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Thread ID: 121597	2011-11-02 02:45:00	New gearbox in car - speedo now reading fast?	wratterus (105)	PC World Chat

Post ID	Timestamp	Content	User
1241436	2011-11-02 02:45:00	I'm not sure if I'm imagining things here, but I'll see what you guys think anyway. :) Got a new gearbox put into a 2000 Corolla, I don't have the old and new gearbox model numbers unfortunately, but the car now revs a lot lower in 3rd, 4th and 5th, which is fantastic. 2300rpm at 100k in 5th rather than 3100rpm, it's very nice. The gearbox must be slightly different, taller at the top end, but as well at that, it feels like the speedo is reading a bit fast. I haven't driven it enough to get a proper feel for it, but to me it would seem to be reading at least 10k fast at 100kph. I guess some of it would be the feel of the car, revving lower therefore it feels like it's not going as fast, but if I drive around without looking at the speedo I often find myself (according to the speedo) going 10 - 15kph over the limit, when I would have thought I was on the limit. The speedo is run off the gearbox - I haven't actually looked but other similar aged corollas I've seen had a few cables that click into a plug on the top of the gearbox - not a cable run thing like the good old days. Guess after all that, what I'm asking is.. is it possible that a different gearbox (higher geared) could cause the speedo to read wrong. Cheers. :)	wratterus (105)
1241437	2011-11-02 03:32:00	Try getting someone to pace you. The ratio changes may alter rpm but if the speedo pickup is on the output it may not affect the speedo readings. You may be just driving to the old noise levels :D	PaulD (232)
1241438	2011-11-02 03:57:00	Check your speed with a gps, just to be sure.	nerd89 (14761)
1241439	2011-11-02 04:00:00	Check your speed with a gps, just to be sure. Now that is the most obvious answer.. why on earth I didn't think of that is beyond me. :p Thanks.	wratterus (105)
1241440	2011-11-02 05:59:00	I'd be very surprised if a 2000 Corolla uses a cable speedo, it will be electronic. Yes, it's possible that a different speedo module is required. You could try the one from the old gearbox to see if that fixes it. Interesting you have had that issue, I'm guessing you have a 1NZ-FE powered car but a gearbox off a 1ZZ-FE or something like that?	Alex B (15479)
1241441	2011-11-02 21:22:00	All is well! You will not get a speeding ticket. If it is cable drive (rear wheel drive) there are different speedo drive gears for different diff ratios. Also the tyre size/wheel diameter makes a difference. If your wheels are smaller than the car which the box came from, it will read fast. Also the diff ratio could be different.	mzee (3324)
1241442	2011-11-02 21:31:00	Yeah electronic speedo, not cable. I did mean that in the first post, I just worded it rather badly. It's actually a 2001 corolla, front wheel drive, 4A-FE engine.	wratterus (105)
1241443	2011-11-02 22:53:00	Check your speed with a gps, just to be sure. Well I'm not so sure that works.... I had a Navman and a TomTom and tested them in my car - at 60kmph the Navman was reading 52kmph and the TomTom was reading 58kmph They should be more accurate than a car speedo but still not 100%...	Disco_Dan (16576)
1241444	2011-11-03 01:15:00	We have the odd "Speed Indicator" signs around schools down here ... they work the same as police radar and give you your speed in big orange letters when approaching the school area ... think they're reasonably accurate. Other option is to take it to someone with a rolling road used to test engine performance.	SP8's (9836)
1241445	2011-11-03 01:32:00	We have the odd "Speed Indicator" signs around schools down here ... they work the same as police radar and give you your speed in big orange letters when approaching the school area ... think they're reasonably accurate. Other option is to take it to someone with a rolling road used to test engine performance. They are KNOWN to give a high reading. The amount of times I've gone past one telling me "60kmph" when my speedo says 45-50kmph - the gps different again. Calibrate it yourself - on a rolling road. Or a analogue version is hop on the mway and use the power poles - they are at set distances so you can work it out yourself.	Disco_Dan (16576)
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