Hi, guys. We just received an A/C replica,( I believe it is an '07) in our shop. The Customer has an issue with the rear ride height and the difficulty in adjustment. I got the car up on the lift and had a look. Off the cuff, shortly after meeting with the owner of the car, I just suggested installing a set of QA-1s and being done with it. After a little poking around, I thought better of supporting the rear of the car from the upper shock mounts, as there is no crossmember to keep the frame from distorting over time. I had one of my very good LPME friends over last night and we went to the shop, for another look around. We came up with a solid mounting configuration and I submitted the proposal to the owner. He came back with the suggestion of doing the F5 IRS. I have no issue with that, I would like to know if anyone here has done a retrofit on this particular install. We incorporate certified welders and I am an AWSCWI. We have Professional Engineers on hand. We have the ability to do this task, I was just wondering what all is included in the kit and how long it took YOU to do it! This is a sweet car and I'm excited to be involved. We have a chassis Dyno, in cooperation with Merrit Performance. We will also be taking care of some drivability issues. It currently has a 351W with a Tremec. We'll get the rear end hung and get her on the dyno. Any info/Advice is appreciated!
Cheers-MFR
Retrofit has been done. You need to buy the cage from FFR, hack out the stuff not used, and weld in the cage
__________________
Bill D
FFR 3378 - 503 BB, $old and missed
RCR GT40 - 1051P clone, $old
FFR 7991 - becoming a 289 FIA with a Mr. Bruce body, 331, dual quads, T-5, IRS, Trigo pin drive wheels, and Goodyear billboards http://www.bills289fia.com
You can get the Qa1s from Breeze Breeze Automotive Factory Five Racing
I would go w/ the 250 springs and the double adjustable shocks to better assure you can get a ride the owner likes.
or a Carrera setup here Vintage Performance Motorcars
I have driven a friends car w/ these and it rides very well.
BTW there is no worry about the frame structure as it's been used since FFR started w/o problems. The IRS is the ultimate but it's quite expensive easily in the $5K+ range. If you decide to go that way make sure to read this thread so you can be assured by FFR that you won't have the short axle problem. Help! Axles are still too short...
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FFR 5353K,351/400hp,TKO 500, 3-link w/3.08 and Truetrac, Koni DA coilovers front and rear,APE hardtop,Forte front and VPM rear swaybars
Cool! I'll be in communication with the owner of the car before we make any decisions. I believe he wants it to be an enjoyable, well ridden car. Not too harsh, nor to soft. I really doubt the car will be entered into any formal competition, beyond casual weekend events. We will perform as instructed and take this car to whatever level is desired. I like the QA-1 coil overs, for their ease in adjustability. Dual adjust will be recommended. He is leaning towards IRS, which I fully support. For all out drag racing, live axles are superior, but this car needs some comfort and with the power to weight ratios, an IRS will be more than adequate. We are laying down impressive numbers with our C-6 Corvettes, in stock suspension form, with no ill effects. This will be an interesting project whichever route we go. I will post pics and documentary along the way. You guys have a great forum, it's nice to be here.
Cheers,
MFR
I believe he wants it to be an enjoyable, well ridden car. Not too harsh, nor to soft.
MFR
With over 15,000 miles on my retrofit IRS I believe it fits this criteria exactly. It has seen track days, 500+ mile road days, and a lot of spirited back road miles. I am very happy with the way it rides and drives.
Arch
__________________
FFR# 6530 non donor, IRS, small Block w/carb build. GraduationPOM3000 Mile Trip 3500 Mile Trip
Built to be driven. The mission statement for the build was - build a comfortable and fun long distance driving machine that is capable of spirited street driving and the occasional track outing.
You didnt not say what brand you were working on. From your concern about lack of strength at the shock mounts, (I thought better of supporting the rear of the car from the upper shock mounts, as there is no crossmember to keep the frame from distorting over time) I think it may not be a FFr. If is a kit from another company, not sure you can just install the FFR IRS cage.
