12:05 Garage- ’70 Duster build

[racerjoe]

As most know, the G3 Hemi comes with a drive by wire throttle body. My EFI controller can't operate DBW. There are t-body adapters on the market, but the only ones I found are for the 6.1 and later 5.7s, not the early 5.7. The also keep the t-body on an angle, which hurts my eyes. So I did what anyone would do and made my own. I started with a 1/2 piece of aluminum with a big hold in it from my favorite online parts cutter, send cut send.
The pictures show the progress. This is a universal LS throttle body I bought off ebay a long time ago. Someone apparently couldn't tune since they drilled a hole in the throttle plate. I'll weld that up at some point. I had to do some trimming on the throttle arm to get it to clear the timing cover casting but there's still plenty meat left for it to function properly. I like the end result, and happy that it actually disguises that ugly giant casting on the top left. I still don't know what that is for and considered cutting it off. That would require some aluminum fab because the cover is hollow behind it. Next up is a throttle cable bracket. I already have it drawing up in cardboard aided design. I just need to transfer it to some steel and get to cutting and bending.

For those wondering, the factory throttle body is turned approximately 20 degrees from square... There's some useless G3 Hemi info for you.

 

[DionR]

Keep in mind as you add caster the steering arm end / tie rod pivot changes as it is lowered.....and that causes bump steer.

So by bouncing the car before checking it, I was potentially changing the toe? Hadn’t thought about that. Can’t help that I had a significant different between the left and right caster, too.

I did think about that for my fabricated spindle project. In the end I decided to leave the LBJ bolt angles alone as I haven’t heard about anyone with lots of caster complaining about bump steer on a TB suspension. And with the car lowered, I figured maybe more caster was actually reducing bump steer. But it’s just a theory and my spindle project is still in its infancy so plenty of time to change it if the need arises.

 

[DionR]

I like the end result, and happy that it actually disguises that ugly giant casting on the top left. I still don't know what that is for and considered cutting it off.

I think that added casting is just used for picking the motor up. The factory tool uses the 2 bolts in the middle of the block next to the MDS solenoids and a stud in that spot to create a stable method of moving the engine around. Far as I can think, I don’t remember anything else using that mount unless maybe the factory used it to brace the shaker scoop on the Challengers or something.

 

[72bluNblu]

Keep in mind as you add caster the steering arm end / tie rod pivot changes as it is lowered.....and that causes bump steer.

So that's not entirely accurate. Changing the caster can raise/lower the location of the end of the steering arm, but it doesn't necessarily make the bump steer worse or "cause bump steer". Depending on the ride height of the car, suspension components, and the rest of the alignment specs adding caster may actually improve bump steer.

Changing the caster can alter the bump steer profile, but whether it makes it better or worse depends on how the suspension is set up and the rest of the alignment. It's not as simple as "you added a bunch of caster, therefore you have bump steer".

So by bouncing the car before checking it, I was potentially changing the toe? Hadn’t thought about that. Can’t help that I had a significant different between the left and right caster, too.

I did think about that for my fabricated spindle project. In the end I decided to leave the LBJ bolt angles alone as I haven’t heard about anyone with lots of caster complaining about bump steer on a TB suspension. And with the car lowered, I figured maybe more caster was actually reducing bump steer. But it’s just a theory and my spindle project is still in its infancy so plenty of time to change it if the need arises.

Any time the ride height changes the alignment specs change. That's true of all suspensions, it's a little more of an issue with torsion bar suspensions just because you can adjust the static ride height more easily.

The alignment we set is the static alignment, the dynamic alignment numbers are always changing when the wheel travels up and down. That's why camber curves come into play, where bump steer comes from, etc. Remember that bump steer is just the toe change curve, the toe you set at ride height is not the toe at full compression or extension.

 

[HemiDenny]

So that's not entirely accurate. Changing the caster can raise/lower the location of the end of the steering arm, but it doesn't necessarily make the bump steer worse or "cause bump steer". Depending on the ride height of the car, suspension components, and the rest of the alignment specs adding caster may actually improve bump steer.

Changing the caster can alter the bump steer profile, but whether it makes it better or worse depends on how the suspension is set up and the rest of the alignment. It's not as simple as "you added a bunch of caster, therefore you have bump steer".



Any time the ride height changes the alignment specs change. That's true of all suspensions, it's a little more of an issue with torsion bar suspensions just because you can adjust the static ride height more easily.

