Freelancelance Posted October 27, 2012 Share Posted October 27, 2012 Hi,I am still in the process of a build list, and this site has answered every question but one.. I have searched, and found one person, that is going to go with an new IFS in his Z,and I am stalking that post to see how he goes about it.. I know they make great aftermarket for the strut suspension in the front, it seems like it would be a no brainer if it is a better option.. I would like to hear everyones opinion, for or against... BTW, this car will probably see a little of everything, but mostly street... as I build to drive um...Thanks in advance.. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted October 27, 2012 Share Posted October 27, 2012 Hi,I am still in the process of a build list, and this site has answered every question but one.. I have searched, and found one person, that is going to go with an new IFS in his Z,and I am stalking that post to see how he goes about it.. Who's post, and what car? Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 28, 2012 Author Share Posted October 28, 2012 I am not as good with how to link on a forum as I am with fabricating steel... but here goes..http://forums.hybrid..._1#entry1005609 Who's post, and what car? Quote Link to comment Share on other sites More sharing options...
Snailed Posted October 28, 2012 Share Posted October 28, 2012 In the thread you linked he is just buying a mustang II style front suspension. You just buy it, weld in the crossmember (correctly) and bolt on all the parts. Roll center, bumpsteer, camber gain, caster, KPI and even the brakes are all worked out for you (for better or worse). The kits are made by a lot of manufactures and start at a couple grand and go up from there. I'm actually installing a Heidts setup on an old Ford tomorrow. It's boring, but it works. There are lots of people that have adapted other IFS setups from stock vehicles too. I think I have seen BWM and Nissan 240sx front suspensions adapted into a Z also. Another option is to fabricate your own suspension to suit your needs/wants. If you are not sure what this entails, either froget about it or plan on reading A LOT before you start. Probably the most practical is to modify the stock strut design and optimize it for your car. Unless you want it to be really low, it seems like it can be made to work and work well for most applications. Every design is a compromise and I think your skills and understanding of suspension design should be your guide rather than what people on a forum think. Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 28, 2012 Author Share Posted October 28, 2012 (edited) Im am no stranger to IFS or the fabrication needed to put one in, my last 4 builds all had IFS in old muscle cars.... I am asking the question because I wanted to know if anyone thinks its worth doing an IFS, or that the aftermarket has built everything that enhances this somewhat "dated" strut technology.. Thanks for sharing the build of your frame... It confirmed a number of things for me, which is awesome to know before I start digging in... In the thread you linked he is just buying a mustang II style front suspension. You just buy it, weld in the crossmember (correctly) and bolt on all the parts. Roll center, bumpsteer, camber gain, caster, KPI and even the brakes are all worked out for you (for better or worse). The kits are made by a lot of manufactures and start at a couple grand and go up from there. I'm actually installing a Heidts setup on an old Ford tomorrow. It's boring, but it works. There are lots of people that have adapted other IFS setups from stock vehicles too. I think I have seen BWM and Nissan 240sx front suspensions adapted into a Z also. Another option is to fabricate your own suspension to suit your needs/wants. If you are not sure what this entails, either froget about it or plan on reading A LOT before you start. Probably the most practical is to modify the stock strut design and optimize it for your car. Unless you want it to be really low, it seems like it can be made to work and work well for most applications. Every design is a compromise and I think your skills and understanding of suspension design should be your guide rather than what people on a forum think. Edited October 28, 2012 by Freelancelance Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 28, 2012 Share Posted October 28, 2012 IFS = independent front suspension. The advantage would be to go to SLA (short long arm), as Z's already have IFS. The Mustang II suspension that most hotrodders and drag racers use is supposed to be really bad in terms of geometry for handling. There are people that swap to SLA for better handling in Z cars, but they're usually engineering it themselves. I'd suggest you just work with the strut setup. You can get a Z to handle really well with struts, just take a look at some of the autocross and road race videos. If you really want SLA, I'd do a lot of research on the setup you want and not just pick something out of a catalog. