I’m impulsive....subframes let’s talk about it.

[mjannusch]

I personally wouldn't do that either... Those rails from Mitsu are designed to deform in specific ways on impact. Putting in solid bars is going to change how the car absorbs impact.

I never mess with anything on a car that's going to change how it reacts in a crash. Just too risky, IMO.

[DCIV]

[quote=""mjannusch""]I personally wouldn't do that either... Those rails from Mitsu are designed to deform in specific ways on impact. Putting in solid bars is going to change how the car absorbs impact.

I never mess with anything on a car that's going to change how it reacts in a crash. Just too risky, IMO.[/quote]

Don’t take this question the wrong way, I looked at those bars a lot lately. How can you tell they are meant to crumple anywhere? They are beefy freaking bars! And I want your opinion. In fact if anyone can explain their opinion to me I want it as well. Then at least I’m informed on the choices I make.


Coop

[mjannusch]

That's what those bars are for - to control the crumpling and absorb energy in a frontal crash. They are boxed in over a flat steel piece with geometry that will push the bar down instead of up when crushed. The motor has to exit down or you are going to end up with it in your lap.

[mjannusch]

Here's a crash test of an Eclipse of the same era as our cars.

https://www.youtube.com/watch?v=6UpcHo1D-Zk

This one the motor mounts don't break and drop the motor, but if you replace sections of the front cradle with parts that don't deform, then you are going to be absorbing that impact instead of the car.

[DCIV]

[quote=""mjannusch""]That's what those bars are for - to control the crumpling and absorb energy in a frontal crash. They are boxed in over a flat steel piece with geometry that will push the bar down instead of up when crushed. The motor has to exit down or you are going to end up with it in your lap.[/quote]

Yeah that’s how all unibody cars are designed right? To dump the engine on the ground. I guess I just don’t know if those bars are made to transfer energy to the unibody (Which would be fine with the pic I posted.) or actually meant to bend and absorb energy and thus not fine with what I posted.

I’ve looked for pics of them in a crash with no avail. I guess it would be just as easy to weld on a spot to tie those in as it would be to make the bars I posted. I want to be safe. My life isn’t worth that little weight savings.


Coop

[aaronatstate]

[quote=""DCIV""]Don’t take this question the wrong way, I looked at those bars a lot lately. How can you tell they are meant to crumple anywhere? They are beefy freaking bars! And I want your opinion. In fact if anyone can explain their opinion to me I want it as well. Then at least I’m informed on the choices I make.


Coop[/quote]

Yeah, like Matt said, everything is 100% designed to absorb energy, and move the stuff in the front end in specific ways in a crash. It may not look like it would move a certain way, but it definitely will.

[mjannusch]

Not sure if you saw it since we posted at the same time, but I added a post above yours with some crash video of an Eclipse which has the same engine cradle area as 3S cars. That's only a 35 MPH crash, so the motor doesn't drop out, but there's a lot of crumple there to absorb crash energy. If the car doesn't absorb the energy, then you get to take the full brunt of it against the seatbelt and airbag.

[DCIV]

[quote=""mjannusch""]Not sure if you saw it since we posted at the same time, but I added a post above yours with some crash video of an Eclipse which has the same engine cradle area as 3S cars. That's only a 35 MPH crash, so the motor doesn't drop out, but there's a lot of crumple there to absorb crash energy. If the car doesn't absorb the energy, then you get to take the full brunt of it against the seatbelt and airbag.[/quote]

I didn’t but I did get to watch it. Wish it would have shown us what crumpled but it’s obvious everything took that energy to keep the cockpit alone.


Good video.


Coop

[mjannusch]

Yeah, and those old DSMs from '90-94 didn't have airbags either, which seems crazy now.

You want to maximize your chances of survival. The crumple zone turns a lot of fatal crashes into survivable ones. That video is just a 35 MPH crash straight-on into a barrier. If someone hits you head-on and you are both going 35, that's a 70 MPH crash into a wall and you want every part in front of you to do what it is designed to do.

I'd guess that you've seen this in action at accident sites that you've had to respond to.

[ChargerX3]

Coop do you still have your front crash bar under the bumper?