If it is not an FFR you will at least get some good data about how FFR did the IRS.
__________________ FFR1000194CP, Type 65 coupe, 302, 4 webers, TKO II, 3.55 IRS. '98 Z28, '35 Pierce Arrow, '27 DB Coupe, '27 DB 4 DR Sedan Thank You FFR and FFCARS.
are u sure its a ff5. whats your front suspension like is it mustang control arms or tubular. it sounds like your rear suspension is all mustang with coil springs not coil over. got a pics of the suspension and car.
It is a Factory Five car. My statement about there not being a crossmember, is referring to the area of the shock absorber mount, upper. There is small square tube member in the vicinity, but it is not sufficient in size to support the weight of the vehicle, from a dynamic standpoint. I just feel the frame will flex inward at the top and fatigue over time, especially in the Heat Affected Zone of the welded members. I haven't heard from the owner of the car for a couple days, so I don't know where he is on the IRS as of yet. I'll shoot some pics when I get the car back on the lift. The Art Morrison rear and full frames, I am pretty familiar with. They are 2X4 tube, are well engineered and stout. Coil Over shocks are incorporated, aft of the axle center line, leaving the trailing arm, as only a trailing arm and not doubling as a vehicle support point. I am just looking at the best performing and reliable option out there. Here's a couple shots ofa Corvette I'm in the middle of now. I appreciate your input and look forward to hearing other's point of views and technical expertise...
Cheers, MFR
With over 15,000 miles on my retrofit IRS I believe it fits this criteria exactly. It has seen track days, 500+ mile road days, and a lot of spirited back road miles. I am very happy with the way it rides and drives.
Arch
Hey stranger!! Socal must be agreeing with you since we've hardly heard a peep from you. Hope all is well - we all miss your friendship up here.
__________________
Howard
408W, IRS, TKO600, PS, PB, QF SS 750, POM Sept 2010.
FFR 6817 // Delivery Date: 11/20/08 // Roller: 9/25/09 // First Engine Start: 3/31/10 // Gokart: 4/11/10 // Painted: 7/2/10 //Graduated 10/03/10. Graduation thread with my progress links is here.
Hi, guys. We just received an A/C replica,( I believe it is an '07) in our shop. The Customer has an issue with the rear ride height and the difficulty in adjustment. I got the car up on the lift and had a look. Off the cuff, shortly after meeting with the owner of the car, I just suggested installing a set of QA-1s and being done with it. After a little poking around, I thought better of supporting the rear of the car from the upper shock mounts, as there is no crossmember to keep the frame from distorting over time. I had one of my very good LPME friends over last night and we went to the shop, for another look around. We came up with a solid mounting configuration and I submitted the proposal to the owner. He came back with the suggestion of doing the F5 IRS. I have no issue with that, I would like to know if anyone here has done a retrofit on this particular install. We incorporate certified welders and I am an AWSCWI. We have Professional Engineers on hand. We have the ability to do this task, I was just wondering what all is included in the kit and how long it took YOU to do it! This is a sweet car and I'm excited to be involved. We have a chassis Dyno, in cooperation with Merrit Performance. We will also be taking care of some drivability issues. It currently has a 351W with a Tremec. We'll get the rear end hung and get her on the dyno. Any info/Advice is appreciated!
Cheers-MFR
If you think the FFr frame is going to distort at the rear shock mount, then I would question your engineering. A 2300# car isnt going to move that frame.
White Flag Motorsports,
If you're talking about the rear upper shock mount (pictured below), you don't have to worry about distorting over time.
Factory Five has been using that design on their live axles suspension since 1995 without any complaints of distortion (No need to reinvent the wheel).
Rich A; This is exactly the what I was thinking of doing. Simply utilzing the existing shock mounts as main support for the car. So, the question is, how long have you run it, and how hard do you run the car? This car has disc brakes, so either we must move the shocks inboard to clear the calipers or reverse the configuration and that requires redesign of the park brake routing. If we stay with the live axle, we may run and monitor.