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted October 28, 2012 Administrators Share Posted October 28, 2012 Im am no stranger to IFS Can we not refer to this as IFS? Struts are IFS too. Thread title changed. Worth it? Only you can answer that. Building a Double-A Arm suspension is not trivial. It’s FAR easier to get it wrong than it is to get it right. Get it wrong and you’ve spent a large amount of blood and sweat for nothing… unless you just want the challenge of it or wow factor. Get it right, and even then, it will probably only be incrementally better than a well prepped set of struts. So the question is… are you capable of making an improvement, and if you are, will it be enough better to justify the effort? Or is it just to say “I did it� Here is a copy of a discussion by a couple of our members… What are the arguments with stut vs double a-arm suspensions, specifically when building a tube frame car for SCCA competition? It seems like double a-arms are all the rage. Is this mainly because of the rules? Hi Phil, I've been trying to reply to this for a little while now but haven't been able to find the time to get it all down. This last weekend I was lucky enough to attend a race engineering seminar and asked this very question (for obvious reasons of my own). The answer I got was rather interesting. The single biggest performance increase for double a-arms has more to do with steering geometry than anything else. We did some calculations and looked at on car data and it showed this to be true. So in that respect the double a-arm setup is superior. Now there are some downsides depending on what how you implement. If you use coilovers you won't have as high a motion ratio as you will with a mac strut. This is a disadvantage. But a strut has a lot of friction in cornering, advantage a-arms. The bottom line what I got is that unless you can create a a-arm setup that has instant centers of 120 to 150 or more inches you won't see the major advantages that most people tout (other than steering). When asked about camber gain both engineers laughed and said that no one cares about that these days. If you're using modern stiff tires and control roll then it isn't an issue. Some anecdotal info you might find useful. I had a friend that converted a 510 from struts to a-arms. Keeping all else the same it wasn't any faster at an autox but the steering felt much better. We had been expecting to see increased front grip but it wasn't there. I also talked a gentleman who has a RX-3 GT car that was converted from struts to a-arms. He mentioned that it is kinder to its tires, which in autox may not help and may acutally hurt you. I'll aslo add that a local shock expert was on hand to demonstrate dynoing shocks. He told me that the advance design shocks I have are junk and showed me some traces to back this up. While I really like them I'm intrigued to see what could be done with good shocks. But I'm not yet to the point of paying $1500 a corner to find out. Hope that helps. Cary Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 29, 2012 Author Share Posted October 29, 2012 Thank you, I refer to the Double A Arm Front Suspension as IFS, because the world I came from (building old muscle cars) called it that.. I will not refer to it like that anymore... I have had some good luck with the Double A Arm Front Suspension on heavier older cars (was night and day in a 55 Bel Aire, I have quite a bit of experience with them, Having done 4 of them, 3 that were made for the vehicles they went in, and one I had to make work,, and I got it right, maybe beginners luck? So thats is why I was thinking of going this way, I also like the idea of 5 lugs, and the rim and brake choices that affords me, but with the lightness of a Z... probably what I am thinking might be overkill... Thanks so much for the posts, As for capable.. I'd like to think so.. as for will it be enough to justify the effort.. I still don't know,.... To do it, just to say I can... I been there.. although I am building this to be my last and a keeper...I guess I have more to mull over Thanks again, Can we not refer to this as IFS? Struts are IFS too. Thread title changed. Worth it? Only you can answer that. Building a Double-A Arm suspension is not trivial. It’s FAR easier to get it wrong than it is to get it right. Get it wrong and you’ve spent a large amount of blood and sweat for nothing… unless you just want the challenge of it or wow factor. Get it right, and even then, it will probably only be incrementally better than a well prepped set of struts. So the question is… are you capable of making an improvement, and if you are, will it be enough better to justify the effort? Or is it just to say “I did it� Here is a copy of a discussion by a couple of our members… Quote Link to comment Share on other sites More sharing options...
Lazeum Posted October 29, 2012 Share Posted October 29, 2012 (edited) I believe you need to think about how camber, caster & toe will change according to Z height (up/down). Benefit of double A-arm is used to better keep control of camber & other components in accordance to Z height: less positive camber are rebound & less negative camber in jounce. It is linked with arm length relashionship between top one & bottom one. You could also control how the nose of the car will dive or not during braking & accel phases with position of hard points locations. You'll affect toe a lot also with any setup, it also has to be taken into consideration. Short tie rod asm (inner+outer) will affect your toe more than a long asm unit with Z height variation. Damper/spring connection could also affect the behavior of the car. Mark Olston uses in his build a front suspension from Corvette (C5 or C6, they are very similar). I think it is smart move since you already know it works well. You also know it will be up to the task regarding stress since it is capable for +3000lbs 600hp car. Edited October 29, 2012 by Lazeum Quote Link to comment Share on other sites More sharing options...