The alignment we set is the static alignment, the dynamic alignment numbers are always changing when the wheel travels up and down. That's why camber curves come into play, where bump steer comes from, etc. Remember that bump steer is just the toe change curve, the toe you set at ride height is not the toe at full compression or extension.

It can indeed be that simple....

Lets see????.....he (DionR) made two changes. He added some re-enforcing (should have zero effect on wandering) and offset bushings (my read is to add more caster...why else?) and started experiencing the car wondering.....IMO, a classic case of bump steer.

From my 50 year old memory (mid 70's) reading and applying the Mopar Performance Chassis manual I remembered "blueprinting" our front ends to reduce toe changes thru suspension travel on our drag cars by changing the location (up / down and in / out) of the steering arm / tie rod end pivot........ which just happens to be one of the effects of adding caster. FYI, as the top of the spindle tilts further rearward (adding caster), the end of the steering arms moves downward respectively. Most that add (a significant amount) caster NEVER even consider the change in front end geometry.

I'm just trying to point to a solution to a problem he might not have considered.

 

[DionR]

@HemiDenny , @DionR , @75slant6 , check this out! This is another Ride Tech product that come with their Mustang kits. It uses a S550 Mustang hub, so the bolt pattern is 5x4.5. They also have a caliper brackets that will allow the use of the S550 brake components. I'm not seeing these parts listed individually on their webpage, only included in kits. I kinda wish I would have found this earlier. This open options to use a factory Brembo caliper and have parts store availability for replacement parts.

View attachment 1716186738

FYI, I was able to order the hub washers from RideTech using the part numbers on their instructions. Kind of spendy at over $80, but now I have them.

The center bolt is just a 3/4” bolt, but the washers would have been more work to replicate.

 

[Ozyduster]

lol! If I had a dollar for every time I went out to my car in my pajamas to measure something I could probably buy a HellCrate for it!

Ok, so with a motion ratio of .807 and a 450 lb spring you should end up with a wheel rate of ~293 lb/in, which is really close to the 300 lb/in wheel rate I run with my 1.12” torsion bars.

Your previous 400 lb/in bars have a wheel rate of ~260 lb/in

I think the 450 lb springs should be a pretty good improvement for you, certainly should cut a little more body roll and give you a good base rate to tune from. There’s still probably more room to go higher, but it will depend on your tire set up and compounds. With the Azeni 615’s at 200 treadwear on my Duster and 275’s up front I’m back to being able to put a little roll into it with spirited mountain road driving. I have a set of Firm Feel 1.18’s sitting in my shop, that’s a 370 lb/in wheel rate. I talked to Firm feel about it, I’m a little skeptical about that big of a jump in WR but they seemed to think it wouldn’t be as crazy as it sounds. Maybe I’ll have to go with some adjustable shocks at some point.


View attachment 1716153479

Here you go! Yeah my factory ‘74 retractors were inside the quarter structure behind the door. But the mechanisms were a PITA so I replaced them with the ones from seat belt planet. I just mounted the retractors to the floor where the lap belt anchor was, I don’t recall exactly why I didn’t try to put them in the quarter but they work fine on the floor

Hey mate i am fitting the exact same belts to mine as engineer requires it due to the 6.4 swap. With the standard drop do you find it sits nice on the shoulder or wants to ride up? Love the build have read pretty much the entire build thread haha

 

[Ozyduster]

Also did i see you are using the Holley sump for the conversion with the tti headers and engine mounts? Any reason using the tti mounts over the holley ones? I am about to pull the trigger on parts but want to make sure get the right stuff as over in Australia so postage isnt cheap. I want to try to avoid modifying parts as much as possible for ease of install and engineering reasons

 

[72bluNblu]

It can indeed be that simple....

Lets see????.....he (DionR) made two changes. He added some re-enforcing (should have zero effect on wandering) and offset bushings (my read is to add more caster...why else?) and started experiencing the car wondering.....IMO, a classic case of bump steer.

From my 50 year old memory (mid 70's) reading and applying the Mopar Performance Chassis manual I remembered "blueprinting" our front ends to reduce toe changes thru suspension travel on our drag cars by changing the location (up / down and in / out) of the steering arm / tie rod end pivot........ which just happens to be one of the effects of adding caster. FYI, as the top of the spindle tilts further rearward (adding caster), the end of the steering arms moves downward respectively. Most that add (a significant amount) caster NEVER even consider the change in front end geometry.

