LS swap into WJ / WG Grand Cherokee and other stuff (ahem...attempt).

[Grippy]

Is the 2inch lift gauged on what the yanks get or what we get here which I believe was 1 inch higher from factory?
Why are the spring airbags a problem Straubz?

Sent from my SM-T590 using Aussie Jeep Offroad mobile app

[Straubz]

Originally Posted by Grippy

Is the 2inch lift gauged on what the yanks get or what we get here which I believe was 1 inch higher from factory?
Why are the spring airbags a problem Straubz?

i only got 1" more lift when i went to the IRO 4" springs so i guess it was calculated off the height here in aus.

Apparently if you have any srs airbags in a vehicle you are not allowed to modify the ride height in any way, he recons even patrols and cruisers with airbags can't be lifted at all, pretty sure he didn't know what he was talking about yet he is still a registered engineer in vic.

[Hoobz]

Engineer certification for modified vehicles is an interesting subject. It's not straight forward.

VASS stands for Vehicle Assessment Signatory Scheme. VicRoads has a list of engineers they approve of, through a link on this webpage Vehicle modification VASS Approval Certificate. CLICK for pdf download >>> VicRoads VASS signatories

You can pick from the list, contact them yourself.

I'm interested in building a working relationship with my engineer. I'm keen to do some other stuff. So I made sure to spend some time with him to understand his position, how it all works, and to hopefully earn his trust that I'll do the right thing by him.

He's seen it all. As you can imagine. He's also got a massive cache of auto mod info in his head.


A good analogy, that my engineer liked that's familiar with me, and agreed with, was this;

A VASS signatory is like a construction supervisor. A good supervisor is trusted to be a fair judge on what is sound building practice. You have to make sure that 'ALL' the work gets done, to at the very least, industry approved standards.
At the same time he is the meat in the sandwhich between the tradies, and the Developer/Contractor/Builder/Project Manager.

On one hand you got developers that want the job to be of the highest standard. On the other hand you have tradies that have quoted the work and want to get done asap, and outta there, and paid as much as possible.

The kicker is, what one supervisor would accept as quite acceptable workmanship, a different supervisor will know is shit.

VASS signatories are the meat in the sanga too. Going between people modifying their vehicles on one hand, and VicRoads on the other. People constantly want to take the shortest, easiest route. One VASS signatory will approve something another sigantory won't. It is a gray area.

The VASS recommended engineers are not employed by VicRoads, they are independant contractors. My engineer spends a lot of his time overseas consulting as an automotive engineer. This is just one avenue of work for him.

It's important to do the right thing by you particular engineer. Just like it is important to do the right thing by a building supervisor. So I know exactly where he is at.


It's guaranteed that there will be different opinions and different ways VASS engineers will enterpret the occassional reg. None of them may be wrong, or right, at some points.



It's a bit like this:

Recently I had to get a Vic Road Worthy Certificate for the GC my missus bought from interstate.

The list my very local VACC (RWC checker) mechanic gave me was pretty short, and easy. I am not a road worthy official at all, but I knew a few things he missed, or at least could have been enterpreted as failing.

He fitted us in his very busy diary, it was chockers. It took some arm twisting.

But, and it's a big but, he put removing the side window tint completely. The side window tint was 24% light transmitting. I've been here before, a few times. I suggested I'd take the driver's and front passenger tint off and leave the tint on from the B Pillars back. He wouldn't accept it, becaue he said the rules changed recently. I knew different but let it slide, went home started on the rest of the list.

I looked it up, and there is actually a recent addendum to the regs about tint, saying you can have down to 30% light transmitting tint on the side windows from the B-Pillar forward. So they did have to come off, because they were 24%, too dark, and I was ok with that because I actually hate side tint for driver and front passenger.

Any side window from B-Pillar back can be down to 20% light transmitting, so by the regs we could keep those tinted the way they were.

My missus wanted me to go correct him. She really really likes dark side tint, it's her car. I consulted an old buddy of the mechanics, and two other mechanics and my engineer. They all said just do what he wants, he fitted you in his tight schedule. He is indeed wrong, but FFS don't ruffle his feathers. That was my thought all along. Just take it all off, get it rego and move on.

My missus still insisted I go show him before taking it off. I told her, okay you F'n go show him this print out of the regs. If he then says we can jam it, YOU find another VACC tester, and YOU f'n fix anything that is wrong that will f'n take a lot more to fix than bloody tint.