Rich grsc; The reason I am asked these questions is to mayhaps glean some practicle knowledge from people that have experience running/modifying and building these cars. This objective is being met and I respectfully appreciate the opinions and experiences shared thus far. This is my very first experience with a F5 Roadster. I do not know who performed the fabrication of the frame. I do not know what materials were used in construction, I have no information as far as material specifications and no idea what filler material is incorporated. Performing Chemical and Physical testing is not practical, as the vehicle is already complete. I do not know the qualifications of the craftsman who performed the actual work and I don't know the conditions under which the construction took place. I do know there are some questionable welds and a lot of mismatched hardware, some of which have known suspect origin. I have a good friend, who is a Licenced Professional Mechanical Engineer that lends his opinion and reinforces the validity of my concerns and that was the basis of my question line. We are attempting to correct some of the problematic areas on this car, in a cost effective and acceptable timeline.
I will photograph and submit what I am dealing with , when I get it back on the rack.
Cheers
MFR
Retrofitting an IRS to solve the problem of adjustable ride height seems like overkill unless there are other issues with car. There are three main configurations of rear end suspension for these cars - a 4 link setup that is similar to a fox body mustang set up with springs and upper and lower control arms. This is the least expensive option and is the poorest in terms of handling and adjustability. If the owner just plans on a cruiser and has no intention of pushing the car in the corners etc it will probably be okay. However if he wants to be able to some spirited back road driving, the odd track day, autocross etc, the next step is to go to the 3 link rear suspension. The majority of Factory Fives have this suspension - it's tried and proven and works very well as designed. It gets rid of the upper control arms and springs and uses coil overs as shown in the pic above. There's a single upper suspension link, and a panhard bar. Used with Koni shocks it gives a lot of adjustability in ride height. If your car has the 4 link, it would be definitely worth going to the 3 link. Post up some photos when you get the chance.
The third option from F5 is the IRS which is based off a Thunderbird IRS - it uses the tbird pumpkin and spindles. It uses the same coil over mounting points. I have it in my car and like it a lot. I don't know how much better it is than the 3 link - on crappy rough roads like what we have in the NW it definitely gives a nice ride. I've autocross and tracked my car and it has performed very well.
I get the impression your considering re engineering the rear end - it's really not needed - the 3 link is tried and tested and works very well as designed. I don't think the IRS retrofit in a finished car is a great option unless the owner absolutely wants to have IRS just to have it.
BTW I just live down the road from you in Woodinville - you're welcome to look at my car anytime if you want to see what the IRS looks like. Also where is the chassis dyno - I haven't heard of Merrit Performance before.
Edit - what doesn't the owner like about the ride height? - it looks pretty good in the photos from what I can see.
__________________
Howard
408W, IRS, TKO600, PS, PB, QF SS 750, POM Sept 2010.
FFR 6817 // Delivery Date: 11/20/08 // Roller: 9/25/09 // First Engine Start: 3/31/10 // Gokart: 4/11/10 // Painted: 7/2/10 //Graduated 10/03/10. Graduation thread with my progress links is here.
Rich A; This is exactly the what I was thinking of doing. Simply utilzing the existing shock mounts as main support for the car. So, the question is, how long have you run it, and how hard do you run the car? This car has disc brakes, so either we must move the shocks inboard to clear the calipers or reverse the configuration and that requires redesign of the park brake routing. If we stay with the live axle, we may run and monitor.
White Flag Motorsports,
If you don't have (upgrade) coil over shocks (shown in the picture above), you must have the donor set up (pictured below).
Factory Five has been using that coil over design on their live axles suspension without any complaints of distortion
Those suspension pics w/ the Strange brand coilovers are not of an FFR. Did I miss something maybe? look at the nicely curved frame rails compared to the straight rails in the car in Rich A's pics.
