How far can you tub it before you run into the framerail?
How far can you tub it before you run into the framerail?
Almost any tubbing if I want 315's. The main contact area of the vehicle and tire will be the frame rail area immediately behind the mount area for the IRS. Just about exactly where quad shocks are mounted on the newer foxes. Though I will probably just bring the tubs in about 1.5", That rub area shouldn't be an issue in the end though. That's just the narrowest point on our tubs for inner tire scrub.
I would need to notch the frame rail slightly for the needed coilovers since I'll loose the upper spring perch in the tubbing. Also I will need to make an upper mount for the coilovers to provide the needed support since all of the vehicle weight will be in that one area.
I also will have to modify the IRS. The rear mounts will have to be narrowed. I will mount them 'hardtail' directly under the frame rails.
Crazy green and IRS? This car just keeps getting better and unique!
I think the new color choice is cool! I loved the blue, but the green just stands out better to me. Maybe I just like different.
Brock
1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
1984 Mustang GT Hatchback 5.0 V-8/5 Speed
I'm an FEP Supporter and proud of it. Are you?
Brock
1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
1984 Mustang GT Hatchback 5.0 V-8/5 Speed
I'm an FEP Supporter and proud of it. Are you?
IMHO the custom swaybar and wheels are the easy part. To minitub it, you are going to have to modify the cradle for the IRS or at least the mounting points for it. The front mounts to the stock front lower control arm and the back mounts where the quad shock would go. So if you move the frame rails inward at all you will have to modify both of the mounts on each side to compensate the same amount you move the frame rails inward.
After that you will have to modify your lower shock mount most likely due to the frame rail change and/or your custom wheels. I assume you are planning on running a coil over setup at this point as I don't see how you can run a standard coil spring without modifying the cast aluminum lower control arm.
The other issue I see that may be more personal taste than anything is the backspacing/offset on any wide wheels in a Fox with the Cobra IRS is going to be insane, but unfortunately still look pretty much like a FWD wheel. The Cobra IRS is the widest SN95 axle at @ 60.3" track width which is 1.5" wider per side than your current setup.
I can tell you from my experience with my 79 PC and the 03/04 IRS that a 17X9 (9" wheel has a 36mm offset (@6.4" BS)) with a 255/40/17 just barely clears the rolled outer lips and has less than 0.5" of clearance between the wheel/tire and the rear cradle mount. Most likely you will be running a Corvette C6/7 offset/backspacing to make it all work.
In regards to the Plasma cutter, I can't say anything about the HF unit as I have never used one. I did recently purchase the Eastwood Versa Cut 40 to do some work at the shop here in TX since my big Hypertherm is back in CO. So far I have been impressed with it. Very light and works on both 120/240. If you don't need the larger size, then consider the Versa Cut 20 that will do sheetmetal up to 1/8". I have seen the Eastwood on sale for I believe $299 Might be able to sell it after you are done and recoup most of your $$. Good Luck!
Trey
"I Don't build it hoping for your approval! I built it because it meets mine!"
"I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."
Mustangs Past: Too many to remember!
Current Mustangs:
1969 Mach 1
1979 Pace Car now 5.0/5 speed
1982 GT Stalled RestoModification
1984 SVO Still Waiting Restoration
1986 GT Under going Wide Body Conversion Currently
Current Capris:
1981 Capri Roller
1981 Capri Black Magic Roller Basket Case
1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
1984 Capri RS T-top Roller
1983-84 Gloy Racing Trans Am/IMSA Body Parts
I’m thinking the front mounts won’t need modifying. The rear cradle mounts without a doubt will need modification.
i want to bring them in enough to hardtail mount them below the frame. I’ve got an idea on that one.
I would have to get coilovers since the area where the springs mount on the frame rail will have to go.
The reason for the custom sway sway bar is the coilover clearance when I move the upper shock mount inboard. This will be the area I need to modify the frame rail a little. A little slicing and dicing for an area for the coilover to be leaned in. The lower mount won’t be affected.
i believe I will need a set of Kenny Brown lower control arms too. Maybe not need, more of a want. I’ve read about their problems but I believe i could rectify those issues. Do you know anyone else making an aftermarket lower?
