

s2000Junky

I liked your graphs but I would like to see the accurate information put in the the equation so we can get the proper outcome. Im not sure how you got your figures but your numbers seem to reflect 3-4mph on the high side, almost like you used one size larger then stock, did you punch in 225/50/17?

This is the one, thanks for findig it. The calculator will have the right ratio's for each gear already, just make sure your putting in the right tire size and 4.10 should already be in. If you do this you will find 4.56 to be under 60. 4.44 is a almost perfect 60. Stock 4.10 is 65mph. Also there is a selection for tire deformety, I beilive I chose not to select this because tire pressure plays to much into this and I wanted a strait up rate for a good basis to work from. To the guy that is a 4.44 hater I'm sorry if you invested in the 4.77's, I asume you did because your offely defensive about it, I'm sure their fun though man, push you back in your seat nicly and make you feel like an F1 driver shifting quick all the time, but the fact is they don't cover ground faster the 4.44's and this is what counts. Would bet you your car that you will have a quicker time to 60 and quarter mile with 4.44's then your 4.77's asuming same driver and same hp and tq numbers from the car. I understand fully how grears work relative to engine power curve and shift points. Your right that in the same gear the higher gear ratio will pull on the lower initialy but what happens when it runs out of rpm's and the other car is still pulling? now you have a situation where your at the disitvantage because you will be pullig a taller grear wile the other guy is in his sweet spot still pulling and also does not have a time loss do to making the shift you just made. Its all relitive the the speed and power curve of the motor and for an s2000 4.44's is the sweet spot for 80% of the time. sorry for the poor spelling.

TheCarGuy2021

I love the setup. I'll be going turbo with the 4.77s in a few weeks until I swap something less aggressive in.

S2-3456789-K

if i had a radar gun and GPS, that would defeat the purpose of sitting at the PC and punching numbers

S2-3456789-K

i'm sure i used 225/50/16. my code calculates max speed in each gear, and you're right, they're a few mph higher than what that site suggests. as red_mx5 mentioned, this could be due to tire slip and deformation.

i agree with you that the 4.77 is definitely slower to 60 compared to 4.44, and i would even give you the benefit of the doubt that 4.56 is also slower than the 4.44 (if we can confirm significant tire slip and deformation, or run slightly smaller tires) but it seems that the 4.77 is definitely fastest in the quarter mile. if the max speed in each gear are a few higher than actual, they are that way for all the FD gears in comparison. an interesting note is that even though the 4.44 is faster to 60 than the 4.77, the 4.77 geared car is actually in front of the 4.44 car the whole time. you simply integrate the speed vs time plot to get distance vs time, which is exactly how i've produced the latter plot. and in that distance vs time plot, the 4.77 curve is always above the 4.44 curve. (just my observations from the plots)

one question thought, i remember seeing a thread about a SC'ed S going slightly over 170 mph. how credible is that? i know some argue that it was on a downhill, but the drag at that speed alone would not allow it to reach that speed unless it's geared for it.

S2-3456789-K

this is a blown up view of the first 6 seconds of the quarter mile run. the thing is...even when you're shifting, you're still covering ground, and so the distance vs time during shifting is more linear than higher order.

s2000Junky

Thanks for your reply, I find your work very interesting and valuable. I will also give you the benifit of the doubt on the quarter mile do to my foccuss being more on the 0-60 time. This was more important to me at the time of my resurch, I look forward to futher work from you regarding these gear ratios and quarter mile time once we can get some more exact numbers. I would be interested in knowing at what rpm the car will be at for each available gear ratio once it hits 1320' and in what gear the car is in at that mark.