I understand, and see why, honestly the only thing I'm really worried about is bump steer, and how much your, and the other systems have, I wish all manufactures were on here to all weigh in, and compare. I like to keep bump steer under .050 per inch of travel, but I'm also very picky, that may not be practical on any of these systems, who knows. But thanks for the information denny!
Best ifs kit? rms, hdk, gt suspension, or magnum force?
- Thread starter 440 dart.
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I understand, and see why, honestly the only thing I'm really worried about is bump steer, and how much your, and the other systems have, I wish all manufactures were on here to all weigh in, and compare. I like to keep bump steer under .050 per inch of travel, but I'm also very picky, that may not be practical on any of these systems, who knows. But thanks for the information denny!
What ever works best for you .....and any potential front end buyer...... is what works the best for me. I am still a hot rodder at heart.
I would love to see the Facebook video you spoke of....can you supply a link.
I would love to see the Facebook video you spoke of....can you supply a link.
Ya, I'll try to find it, I randomly stumbled across it, I think on fb, may have been YouTube, but I'll run it down and post a link, and sounds like I get a new phone, so I'll be able to call you and a Carl Tuesday, and really get the low down.
Bill_Reilly
Member
A few things
First, if customer service is based on forum activity, consider this forabodiesonly, forbbodiesonly, forebodiesonly, bigblockdart, moparts, lat-g, pro-touring, dodgecoronet, cuda-challenger, protouringmopar, yellowbullet, facebook-personal, facebook-rms, twitter, instagram, google+, mymopar, moparstyle, linkedin, and on and on, with more popping up every day. Add in a jillion emails and phone calls and I think youd agree that maintaining a presence on forums is impossible. Facebook messaging and regular email are two methods to reach me anytime Im not asleep if you have a problem, I think thats pretty good customer service. In addition, there are three topics that almost always devolve into a fire storm cylinder head air flow numbers, manifold or ported vacuum advance, and front suspension geometry. Getting into these battles is unproductive and time consuming when, in the end, it usually yields nothing for all involved.
Someone mentioned Pro spindles are much lighter. This is false.
Wilwood Pro, RMS, and stock MII spindles are all the same, a squeak over 8lbs each.
Instant center and roll center are both raised by a taller upper pivot, not lowered as I read here somewhere.
As the stance goes up, so does the roll center. Raising the upper pivot point only raises the RC further. This creates a geometric roll resistance, but leads to unpredictable jacking in a corner, which can be unsettling. Far better to keep the RC low and use sway bars to control roll resistance. In theory, behavior changes as the RC goes above and below ground, because the effect of the pendulum changes direction - RC left above ground becomes RC right below ground. But even in professional racing its debatable how much is gained or lost by this. In hobby racing and street cars its barely worth mentioning, but it is fun to think about.
Changing the upper pivot point does in fact change bumpsteer geometry. Bumpsteer has nothing to do with the lower arm and the tie rod being parallel. The reason unequal length IFS has bumpsteer is because it causes the spindle to travel in an elliptical pattern, while the tie rod swings in a perfect radius. Changing any pivot point will change the shape of the elliptical pattern, which requires changing the position of the tie rod on the arc to maintain minimum bumpsteer in the useable range. Not changing it will create a completely different bump curve. Caster settings also change the bump curve, so a bump curve is designed at a particular caster angle, any other caster angle and the curve also changes. Even 1/16 height change in the pivot can change the bump curve, but it is minor and if the bump curve is really good, those small changes will still be well inside the acceptable range. But if the curve is questionable to start with, small changes can move the curve into the red.
As for a chart, image attached. This was measured at 6 degrees caster. For reference, second image is ½ raised upper, all else the same. Probably just fine, but definitely increased and definitely different.