__________________
FFR 5353K,351/400hp,TKO 500, 3-link w/3.08 and Truetrac, Koni DA coilovers front and rear,APE hardtop,Forte front and VPM rear swaybars
Rich A, yes, it has a setup similar to the second one. And so full circle we have come. Currently, the car does not have coilovers. Looking at the earlier photos, with QA-1s or Konis, the existing shock bracket can safely support the vehicle. I'm not attempting to re-engineer anything, I just didn't want to put the owner in any kind of danger by utilizing a support bracket that was not intended for full time support. All of this info is very helpful, and will help educate in the decision making process, as to which way to move forward. The ride height looks acceptable but exhibits less than satisfactory handling from what I gather. I have to go race this week in Bakerfield, so I will be lurking periodically, but not making any progress on the Roadster. Once we get back, I'm sure there will have been a directive and we will proceed. All very good info, with various viewpoints and much appreciated.
Cobra, DVM; I would love the opportunity. PM headed your way now!
Thank You all, for your input. I will get pics and progress on here. Great forum, great cars!
Matt Ringer
White Flag Motorsports
425.239.5562
Those suspension pics w/ the Strange brand coilovers are not of an FFR. Did I miss something maybe? look at the nicely curved frame rails compared to the straight rails in the car in Rich A's pics.
Sorry, didn't mean to muddy the water! That's a Morrison Chassis under the 59 Vette I'm dealing with!
Fabbed up a crossmember out of 2X2 heavy wall. I notched the mount points to swallow the existing shock gussets.
Slipped it up into position
Detail of the surround
With the coil overs installed
Installed, with a 12" shock, it puts the angle right at 40 degrees. A little more than I aimed for, but still works well. The reason is that I was able to retain the original suspension stop cables.
Dropped the car on the suspension and it sat pretty good. With the adjustable shocks, we can really tailor the ride and travel.
Installing a new Holley Ultra HP series mechanical secondary carb, a new MSD distributor and HVC coil. We will get this car on the dyno soon and post up numbers.
the original shock mounts are ok for coilover use and position the shock almost vertical. At the angle shown, I'd be a little concerned about the strength of the axle brackets (side loading). Most likely, it'll be ok on such a light car, but you didn't have to reinvent the wheel.
The angle of your coilovers is really going to affect your actual wheel rate but I'll assume you factored that in when making spring selection. I find it surprising that after having such serious concerns about the upper frame mounts the redesign appears to still incorporate the bolt on shock tab in single shear as a lower mount. Just as an FYI you might want to take a look at the FFR design for the axle brackets used for coilover applications:
the original shock mounts are ok for coilover use and position the shock almost vertical. At the angle shown, I'd be a little concerned about the strength of the axle brackets (side loading). Most likely, it'll be ok on such a light car, but you didn't have to reinvent the wheel.
The brackets will hold, that's not the issue. The problem is the shock angle by itself.
The shock (coilover) needs to be in the around 20 to 25 degree range not in the almost 45 degree position.
More harmonic with the motion of the solid rear end. See center line as starting point.
Setup like this gives you a very bad ride characteristic. The car will roll to a great amount and have friction problems in corners.
I don't understand your concern with the original mounting points. It is the same mount used on about 8000 cars so far. It is also the same as the FFR Challenge cars which I guarantee are run harder and more frequently than your customer will run his car. Factory Five builds the frames not the customers and I've never heard of a failure. I have to agree about the angle of your modified mounts. The closer to in line with the wheel travel the better. You will be utilizing very little of the actual shock travel compared to wheel movement and I think it will actually cause a side loading of the shock piston and premature failure. Welds look good though.
I'm going to move the upper mounts outboard and relocate the stops. At the current angle, I lose almost 30 percent of the spring strength and it does put the mounting bolts in higher than desired shear. I don't mind doing some reinvention now and again. If we reach the customers goal of better handling and easier suspension adjustability, along with added structure I think it's a win. I didn't incorporate the original shock mounts into the load bearing aspect of the crossmember, I simply went around them instead of removing them. I'll move things around a bit today and post up. I appreciate your guy's input
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