Thread: Switching to IFS

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I am thinking of replacing my straight axle with an IFS . This is my fourth year and I have had enough of looking cool/traditional etc. My old bones need some relief if I am to continue driving my rat . My 2x3 x 3/16 frame rails are 23" OD so i am thinking most any IFS would fit around my frame , quite possibly all would have to be narrowed to fit snug against the frame . My search has just started after returning from a 110 mile trip SAt and deciding it was time for a change . My present front suspension has all new Posies parts with a Vega box and super bell dropped axle . A friend is starting an open wheel project and wants all the parts , so money wise it will probably be close to a swap which makes it a little easier . As a frame of reference and the only place I have looked so far is Speedways catalog . They have a stock Mustang II for $999.99 with all new parts and a crossmember which i'm sure i could snug up to my existing frame , shipping would add about $170.00 Dollars . Looking at their individual prices for components , I'm wondering if buying a used IFS and rebuilding it would be cost effective . I'm also wondering if my 23' frame width would be too narrow to graft a whole clip on . I'm sure lots of other IFS set ups could be made to work but would parts to rebuild be hard too get or expensive. Any comments or suggestions would be greatly appreciated . I'm not out to reinvent the wheel , done enough of that all ready on this project . Seems like here on the east coast the roads are going to pot and the ones under construction are worse . Thank again LFE

I have a Mustang II under mine,love the ride. Horton's Hot Rods, in Ontario Can. have new front crossmebers in kit form, cheap and easy,and they ship as well. You might want to give them a try. I bought all the parts to rebuild mine last winter,good stuff at fair prices too.Brian

Heidts or FatMan both good stuff. Prices can vary depending on how much pretty you want.

Eddie, if you're a decent welder, here is another source to consider for your Mustang II IFS, Welder Series. D.W. Horton is a great guy to deal with.

Mike

Originally Posted by luckyfasteddie

quite possibly all would have to be narrowed to fit snug against the frame

As soon as you start narrowing an IFS, you throw all the original geometry right out the window and you're on your own. Just so you know.

Want to do it properly? Get the book "Tune To Win" by Carroll Smith. It will teach you how to engineer your own IFS specifically for the track width you want to use.

[QUOTE=techinspector1;389606]As soon as you start narrowing an IFS, you throw all the original geometry right out the window and you're on your own. Just so you know./QUOTE]

Been looking in magazines , sent for some catalogs , and asking around . What do you mean when you say narrowing an IFS . I see cross members of different widths being advertised and some are narrower than others by having a different width crossmember .If I find a MII front end at a swap meet , can't it be narrowed by cutting a piece out of the crossmember ?

Yes!
But you'll have to get a different width rack to go with it, or the inner rack ball joints will be out to far and cause bumpsteer, how much depends on how much you narrow the center.
Plus you'll need to put the rack mounts back out to the same place they were for the stock type rack.

The original geometry won't change, only bumpsteer will!

There is many things on the internet written on MM II front ends and on suspensions. Street driven suspensions theory is basic.
Most aftermarket MM II's are a manufacturers interpret of factory MM II's factory spec's, some are close, some arn't.

Pat

Although I have no experience with Fat Man, they advertise that they have made IFS for many different chassis. With luck, they may already have a design that will fit yours.

The Carroll Smith book the Tech suggests is a very good primer and will give you a lot of good suggestions on what makes a chassis/suspension work. What it is NOT is a recipe on how to build one that will fit yours like a glove. The book that precedes it 'Prepare to Win' should be included as well. Then there is a third, 'Engineer to Win' to finish the series and I do need this one to finish my collection (Richard, you are costing me $$$$)

when you do this make sure you have the right A-arms. You want to have at least 3-4 degrees caster after the setup. You also want to be sure it can be aligned. Also take into consideration where the motor will mount and how the steering will attach.

Originally Posted by IC2

Although I have no experience with Fat Man, they advertise that they have made IFS for many different chassis. With luck, they may already have a design that will fit yours.

The Carroll Smith book the Tech suggests is a very good primer and will give you a lot of good suggestions on what makes a chassis/suspension work. What it is NOT is a recipe on how to build one that will fit yours like a glove. The book that precedes it 'Prepare to Win' should be included as well. Then there is a third, 'Engineer to Win' to finish the series and I do need this one to finish my collection (Richard, you are costing me $$$$)

Overweight guy is the worst on the market LOL Great marketing but not so good if you have to drive one

Originally Posted by sunsetdart

when you do this make sure you have the right A-arms. You want to have at least 3-4 degrees caster after the setup. You also want to be sure it can be aligned. Also take into consideration where the motor will mount and how the steering will attach.

I think you will find 6 to 8 degrees will make it comfortable to drive....most kits cant get that much. Plus the guy installing it needs to know the rake of the chassis before he starts.
Also stang II and pinto racks drive real bad. If your any kind of builder you will find that the t-bird rack works much better.
Done over 100 of these and fixed maybe 30-40 bad installs.

Originally Posted by Phat

Overweight guy is the worst on the market LOL Great marketing but not so good if you have to drive one

Just to be clear, I'm not recommending them, just stating the fact that they have many choices. But with that said, I have looked at their product several times and as late as 6 June and really can't see anything really poorly designed - so is it the installer's fault/poor instructions or is there a deficiency.

I do have a TCI IFS on my TCI chassis - with the caster at 1.5* - and it tracks just fine tho I'll probably add another .5 or so.

Ratzilla's engine is in the back and I have added weight ( 700+ lbs ) to the front . I went to the local dump and weighed it on their scale . With me in it (235 lbs ) the gross weight is 3600 Lbs - yes 36 not 26 lbs . original Fiero if I remember right was 2600 with 1000 on front and 1600 on rear . mine is 1500 front and 2100 rear almost the same ratio as the Fiero . I have a coil over type spring set up in the rear using 450 Lb springs these are the heaviest springs TCI makes . I decided to work on the rear before making a drastic change up front . After doing some searching on coil springs , I decide to install some type of pad or cushion between the top of the spring and the spring perch .BMW among others uses them on their vehicles . Picked up some rubbeer spring stiffiner thingies at the Boys . Spent the aft modifing my spring top pockets to accept them , after some alteration . Will weld them together tomorrow and test em out . Who knows , start with the easy way first . $ 7.50 invested so far . Heidts tech told me 450 's should be enough .pic of old spring top and new spring top with pad installed.

No work again today so I got to finish em up . Bolted everything together and took a spin . Can't believe the difference , like night and day . Am thinkin now , a new set of some good gas shocks on the front and who knows . Any sugestion on the shocks . Bilsteins want 175 for a pair . not against paying for something thats worth it but that's a bit pricey to be throwing parts at the problem .