Last thing about bumpsteer far too much attention is paid to bumpsteer and not nearly enough attention to other matters. If you have a drag car one that really is only for drag racing and nothing else, bumpsteer is as far as you need to worry about. But for the other 99.9% of the cars on the planet, If you have 15 rims and big fat BFGs, you can easily stand ½ of bumpsteer without even noticing the tires flex so much it makes no difference. While its best to have nice angles for everything, even the OEMs typically have well over ¼ of bumpsteer my 06 SRT8 Charger has .375 total bumpsteer even with Nitto Invos on 20s you cant tell and nobody questions how these newer cars handle. But on aftermarket suspension bumpsteer is all the rage, yet no one ever seems to wonder where the RC is, or what the ackerman error is, even though they are far more important items to consider in a street car with spirited cornering.
By cranking up preload on a coil over, you change nothing. Preload only serves to require more weight before the shock begins to compress which means it wont compress as far with full weight on it, which is just another way to say it raises the ride height. The effective spring rate, and ride quality remains unchanged.
Having a level lower control arm is also an old wives tale. It's an easy way to minimize bumpsteer and other problems in a suspension that isn't quite right. But if it IS right, the arm angle doesn't matter much within reason. As for camber gain, you only need to have X amount, there are a number of ways to achieve it, so the combined arm angles merely need to satisfy your gain requirements, not necessarily be at a particular angle. But because the arm angles also dictate a number of other functions, you often have to settle on the best balance between them. Getting too perfect with one angle may have a detrimental affect on another, and even though the numbers are perfect for one aspect, the suspension may have some quirky behavior because of some other aspect thats too far out. Shorter control arms also cause excessive angle changes and too much track width change, which also can cause mysterious behavior. Theres no set number as to what is too short, merely the shorter they get the more likely a problem will arise, so its best to keep them as long as physically possible.
Speaking of track width, like wheel alignment, its measured at ride height, not with the wheels hanging down. And depending on the needs, there are a bunch of brake kits. Baer brakes all have about 58.5 on an A-body RMS kit, as do the smaller Wilwoods with a zero offset. 13 and 14 Wilwood are all basically 60, and I also use smaller Wilwood kits with this 60 track for certain wheel requirements. I prefer the 60 versions on my own stuff, as its cheaper to get 18 wheels with a higher offset. There are plenty of cheap brake kits out there using basic auto parts, some have custom hubs that usually run zero offset, while others use a Ford Granada rotor which is +0.25. Prior to 2007, I used a wider track width to accommodate air ride because of demand that the system fit either air or coils. By late 07 I discontinued air ride and moved the track in. I ended up shortening the arms on a number of those earlier ones to the later specs if they called me about it. Theres no way to help someone I dont know about, so if they prefer to just complain on the internet theres not much I can do. So stories of too wide of a track have been inaccurate for 8 years now. Maybe by the time I retire those stories will fade away.
And while Im not saying anyone else is wrong, Ill tell you that modifying spindles is not easy or cheap, and neither is making custom adjustable tie rod ends. Disallowing 15x7 or 8 rims is also a big pain. If there was a way to use stock items with a front rack, while maintaining proper geometry and stock engine height, I would do it in a heartbeat. But all of that is not possible in a Mopar. Chevys have the engine higher above the suspension and slightly further back, allowing a higher rack height under the oil pan. Mopars do not. And raising the engine is out of the question. Most customers I have already need 3 or 4 hoods because the engines are so tall, if the engine was higher than stock these guys would need cartoonishly tall scoops. Some guys have regular engines under a stock hood, but most are not.
If it was for my own car just for fun it might be possible to skimp on the geometry to allow some other things, but when people pay thousands, they expect it to be right on the money for a particular use and they expect me to stand behind it. Some customers are running standing mile at well over 200mph, others are stunt drivers that need to make repeatable maneuvers without wasting expensive camera time. Others yet are road racing in France or Poland or some other far away place. These people will not stand for compromises of any kind and many of them want the data to back it up before theyll order. So if I use a more complicated method to make something, its for good reason.
In the end though, people will make what they like and others will buy what they like so I dont really push trying to convince people. You have to buy what makes you happy. It is just a hobby after all.
