Coil over preload??? What am I misunderstanding?

[DionR]

The Questionable Garage is doing a Demon build for all 3 of Holley's Grand Champion challenges using 3 different motors (Hemi, LS, Coyote) but the same car. Pretty cool idea, I like it.



He is using a QA1 coil over conversion kit, which completely makes sense to me with his 3 motor criteria.

What I am curious about is it in the first video (above) he makes the comment that the TB suspension is lacking in adjustment. I asked in the comments what it was missing in the way of adjustment and his answer was; "You can change ride height with the spring preload but you also end up loosing some spring preload to achieve that, so you can make quick changes but you can dial in a coil over way better".

Not questioning his use of a coil over kit, just (apparently) not understanding how coil over pre-load works. I did read one article on it and it sounds to me like tensioning the torsion bar when the suspension is on the stops is the same deal. And the only issue would be if the TB is too strong and/or the car too low resulting in the TB losing all tension when the suspension droops.

And the only reason to preload the spring is to make sure the spring doesn't move off it's seat at full extension, right? So no real handling benefits?

Am I missing something?

And just to be clear, I'm not poking at Jerad, just making sure I'm not missing something.

 

[72bluNblu]

Jared is just parroting the same thing people always say. The factory suspension does lack adjustment, ALL factory suspension does. The fact that it was factory suspension designed for bias ply's is the real issue, but one that is easily solved with tubular UCA's or even just offset bushings. Honestly his answer just tells me he doesn't know how to tune a torsion bar suspension.

With linear springs, preload is basically just making sure the spring still has tension at full extension so nothing becomes unseated. That goes for torsion bars (linear springs!) and most coil overs too, because most coil overs are linear. Once the weight of the car is on the suspension, the load on the suspension is the weight of the car. It's not the weight of the car + the preload, which means regardless of the preload you have the same amount of energy in the spring. And with a linear spring, it means it's compressed the same amount at ride height regardless unless you've made your preload more than the weight of the car.

Most coil springs are designed to work with a specific amount of preload. What it generally shows if you have/need a ton of preload is that you picked the wrong springs for your application. It's something that you should be setting up when you pick your spring rates and spring lengths, and not really changing all that much on the car. Meaning, for most applications the preload is something you should set according to the spring manufacturer, and not mess with later.

This article does a decent job of explaining it, the videos are a little long but they're pretty thorough...

How to Adjust & Fine Tune Coilover Preload | Low Offset

The exception is progressive springs, because with progressive springs changing the preload is actually going to change the effective spring rate.

 

[DionR]

Jared is just parroting the same thing people always say. The factory suspension does lack adjustment, ALL factory suspension does. The fact that it was factory suspension designed for bias ply's is the real issue, but one that is easily solved with tubular UCA's or even just offset bushings. Honestly his answer just tells me he doesn't know how to tune a torsion bar suspension.

Jared has done a couple of Mopars recently, but I highly doubt he has done much if any TB tuning.

And the reality is, pretty sure QA1 sponsors him and they probably wouldn't be happy if he didn't make it sound like people had to buy their $5K kit to make a Mopar handle. So either he honestly doesn't know, or he is parroting what they told him.

This article does a decent job of explaining it, the videos are a little long but they're pretty thorough...

How to Adjust & Fine Tune Coilover Preload | Low Offset

Thanks! That helps.

I like the guys comment in the first video; "Preload is hookum".

I did respond to Jared and now I think I am off in what I said. But at least I understand better.

 

[Kern Dog]

I wouldn't watch any idiot that puts a GM or Ford engine in a Mopar.

 

[DionR]

I wouldn't watch any idiot that puts a GM or Ford engine in a Mopar.

View attachment 1716123217

Understandable. I am just glad to see a Mopar get the build time and at least one of the motors is a Mopar.

The idea is cool to me, to compete in all three of the competitions with the same car, and the only way to do that is with a motor that matches the event (LSFest, Moparty, etc.). Not something I would put effort into, but a fun idea.

