Hi,

This is a MOD of the 8880 supercar and its 4WS: in real 4WS-implementations the behavior of the rear steering changes depending on the car-speed: with low speed the direction of the rear steering is contrary to the front-steering (behavior of the standard 8880) to achieve a small turning circle and a good manoeuvrability whereas with high speed the direction of the rear steering is the same (but with much smaller steering angle) as the front-steering to get high stability for lane-changing on the highways etc... as a side effect this MOD removes the chain-link to the V8 engine which always runs with vibration in the first gear... lego chain links are a suboptimal solution with drive trains with high rpm...

I have only used parts which were available at the time of the 8880 at '94 and i have tried not to touch the overall structure of the car and also to preserve the look as good as possible... but some picture says more than 1000 words, so here we go:

First the end-results:

here you see the 8880 default steering behavior (new selector in back position) - this is 100% identical to the standard behavior of 8880 and is for good manoeuvrability at low speed:

here you see the new steering mode (selector in front position): This is for high stability when lane switch at high speed (back steering has same direction as the front one but with smaller steering angle):

Here you see the new indoor look with the new selector gate:

Well, overall it looks more or less as before but has now more clever steering (means one feature more at the feature list) and better and direct driven engine:

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Well, now its time for the internals: it's more or less a crash gearbox like these ones in 8860 and 8865... some days ago i asked in this forum for solutions for switching the rotation direction - i got some very smart and clever solutions (thanks to all suporters) but unfortunatelly all of them uses either newer studless parts or needs to much space - the availble space in the transmission tunnel of the 8880 is somehow limited if you want to preserve the look of the car and the position of the seats.

So here you the the gears involved - on the right hand side you see that now the engine is driven just be gears which results in a much smoother engine operation: The solution fits exactly with the HOG train but needs very careful axle into playe fitting and trimming:

(One remark to the image above: the final version has an undriven counter pinion on the left side of rack - symmetrically to the driven pinion on the right side - the picture was taken before this pinion has been built in)

Here you see how this fits into the rear suspension and HOG structure (1) and with the selector gate (2):

P.S.

I do not want to conceal one small drawback of this new feature: switching between the 2 rear-steering modes is only allowed when the car drives straight ahead, means both steerings are centralized - otherwise the 2 steering would go out of sync.... but this is not prevented by a mechanism... maybe this would be possible too with a clever linkage from the HOG which prevents the sliding axle from sliding when not centralized... but for me this is an acceptable constraint...so i do not want to spend the effort

Edited February 2, 201312 yr by Kumbbl

Great mods. I'll have to try them out on my 8880 as well. I made some other simple changes to mine, like moving the suspension assemblies higher (so the wheels sit closer to the body) and increasing the gear ratios in the overall drive train.

I find that the chain works a lot better if you use one less link than the manual says, so that it fits tightly and contains no slack. Your solution of removing the chain altogether is probably ideal though.

Great mods. I'll have to try them out on my 8880 as well.

thanks! you will see the most stuff you need are a lot of brick 1x1 with Hole in gray and some plates 1 x YYY i gray and white... unmounting and later remounting the boot, engine and some of the black beams of the upperstructure is very modular and can be done in 20 min...

and increasing the gear ratios in the overall drive train.

i would be interested in pictures...

another feature i think off: adding a switch for activating/deactivating the front-drive - but this can be done very simple with a driving ring... would be a very realistic feature for 4WD cars but with the unmotorized 8880 the effect would be quite unvisible so i'm not sure if it's worth the effort...

so probably most senseful work would be spend improving the car body (doors, front cowl).... but one the other side pure aesthetic isn't very intersting and buidling fun... so probably by 880 will remain exactly as it is now....

i would be interested in pictures...

I just switched the 16t gears in this and this step with an 8t and 24t. It makes the engine pistons move much faster.

I just switched the 16t gears in this and this step with an 8t and 24t. It makes the engine pistons move much faster.

Would that not make it only faster in first and third gear? although you could also replace the 8t gear (added in step 5) and 24t gear (added in step 13) with a couple of 16t gears to speed up 2nd and 4th the same, but yeah, I likes me a fast spinning engine.

yes, allanp is right - changing only the gears like CP5670 would only speedup third and third gear... and yes, allanps suggestion is also right, then the 4 gears are lined up again... but with my mod and its removed chain-link (s.a.) speeding up the pistons overall is much simpler: just change the gear-set at this place - there are several possibilities ... it is always a good design principle (not only with lego but also with software e.g. ;-) to build up stuff so, that changes can be done at one single place if the behavior of a cerzain feature should be updated...

Would that not make it only faster in first and third gear? although you could also replace the 8t gear (added in step 5) and 24t gear (added in step 13) with a couple of 16t gears to speed up 2nd and 4th the same, but yeah, I likes me a fast spinning engine.

Actually, looking at my model more closely, it appears I had done exactly that. I made this change several years ago and had forgotten exactly what I did.

So here you see the gears involved - on the right hand side you see that now the engine is driven just be gears which results in a much smoother engine operation: The solution fits exactly with the HOG train but needs very careful axle into playe fitting and trimming:

(One remark to the image above: the final version has an undriven counter pinion on the left side of rack - symmetrically to the driven pinion on the right side - the picture was taken before this pinion has been built in)

For these guys who wants the pistons "fly":

Replace the engine drive in the picture above with this bunch of gears:

(you see that the idler axles have a second bearing to the right of the steering rack - this is necessary for a vibration free drive train - but all this fits very well in the structure of the 8880)

In the following picture you see the full "engine drive train" - you see also how easy you can choose different engine speeds:

For the two gears marked in the picture below as "upper gear" and "lower gear" you can choose on of the following combinations (lower --> upper):

- 24 ---> 8 (high speed pistons - my current setup)

- 8 ---> 24 (low speed pistons)

- 16 ---> 16 (standard speed)

The advantage of this solution - compared to the approaches mentioned above by CP5670 and allanp - is that the gear numbers at the switch box are still correct..

Any yeah, these flying pistons are funny, i like them too...

Edited February 6, 201312 yr by Kumbbl

nice mods indeed

I remember I once added rear-steering and 3-steering mode gearbox to 8865 (I could not afford to buy 8880)

MODE 1: Full 4WS

MODE 2: Partial 4WS (a la 8880, back turns a little front turns a lot)

MODE 3: CRAWL mode

Of course there was plenty of room in 8865 to do these things...