IMHO
First, if customer service is based on forum activity, consider this forabodiesonly, forbbodiesonly, forebodiesonly, bigblockdart, moparts, lat-g, pro-touring, dodgecoronet, cuda-challenger, protouringmopar, yellowbullet, facebook-personal, facebook-rms, twitter, instagram, google+, mymopar, moparstyle, linkedin, and on and on, with more popping up every day. Add in a jillion emails and phone calls and I think youd agree that maintaining a presence on forums is impossible. Facebook messaging and regular email are two methods to reach me anytime Im not asleep if you have a problem, I think thats pretty good customer service. In addition, there are three topics that almost always devolve into a fire storm cylinder head air flow numbers, manifold or ported vacuum advance, and front suspension geometry. Getting into these battles is unproductive and time consuming when, in the end, it usually yields nothing for all involved.
Someone mentioned Pro spindles are much lighter. This is false.
Wilwood Pro, RMS, and stock MII spindles are all the same, a squeak over 8lbs each.
Instant center and roll center are both raised by a taller upper pivot, not lowered as I read here somewhere.
As the stance goes up, so does the roll center. Raising the upper pivot point only raises the RC further. This creates a geometric roll resistance, but leads to unpredictable jacking in a corner, which can be unsettling. Far better to keep the RC low and use sway bars to control roll resistance. In theory, behavior changes as the RC goes above and below ground, because the effect of the pendulum changes direction - RC left above ground becomes RC right below ground. But even in professional racing its debatable how much is gained or lost by this. In hobby racing and street cars its barely worth mentioning, but it is fun to think about.
Changing the upper pivot point does in fact change bumpsteer geometry. Bumpsteer has nothing to do with the lower arm and the tie rod being parallel. The reason unequal length IFS has bumpsteer is because it causes the spindle to travel in an elliptical pattern, while the tie rod swings in a perfect radius. Changing any pivot point will change the shape of the elliptical pattern, which requires changing the position of the tie rod on the arc to maintain minimum bumpsteer in the useable range. Not changing it will create a completely different bump curve. Caster settings also change the bump curve, so a bump curve is designed at a particular caster angle, any other caster angle and the curve also changes. Even 1/16 height change in the pivot can change the bump curve, but it is minor and if the bump curve is really good, those small changes will still be well inside the acceptable range. But if the curve is questionable to start with, small changes can move the curve into the red.
As for a chart, image attached. This was measured at 6 degrees caster. For reference, second image is ½ raised upper, all else the same. Probably just fine, but definitely increased and definitely different.
Last thing about bumpsteer far too much attention is paid to bumpsteer and not nearly enough attention to other matters. If you have a drag car one that really is only for drag racing and nothing else, bumpsteer is as far as you need to worry about. But for the other 99.9% of the cars on the planet, If you have 15 rims and big fat BFGs, you can easily stand ½ of bumpsteer without even noticing the tires flex so much it makes no difference. While its best to have nice angles for everything, even the OEMs typically have well over ¼ of bumpsteer my 06 SRT8 Charger has .375 total bumpsteer even with Nitto Invos on 20s you cant tell and nobody questions how these newer cars handle. But on aftermarket suspension bumpsteer is all the rage, yet no one ever seems to wonder where the RC is, or what the ackerman error is, even though they are far more important items to consider in a street car with spirited cornering.
By cranking up preload on a coil over, you change nothing. Preload only serves to require more weight before the shock begins to compress which means it wont compress as far with full weight on it, which is just another way to say it raises the ride height. The effective spring rate, and ride quality remains unchanged.
Having a level lower control arm is also an old wives tale. It's an easy way to minimize bumpsteer and other problems in a suspension that isn't quite right. But if it IS right, the arm angle doesn't matter much within reason. As for camber gain, you only need to have X amount, there are a number of ways to achieve it, so the combined arm angles merely need to satisfy your gain requirements, not necessarily be at a particular angle. But because the arm angles also dictate a number of other functions, you often have to settle on the best balance between them. Getting too perfect with one angle may have a detrimental affect on another, and even though the numbers are perfect for one aspect, the suspension may have some quirky behavior because of some other aspect thats too far out. Shorter control arms also cause excessive angle changes and too much track width change, which also can cause mysterious behavior. Theres no set number as to what is too short, merely the shorter they get the more likely a problem will arise, so its best to keep them as long as physically possible.