I'm just trying to point to a solution to a problem he might not have considered.

He had +7° caster on one side and +1° on the other. It wasn't bump steer, he had a shopping cart wheel on one side.

And yes, changing the location of the end of the steering arm can alter your toe change curve. But when you're adding caster with eccentrics you're never just changing a single spec. So, it's not a given that you're always adding bump steer by adding caster, you're not making a single change so it's not simple. It depends on ALL of the other alignment specs, in addition to the ride height. Adding negative camber can change the bump steer, lowering the car the can absolutely change the bump steer, changing the bump stop heights can change the bump steer curves because you're altering the angles on the upper and lower control arms and the steering arms by changing the travel range, etc.

Most people that buy $5k coil over conversions don't actually spec out the changes in front end geometry either, they just go on advertising. Doesn't make it right, doesn't mean it doesn't work either.

Bump steer is pretty obvious when you're driving a car, and it doesn't just result in "wandering". If everyone that added positive caster had lousy bump steer, someone would have noticed it by now. I certainly haven't noticed a significant change in bump steer in my own car, and I run +6.5° of caster. But my car is also lowered 2", had the bump stop heights altered, runs tubular LCA's and double adjustable UCA's. Every single one of those things altered the toe change through the suspension travel, and yet somehow my car isn't a bump steer nightmare.

Hey mate i am fitting the exact same belts to mine as engineer requires it due to the 6.4 swap. With the standard drop do you find it sits nice on the shoulder or wants to ride up? Love the build have read pretty much the entire build thread haha

The belt sits on my shoulder well, doesn't ride up. It's an 8" drop on the shoulder belt. The Procar seats sit up a bit taller than the factory buckets though.

 

[HemiDenny]

And yes, changing the location of the end of the steering arm can alter your toe change curve. But when you're adding caster with eccentrics you're never just changing a single spec. So, it's not a given that you're always adding bump steer by adding caster, you're not making a single change so it's not simple. It depends on ALL of the other alignment specs, in addition to the ride height. Adding negative camber can change the bump steer, lowering the car the can absolutely change the bump steer, changing the bump stop heights can change the bump steer curves because you're altering the angles on the upper and lower control arms and the steering arms by changing the travel range, etc.

I beg to differ ...it is a given that adding caster changes the toe curve, might be minor but could be extreme. The more you add, naturually, the more it changes. Depending on the other factors that you mentioned, it may improve bump steer (if you get lucky) but if it was driving decent before (as DionR mentions) and now wanders....chances are the related change in steering arm end / tie rod end made it worse. And yes, I understand very well other factors can change the toe curve....but NONE of those changes were mentioned.

BTW, for anyone wondering, for the most part toe curve isn't effected by what type of spring....coil or torsion bar is holding up the car.

If anyone wants a lesson in what an way off toe curve feels like....add a rack & pinion with OEM spindles and flipping the steering arms side to side ....then hang on as you accelerate up and beyond 45mph. As the suspension moves up / down (rises , then settles) thru acceleration, wandering barely describes the dance you get as it feels like the steering wheel has a big delay in response and cannot keep up with corrections. After that they can go strait to ackerman class and attempt a high speed 90 degree turn.


Not sure what others want to do, but I'm turning the channel back to our regularly scheduled program.................................................................................

 

[racerjoe]

Also did i see you are using the Holley sump for the conversion with the tti headers and engine mounts? Any reason using the tti mounts over the holley ones? I am about to pull the trigger on parts but want to make sure get the right stuff as over in Australia so postage isnt cheap. I want to try to avoid modifying parts as much as possible for ease of install and engineering reasons

I do have the center sump Holley pan. I had planned on using the TTI mounts and actually have them, but I had an opportunity to work with Denny on a coil over conversion before the G3 made it into the car. So now I'll be using HDK mounts.
Holley mounts move the engine forward 2" which won't allow the TTI headers to work. Moving the engine forward would also require a new trans mount and a new drive shaft. Oh, I run mechanical clutch linkage, so I'm sure moving everything forward would create loads of problems with that. It's a snow ball effect that I wasn't interesting in dealing with. Now that Holley has discontinued their headers, you are stuck with their exhaust manifolds. I personally don't see any advantage of using their conversion kit unless you want to use the SRV on a 6.4 and don't want to cut the firewall.

