PORTALS! Realities and Tradeoffs

[CodyFungi]

I'm in love with portals but my car was designed to have them.

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[87-Z28]

Just to be crystal clear. I am NOT anti portal.

We all know suspension lifts have advantages allowing bigger tires and more clearance. We all also know they can’t be extrapolated or unbounded without issues. As lift increases there are diminishing returns. Nothing is free.

A portal lift is no different. Depending on objectives it has real advantages, but also suffers from various consequences. Nicely articulated by sierrabronco.

There is no ultimate solution for all. The objectives of the use case dictate better or worse solutions.

 

[5GENIDN]

Just to be crystal clear. I am NOT anti portal.

We all know suspension lifts have advantages allowing bigger tires and more clearance. We all also know they can’t be extrapolated or unbounded without issues. As lift increases there are diminishing returns. Nothing is free.

A portal lift is no different. Depending on objectives it has real advantages, but also suffers from various consequences. Nicely articulated by sierrabronco.

There is no ultimate solution for all. The objectives of the use case dictate better or worse solutions.

Andy, you have always been very thoughtful and deliberate. You back up everything you say with math.... I love your contributions. If anyone wants to understand the pros and cons... I suggest they read your posts. You never pass judgment you just state the facts. Thank you!

 

[SierraBronco]

Just to be crystal clear. I am NOT anti portal.

We all know suspension lifts have advantages allowing bigger tires and more clearance. We all also know they can’t be extrapolated or unbounded without issues. As lift increases there are diminishing returns. Nothing is free.

A portal lift is no different. Depending on objectives it has real advantages, but also suffers from various consequences. Nicely articulated by sierrabronco.

There is no ultimate solution for all. The objectives of the use case dictate better or worse solutions.

Andy, you have always been very thoughtful and deliberate. You back up everything you say with math.... I love your contributions. If anyone wants to understand the pros and cons... I suggest they read your posts. You never pass judgment you just state the facts. Thank you!

Absolutely spot on. And that’s the point of this thread. Providing feedback on what the true expectations should be when running portals. Or at least if you truly plan on running them. It does seem like portals have become more of a status symbol, the gucci purse of offroading. Many people want portals just to say they have them; a flex for their instagram page in between reminders to like and subscribe. They might hit some light wheeling on dirt roads before talking about doing adventuring and getting off the couch. Will the center of gravity be an issue for these people? Not at all. Suspension compromises? Nope. As long as it’s a shiny big-brand name, the suspension is dialed! Now smash that affiliate link and show some support for the channel by donating to the patreon. But I digress.

How many portal owners will realistically notice the effects mentioned in the original post? Tough to say. We put a lot of wheeling in, on very hard trails of varying terrain, with a lot of different builds and platforms. Some things were evident very early on or known before even installing the portals, but other items presented themselves with time. And that’s the intent behind the thread-providing real feedback on what to expect with ownership (at least for those doing more than carshows)

 

[Brian_B]

Edit to include more explanation from @87-Z28 from another thread

Link to post with pictures

The distinction between loading and response is necessary. For the scenario of interest, body rotations in the for-aft and up-down plane must be considered. So pitch motions.

The loading occurs from traction forces at the tire/ground interface generated by torque at the wheel hub. That torque is multiplied by the portal gear ratio. The torque from the portal box also adds a moment at the axle shaft due to the moment arm (leverage). This doesn’t exist in non portal configuration. First plot shows a free body diagram. Second plot shows the increased reaction forces at the lower link due to portals. Link forces in non portal rig are fairly symmetric. Lower link forces for portal rig can double.

Now the response to this loading. If instant center for rear links is located on 100% anti squat line then the links will take all of the load and the springs will not be loaded. This is however not the case with the Bronco platform with oem link hard point locations. Plots 3, 4, & 5 show the “effective” anti squat for oem on 35s (sas), oem on 38s with a 3” suspension lift, and portals on 40s. Notice instant center moves further away from 100% anti squat. Hence the springs will need to respond to applied loading.

Springs are only slightly more engaged for portal build (as compared to a typical non portal build on 38s), but applied loading is more severe in portal rig. This will begin to engage pitch motions and thus portal bounce. The applied loading is the cause.

Stuff like this right here is why these forums are the best.

 

[Dusty]

Finally had a chance to read this post and wow, awesome writeup! This thread will become the Portal Bible.

 

[SierraBronco]

Stuff like this right here is why these forums are the best.

Basically me any time @87-Z28 posts

Finally had a chance to read this post and wow, awesome writeup! This thread will become the Portal Bible.

Well damn dude. Thank you! Hopefully it is helpful for people when trying to figure out what to expect if they take the plunge.

 

[userdude]

Finally had a chance to read this post and wow, awesome writeup! This thread will become the Portal Bible.

So is @SierraBronco now known as Portal Jesus?? lol

 

[GooseTuned]

Great post man!!!

 

[SierraBronco]

So is @SierraBronco now known as Portal Jesus?? lol

 

[SierraBronco]

Great post man!!!

Thanks!

 

[jtgensler]

Basically me any time @87-Z28 posts

Well damn dude. Thank you! Hopefully it is helpful for people when trying to figure out what to expect if they take the plunge.

Have I said "portals would be cool", sure...
Have I ever seriously considered them - no, they're cost prohibitive to me, so I never really thought out pros/cons.

Did I read every post of this thread just to learn more. Absolutely.
And the more modding I do to my own rig, the more I agree with the "nothing is free, everything has a trade off somewhere" mantra.

 

[SierraBronco]

Have I said "portals would be cool", sure...
Have I ever seriously considered them - no, they're cost prohibitive to me, so I never really thought out pros/cons.

Did I read every post of this thread just to learn more. Absolutely.
And the more modding I do to my own rig, the more I agree with the "nothing is free, everything has a trade off somewhere" mantra.

Join us Sunday for a special sermon prepared by disciple @87-Z28 with an introduction to gearing by @5GENIDN

 

[popo_patty]

I'm too poor for this...

 

[Felix808]

I'm too poor for this...

Hey as a Pit Crew member, you should know if you aren't in the Red you aren't racing .
& to paraphrase @SierraBronco just finance it Bro so you can flex on YouTube. It's so worth it .

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