Did the early '90s 740 and 240 have different diffs?

[AllHailKingVolvo]

Originally Posted by Laird Scooby

Have you got another rev counter you could fit (even temporarily) Phil to compare the 2 readings? You may be worrying over nothing! Even something like this would help :

https://www.ebay.co.uk/itm/12V-3-75-...2/273333770774

Alternatively :

https://www.ebay.co.uk/itm/AT2150B-D...0/352452868249

Run a couple of extension wires into the car from the coil and use it on the Tach function to see what your engine is really doing.

Thanks Dave, I'll pick one of those up!

[AllHailKingVolvo]

Originally Posted by TonyS9

Diffs do vary alot even with similar models, certainly likely to be the difference between the cars for the rpm difference. Boost starts at 2000 rpm in my 940, full boost easily at 2500, well below 70 on my B230FT 940 Turbo.

More likely the difference in low end torque is the the Cam, compression Ratio and ignition, which is all related to the fuel octane. The early UK 240s where very torquey used with 4 star, and 'mostly' worked with unleaded, but later cars became more lower octane friendly (ie 92ron) with more margin and alot less low end. The Uk finalised on 95ron so the early unleaded cars are a bit gutless. Saw this particularly on 1987/88 360s (red block), totally ruined the engine. Having said that a 1993 240 should then be gutless lol, what do I know...?

Yeah I gather the B200F motors are less gutsy than the B200E which was K-Jet of course and intended for four star. I drove a 240 recently with an E engine which was being run on Momentum 99, really punchy for a two litre engine.

I could improve both cars with a cam change as a starting point I'm sure. The temptation of course is to add a turbo whilst I'm at it, but I'm still on the fence over that...