This build just keeps getting better-and-better! 408 is an interesting choice, and I'm sure your late brother would approve. You might think about wheelie bars and a blower too, as the icing on the cake
I missed your post clarifying a few things before I made my post so I apologize for repeating things you had already stated or answered.
I don't disagree that the front mounts are probably fine, especially if you are only looking to fit a 315 rear tire.
We concur on the coil over option, although I still have concerns as to what this will do to the actual dampening quality and wheel rates depending on where you end up placing the rear shock/coil spring upper mount. I can't go out and look at my set up right now to verify, so I will have to take your word that you feel the lower mount will be able to remain in it's current location. I too have looked at the KB lower and upper arms, but just haven't decided they were worth the $$ at this point. Nothing against them, just not sure they gain me enough to justify the $$ is all. I am not aware of any other options at this time myself.
In regards to the upper mount for the rear shock/coil over setup I would highly recommend the MM Racing Rear upper shock mount http://www.maximummotorsports.com/Ra...IRS-P1089.aspx I think you may want that additional support and secure mounting depending on how you decide to make it work. You will definitely want a significant structure for the mount that can handle the loads that are required.
I will admit that I too have considered an IRS with tubs, but I was considering narrowing the whole IRS setup to gain some additional room and improve the rear wheel visuals from my perspective. I have another Cobra IRS (non Terminator) that I just might do that with for one of the projects, then again I might just stuff it under the SVO and call it good! For all the custom work and expenses there are Ford 9" based aftermarket IRS that would probably save me a ton of time and money in the long run. Good Luck!
Trey
"I Don't build it hoping for your approval! I built it because it meets mine!"
"I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."
Mustangs Past: Too many to remember!
Current Mustangs:
1969 Mach 1
1979 Pace Car now 5.0/5 speed
1982 GT Stalled RestoModification
1984 SVO Still Waiting Restoration
1986 GT Under going Wide Body Conversion Currently
Current Capris:
1981 Capri Roller
1981 Capri Black Magic Roller Basket Case
1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
1984 Capri RS T-top Roller
1983-84 Gloy Racing Trans Am/IMSA Body Parts
Thanks Trey. I’ve allowed my brain to wonder a bit today. As you know the KB control arms cost $1400 for lowers and uppers. Yikes!
How hard do you think it would be to make my own set of control arms? Get some chrome moly tubing, make some detailed measurements, create and jig and do some cutting and welding.
I’ve given some thought of either making a set of arms that are shortened or possibly relocating their mounts a little more inboard and finding a half shaft that’s a couple inches shorter and move everything in. Hummmmm.....Sexier wheels that way.
Anything is possible! The question is if it is worth all the time and expense? Only you can answer that. I would likely recommend using a program such as Suspension Analyzer to make sure anything you build will ride and handle as well as OEM, otherwise what is the point. Unfortunately a good IRS is just as complicated as a good IFS in design and fabrication, so not something you want to take lightly. Nothing that a good DIY'er can't tackle, but I feel you want to make sure you are making the car as good if not better, rather than just able to run wider wheels.
Trey
"I Don't build it hoping for your approval! I built it because it meets mine!"
"I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."
Mustangs Past: Too many to remember!
Current Mustangs:
1969 Mach 1
1979 Pace Car now 5.0/5 speed
1982 GT Stalled RestoModification
1984 SVO Still Waiting Restoration
1986 GT Under going Wide Body Conversion Currently
Current Capris:
1981 Capri Roller
1981 Capri Black Magic Roller Basket Case
1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
1984 Capri RS T-top Roller
1983-84 Gloy Racing Trans Am/IMSA Body Parts
Yeah, the whole tubbing thing is just speculation to see if it is possible or not.
It helps me to talk through the varying thoughts.
Like the halfshafts, couldn't i just disassemble them and send the shaft to Strange or Moser and have them shorten and respline them? They do that for sra axles.
Brock
1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
1984 Mustang GT Hatchback 5.0 V-8/5 Speed
I'm an FEP Supporter and proud of it. Are you?
