Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) ARP4 "Handbook", and other useful information

Thanks Thierry, that was my thought too, but it would also need to be remapped, and as Morgan have, in their wisdom, locked the ECU, it would mean a new ECU plus remapping, so could cost another £1500, plus the cams and fitting plus the exhaust system, which won't be cheap, judging by their quote to me for a new silencer box. So, all in all, prohibitively expensive.

As a matter of interest, I did a rolling road power run recently, and it showed a peak torque of 168.7 lbs/ft at 6041 revs, a long way short of the 220 Nm, but interestingly peak power was 220.8 bhp at 7576rpm. But as we suspected there is a hole in the graph between 2750 - 3750, when it starts climbing again.

Hello Paul J,
following your remark, I tried this morning my ARP4 with modified exhaust and I did not find the hole you speak, between 2700 and 3700rpm) certainly to this regime this is Not a bolide, but enough to cruiser.
Thierry (who has mounted the same exhaust as mine) should be asked if his impression is the same at this engine speed.

With the modified exhaust the car run better untill 4500rpm.
For me the torque is enough to drive confortably and with less noise.I can accelerate in 4 th without problems at 2000rpm.
But it is not a V6 a V8 or a turbo diesel.

Do either of you know what the differences are for the modified exhaust system over the standard offering, which appeared to have caused so many problems at production?

As a matter of interest, and to easily demonstrate the problem with the way the Cosworth is currently tuned as standard, on occasions and when traffic conditions allow, I like to indulge in little oversteery opposite lock moments when exiting roundabouts and sharp corners etc, and the ARP4 won't even break traction, there is so little torque. I guess with the uprated exhaust system it will now do this?