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Old 27-09-2014, 04:22 PM   #31
ed4ran
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Yeah guess it makes sense!
Keeps it easy as well if it's just all the standard stuff on the back! Ever thought of making / replicating the standard rear frame in aluminium??? Worth the hassle or not?

At the front I have it all fitting with standard cones and hilos, and don't think they get in the way of anything. This engine fits pretty well which is why I'm surprised someone hasnt done it before!

I'll see if I can get pics of the tower clearance, but haven't done any real progress with it, too busy sorting out the garage and doing bits for other people! 😣
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Old 27-09-2014, 09:33 PM   #32
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It really depends on your reason for modifying the rear end, I am currently considering the same options.

In my mind the only reason to do it is to save weight.

The std rear subframe weighs anything between 16 - 18kg, I weighed mine at 18kg, I suspect the variation in weight is the difference between OEM and 'pattern' versions of the frame.

If you want to save most weight then just buy one of the heelboard mounted box sections that KAD, Minispares,TDK etc... make they seem to be touted at 6 - 7kg but you will have to fit coilovers.

The rear is just the same as the front in that suffers from the fact that coilovers have a very different motion ratio to the std cone setup, so you need to be careful with spring rates / progressive springs to get it to handle properly.

Then its the usual ally radius arms, minifins or discs etc.

I would start off as std and then I would consider fitting coilovers (probably need to be the offset type) first and see if you can get them handle similar way to std. This way if you hate them your out of pocket the cost of the coilovers and no more, if you make it work than you can make all the other changes, you will probably have to retune the springs a tad again if you remove all of the weight that is possible as it's a reasonable percentage of the axle weight.

So the only reason I would attempt to make a lighter conventional rear subframe (ally or otherwise) would be if you didn't like the coilovers and you wanted to make cone based setup work but still save some weight.

The other thing you need to be mindful is that you are making the weight even more front biased down this route, without knowing your plans this may or may not be a problem to you

Again just my opinions
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Old 27-09-2014, 10:17 PM   #33
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I was considering a k based rear so the suspension was common both parts and angles / adjustability. Also my thoughts where that with it being a pickup, if I wanted to put any weight in the back it would just be on the thin metal wheel wells if I have coilovers where the standard frame or similar spreads the weight / strength through 4 points on the rear (subframe mount points).

I already have a set of protech coilovers but non offset. I had planned to run them seeing as I already had them but now edging towards standard cones! 😣

Maybe just a tubular rear frame that uses standard radius arms and cones might save some weight?!
But as you say, for now fit standard and go from there!
I may gently adjust the rear wheel wells to help with coilovers so I have the option, just don't want to be too obvious because they will be on show unlike a normal saloon.

Thanks for your opinions! They make sense and you are making it easier to get some direction!
Maybe I should start weighing things! 😂 sure be interesting to get a good measure of the engine weight as it seems to vary on the web a lot and depends on what is attached!!
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Old 27-09-2014, 10:21 PM   #34
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Plus with the k rear stuff I could use the disc brakes etc as more common parts, I know people say a mini is too light to need rear discs but it's got to be nicer than adjusting drums!!
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Old 28-09-2014, 11:44 AM   #35
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Weight would still be my biggest concern with adding MGF / R100 stuff to the rear (That is compared to any real advantage the parts will give). I am not completely sure I assume you mean an MGF rear frame or do you mean a R100 / radius arms / frame?

You mention that you should start weighing things and I think this should be a very important part of any decision you make regarding the rear end

When I got hold of an MGF front subframe / suspension etc the first thing that shocked me was how heavy the whole lot was, when I took it apart and weighed the individual parts it was quickly clear why, the subframe alone was 30+kg

As soon as you change your suspension type or type of subframe at the rear you invariably have to add weight in order to mount it as well.

I hadn't realised your project was a pickup, I guess the pick up is somewhat unique in that the rear end is totally 'open' it doesn't have the rear seat panel / rear parcel shelf to tie the two halves together which could well place further difficulty on a coilover setup working due to the potential lack of torsional stiffness from the rear structure being 'open'.

With the amount and type of work you have to get all of the front end sorted (very similar to what I have) I really would leave the rear end stock and just experiment with coilovers > almost treat the rear as a separate phase 2 project to move onto once all of the front end issues are sorted?

With my RWD project a couple of things de-railed it, a large change in personal circumstances was the main cause, but weight was an area I really underestimated and was starting to become a significant obstacle as it progressed as far as justifying the effort c/w a lightweight FWD

I guess the point I am trying to make is that sometimes we justify what we do based on what we think is the best technical solution, say lightest possible weight / highest power we can sensibly achieve. And sometimes we do it because we just want to do it... Both are equally valid.

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Old 28-09-2014, 10:29 PM   #36
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Yeah I will leave the rear stock for now, I have a subframe in ok condition and most of the bits ready to go on. But I was thinking I can use the coilovers without the coils if I end up using standard rubber cones.

Yes it would be a k series rear frame, either mgf or tf. Although not really the complete frame, and more likely a tubular made frame to take the mount points of the standard mini one but the suspension points of the k frame. Also narrowed to match the front. Couldn't the hubs and arms of the k be lighter than the radius arms etc of the mini? Or is that just wishful thinking!! If I get some time tomorrow maybe I'll have to weigh them and compare! (Not that I'm doing anything on the rear at all for a while!!) 😉

It is the torsional strength at the back I'm not happy with and the main reason I don't want to use a beam!
Anyway as you say lots to do on the front before looking at the rear! 😂
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Old 28-09-2014, 11:36 PM   #37
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I love the long wrighting without looseing intrest at all,
Dam makes perfect sence,
Wat was it about rear discs i read?
Surely disks are better than drums?
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Old 29-09-2014, 08:18 AM   #38
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I know lots of writing isn't what people always want to see in a build thread and they prefer nice pictures of shiney fancy bits being bolted on, but I always struggle to make a decision and often end up making things harder because I thought something would be cool rather than weighing up the best options first!
Spencer has done a lot of good research into the same areas and has already gone through very similar thought processes so he is great for pointing me in a sensible direction.

