Denis K Posted March 13, 2013 Share Posted March 13, 2013 I am building a manta road car with a c20xe with at power throttle bodies, motec m4 ecu and mild cams around 270 duration. It will be running around 200- 220 bhp and around 160 - 170 foot pounds of torque. It will be a full road car that will occasionally see a bit of spirited driving but nothing too crazy and it will never ever be took to a track or used in motorsport of any kind. how would the manta 5 speed 1.8 gearbox and standard rebuilt back axle with lsd and steel torque tube with uprated rubbers hold up with this kind of power on a road car?? i dont want to go for an omega box as i want to keep the stock speedo and cable clutch but i am strongly thinking of going for a 2 litre ohc carlton box which is supposed to be stronger than the manta box and has a cable speedo and cable clutch. I already have a good manta 1.8 box in the shed though so i dont know which box to go for really. I am also strongly thinking about going for a stronger 5 link axle as the standard axle might not cope so well with that level of power. But maybe is a carlton or omega box and 5 linked axle overkill on a road car that will not be driven too hard that often and with only 170 foot pounds of torque max. I just dont know. So come on lads. Give me your opinion please. Cheers Quote Link to comment Share on other sites More sharing options...
rutts Posted March 13, 2013 Share Posted March 13, 2013 standard axle will be ok get it rebuilt with new bearings and put good quality oil in. standard 1.8 box should be ok get that rebuilt also then you have got rid of any niggles. Quote Link to comment Share on other sites More sharing options...
jamie077366 Posted March 13, 2013 Share Posted March 13, 2013 I'v a 3.9 rover at a good 185hp though standard axle, does track days etc, it's taken if fine,,,,,, for now! Quote Link to comment Share on other sites More sharing options...
399Road Posted March 14, 2013 Share Posted March 14, 2013 I'd say that all the standard stuff would be fine for your car. I'd think that drag racing would be the only kind of thing that would maybe break something, otherwise the standard stuff would do for me. I've got the standard stuff in my cars and the Asconas had some right fist! Make sure you put exactly the right grade of oils in your Getrag box and LSD'd axle though. ...Luke. Quote Link to comment Share on other sites More sharing options...
Retro Power Posted March 15, 2013 Share Posted March 15, 2013 The gearbox is probably weaker than the axle. The axle's first failure is usually the pinion shaft bearings, these are the weak point. if you rebuild it with new bearings it will take 200hp fine. Only real issue then is tramp on hard starts caused by the torque tube mounting rubber. Extra rubber bobbins in the mounting plus a steel torque tube help there. I broke 3 1800 gearboxes with a 200hp XE in my manta back in the mid nineties, but I was driving them very hard, though only a road car. Two had bearing failures, one had the synchro on 2nd gear explode and go through the rest of the box doing a lot of other damage! once you have an 1800 box though, the odd hiccup isn't too bad as the internals from a GTE box fit straight in very easily and are cheaply available! Quote Link to comment Share on other sites More sharing options...
Denis K Posted March 16, 2013 Author Share Posted March 16, 2013 Thanks for all the replies lads. Ya i reckon I will stick with the standard axle and 1.8 gearbox. I will rebuild the axle with a lsd, new bearings and steel torque tube. As for the box i will just buy up a few gte boxes for cheap and have as spares and if my own box goes i will just swap the guts out and use the guts of the gte ones instead. Cheers lads Quote Link to comment Share on other sites More sharing options...
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