Outer Limits 4x4 Board

Has anyone tried to strengthen the Sierra chassis at all? Surely it cannot be all that strong and would twist a lot under load and flex. As I plan to put a fair bit of power through it I am wondering if it would be wise to add some strength.

Bazooka wrote:Has anyone tried to strengthen the Sierra chassis at all? Surely it cannot be all that strong and would twist a lot under load and flex. As I plan to put a fair bit of power through it I am wondering if it would be wise to add some strength.

how much is a "fair bit" ?
Add a decnet roll cage that will stiffen it up quite a bit.

I think Greg's hairdressers car (built by Gwagensteve) has had some rigidity built in.

But yes, a well designed 6 point will stiffen the rear 2/3rds.

Just remember that a chassis will always TRY to flex, every time you stiffen it somewhere it will stress somewhere else.

love_mud wrote:
how much is a "fair bit" ?
Add a decnet roll cage that will stiffen it up quite a bit.

Oh about 180kw to start with.
I know a cage would help but was wondering if anyone had gone to the lengths of cross bracing the chassis itself for more rigidity.

Front end of mine was extended around 200mm, this meant an extra chassis rail only 120mm from the front most one (stock)... this plus 6mm plating top and bottom means the front end is practically solid steel, but as someone else mentioned - the weak point is the next bit further back now... haha but still - i got a good tree pusher now.

Bazooka wrote:

love_mud wrote:
how much is a "fair bit" ?
Add a decnet roll cage that will stiffen it up quite a bit.

Oh about 180kw to start with.
I know a cage would help but was wondering if anyone had gone to the lengths of cross bracing the chassis itself for more rigidity.

Laminating the rails , the whole thing needs to be thought out as the thing will still need to flex , if it dosnt it will crack at the pionts you attach your " stiffness "

How about asking if anyone has cracked a chassis from flex before?
if it ain't broke,,,,,
Peter.

Not sure what chassis you're starting with Bazooka, but the WT chassis is stronger - it has gussets under the front spring hangers and a few other things.

I have done some "strengthening" but only through fitting new crossmembers where required, not through laminating. the extension on Greg's hairdressers car did end up pretty heavily laminated at the request of the engineer.

Apart from front spring hangers, I haven't heard of a sierra chassis cracking. I don't really even think they flex all that much for what they weigh.

Steve.

no problems so far with the chassis but as somebody allready said a cage stiffens things up,my old zuk would lift both front wheels evenly with only an alloy rear half roll bar

A zook chassie would have to be stronger than a ricer, or other 2wd chassie. Some of those pack the ponies.

With 180 kw "to begin with" in a swb chassis you will not have any real issues unless you are running tyres with som stupid serious grip on a high taction surface .. you will have serious issues getting power to ground I would say at least 100 of them KW will disapear as smoke ...

Joey with his SR20 went to a serious amont of trouble to get just 100Kw to ground ...

Install a decent cage, with an 88inch wheel base and that many KW you may end up using it. Also the chassis is so short it does not have a hel of alot of twist in it
If you have issues down the track beef it up then I somehow doubt you will.

I recall that Sky (from skymanfufacturing.com) had a 350 in a Zuk for a while without chassis mods (apart from the nessecary mounts etc) Also with the lightening manufacturing 4.3 V6 conversions I dont believe that there are any chassis plates .. I rekon a 4.3 V6 will create a fair lump of torque around the 250Nm mark at the absolute minimum.

Torque is the issue not power, if you're running a ricer engine all the power will be high revs hence the torque won't be that much.

just cruizin' wrote:Torque is the issue not power, if you're running a ricer engine all the power will be high revs hence the torque won't be that much.

Most turbo JDM performance motors do make some serious torque. My STi runs 392Nm in stock form- even the new V8 turbo diesel cruisers are only running 430Nm. Yes, it is at higher RPM, but the torque is very strong from about 3000rpm up.

My Mum had an S14 200SX, auto, that had massive midrange punch.

It wouldn't be hard to end up with three times stock sierra torque or more.

Steve.