 

[Ozyduster]

I do have the center sump Holley pan. I had planned on using the TTI mounts and actually have them, but I had an opportunity to work with Denny on a coil over conversion before the G3 made it into the car. So now I'll be using HDK mounts.
Holley mounts move the engine forward 2" which won't allow the TTI headers to work. Moving the engine forward would also require a new trans mount and a new drive shaft. Oh, I run mechanical clutch linkage, so I'm sure moving everything forward would create loads of problems with that. It's a snow ball effect that I wasn't interesting in dealing with. Now that Holley has discontinued their headers, you are stuck with their exhaust manifolds. I personally don't see any advantage of using their conversion kit unless you want to use the SRV on a 6.4 and don't want to cut the firewall.

Yep have spent hours reading and literally just came to the conclusions if you go holley needs to be all holley. So what are people using for headers if using holley? I cant find any info about their exhaust manifolds that i guess rob power. I will be using the 6.4 and was trying to avoid cutting fire wall, i also want to run the 904 to avoid changing the trans tunnel. Does the tti mounts work with the holley sump?

 

[racerjoe]

Yep have spent hours reading and literally just came to the conclusions if you go holley needs to be all holley. So what are people using for headers if using holley? I cant find any info about their exhaust manifolds that i guess rob power. I will be using the 6.4 and was trying to avoid cutting fire wall, i also want to run the 904 to avoid changing the trans tunnel. Does the tti mounts work with the holley sump?

Maybe some people got the Holley headers early, but I feel like they were discontinued very quickly after their release. I still don't understand the reason because they still have headers for LS platforms of similar year cars.

Check out this thread. He modified mounts and used shorty headers to keep the SRV off the firewall. He's using a 904 as well.

Things Change.. Butters is now getting a 392

So, things changed up after stumbling across a 6.4 that just had to good of a price to pass.. Sold off all the 5.7 stuff. With that, I'm starting a new thread to track things and progress. The 6.4 that I grabbed was out of a 2019 Charger with 32k miles (got Hellcat Swapped) So this past...

www.forabodiesonly.com

To my knowledge, an center sump pan should work with TTI. I haven't heard of any of them having clearance problems with headers, except maybe some pans with really larger side kick outs. Pay attention to the TTI part numbers since they have a few options based on what steering box you have.

 

[DionR]

I personally don't see any advantage of using their conversion kit unless you want to use the SRV on a 6.4 and don't want to cut the firewall.

Don’t forget the option to use a low mount AC compressor on a VVT motor and that the 90 degree adapter works with no issue.

For me, the ability to use the stock AC compressor and not cut my firewall for the 6.4 intake was enough to push me to go all Holley. Add that I already had a spool mount k-frame made it all the easier. And I got in before the headers were discontinued. Now that the headers are discontinued and others are getting the 6.4 intake to fit with smaller adjustment, not sure what direction I would take if I had to choose. Still haven’t seen a clean option for the OEM compressor yet with the other options, but maybe i missed it.

 

[Ozyduster]

Don’t forget the option to use a low mount AC compressor on a VVT motor and that the 90 degree adapter works with no issue.

For me, the ability to use the stock AC compressor and not cut my firewall for the 6.4 intake was enough to push me to go all Holley. Add that I already had a spool mount k-frame made it all the easier. And I got in before the Headers they were discontinued. Now that the headers are discontinued and others are getting the 6.4 intake to fit with smaller adjustment, not sure what direction I would take if I had to choose. Still haven’t seen a clean option for the OEM compressor yet with the other options, but maybe i missed it.

Well pulled the trigger, purchased the holley mounts and the gear box mounts as well ,think all up 112 bucks. I like it, as definitely going a 6.4 so no cutting fire wall. I am in Australia and have to get it engineered so less items i cut and modify the easier and cheaper engineering is. I am changing to an 8, 3/4 diff anyway so would require tailshaft work regardless. Due to the cost of headers and shipping i may just have them custom made and copy the holley design or cut up set of tti. I like the holley pulls motor forward as more likely to get steering components etc to work as well.

