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22 Jul 2008, 20:40 (Ref:2256159) | #1 | |
Racer
Join Date: Nov 2005
Posts: 312
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Is it worth lowering the engine?
Lotus Cortina - about as mechnically sophisticated as a wheelbarrow.
Used for hillclimbing. Always looking for the ultimate but getting to the point where the nth degree of modification is not going to make a vast amount of difference. The question is whether lowering the engine by, say 1 - 2 inches is worth bothering with. Will necessitate some expensive mods but I was contemplating some of them anyway I know its difficult to answer a question like this in a vaccuum without more info but what I'm looking for is whether in principle it's a very worthwhile mod in any circumstances or if it's a bit over the top for a low level clubman |
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22 Jul 2008, 21:28 (Ref:2256192) | #2 | ||
Veteran
Join Date: Nov 2006
Posts: 9,441
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Anything that puts weight lower down is a plus point for handling.
However the mods needn't be that difficult or expensive depending on your expertise and ability. Presumably you have a dry sump set up so you could mod the crossmember to take the sump rail and starter motor The main problems start with the standard steering assembly and would probably need a rack and pinion in front. Also the gearbox will be lower and ground clearance may cause a problem on the bellhousing especially on excursions off the track!! Seems a shame to do it to a LC |
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22 Jul 2008, 21:29 (Ref:2256193) | #3 | |
Rookie
Join Date: Jun 2008
Posts: 21
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You want the engine as low and far back as possible, if it can be done without causing further issues then the advantage will be considerable.
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22 Jul 2008, 22:10 (Ref:2256218) | #4 | |
Racer
Join Date: Oct 2006
Posts: 253
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Every little helps. It wont knock many seconds of your times in itself but will certainly help give you a better foundation on which to base your chassis dynamics.
If you choose to do it I would also use the oportunity to try and move the engine back for improved PMI. At the moment we are in the process of building a Grp4 mkII Escort rallycar for the forrests, we decided that it made sense to start with the very best possible chassis foundation we could, within the constraints and regs we had, while still at fabrication stage. We fabricated an extremely large gearbox/propshaft tunnell to aid chassis stiffness and allow for excellent engine/gearbox positioning options and to accomodate any future suspension travel modifications we might want to do. We replaced and moved the front bulkhead rearwards which allowed us to mount the engine 20cm further back which in turn allowed us to make the most of moving the drivers seat position rearwards by the same amount. We had to build a new steering collum and fit a floor mounted peddlebox which can adjust for reach rather than compromising by moving the seat forwards. We have also purchased a Fuel cell which will allow us to site it behind the drivers seat mid-ship due to having no need for a firewall. We've yet to decide where the spare wheel will be sited (probably beaneath the navigators footrest) but hopefully the end result will be to have the very best weight distribution and PMI by moving as much weight as possible to the centre of the car. This perhaps sounds very OTT for most but it makes sense when building from scratch.. Might be a bit of work involved but every little helps and its a free gain.. I guess its down to how serious you want to take your hillclimbing. Last edited by Zico; 22 Jul 2008 at 22:17. |
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23 Jul 2008, 07:37 (Ref:2256374) | #5 | ||
Veteran
Join Date: Aug 2002
Posts: 1,686
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We did the Corolla's engine last winter. It wasn't difficult at all.
Just moved it back as far as the firewall allowed and down as far as the cross member would allow so not a great amount (and 1.5 inches or so back and 5/8 of an inch lower). The car now doesn't understeer but we also changed some other stuff at the same time so I not sure how much difference just moving the engine would have made. |
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23 Jul 2008, 12:57 (Ref:2256571) | #6 | |
Racer
Join Date: Nov 2005
Posts: 312
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Interesting stuff - thanks to all for your comments.
Hillclimbing allows flexibility in terms of the tech regs so more or less anything goes but we won't be relocating the bulkhead or anything like that. We don't run a dry sump at the moment so that's where most of the expense lies but that has advantages in itself. We would weld engine mount brackets to the chassis rails and modify the cross member. Might be able to move the engine back a fraction but not much so probably won't bother. It's a Mk 2 Lotus \Cortina so there's more space than a Mk 1 - should be ok with the steering and we're already using a small starter so hopefully ok there too. Exhaust manifold will need looking at and we're using a Sierra Type 9 gearbox casing which is bigger than standard so that's going to hang down a bit more than we'd like. What I want to achieve is better handling - finding really beneficial improvements on a car such as this isn't hard because the standard set up is so crude and we've already worked on that but the more I learn the more I realise we're way off as good as we can get. The point is - and this is the mission statement behind the whole project that has been running now for years and years - we want to make the car as good as possible by doing the right things not just by whacking on the stiffest springs and turning it into a nightmare. I should add that we don't have a trailer... So 1 - 2 inches is enough to make a difference then? Our engine block is heavier than standard as it's both chunkier and taller so it's got to be a step in the right direction - just wondering if in reality 1 - 2 inches is not enough to make a big difference in the crude world of 60's Fords.... |
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27 Jul 2008, 13:34 (Ref:2258522) | #7 | ||
Racer
Join Date: May 2002
Posts: 153
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There's maybe better things to be spending your money on, but most of racecar performance is not about the big things, it's about all the little things. Don't know if it's possible to offset the motor slightly in the chassis at the same time, allow for some compensation on driver weight. Shouldn't need to move it much for that.
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29 Jul 2008, 20:56 (Ref:2259876) | #8 | ||
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Join Date: Sep 2003
Posts: 1,074
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jonners,
Lowering the engine in stage rally car? With a standard sump, rather than a dry one with greater clearance? You'll know better than I, but is that wise? What do other Cortina drivers do? Is this a common mod? They've been around so long, I would have thought there was a consensus on the 'standard' mods and what was unwise. John |
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30 Jul 2008, 19:16 (Ref:2260486) | #9 | ||
Racer
Join Date: Oct 2006
Posts: 253
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Quote:
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16 Sep 2008, 21:55 (Ref:2292120) | #10 | ||
Veteran
Join Date: Apr 2007
Posts: 2,852
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In my experience even half an inch lower made a difference.
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