Been busy decorating recently so haven't had chance to get in the garage for very long, I might even go as far as booking a day or two off just to spend in the garage! 😂
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Old 29-09-2014, 07:18 PM   #39
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Sorry, "more long wrighting"

Ed, I have a suspicion that you have a hidden agenda, you are preparing for AWD with your MGF/TF rear suspension possibility?

I can have a pretty good estimate of the MGF rear suspension weight (Not the TF) as quite a few parts are common front to rear, I'd say within 1kg the MGF setup will weigh 19kg per corner (Brakes, knuckle, hub, links etc) a bog std Mini is 12kg and with the stuff you have seen in my build thread I am down to about 9kg so far, but this can easily become 7kg with KAD ally radius arms. (All figures per corner)

So I would say a hefty weight penalty (20kg total over my setup) for no obvious benefit, sure discs look better, they are self adjusting and if you are really, really careful you might save 1kg over the lightest drum setup with a Mini based setup.

IMO The MGF rear suspension has a few 'characteristics' that you need to be aware of...

It comes from a mid engined car that didn't handle especially well, because it was mid engined Rover had to build in some 'elasto-kinematic' (rubber bushes) steer and some kinematic (hardpoints) steer.

Basically to overcome the rear weight bias the various MGF 'steer' characteristics are to try an induce undertsteer from the rear .suspension, so it will toe-in very heavily when loaded up whilst cornering.

So your introducing a rear suspension which is deliberatly trying to induce understeer

If you are trying to prepare for AWD then use double wishbones and get proper kinematic benefits with the weight disadvantages.

However, from your previous comments about trying to 'gently adjust' the rear to house the coilover I am guessing you want the flat load bay to remain standard looking? I don't think any of these options will hide below it?

As always... IMHO
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Old 29-09-2014, 07:33 PM   #40
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don't say sorry I like all the words, I did try to say that,lol
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Old 29-09-2014, 10:52 PM   #41
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Lol it's not that I have a hidden agenda, I have considered awd and I would if I could, (if I could get a cheap gearbox id strap it in and measure everything), I just don't see it possible without major body mods and on the pickup my aim is minimal body mods as possible. At this moment (fwd) I will probably loose half an inner wing, maybe two. It's the same reason I don't want to turret for coilovers, as you say, to keep the bed standard looking.

I didn't know the mgf rear was so bad! 😣
I suppose then the next option could be to use the knuckles and brakes but remake the arms and suspension points?! But then that goes beyond me (again one reason for using an existing setup)
I recon with the mgf stuff I could have used inbound coilovers and not had to use the normal location. Anyway just more thoughts not likely to go anywhere! 😄

I managed to get a couple clearance shots while I was shifting rubbish in the garage this evening.

Back of the engine showing drivers side tower


Passenger side:
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Old 30-09-2014, 06:43 AM   #42
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Will the bonnet of a standard round nose close over all this?

I seem to remember a mate having a 1.8 mk3 Golf GTi with induction and exhaust on the back of the engine, like an A series?

Thought that might make a good conversion
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Old 30-09-2014, 09:45 AM   #43
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Yeah will close fairly easily, the close bit is the inlet, but that's being modded!

The only vw engine I've seen with inlet and exhaust on the same side is the diesels?!?!
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Old 30-09-2014, 09:53 AM   #44
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I wouldn't say the MGF rear suspension is so bad (but certainly not my first choice) it's more that it is trying to fix a problem that wont be present on your chassis, as lateral force builds and the suspension rolls the MGF rear suspension is trying to generate more and more grip because it's expecting to try and keep a smallish, low inertia mid engined car from oversteering. Mini trailing arms are doing pretty well the exact opposite, they are rigidly mounted so no compliance steer (the subframe trunnion bushes may give some compliance steer?) the trailing arms have no roll steer or camber compensation so the grip is reducing with roll as the rear tyres end up at positive camber

If you were to try and remake the arms and use the knuckles and brakes I still can't see it fitting below the pick up load bay floor.

Thanks for the images, still suprisingly compact, do you have one showing the diff casing to rack clearance, I imagine the diff centreline to crank centreline distance must be less than say the Vauxhall or the Honda in order for the block / cam pulley end covers to be so close to the bulkhead and the diff casing still not the interfere with the rack body? I moved the rack 50mm ish and the diff casing still only has say 7- 8mm clearance but the cam pulley end cover is still not as close to the bulkhead as yours, I know it's not entirely comparable as the cam drive is different and it will vary with engine angle but your cam cover looks pretty near horizontal.

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Old 30-09-2014, 12:15 PM   #45
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Yeah I understand what you are saying about the differences in car layout and suspension.

The load bed on the pickup has space under it of 20cm, so it's not impossible to get a subframe with arms etc under there. Obviously comes down to design and mainly knuckle height.

This engine leans back rather than most that lean forwards! So yes the cam cover is close but it pushes the gearbox forward! Diff clears the rack by just under 1cm approximately, but if I want more I could grind off a mounting lug. I'll see if I can get a pic!
One other miss leading thing is there is only 1 cam pulley so the front seems low and fits under the level of the inner wing.
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