With your body work skills wouldn't it be easier to add a subtle 1 1/2" flare to the car? Wheel choice would be easier. IRS would be a bolt in deal, wouldn't have to re-engineer what Ford made. Car would look meaner being a little wider. Many wouldn't pick up on it at a glance.
Jess
Previously owned;
1979 Mustang, v6 swapped to EFI 393, custom installed m122 blower, 4r70w trans, Megasquirt II, T-top swaped in.
1990 Mustang, 545 BBF, C-4 with brake, ladder bars.
1983 Mustang, 1984 SVO Mustang
1984 Mustang convertible, v6 swapped to 351
1986 Mustang GT, 1989 Mustang GT convertible
1992 Mustang coupe, 4 swapped to 302
I read this article this morning....it has me rethinking the IRS. This and the costs of upgrading the IRS.
http://www.griggsracing.com/pdfFiles...e%20Debate.pdf
One thing I hadn't considered in actually narrowing the IRS would be the angle of the CV joints, would that be beyond their capabilities?
Griggs makes several good points. The caveat being that he is really addressing most of this from a competition angle and not a street car angle. This is especially true in regards to a Fox with the IRS since the IRS was an add on by Ford to a chassis that was originally designed in the late 70's and was never intended to have an IRS much less be a real road course handling car by any means. What Griggs, Maximum Motorsports, Agent 47, Kenny Brown, and others have been able to do with the Fox chassis over the years is really pretty amazing when consider the humble beginnings of the design.
With all that said, I think the big question for you is what do you plan to do with the Mustang. Is this a street car or a track car or a hybrid of both? If this is a street car, then full on race tuning is neither needed or desirable in most cases. If this is a hybrid, then you will want to consider many upgrades to the IRS, if this is a full on race car, then you might want to reconsider the "Perfect Paint" if going Wheel to Wheel.
Maximum Motorsports and Full Tilt Boogie Racing both offer several upgrades to the IRS that will improve the whole rear suspension even for the street car. Not necessarily cheap options, but definitely make improvements over the compromised OEM design. Everyone here knows I am a big proponent of Maximum Motorsports and their products, but I do have to admit that FTBR has done a ton of hands on work with the IRS and makes some very nice products. I have a few of them on my 79 PC and as the budget allows there will be more.
I do have to agree with the statements above that doing a 1.5" flare kit to your Mustang may be the better option for what you want to accomplish with this Mustang. I would recommend the Maier Racing flares as IMHO the 1.5" kit is subtle but does give that added width that allows much wider wheels and tires at all four corners. YES, the kit will require some extensive body work to be perfect, but you have shown that is an area you are highly skilled in and shouldn't be an issue. I currently have their 1.5" fenders on my 85 Road Racer GT and I love the look, most people don't realize their are wider than stock and they look great. I still need to do the rear quarters, but not being home in CO and budget have not allowed that to happen just yet. I will say that with my experience with my PC and the IRS, adding the rear quarter flares should allow you to easily run a 10-10.5" rear wheel and possibly even an 11-11.5" if you go to the hard mount on the rear cradle with no clearance issues. That will be plenty of wheel for 315 tires and give you a subtle wide body that just looks killer.
That would allow you to install the IRS as is without any need to modify the control arms, shock mounts or even Mini Tub the Mustang unless you just want the additional work. The flares will work with your stock front and rear bumper covers and all the stock side moldings, etc can still be attached to look like an original Mustang if you choose. I highly recommend checking into a Maier Racing's Website. https://www.maierracing.com/product-...79-93-mustang/
Here is a picture of the Maier Racing 1.5 fenders I have.
Here they are on the car with stock rear quarters at this time.
Trey
"I Don't build it hoping for your approval! I built it because it meets mine!"
"I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."
Mustangs Past: Too many to remember!
Current Mustangs:
1969 Mach 1
1979 Pace Car now 5.0/5 speed
1982 GT Stalled RestoModification
1984 SVO Still Waiting Restoration
1986 GT Under going Wide Body Conversion Currently
Current Capris:
1981 Capri Roller
1981 Capri Black Magic Roller Basket Case
1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
1984 Capri RS T-top Roller
1983-84 Gloy Racing Trans Am/IMSA Body Parts
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