Tint is off. I am happy, mechanic is happy. Missus has new massive light bar and she's happy too



TL;DR The whole engineer thing is a gray area. What one engineer will certify, another may not. Don't rock the boat if you are generally on a good thing. Give and take here and there.

[Classic Boy]

You are wiser to engage the engineer early in the process as they don’t willing pickup a half complete modified car or in some cases fully complete modified vehicle and then assess it after the fact. They like to be involved in the planning and implementing stage to both advise their preferred methods and what they will and won’t accept. They rely heavily on previously approved precedent and they assess it against the design rules in place.

[Hoobz]

Originally Posted by Classic Boy

You are wiser to engage the engineer early in the process as they don’t willing pickup a half complete modified car or in some cases fully complete modified vehicle and then assess it after the fact. They like to be involved in the planning and implementing stage to both advise their preferred methods and what they will and won’t accept. They rely heavily on previously approved precedent and they assess it against the design rules in place.

Ahhh yes.

Good points I forgot to mention. So true. Get them in on it from the start for sure.

Thanks Classic

[Straubz]

Originally Posted by Hoobz

Ahhh yes.

Good points I forgot to mention. So true. Get them in on it from the start for sure.

Thanks Classic

Really good points and completely agree, i am still learning engineering but in a different trade i so i can't get any VACC certification but i do know what they have to put up with, i have tried finding previous WJs that have been engineered so i can get a copy of the results from swerve tests and what not, one engineer said that would help alot since its a bolt on kit, full custom is a completely different story tho.
The same thing they have all said so far is, the more people the better the price since they will need to hire a track and driver for testing.

Basically an engineer that is willing to work with you is worth keeping happy, the one that knocked me back was some old guy who wanted nothing to do with any later model cars, he would only do old stuff.

[Hoobz]

Here's an abbreviated rundown of what we're aiming to do, and the sequence.


1. Convert the GM 4L60E auto from 2WD to 4WD.

Fully disassemble and service trans. Light rebuild kit through it, new frictions and steels, o-rings, seals, gaskets, and all the usual improvement bits. Sonax stuff, whatever.

Fit shorter transfer case output shaft, and tranfer case end/tail housing.

Fit transfer case. Haven't locked in which transfer case yet. Depending on which TC, output speed sensor mod and others probably required.


2. Install powertrain.

Fabricate engine - transmission mounts and fit engine and trans.

Fit rear driveshaft only. There won’t be an AWD transfer case.

Fit exhaust system.

Fit radiator. All plumbing, including fuel/brakes.

Fit all engine accessories.

Install GM 411 PCM and engine/trans wiring harness.

Make it run and drive, before continuing with further stages.


3. Merge GM and Chrysler electronics modules.

Google the F out of the net, like all good programmers and techs do.

Visit psychiatrist. Often.

Pin up motivational posters and read self confidence books…podcasts. ‘YOU CAN DO IIIIT’ stuff.

Ensure ABS works as intended by Chrysler.

Ensure airbag system functions as intended by Chrysler.

Make it so all powertrain and body module diagnostics can both be read from the one OBD port. Cannot have two OBD ports.

Make it so OEM instrument panel gauges work, or design and construct an Android / microcontroller based custom system in the OEM position, with an appropriate UI.


4. Long arm lift system changes.

Make required improvements to current Iron Rock Offroad Premium front and rear long arm 6” lift kit. There’s a little list. Easy to do.

Calculate through practical testing minimum lift required to fit 35” tyres. Tyres cannot scrub anywhere, at anytime during suspension cycling.

Lowest COG possible the goal. Find the best compromise between uptravel and height of vehicle.

Trim / adjust / tub / flare wheel guards and arches. 150mm max lift from OEM original Upcountry version. Max allowable track increase to be used.

Fit upgraded brake callipers and rotors to front.

Fit new brake lines front and rear.


-------------------------------------------------------------------------------

If 3. Merge GM and Chrysler electronics modules. turns out the impossible for me, the project ends, before the suspension/body mods.

Plan B begins. XJ LS1.




TL;DR

Power train fit first.

Electronics next.

If electrics/PCM issues prove my breaking point >>> XJ LS1 swap instead.

If electronics/PCM challenge beaten, keep going with long arm lift and 35’s compliance mods.