Speaking of track width, like wheel alignment, its measured at ride height, not with the wheels hanging down. And depending on the needs, there are a bunch of brake kits. Baer brakes all have about 58.5 on an A-body RMS kit, as do the smaller Wilwoods with a zero offset. 13 and 14 Wilwood are all basically 60, and I also use smaller Wilwood kits with this 60 track for certain wheel requirements. I prefer the 60 versions on my own stuff, as its cheaper to get 18 wheels with a higher offset. There are plenty of cheap brake kits out there using basic auto parts, some have custom hubs that usually run zero offset, while others use a Ford Granada rotor which is +0.25. Prior to 2007, I used a wider track width to accommodate air ride because of demand that the system fit either air or coils. By late 07 I discontinued air ride and moved the track in. I ended up shortening the arms on a number of those earlier ones to the later specs if they called me about it. Theres no way to help someone I dont know about, so if they prefer to just complain on the internet theres not much I can do. So stories of too wide of a track have been inaccurate for 8 years now. Maybe by the time I retire those stories will fade away.
And while Im not saying anyone else is wrong, Ill tell you that modifying spindles is not easy or cheap, and neither is making custom adjustable tie rod ends. Disallowing 15x7 or 8 rims is also a big pain. If there was a way to use stock items with a front rack, while maintaining proper geometry and stock engine height, I would do it in a heartbeat. But all of that is not possible in a Mopar. Chevys have the engine higher above the suspension and slightly further back, allowing a higher rack height under the oil pan. Mopars do not. And raising the engine is out of the question. Most customers I have already need 3 or 4 hoods because the engines are so tall, if the engine was higher than stock these guys would need cartoonishly tall scoops. Some guys have regular engines under a stock hood, but most are not.
If it was for my own car just for fun it might be possible to skimp on the geometry to allow some other things, but when people pay thousands, they expect it to be right on the money for a particular use and they expect me to stand behind it. Some customers are running standing mile at well over 200mph, others are stunt drivers that need to make repeatable maneuvers without wasting expensive camera time. Others yet are road racing in France or Poland or some other far away place. These people will not stand for compromises of any kind and many of them want the data to back it up before theyll order. So if I use a more complicated method to make something, its for good reason.
In the end though, people will make what they like and others will buy what they like so I dont really push trying to convince people. You have to buy what makes you happy. It is just a hobby after all.
IMHO
darndart
Well-Known Member
Subscribed.
mopowers
Well-Known Member
Good on you, Bill. Thanks for replying.
DR HEMI
Man on a Mission
Thank you very much for replying Mr. Reilly. A rare occurrence but I can understand how busy you are and agree that such endeavors can be unproductive.
One comment is in regard to the weight difference of the Wilwood Pro. I believe the (significant) weight difference is in relation to the whole spindle/caliper/rotor assembly with the difference actually being in the brake parts; not the spindle itself. I'm sure you already know this but I just wanted to clarify it for the forum readers.
Thanks for weighing in Bill.
While our trade offs for front ends differ, I consider you the Professor. Furthermore, anyone looking for a customer service model to emulate, yours should be at the top of the list.
If I didn't have such a sweet gig (my wife actually thinks I work) , I would be camped at your doorstep.
Mopar to ya'
Denny
While our trade offs for front ends differ, I consider you the Professor. Furthermore, anyone looking for a customer service model to emulate, yours should be at the top of the list.
If I didn't have such a sweet gig (my wife actually thinks I work) , I would be camped at your doorstep.
Mopar to ya'
Denny
Thank you bill! As others have danced around my question of bump steer, and started making me wonder if they even know what their own specs are, you have every number, and I'm glad you touched on changing caster, how that effects bump steer, I was just getting ready to state that. And I was wondering why (not really) why every kit modifies their spindles, but 1 certain guy doesn't (unless like you say he's moving the engine, or his geometry isn't all its cracked up to be), you obviously know your stuff or you wouldn't be the leading manufacturer of these kits, you answered EVERY question I was going to get around to answering, before I got a chance to, sorry I got caught up arguing about brakes, but I'm glad SOMEONE who knows their stuff is actually backing me up. Thanks!