johnc Posted October 29, 2012 Share Posted October 29, 2012 The stock 240Z strut front suspension has much better geometry through its full range of travel then the two heavily modified (TCI and I forgot the other) Mustang 2 front suspensions I've had experience with. The worst one had the anti-roll bar bind the front suspension at anything more the 1" of bump travel. The second worse one had silly amounts of bumpsteer. These Mustang 2 setups were both on mid 50's F100 pickup trucks. As an engineering exercise building a SLA front suspension on the S30 chassis has been done by a few folks. A member here has also swapped in a E36 BMW M3 strut front suspension which has fantastic geometry. Excluding some really bad front suspension designs (Morgan sliding pillar, beam axle, Fox body Mustang) the devil is in the details. If you want to build a SLA front suspension for your S30 go for it. Will it be better the a well modified S30 front strut setup, probably not. Is it worth it, that's up to you and your wallet. Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 29, 2012 Author Share Posted October 29, 2012 Got a few more books on chassis and suspensions.... more things to look up and cost out before I go one way or the other... Interesting that you had those issues with a Double A Arm... I have used Heidts exclusively (although they are all close to the same) and I didn't have either of those issues on any of my installs....I guess that is why I was / might be still leaning that way... Its what I have had success with..getting well versed in what a well modified strut set up is all about, before I do anything else, tonight starts the beginning of the tear down.... I have time...Thanks for the thoughts and knowledge. . The stock 240Z strut front suspension has much better geometry through its full range of travel then the two heavily modified (TCI and I forgot the other) Mustang 2 front suspensions I've had experience with. The worst one had the anti-roll bar bind the front suspension at anything more the 1" of bump travel. The second worse one had silly amounts of bumpsteer. These Mustang 2 setups were both on mid 50's F100 pickup trucks. As an engineering exercise building a SLA front suspension on the S30 chassis has been done by a few folks. A member here has also swapped in a E36 BMW M3 strut front suspension which has fantastic geometry. Excluding some really bad front suspension designs (Morgan sliding pillar, beam axle, Fox body Mustang) the devil is in the details. If you want to build a SLA front suspension for your S30 go for it. Will it be better the a well modified S30 front strut setup, probably not. Is it worth it, that's up to you and your wallet. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted October 29, 2012 Share Posted October 29, 2012 Funny, I was just talking to a fellow dragracer at the strip just yesterday who was trying to unload (sell off) a tube-chassis 280ZX that had a Mustang II front suspension. He said the car ran great and straight under power, but that the car wanted to run off the side of the track under braking and was quite scary. It could be anything from improper alignment to worn parts that would cause that. I just thought is was interesting that this thread came up just a day after. I'm happy with how my stock-style front suspension works. It is very light and behaves predictibly-if it ain't broke, don't fix it! Quote Link to comment Share on other sites More sharing options...
Snailed Posted October 29, 2012 Share Posted October 29, 2012 Check out VSUSP Quote Link to comment Share on other sites More sharing options...
Snailed Posted October 29, 2012 Share Posted October 29, 2012 if it ain't broke, don't fix it! Wrong forum? Hahaha! Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 29, 2012 Author Share Posted October 29, 2012 WOW,Thanks for the link, that will answer a lot of my questions... Check out VSUSP Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 29, 2012 Author Share Posted October 29, 2012 Interesting, because it hasn't been that way on any of my installs, and like you said, a number of things would make it pull to one side... Off to pull out the motor trans now.. I got good help... and time.... I think it will be like anything else.. a game of numbers... Thanks, Funny, I was just talking to a fellow dragracer at the strip just yesterday who was trying to unload (sell off) a tube-chassis 280ZX that had a Mustang II front suspension. He said the car ran great and straight under power, but that the car wanted to run off the side of the track under braking and was quite scary. It could be anything from improper alignment to worn parts that would cause that. I just thought is was interesting that this thread came up just a day after. I'm happy with how my stock-style front suspension works. It is very light and behaves predictibly-if it ain't broke, don't fix it! Quote Link to comment Share on other sites More sharing options...
johnc Posted October 29, 2012 Share Posted October 29, 2012 BTW... I'm not saying that all Mustang 2 front suspension setups are bad, just the two I've had direct experience with. I also have a 1951 Chevrolet Coupe coming into the shop in a month with another Mustang 2 style front end conversion. His steering rack mounts have torn off the cross member. I think the big issue is, as I mentioned before, in the details. Some vendors of Mustang 2 front end conversions pay attention to the details and others just slap crap together, powder coat it black, and call it good. Quote Link to comment Share on other sites More sharing options...
beermanpete Posted October 30, 2012 Share Posted October 30, 2012 if it ain't broke, don't fix it! That's what my cat said. Quote Link to comment Share on other sites More sharing options...
Freelancelance Posted October 31, 2012 Author Share Posted October 31, 2012 Its one of those things.. you get what you pay for.... I have seen some that look like someone just fired up the welder, and tossed parts at it...... I have had success with Heidts and if I decide to do it again... I will invest in one from them, and make it work... had to do the same thing for a 57 T-Bird, , considering it had a big block ford, and that front bumper came close to giving me a hernia putting it on...it was worth the effort...LOL... thanks for all the input.... I have a lot of reading and costing to do... BTW... I'm not saying that all Mustang 2 front suspension setups are bad, just the two I've had direct experience with. I also have a 1951 Chevrolet Coupe coming into the shop in a month with another Mustang 2 style front end conversion. His steering rack mounts have torn off the cross member. I think the big issue is, as I mentioned before, in the details. Some vendors of Mustang 2 front end conversions pay attention to the details and others just slap crap together, powder coat it black, and call it good. Quote Link to comment Share on other sites More sharing options...
chelle Posted December 11, 2012 Share Posted December 11, 2012 We're using a 350z front suspension in our latest project.. it's a lot of work but there are so many advantages.. many more brake and strut options, larger bearings, but most will require chopping off the entire front structure and starting over. IMHO though it's well worth it Quote Link to comment Share on other sites More sharing options...
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