Good & Bad News
Discussion
Good news: passed the MOT Saturday morning with flying colours - the examiner even asked how much it would cost to get one ... :goodmove:
Bad news: took the bleeding splitter right off in one while entering the MOT station as they have a raised hump to get down the road
Never mind, Offord can put it on back at the service.
Thing is, he said he couldn't test the brakes on the rolling road because of the LSD so had to go out with some kind of funny looking miners lamp thingy on the front seat
Bad news: took the bleeding splitter right off in one while entering the MOT station as they have a raised hump to get down the road
Never mind, Offord can put it on back at the service.
Thing is, he said he couldn't test the brakes on the rolling road because of the LSD so had to go out with some kind of funny looking miners lamp thingy on the front seat
Good news: passed the MOT Saturday morning with flying colours - the examiner even asked how much it would cost to get one ... :goodmove:
Bad news: took the bleeding splitter right off in one while entering the MOT station as they have a raised hump to get down the road
Never mind, Offord can put it on back at the service.
Thing is, he said he couldn't test the brakes on the rolling road because of the LSD so had to go out with some kind of funny looking miners lamp thingy on the front seat
Apparently they have to test it with an accelerometer - which seems pretty pointless to me since it doesn't check the wheels individually, but there you go.
Some places seem to use the accelerometer and others use the rollers - I've seen both done to my Chimaera. I guess the former is less exact. I'd rather they used the rollers myself so I know the brakes are all working properly. They can certainly do the front brakes and the hand brake with the rollers.
Driving down a nearby country lane in the ice and testing my brakes is not something I was keen on them doing!?!
T/.
Driving down a nearby country lane in the ice and testing my brakes is not something I was keen on them doing!?!
T/.
dannyboyo said: Is the speedometer part of the MOT test? As mine packed up the other day, and my MOT ran out today. Also, anyone know whats revs 30, 40 and 70 are in various gears?? Gotta drive back to London in 1/2 hour!
Roughly, mph/thousand rpm in each gear will be something like 7, 11, 17, 21, 27. Multiply by rpm/thousand to get mph.
For example, in third gear 2000 rpm is about 34 mph, in fourth 2000 rpm is about 42 mph, in fifth 3000 rpm is about 80. These figures are pretty exact for the Vitesse box and my back axle, later Griffiths & Chimaeras have slightly different gearing but I would expect them to be within 10% (which is probably better than your speedo accuracy anyway!)
Cheers,
Peter Humphries (and a green V8S)
GreenV8S said:
dannyboyo said: Is the speedometer part of the MOT test? As mine packed up the other day, and my MOT ran out today. Also, anyone know whats revs 30, 40 and 70 are in various gears?? Gotta drive back to London in 1/2 hour!
Roughly, mph/thousand rpm in each gear will be something like 7, 11, 17, 21, 27. Multiply by rpm/thousand to get mph.
For example, in third gear 2000 rpm is about 34 mph, in fourth 2000 rpm is about 42 mph, in fifth 3000 rpm is about 80. These figures are pretty exact for the Vitesse box and my back axle, later Griffiths & Chimaeras have slightly different gearing but I would expect them to be within 10% (which is probably better than your speedo accuracy anyway!)
Cheers,
Peter Humphries (and a green V8S)
Sounds complicated.
I thought when you know the final drive in 5th is say 28mpg per 1000rpm that if you're doing 2000rpm = 56mph and 3000rpm = 84mph and so on? Certainly is about right on my car - 3000rpm in top is about 87mph on the clock and 2000 is 59mph.
BTW, this is what I believe the final drive to be for a '95 Chimaera with the T5 box like your car and mind Danny.
Trefor/.
The wheel speeds etc are in Bible 2 and on my website and there is a spreadsheet to play what if games.
Steve
www.tvrbooks.co.uk
Steve
www.tvrbooks.co.uk
I think my speedo needs recalibrating ! I have just done some calcs and I'm not too pleased with the answers 
. It looks like my speedo is upto 17% out (seems to get worse the higher the speed/gear about 10% in third & about 17% in 5th at 2000 revs - need to check at 3000 although not in 5th 
on the roads ). I have used SHPub's spread sheet adjusted for contact patch (radius -12 mm) & tyre creep (1%) and this validates GreenV8S's speeds in mph/1000.
Anyone know how much it is to calibrate a speedo ?
Bob
. It looks like my speedo is upto 17% out (seems to get worse the higher the speed/gear about 10% in third & about 17% in 5th at 2000 revs - need to check at 3000 although not in 5th on the roads ). I have used SHPub's spread sheet adjusted for contact patch (radius -12 mm) & tyre creep (1%) and this validates GreenV8S's speeds in mph/1000. Anyone know how much it is to calibrate a speedo ?
Bob
Get a mate to follow you and compare "thumbs ups" i have done it in the past! It might be that you dont actually have a problem. My Griff reads 5 mph faster than my sat nav gives me, strangely it doesnt alter, 8 mph up to ??? Something to do with the black box before the speedo that recalculates the speedo sender. I can crawl along all day at 6mph and the mileometer will not move, handy in London i guess!
Getting back to MikeyT's original Q - the MOT station should NOT use the rolling dyno to check the rear brakes on anything with a LSD - it can F up the diff as the rollers work independantly. They should always use a "decellerometer"(?).
And (see other thread on General gassing) I have just had my speedo calibrated by PC Plod on the M11. At 3,000rpm in 5th mine showed 70 mph but Mr Traffic cop showed me his VASCAR reading at 91 mph. OK it may have been a bit over 3k rpm but he nonetheless has awarded me 3 points and I get to contribute £60 towards the local force's Xmas bash!
And (see other thread on General gassing) I have just had my speedo calibrated by PC Plod on the M11. At 3,000rpm in 5th mine showed 70 mph but Mr Traffic cop showed me his VASCAR reading at 91 mph. OK it may have been a bit over 3k rpm but he nonetheless has awarded me 3 points and I get to contribute £60 towards the local force's Xmas bash!
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