Suspension collaboration?
There certainly are a lot of variables......and it is a balance.
I think some are confused on why builders modify the spindle....check the websites. Is there ANY mention of bump steer adjustment in their instructions?....NO!, simply bolt it on....much like you would if they made a tie rod end long enough for the geometry THEY are working with
I would be surprised if, other than the serious racer, most "fine tune" for bump steer. When I utilized the modification years ago, it was more to SET the tie rod angle where it needs to be in relationship to the rack and LCA pivot location for minimum bump steer.
on the slammer models....the motor is not raised, the chassis / car is dropped....which, BTW require different pivot points from the standard models.....but the look is awesome.
I realize the the spring rate does not change....a 400 lb spring still takes 400 lbs to move it 1" regardless of pre-load setting, but when excessively cranking up the pre-load to. raise the ride height, it also shortens the spring and IMO sure makes the front ride stiffer. You can be your own judge. Try this, take a spring out of a ballpoint pen and compress it 50%....now squeeze it...feel stiffer?
just some things to ponder on.
I think some are confused on why builders modify the spindle....check the websites. Is there ANY mention of bump steer adjustment in their instructions?....NO!, simply bolt it on....much like you would if they made a tie rod end long enough for the geometry THEY are working with
I would be surprised if, other than the serious racer, most "fine tune" for bump steer. When I utilized the modification years ago, it was more to SET the tie rod angle where it needs to be in relationship to the rack and LCA pivot location for minimum bump steer.
on the slammer models....the motor is not raised, the chassis / car is dropped....which, BTW require different pivot points from the standard models.....but the look is awesome.
I realize the the spring rate does not change....a 400 lb spring still takes 400 lbs to move it 1" regardless of pre-load setting, but when excessively cranking up the pre-load to. raise the ride height, it also shortens the spring and IMO sure makes the front ride stiffer. You can be your own judge. Try this, take a spring out of a ballpoint pen and compress it 50%....now squeeze it...feel stiffer?
just some things to ponder on.
if only I was 25 again.....
I really like Bill and his company. Years ago when I started putting Hemis in A bodies, I looked at his beautiful K frames....but I wanted a few things he did not offer and couldn't get myself to cut up what was then $3K (I believe) to fit my specific need. Believe me, IF I could have stroked the check and bolted it in....I would have been an owner.
we differ on a few things.....who da thunk it?....but all good to me.
Bill, thank you for your response. And I agree with you on the whole social media, forum thing as a designator of good customer service......I think that's a load of hogwash. Just because one company or individual is on a forum alot, daily, hourly etc, does not make them the best at customer service, nor does it mean another company who isn't active on a forum is the worst. I'm not digging on anyone in particular but I must wonder, if the person supposedly building these kits is always online or online a lot, when is the building of kit being done? Does he/she sleep? Does he/she farm out the work and just act as a salesman? I don't know.
Anyway, I've talked extensively with Bill on the phone about his stuff. Very knowledgeable, nice guy. As is Carl Gerst from GTS and Carl will answer any question you can about front ends. Denny seems to be friendly as well having talked to him at the Nats and a swap meet a couple years back. I think it's safe to say we've got some good people and good products finally coming out for our old mopars. :blob:
I'm being serious. I have nothing against you Denny, and if my comments make you feel that way, then there is a problem and I'd be more than happy to discuss it with you, any time. Feel free to pm me if you wish.
I'm gonna assume you're taking issue with my comments regarding a company's presence on a forum? If so, please note, I was simply replying to the thought that in order to be considered having good customer service, that one must be a forum member and post alot. I feel it is a valid point.
I have no issues with you, Denny, on any level. And I'll be honest, your kit was heavily considered in my purchase decision, a decision mind you, that took several months for me to make. And several trips from one side of National Trail Race way to the other before completing the deal. You make a fine product and seem to have lots of happy customers, which is a good thing. If I have offended you, make note, it was not my intention. I am simply being honest and asking/answering questions openly. I'm also not trying to take anything away from your product, I'm simply letting people know of another option.