 

[HemiDenny]

Well pulled the trigger, purchased the holley mounts and the gear box mounts as well ,think all up 112 bucks. I like it, as definitely going a 6.4 so no cutting fire wall. I am in Australia and have to get it engineered so less items i cut and modify the easier and cheaper engineering is. I am changing to an 8, 3/4 diff anyway so would require tailshaft work regardless. Due to the cost of headers and shipping i may just have them custom made and copy the holley design or cut up set of tti. I like the holley pulls motor forward as more likely to get steering components etc to work as well.

I truly admire you guys that put these things in with an OEM K and steering and to add a degree of difficulty, a 6.4 / 8HP70.

Just for fun.....pictured is the new

HDK / 6.4 version with the engine / transmission located forward approx 1" and dropped 3/4" to save cutting up the tunnel. Just finishing up a HDK transmission mount that requires only removing the upper portion of the transmission / torsion bar crossmember and re-drilling the inner transmission mount bolts. A no goof template is included.

here are the positives.....
TTi long tube headers...out of the box / no dings or dents
Milodon center sump / Pro Touring pan....no mods
OEM A/C compressor....bolts on in OEM location with no clearance issues
power rack & pinion w/ Holley or similar aftermarket P/S pump.
room for OEM 2016 and up cooling / radiator
windshield wiper motor bolt right in , no mods

 

[DionR]

I always figured the 1.75” number was overkill for the 6.4 intake. Probably based on the HC intercooler manifold.

 

[72bluNblu]

I beg to differ ...it is a given that adding caster changes the toe curve, might be minor but could be extreme. The more you add, naturually, the more it changes. Depending on the other factors that you mentioned, it may improve bump steer (if you get lucky) but if it was driving decent before (as DionR mentions) and now wanders....chances are the related change in steering arm end / tie rod end made it worse. And yes, I understand very well other factors can change the toe curve....but NONE of those changes were mentioned.

No, it can't be extreme, not with anything even mildly resembling the torsion bar suspension. The Chrysler engineers did a lot of work to make sure that changing the caster didn't create some awful bump steer issue, and I would bet they did a better job than they even knew.

You know why? Because I've run everything from bone stock factory suspension, steering and alignments all the up to what I've got on my Duster now- lowered 2", SPC UCA's , tubular LCA's, FMJ spindles, altered suspension travel, -1° camber, +6.5° caster, the works. And from bone stock all the way up to +8° of caster there was no adjustment that made the bump steer on my Duster even noticeable.

There has been literally 1 thing I've done to a Mopar that resulted in a noticeable (but not significant) amount of bump steer. And that was when I put 2" drop spindles on my Challenger. The resulting control arm angles and steering arm length added bump steer, and enough that I was able to detect it while pushing the car on rougher mountain roads. Not enough to be sketchy, but enough to notice. But that was before I did a deep dive on the Mopar suspension and realized that the drop spindles are in fact unnecessary, because with proper upgrades you can lower the car just as much with factory or FMJ spindles and the resulting geometry is actually BETTER than what the factory set the car up with, because of the bias ply to radial tire alignment changes. I had a contact at the time with a suspension geometry program and we ran the numbers on my Challenger lowered 2" with stock spindles and lowered with 2" drop spindles and determined the bump steer was better with the factory spindles, even lowered 2" and running +5° of caster (best I could get with the components at the time). The bump steer with the 2" drop spindles wasn't crazy either, but it was more than "good practice" and I could actually feel it pushing the car in the right (or wrong I suppose) conditions.

So, if you want to preach about how running around with +6.5° of caster is gonna add bump steer, show me the numbers. Because I run my car that way, I drive it on bumpy mountain roads at a very spirited pace more frequently than I probably should or should admit, and I know what bump steer actually feels like. Maybe the bump steer on my car isn't perfect, but I've literally done nothing to tune the bump steer on my car which is a luxury most muscle car owners don't get. And the only reason I haven't measured and plotted it all out is because it's never been an issue in the real world. So the gloom and doom about bump steer with the torsion bar suspension is 100% unwarranted until you show me numbers that say otherwise.

BTW, for anyone wondering, for the most part toe curve isn't effected by what type of spring....coil or torsion bar is holding up the car.

Lol. C'mon man, that's about as misleading as you can be.

From a technical standpoint, of course it doesn't matter to the toe change what kind of spring is used. But the fact that you change the length of the steering arms, the location of the steering arms and the entire spindle changes literally everything there is about the toe curve.