 

[Kern Dog]

I'd love to see a build testing the 5.7, the 6.1 and the 6.4.
I'm a proponent of torsion bars so I'd wince a bit at the use of those darned coil over shock suspensions....
I just can't get behind a Chevy or Ford engine in a Mopar!

 

[72bluNblu]

Jared has done a couple of Mopars recently, but I highly doubt he has done much if any TB tuning.

And the reality is, pretty sure QA1 sponsors him and they probably wouldn't be happy if he didn't make it sound like people had to buy their $5K kit to make a Mopar handle. So either he honestly doesn't know, or he is parroting what they told him.



Thanks! That helps.

I like the guys comment in the first video; "Preload is hookum".

I did respond to Jared and now I think I am off in what I said. But at least I understand better.

Yeah, that entire operation is the kind of thing you wouldn't undertake without some kind of sponsor. Looks like he's QA1 and Holley sponsored, so it totally makes sense.

Preload is one of those things that all the coil over guys throw around all the time, and maybe because they know it's a thing that you have to set up with a coil over they think it's some kind of thing with the torsion bar suspension too. But really, the way the torsion bar suspension is designed it's not really much of a thing at all. That doesn't mean it's a less adjustable or a worse suspension, it's just different. Like how with a torsion bar suspension changing the ride height is a piece of cake, but with a coil over suspension it requires a bunch of effort/parts.

I wouldn't watch any idiot that puts a GM or Ford engine in a Mopar.

View attachment 1716123217

Oh who cares. Mopar completely screwed the pooch when it comes to supporting the GIII for swaps. The LS platform has so much more factory and aftermarket support it's not even funny. I'm not going to do an LS swap just because I'm not all that familiar with the platform, but for the ease with which you can build a 600+ hp modern engine that will last hundreds of thousands of miles I certainly understand why people do it. That and they're literally everywhere, and cheap as hell for what you get. And with a coil over conversion the swap isn't any harder than doing a GIII swap either. Hell probably easier, way more parts available for the LS.

Understandable. I am just glad to see a Mopar get the build time and at least one of the motors is a Mopar.

The idea is cool to me, to compete in all three of the competitions with the same car, and the only way to do that is with a motor that matches the event (LSFest, Moparty, etc.). Not something I would put effort into, but a fun idea.

It's a neat idea, but yeah, it makes way more sense if he's sponsored. You sponsor one dude and one car and you get advertising at ALL the major events. From an advertising standpoint it's brilliant. From a turning wrenches on the car standpoint it seems like a headache, even if attending all those events with the same car would be fun.

 

[Kern Dog]

Kern Dog said:
I wouldn't watch any idiot that puts a GM or Ford engine in a Mopar.

View attachment 1716123217


Oh who cares.

Is this a rhetorical question?
Clearly I care. The majority of classic car owners care about their cars having the same manufacturer of engines that the car is.
Only a small few "Don't care" and you are obviously one of them.

 

[junkyardhero]

Is this a rhetorical question?
Clearly I care. The majority of classic car owners care about their cars having the same manufacturer of engines that the car is.
Only a small few "Don't care" and you are obviously one of them.

would i put an LS in my barracuda? no. but would i put an LS in a $1500 clapped out 74 4-dr dart that's destined for the scrapper anyway?

*shrugs* sure why not. i don't have anything better to do this weekend.

 

[72bluNblu]

Is this a rhetorical question?
Clearly I care. The majority of classic car owners care about their cars having the same manufacturer of engines that the car is.
Only a small few "Don't care" and you are obviously one of them.

It’s not rhetorical, it’s meant to point out how stupid it is.

All the “brand war” stuff is. A well done classic car is a well done classic car, regardless of brand. And really, if it’s not 100% stock then it’s not 100% stock, so, it’s just splitting hairs after that.

If a Mopar had a clean, well done LS install it wouldn’t bother me at all, and yeah, I’d put it ahead of a Mopar with a poorly done GIII install. Because realistically there isn’t much “Mopar” about a GIII, not in the classic sense. But I’m sure the LS Mopar would command a lower price.