Yeah...my nuts are still stinging
However, I think you are somewhat confused.......
The fact that I am on this site has NOTHING to do with customer service......it has EVERYTHING to do with the fact that I take a great personal interest in many members builds.
When you realize that hot rodding mopars is way more than a business to me.....you just might be starting to understand.
However, I think you are somewhat confused.......
The fact that I am on this site has NOTHING to do with customer service......it has EVERYTHING to do with the fact that I take a great personal interest in many members builds.
When you realize that hot rodding mopars is way more than a business to me.....you just might be starting to understand.
younggun2.0
Well-Known Member
I am very thankful for your contributions here, Denny. I also feel as though your living the dream! you have some awesome rides THAT YOU BUILT! then other people noticed your talent and convinced you to build your products for them. I also understand that you like all of us have a life outside of the forum and garage. I commend you on your efforts and thank you for your contribution to the hobby. Keep up the good work. Don't let anyone's skewed perception of what your life is bother you. I know i sure as hell don't.
haters gonna hate.
I had a guy at the track walk by my car and tell his buddy that my ride was a trailer queen and prob ran 13's. little does he know that i spent 13 yrs of my life and every dime i have to finish it. Or that i drove it 22 miles each way on pump gas to and from the track and rattled off 11 sec. passes
67autocross
A new iron curtain drawn across the 49th parallel
Bill at RMS is a great guy to deal with, I have purchased a front suspension and rear suspension kit from him as well as a steering column and a few other items. Customer service was top notch and if I needed something I would have no problem dealing with him again.
Now if I was going to start building another car I would take a hard look at the Hemi Denny kit, it looks like a great product and the price seems to be a bit less than the RMS is now. To me the Hemi Denny is priced in line with what it would cost to do a really good stock front end build.
Now if I was going to start building another car I would take a hard look at the Hemi Denny kit, it looks like a great product and the price seems to be a bit less than the RMS is now. To me the Hemi Denny is priced in line with what it would cost to do a really good stock front end build.
Again, not my intention Denny.
Second, I think you are confused as to what I'm talking about. I referring to this comment from Rusty(nothing against Rusty either and I normally agree with him especially his old school approaches) But I am disagreeing with the bolded. I am speaking generally here, you can insert any company or person to this and I would say the exact same thing.
Forum presences doesn't automatically equal great customer service or a great product.
What I am NOT saying is ANYTHING against you or your fine product. I also said that in my pm to you. So if your nuts are still hurting, well, I don't know what more I can do to explain my position.
Also, I do think it is important for a company and its owner/workers etc to take pride in their work and show their passion for the hobby. You do both quite well Denny.
First, I do not hate on Denny. Or his product.
Second; I know the type of guys you're talking about and it is quite annoying. Or the ones that walk up and asks who built your car and then are shocked to learn you did it yourself.
abodyjoe
Well-Known Member
That's one expensive stock front end rebuild.
yeah
But then again, you could spend 2 grand or more by the time you went with all new factory components. Either way, this hobby isn't cheap :angel12:
67autocross
A new iron curtain drawn across the 49th parallel
I'm comparing the cost of doing a complete front end rebuild using all new parts as well as installing say all the Hotchkis or firm feel parts, good shocks, big torsion bars and one of those borgeson steering boxes, the price would add up similar to the after market k member.
hmm, now you have me curious. time for math.
Firm feel, rebuilt kits range from 1600 to 3400 depending on what you want/get
Hotchkis, starts at 2400 not including T-bars. or brakes
yeah, you be right. by the time you'd upgrade similarly, youre gonna be about the same
Either way, you're gonna spend a couple grand. I guess it depends ultimately on what you want out of that money.
HemiMark
Well-Known Member
This sounds a lot like my Barracuda build. O
I have driven my car with the magnum Force setup and I can tell you its not what I liked. Going straight a 1/4 mile at a time its fine. I dont recomend it for street use but thats just me. I love my HDK. period. If swapping stock for IFS I wouldnt use anything else.
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