Saying it doesn't matter if it's a coil over or a torsion bar when you've changed spindles and gone front steer is just flat out silly, the type of spring is irrelevant but everything else that was changed is not.

If anyone wants a lesson in what an way off toe curve feels like....add a rack & pinion with OEM spindles and flipping the steering arms side to side ....then hang on as you accelerate up and beyond 45mph. As the suspension moves up / down (rises , then settles) thru acceleration, wandering barely describes the dance you get as it feels like the steering wheel has a big delay in response and cannot keep up with corrections. After that they can go strait to ackerman class and attempt a high speed 90 degree turn.


Not sure what others want to do, but I'm turning the channel back to our regularly scheduled program.................................................................................

I fail to see what trying to run the stock mopar spindles with the steering arms flipped to the front for a rack has to do with anything. It's a stupid drag racer trick that results in piss poor Ackerman, everyone knows this and no one with more than a handful of brain cells would do that for a street or handling car. It's well documented poor practice and you can look up a dozen threads on here where I've told people if they absolutely need to have a rack the only way to do it right is with a full coil over conversion. Personally I'm of the opinion that no one needs a rack and pinion to begin with, but that's just my opinion and I know what that's worth.

Sorry @racerjoe, I'll try and follow more quietly as I'm interested to see what it really takes to optimize the coil over suspension for handling, there's far too many people that just slap them on without actually working through the geometry.

 

[Ozyduster]

I truly admire you guys that put these things in with an OEM K and steering and to add a degree of difficulty, a 6.4 / 8HP70.

Just for fun.....pictured is the new

View attachment 1716191400

View attachment 1716191403

HDK / 6.4 version with the engine / transmission located forward approx 1" and dropped 3/4" to save cutting up the tunnel. Just finishing up a HDK transmission mount that requires only removing the upper portion of the transmission / torsion bar crossmember and re-drilling the inner transmission mount bolts. A no goof template is included.

here are the positives.....
TTi long tube headers...out of the box / no dings or dents
Milodon center sump / Pro Touring pan....no mods
OEM A/C compressor....bolts on in OEM location with no clearance issues
power rack & pinion w/ Holley or similar aftermarket P/S pump.
room for OEM 2016 and up cooling / radiator
windshield wiper motor bolt right in , no mods

Lots of room there hard thing is i am based in Australia and getting parts etc isnt cheap. By time it was shipped quarter panel cost me around 4k. Guessing you are running a tubular front end?

 

[HemiDenny]

No, it can't be extreme, not with anything even mildly resembling the torsion bar suspension. The Chrysler engineers did a lot of work to make sure that changing the caster didn't create some awful bump steer issue, and I would bet they did a better job than they even knew.

You know why? Because I've run everything from bone stock factory suspension, steering and alignments all the up to what I've got on my Duster now- lowered 2", SPC UCA's , tubular LCA's, FMJ spindles, altered suspension travel, -1° camber, +6.5° caster, the works. And from bone stock all the way up to +8° of caster there was no adjustment that made the bump steer on my Duster even noticeable.

There has been literally 1 thing I've done to a Mopar that resulted in a noticeable (but not significant) amount of bump steer. And that was when I put 2" drop spindles on my Challenger. The resulting control arm angles and steering arm length added bump steer, and enough that I was able to detect it while pushing the car on rougher mountain roads. Not enough to be sketchy, but enough to notice. But that was before I did a deep dive on the Mopar suspension and realized that the drop spindles are in fact unnecessary, because with proper upgrades you can lower the car just as much with factory or FMJ spindles and the resulting geometry is actually BETTER than what the factory set the car up with, because of the bias ply to radial tire alignment changes. I had a contact at the time with a suspension geometry program and we ran the numbers on my Challenger lowered 2" with stock spindles and lowered with 2" drop spindles and determined the bump steer was better with the factory spindles, even lowered 2" and running +5° of caster (best I could get with the components at the time). The bump steer with the 2" drop spindles wasn't crazy either, but it was more than "good practice" and I could actually feel it pushing the car in the right (or wrong I suppose) conditions.

So, if you want to preach about how running around with +6.5° of caster is gonna add bump steer, show me the numbers. Because I run my car that way, I drive it on bumpy mountain roads at a very spirited pace more frequently than I probably should or should admit, and I know what bump steer actually feels like. Maybe the bump steer on my car isn't perfect, but I've literally done nothing to tune the bump steer on my car which is a luxury most muscle car owners don't get. And the only reason I haven't measured and plotted it all out is because it's never been an issue in the real world. So the gloom and doom about bump steer with the torsion bar suspension is 100% unwarranted until you show me numbers that say otherwise.



