75-80 mph in second gear !?!

[Monkeylegend]

My neighbours Honda Jazz does 108mph in first gear.

[Byker28i]

ukkid35 said:

Circumference of 255/40/17 approx 2m
Diff Ratio 3.43
km per mile 1.609
Cerb red line 7500

Top Speed in Fourth Gear
2 / 3.43 / 1.609 * 7500 * 60 / 1000 = 163

Gear ratios for T5WC

1352-248 TVR WC U 2.76 2.95 1.94 1.34 1.00 0.80
http://www.britishv8.org/articles/borg-warner-t5-i...

163 / 2.95 = 55
163 / 1.94 = 84
163 / 1.34 = 122
163 / 1.00 = 163
163 / 0.80 = 203

I'm assuming that the rolling circumference is the same as the actual circumference at high speed

Also assuming a 7500 red line, I think the standard rev limit is set at 7600, with the buzzer coming in at about 7250

Rev limit in the ECU mapping is apparently 8250, with the fuel dropping after 8K to prevent damage?

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[LucyP]

Has any of this been done with a GPS speedometer such as on a phone app or on a sat nav? 70-80 on a TVR speedometer could be anything from 40-55 mph!

[baconsarney]

Speedo on my Chim is pretty accurate at 30mph, going through the speed check thingies its always within one or two mph of the roadside display... been through the same ones in my other two cars and they're all within one or two mph.... pretty much the same around 70mph on the odd occasion I've been using my Tomtom......... I think there's a bit of hysteresis in the speedo too, its ok at steady speed and making sure you're within the speed limit but when you give it billy bks it doesn't quite keep up with the acceleration

[Classic Chim]

ChilliWhizz said:

Pretty sure I'm only doing a tad over 60 at 6k rpm in second, but to be honest using WOT in second I'm too busy watching the rev counter and trying not to crap myself to watch the speedo

Edited by ChilliWhizz on Friday 12th December 15:24

I think that’s about right for Chim gearing.
If they do 0-62 in 4 seconds your not having to hit third gear in that time I know that.
Daz with the 308 Dif does 70 + in 2nd easy. Rev limit 6250 I think?

[Byker28i]

LucyP said:

Has any of this been done with a GPS speedometer such as on a phone app or on a sat nav? 70-80 on a TVR speedometer could be anything from 40-55 mph!

Do you only post doom and gloom, what is it with every disparaging post?

Yup done quite a bit with different devices, GPS, proper timing kit. I know that 190 indicated was 182mph at Bruntingthorpe, 152.55 was just over 155 indicated at just over 7k revs at Fighting Torque etc...

[SwanJack]

LucyP said:

Has any of this been done with a GPS speedometer such as on a phone app or on a sat nav? 70-80 on a TVR speedometer could be anything from 40-55 mph!

My Chimaera's Speedo is spot on. My Mazda's is about as accurate as a frog with a crossbow