fiestaturbo.com

[Dave106gti]

I think speedos are normally set to overread by about 10% and 15's with 195/45/15 are a smaller rolling radius than normal so the speedo is probably overreading by 13%ish overall. 130mph minus 13% equals 113mph - which is the manufacturers top speed. I have witnesses that say the speedo said 130on my private downhill racetrack
Dunno whether this is exctly right, but it seems plausible

[elm_us]

my speedo was set up gonna get the buggers to check it again

[SimonT]

My 16v 2i dont pass 115 and thats on a private road!!!

[festajon]

The rolling radius is pretty much the same dave. I had 13s on my car before and i know my 15s are slightly bigger (with tyre) as i held em alongside. I know the si comes with 14s, but im sure it has the same rolling radius as the 13" steelie plus tyre choice, as even ford know 'the bigger the wheel, the lower the tyre profile' for optional extra alloys, etc on same model cars. if anything a bigger wheel will cause it to read more accurately as it will under-read more balancing out the over-reading.
God damn i need sleep

[chumkila]

My speedo's gona be re-calibrated very soon as i've now got the 17's on. But i may hang tight as i gota go on the rollers soon anyhow.

[Mark Si]

I know my speedo is accurate to a certain degree because when I fitted my while dials I had to remove the needles. I wasn't totally confident in their readings so I got someone to follow me and told them what speed I'd be sticking at. I tried cruising at 30, 40 and 60 and told them to check with their un-tampered-with speedo to see how accurate it was. When we stopped up they said it was dead-on at all three speeds so I'm condifent mine's reading accurately.

If anything though, my speedo should be underreading because of my 16s. Like Jon I held them next to my original 14s and the 16s are about 10-15% larger radius, so the car should be travelling faster than my gearbox speedo thinks due to the higher rolling radius etc etc.

But I'm not about to start another geometry lesson with wheel radius etc

[DANIEL 2i]

i hit 132 in my standard 2i 8v no bull got prove

[zetec69]

yes thats right mate!

[TrekkieFRST]

had 3 up on the way to FITP @ 125mph there was 3 of us so no BS

speaking to Mr stewart he thinks even tho it seams like it could pull to 130 (it didnt) it woundnt becuase the SI gearbox would be maxed out


either way 125 with 3 up cant complane

yes i can i want a TURBO


i think it has a lot to do with how it was driven from new if new cars are drove hard from new the engin runs 100% better if drove around by a woman (mark) or a grandad @ 20 mph all day then they run restricted

I was one of these three so I can vouch for this.

Maybe all the scraping rob does has shaved lots of weight off the car allowing more speed

[FiestaMental]

I sometimes climb to about 115-120 and thats in a 1.4si!!! I usually run out of road (a12) by that time now, or some bugger cuts infront

Pipercross Induction kit helped a little though.

[ItsGottaBeDone]

I can't believe 130mph out of a standard car

True, some came more powerful than others by sheer chance...but none were powerful enough to add an extra 15mph on top of terminal velocity of about 115mph...you need serious power to do that

If you sit on the "private test track" flat out for ages, the speedo will creep up even though the real speed remains the same

130mph my white hairy ar$ehole

[CULLEN]

yeah i agree
ive got a Si and ive had just over 110 out of mine
i cant see how you would get 130 out of an Si never in a millon years

[andymac]

Ummn had 120 out of mine other night on [insert private road name here] and it was at about running at about 6k in 5th.

Not forgetting a longer 'box means need more power to pull it I wonder if elms motor is a std 1.6

[BOB.T]

130 in an SI, no feckin chance!

Your speedo might read that but there is no way on Gods earth your car will be doin it!

Thanks tho, I've had a right good chuckle reading the thread

Out of interest, where do folks rev limiters cut in, mine is just over 7000 rpm which seems odd, what with the rev counter stopping at 7000, has it been chipped?