Dear All,
Apologies but I want to regale our dear Mayor of London but my car is 60 miles away so can't check for a week or two. In a manual P38 can someone check and let me know what the engine RPMs are at 20 mph in top and 4th gear and again at 30 mph in top and 4th gear please?

Not that many manuals about and I doubt you can get an auto into top at 20mph, torque converter certainly won't be locked up at that speed. How do you intend offending the Lord Mayor of London? I want to ask why a taxi converted to run on LPG can be exempt from the ULEZ charge yet a privately owned car converted to run on LPG isn't. Wasn't a problem when it was only the very centre matching the CC zone but now it stretches out to the North and South Circular roads, I'd even cop for the charge if I called in at Beckton Sainsburys for a tankful of LPG (or wanted to visit my step daughter in Rotherhithe).....

You could always calculate it using the gear ratios, the transfer case ratios, the diff ratios and the rolling circumference of the tyres......

Not sure how accurate you could get it though.

Gilbertd wrote:

I want to ask why a taxi converted to run on LPG can be exempt from the ULEZ charge yet a privately owned car converted to run on LPG isn't.

You'll never guess who I had in the back of my cab last week....
And it wasn't his missus either!!

Glad I've got the camera... should be good for some extra ULEZ Exemptions!

I wouldn't mind a few lez exemptions in my cab ;-)

Gilbert has a point though... The taxi exemption is a recognition that EV's wouldn't be suitable for taxi use, but if Joe Public needs to use a vehicle for similar range etc that a taxi might cover they get no exemption.

If I were to visit London, why would it be better that I parked my LPG converted car on the outskirts then got a taxi to pick me up and and drop me off at an inner city destination than if I just drove my own LPG converted car to the inner city destination? Fewer vehicles in the inner city maybe but no worse from an emissions standpoint. But from the number of vehicles on the road standpoint - if I had to drive to the outskirts, park my car, then hire an EV to drive into the inners that equates to one extra car on the road in my book?

Not just London, similar schemes exempting LPG converted taxis but not LPG converted private vehicles are being rolled out in Leeds, Manchester, Bristol, Birmingham, Glasgow. At least there's the upside that the LPG refuelling places taxis use on outskirts will usually be available to the public.

Some of the taxis (well, private hire vehicles) have direct injection engines that use a bit of petrol all the while they're supposedly running on LPG anyway.

Some of the LPG components suppliers are partly re-modelling their businesses to meet the demands of taxi LPG conversions. One supplier in the Birmingham area told me 2 installer firms that just they supply jointly convert over 200 taxis to LPG every month. The supplier is offloading stock to make space for the specific sized tanks etc that are fitted on the taxis, they recently sold me 20 large LPG tanks at a knock down price just to make space for the taxi tanks.

Edit (OK I've already edited/amended a few times but they were shortly after posting and this is a while later)... Some of the private hire vehicle LPG conversions aren't going to do the trade or impression of LPG converted vehicles any good, they're making about £200 profit on a conversion and the conversions are going to have some problems.... But the private hire drivers won't mind driving around with engine warning lights on and they've achieved the biggest reason they converted to LPG (avoiding higher emissions zone charges) even if the LPG system doesn't actually work. A driver who delivers parts to me realised I did LPG conversions and asked if he could pass my phone number on to a guy who is involved with taxis / private hire vehicles in some way, sure enough the guy phoned me up and offered me 40 taxis to convert if the price was low enough... My price wasn't low enough and I didn't expect it to be, nor would I really want to convert 40 taxis for such little profit with the prospect of converting yet more taxis after the initial 40. The LPG scene will get an initial boost from the taxi conversions but in the long run they're going to mess up the entire scene for the rest of us. .

The manual and auto boxes are basically identical in ratio. So M5 = A4 and M4 = A3. In my auto, 2500 RPM = 110 kph (70 mph) with the TC locked. Your manual would be doing the same. so 30 mph in 5th would be 3/7 x 2500. 30 mph in 4th would be 3/7 x 4.3/3.15 x 2500.