[DCIV]

Seen a lot, most arnt like a brick wall, most are off center, vehicles diff heights, and tons of other factors but they arnt usually so simple as that.

I saw one last week where a bmw hit one of those trucks that just carries a couple vehicles...,if someone would have been in the passenger seat they would have been dead. 2014 bmw as well. Could barely tell the truck had been hit too.


Coop

[DCIV]

[quote=""ChargerX3""]Coop do you still have your front crash bar under the bumper?[/quote]

I didn’t for years and years. And then just recently I bought one of Wayne’s originals and installed it. Why do you ask?


Coop

[ChargerX3]

That’s also going to affect how your vehicle reacts in a crash. Crumple zones are built into that bar.

[DCIV]

[quote=""ChargerX3""]That’s also going to affect how your vehicle reacts in a crash. Crumple zones are built into that bar.[/quote]

And Wayne’s is a lot stronger than factory. I also didn’t like how the front wasn’t tied together as much. It maybe small but I didn’t like it.

So since we are taking subframes, what’s the thought of the tubular crash bar in place of stock? Add another thing into the mix.


Coop

[mjannusch]

It isn't about strength, it is about energy absorbing capability. Wayne's bar is going to transmit crash energy straight into the bumper shocks and then into the frame. The stock crash bar dissipates energy and extends the time of dissipation as it is being crushed so that bumper shocks and frame don't take the full hit all at once.

Having Wayne's bar is better than nothing, but worse than the stock bar - at least as far as accidents go.

But if your car is like mine, and lives on jackstands most of the time - probably not a problem at all.

[DCIV]

Ok so, I have finished the main frame design and they will be available two ways.

Detachable rear diff support much like the factor version, which basically makes for easier access to the diff cover, and solid design which means you have to drop the diff to service it. The detachable version will be heavier and won't be a total solid mount like the other, but that's for you to decide. The prototype is a solid design. I only need to add the control arm mounts, which I just ran out of time to do today, and the aws/sway bar mounts. These parts are made, just not attached yet.

The stock subframe with the rear diff support, and front diff mounts weighs in at 70+ lbs. Currently without the mounts, this comes in at barely over 20 lbs. I can't see it being much heavier than 30lbs when complete.

The control arms are all designed and completed. Adjustable and probably around the same weight as the stock stuff, but look better and have the adjust-ability you don't get with the stock stuff.

I am attaching some pictures of the progress. I had a few more of the control arms but must not have transferred them to my cloud before I left today. This has been on the car, and back on the jig without issues a few times so fitment is top notch. I will most likely have these ready to ship in the next week or so. The fronts are being designed as well, much less complicated than the rear with all the aws and sway bar mounts.

I also have added on the jig the mounts for the brackets on the aws system, as well as the lines and such. I know not all of you are getting the aws and sway bars, but just a heads up. There is a picture of the jig where you can see the aws and sway bar mounts attached and already located in stock position. As I said, these parts are already designed and cut, just weren't attached just yet.

Coop

[Monochrome]

Oh wow you're really going to start selling these? That's a great!

Did you see what happened with Garrets rear subframe at world cup last year? He twisted the diff after several hard launches running low 8 second passes. It needed more gussets to reenforce.

[DCIV]

[quote=""Monochrome""]Oh wow you're really going to start selling these? That's a great!

Did you see what happened with Garrets rear subframe at world cup last year? He twisted the diff after several hard launches running low 8 second passes. It needed more gussets to reenforce.[/quote]

I’m not. This is someone who is. I just like to throw the info out there now so if anyone has any suggestions during this phase they can possibly make it better.

I thought the weight savings would be more than 40lbs, but if you add that and a tubular rear crash bar (at least to a 1g who didn’t get the nice aluminum one) then your prob close to 50lbs out of the rear of the car.


Coop

[mjannusch]

I don’t think those rear bars are going to cut it to hold the diff up in place. They look like the diff will try to twist them off. Easy to bend a tube the long way like that.

[DCIV]

[quote=""mjannusch""]I don’t think those rear bars are going to cut it to hold the diff up in place. They look like the diff will try to twist them off. Easy to bend a tube the long way like that.[/quote]

You talking about the bars that go towards the front of the car or the back of the car?


Coop