All that purist and resale value stuff is a slippery slope, next thing you know the only thing you can do is putt around on replica bias ply’s when its 70° out, sunny, no chance of rain, in daylight only, and not for too many miles or you’ll lower the value. It’s just boring as hell.

The 3 engine thing is a gimmick, but I get the marketing value, and if they set it up as a good performing driver then that’s all I care about. Another old Mopar back on the road for people to enjoy. The rest is just bullshit.

 

[Kern Dog]

It’s not rhetorical, it’s meant to point out how stupid it is.

More opinions, not facts.
You have opinions like anyone else. You often state them as if they are widely accepted facts.
This is not always the case.
Most enthusiasts prefer to keep their cars powered by engines from the same family.
Some don't have any interest in that.
I'm not a purist as defined by a "Strict adherence to 100% OEM appearance as built".
I am a purist by a more loose description.
I prefer Mopars to retain their torsion bar suspensions. I'm a proponent of upgrades to it too.
I like stock, optional and even late model Mopar engines and transmissions.
I'm okay with aftermarket transmissions and differentials. Brakes too, why not?
Yes, I agree that Ma Mopar was stubborn to embrace the enthusiasts that wanted factory support for the 3G Hemi swaps into classics. It isn't enough to just embrace a Chevy swap, in my opinion.

 

[racerjoe]

The Questionable Garage is doing a Demon build for all 3 of Holley's Grand Champion challenges using 3 different motors (Hemi, LS, Coyote) but the same car. Pretty cool idea, I like it.



He is using a QA1 coil over conversion kit, which completely makes sense to me with his 3 motor criteria.

What I am curious about is it in the first video (above) he makes the comment that the TB suspension is lacking in adjustment. I asked in the comments what it was missing in the way of adjustment and his answer was; "You can change ride height with the spring preload but you also end up loosing some spring preload to achieve that, so you can make quick changes but you can dial in a coil over way better".

Not questioning his use of a coil over kit, just (apparently) not understanding how coil over pre-load works. I did read one article on it and it sounds to me like tensioning the torsion bar when the suspension is on the stops is the same deal. And the only issue would be if the TB is too strong and/or the car too low resulting in the TB losing all tension when the suspension droops.

And the only reason to preload the spring is to make sure the spring doesn't move off it's seat at full extension, right? So no real handling benefits?

Am I missing something?

And just to be clear, I'm not poking at Jerad, just making sure I'm not missing something.

I haven't watched his video. However, I had this exact same idea last year at Moparty when one guy showed up to three grand champion events and won all three. He owns a vette, and he borrowed a mustang and a viper. When I was there, I told my friend (crew chief) that we need to build a foxbody that can accept all 3 engine platforms. I would build it so the engine was an easy swap with connectors for the harnesses and exhaust with v-bands. While I do think it will be fun, I don't have the funds for such a task. The cost to this guy will likely be nothing since I'm sure he's getting sponsored parts, and his youtube revenue will pay for the car. After all, this is his job.

I hope he gets it done in time for next month. Would love to see another A body out there with us beating our **** like it owes us money.

 

[DionR]

I haven't watched his video. However, I had this exact same idea last year at Moparty when one guy showed up to three grand champion events and won all three. He owns a vette, and he borrowed a mustang and a viper. When I was there, I told my friend (crew chief) that we need to build a foxbody that can accept all 3 engine platforms. I would build it so the engine was an easy swap with connectors for the harnesses and exhaust with v-bands. While I do think it will be fun, I don't have the funds for such a task. The cost to this guy will likely be nothing since I'm sure he's getting sponsored parts, and his youtube revenue will pay for the car. After all, this is his job.

I wonder if he overheard you?

He was pretty specific about using one car, because he said someone had done it in 3 different cars. I suspect the Demon was a cost cutting measure since (I think) it was free. He had to do a ton of rust repair just to make it structurally sound, but I bet it was still cheaper than a Foxbody.

Really hope he gets it done. Been pretty quiet on his end on this project, could be good news or bad.

Would love to see another A body out there with us beating our **** like it owes us money.

As it should be!