Lol. C'mon man, that's about as misleading as you can be.

From a technical standpoint, of course it doesn't matter to the toe change what kind of spring is used. But the fact that you change the length of the steering arms, the location of the steering arms and the entire spindle changes literally everything there is about the toe curve.

Saying it doesn't matter if it's a coil over or a torsion bar when you've changed spindles and gone front steer is just flat out silly, the type of spring is irrelevant but everything else that was changed is not.



I fail to see what trying to run the stock mopar spindles with the steering arms flipped to the front for a rack has to do with anything. It's a stupid drag racer trick that results in piss poor Ackerman, everyone knows this and no one with more than a handful of brain cells would do that for a street or handling car. It's well documented poor practice and you can look up a dozen threads on here where I've told people if they absolutely need to have a rack the only way to do it right is with a full coil over conversion. Personally I'm of the opinion that no one needs a rack and pinion to begin with, but that's just my opinion and I know what that's worth.

Sorry @racerjoe, I'll try and follow more quietly as I'm interested to see what it really takes to optimize the coil over suspension for handling, there's far too many people that just slap them on without actually working through the geometry.

Geez-o- Pete....For some reason you just want to ***** about anything I comment on. If wanted that nonsense, I could tune into what my wife is Blah-Blah-Blahhing about, .....NO thanks on either.

Have a nice day .......I'll be in my shop...hot rodding.

 

[HemiDenny]

I always figured the 1.75” number was overkill for the 6.4 intake. Probably based on the HC intercooler manifold.

that far ahead starts causing room issues for cooling / radiator space .....and other things. At least for the HDK, 1" is the sweet spot.

 

[DionR]

Lots of room there hard thing is i am based in Australia and getting parts etc isnt cheap. By time it was shipped quarter panel cost me around 4k. Guessing you are running a tubular front end?

Yes, same front suspension racerjoe is running. Hemi Denny is the proprietor of HDK and was showing some of his recent development work on fitting a G3 into an A-Body. Cool stuff, but the price of admission is way too steep for me.

 

[DionR]

that far ahead starts causing room issues for cooling / radiator space .....and other things. At least for the HDK, 1" is the sweet spot.

I think everything will still fit. Ehrenburg stuffed a 5.7 in a car using the Holley mounts and the Holley FEAD kit which added length to the motor. He was at the limit but got it to fit. With the OEM setup, pretty sure it will be fine.

In a perfect world, I would rather move the motor back and help the weight bias, but everything is a compromise. I’m not building a 10/10th’s race car so this seems like a reasonable compromise to me.

 

[DionR]

I fail to see what trying to run the stock mopar spindles with the steering arms flipped to the front for a rack has to do with anything.

I could be wrong, but think Denny was just sharing his person experience with the issues of bump steer and bad Ackerman angles. Not certain, but I think one of his earliest builds with a certain ‘73 Duster and a Pinto rake might have used those solutions. I am reading between the lines though.

 

[72bluNblu]

Geez-o- Pete....For some reason you just want to ***** about anything I comment on. If wanted that nonsense, I could tune into what my wife is Blah-Blah-Blahhing about, .....NO thanks on either.

Have a nice day .......I'll be in my shop...hot rodding.

Denny, I'm not "bitching". You made some comments about bump steer on these cars with factory suspension that are in fact not accurate. I know that for a fact because I've literally done the EXACT things you said would cause bump steer. And they don't. And frankly that shouldn't be that surprising because a well engineered suspension system should not be so susceptible to bump steer that changing the static alignment will result in a dramatic change.

Now, if you want to call that "bitching" and compare me to your wife, well, that says more about you than me.

I could be wrong, but think Denny was just sharing his person experience with the issues of bump steer and bad Ackerman angles. Not certain, but I think one of his earliest builds with a certain ‘73 Duster and a Pinto rake might have used those solutions. I am reading between the lines though.

I kinda don't think that was all he was doing. But maybe I'm wrong.

It's fine. I'll stop screwing up Tim's thread, I'm truly interested in his modifications and suspension geometry numbers because no one else that's done a coil over conversion has ever posted them.