There is some use in actually talking about circuits that we know and what gears we use. Gurd's has the 2Y 4.25 ratios that are close to what I would consider, so to carry this on a little, any idea of you speed at the end of the start finish straight on Curby - before turn in? and what gear/s do you use coming into, going through and exiting the mole hill? With regards to the same idea, Castle Combe is a circuit most have driven, so the slight high speed right hand corner Folly (at the pit exit after start finish line) what gear and what sort of pace? im doing an indicated 120 more like (110-115 looking at the gears) and im hovering on the red line +7200rpm in 4th so find it sometimes better to change before the corner - mid corner change can upset the car. Also I find I can take all the other corners in third, after quarry i find im again hitting the limiter in third before the esses and after bobbies i change up into 4th for a bit before going back to third for camp corner. It is a good way of understanding how the FD's will change the charactor of the car. some pics always help. 16v 2Y with 4.25FD 2Y 4.25FD 0.8 FIFTH 2Y 4.25FD 0.8 FIFTH AND 1.94 SECOND - One i like and ratios mentioned at start. And one i really am starting to like, 2Y 4.25FD 0.89fifth 1.94 second What I like about this is that the 1.94 second to 1.44 third is a change of 1933rpm as apossed to 2406rpm for the stock 2Y ratios. It will make it much closer to the drops between 3-4 and 4-5 which are 1615rpm and 1593rpm respectively. So changing at 7000rpm in second will mean new revs of 5000rpm in third, bang on my peak torques. What do you think?
You also have to factor in weight. I have taken the inputs you gave and will let the model drive them, from there inputs such as gearing, torque, weight etc can be messed about to give the best package.
before the pending epic simulation output arrives.. Heres 3 pictures illustrating one combination of 020 with smudge level outputs (no losses are included in this & so it's more for illustative purpose) RPM vs MPH in gear Engine BHP vs MPH in gear Wheel torque in Gear ^ box used in this example was 020 for a 16V (easy to redo with other ratios if needed) 1st is way out there on its own & could do with being taller More experienced folk & those with access to G-meters may say otherwise, but with this setup it looks to me that it is best to rev all the way to 7000 in each gear before shifting up
Looking at all of these plots dos point towards a 1.94 2nd to be the way to go. It would make more sense looking at Ben-S' Engine BHP vs MPH & wheel torque in gear graphs. Also highlights what I said about 1st and 2nd not being optimum. Danster's 4 speed is more appealing now Gurds
Tom, I like the look of the 2Y 4.25FD 0.89fifth 1.94 second option too, however, I think i mightbe using a 0.91 5th. Gurds
At Curby I am 2/3/4 on the straight, 2 on hairpin into 3 then back into 2 for the mole hill then 3 and back into 2 for the final larger hairpin. Combe, I will have a think but its all 3/4/5. Into 5 just by the pit end and keep pulling. I don't know my speeds as my speedo is very innaccurate so I ignore it. Gurds
same ratios comparing 3.67 FD and 4.25 FD shows 125mph ish top speed 2nd gear max is now about 52 instead of 60 3rd becomes 77 instead of 89 much more torque in gear at expense of shifting early & lower top speed, but you could say 1st is now even more useless
Yep but in effect you have just gained a new first - second Could you pop these ratios in please Ben? 3.45 1st 1.94 2nd 1.44 3rd 1.13 4th 0.89 5th 4.25FD Thanks Tom.
2.12 2nd 1st 1.44 3rd 2nd 1.03 4th 3rd 0.8 5th 4th 5.1FD? (Brian? had one of these FS the other day) 4 speed Dog leg anyone...124mph @7500rpm?
4.25 5-spd (ratios from page 2) vs. 5.1 FD ^ extended torque to 7750rpm to highlight where torque dropping off in low gear drops below the torque that would be at the wheels in the next gear
Ben is using a macro that combines what you attempted in your thread and adds actual engine effort to give real representation of axle torque..
The MPH = wheel rpm * tyre circumference * 60 (so hr instead of mins) * 0.62 (miles instead of km) (wheel rpm = engine rpm / gear ratio / final drive) Gear Torque = flywheel torque * gear ratio * final drive Use this in excel or similar to make your own (otherwise I could end up doing lots & lots of graphs for folk lol)
There is a slight error in the calculation for MPH, depending how you calculate tyre circumference. Plus you have to convert to Km from M or mm before using 0.62 to convert to miles.
I assumed you would have converted circumference into same units, purposefully left the unit for circumference off etc.
