Hi guys,

slowly working going both forward and backwards on this project. I have the truck frame all measured up and drawn (progress) but I seem to have lost my files in a server swap so I lost the CAD I made of the IRS unit, the one I made the pictures above with. Would someone be so kind as to share some dimensions I miss:
- What is the horizontal dimension between the upper strut unit mounting points? I no longer have the cage.
- What length are the struts compressed, when the drive shafts are horizontal?
The rest I got pretty much figured out from measuring parts again.

Thanks,

Hugo

Hmmm, little response to that... Bummer.

Anywho, today I went back to the IRS and fit two rims. Then I alligned the LCAs and axles as per driving conditions, and measured. I was a bit surprised by the findings, but checking the rims shows they are 8",  not 7. And the offset is slightly different than quoted. I redrew the IRS in CAD to show the proper rim dimensions and rim distance from the center, and the distance between the upright and the centre of the axle. I am glad I did not make any cuts, yet...

I don't think the rims are a bad buy. They are the model and diameter I wanted, and the inward part is as close to the upright as it could be. Widening inward is no option, so that part is perfect. I do want to enlarge to 10", so I only need to add 2" to the outward part.

When tearing apart the lot I made a very nice discover. Although a bit dirty, the brakes are near mint. They seem to be overhauled only just before the IRS was removed from the car. Yeah! I carefully cleaned them and put them in bags.

All is now in pieces in boxes and plastic bags. I hope my truck will finally arrive, we're about 6 weeks past the original due date now. I know all reasons, but I like to see the thing and start taking measurements for the sub frame I designed.

Cheers,

Hugo

Ah, oh, well, no. The shiny-ness has nothing to do with it, actually. They will be powdercoated. But they are the type of wheel I wanted, and dirt cheap. I found Attention Deficit Disorder on WIKI by googling; yes, fit's the bill.

On topic; both LCAs are off. I am very happy with how this axle comes apart, it was obviously well maintained. All nuts and bolts were really tight, but ones losened it all slid apart easily. I will clean the LCAs tomorrow and see about the square tube possibility. I'll try to get some pictures of the details and maybe a sketch of the idea.

Cheers,

Hugo

Well, the wheels are in, and they look good. For the front they will remain the size they are. For the rear, however, I would like them slightly wider. About 2 or 3 inches. Trail fitting them to the axle shows there is no room behind the wheel, so they will have to be extended outward. No problem, I know a company that can, and I think it will look good. All four wheels will be blasted and powdercoated.

When widening the rims, I again feel the axle needs to be narrowed. Not 4" each side but probably only 3 or 2. I have bought 1410 weld yokes to make new axles, I feel that is better than reworking the old ones. I know they will be 3" diamter, but I am going to mess op the suspension anyway.

About shortening the LCAs, I have a question. I can cut, sleeve and reweld, like all of you. But I have thought out another option. I can buy 60x60x3mm square tube. I would like to cut away the whole mid section tube of the LCA, and machine flat surfaces on them. Than sqeeuze the square tube over teh machined ends, and weld. I than have a square tube centre section, which will be very nice to mount suspension parts to. I think. Please shoot at the idea.

Cheers,

Hugo

tyrellracing wrote:

I am guessing that your set up has the shocks mounted in their stock location at presant.

 
Nope:

HugoW wrote:

It also required repositioning of the suspension pick up points, as shortening only between the dif and the pick up points would change the ratio (arm of the force).

 
 
BUT, STOP THE PRESSES:
I was just offered 4 rims of the style I like for 50 bucks. Yes, 50 total for four. They are 7 inch wide, 15 diameter, Jag bolt pattern, ET 27mm. So, that is 27mm less to shorten. My IRS unit is about 60”/ 1.524mm wide flange-to-flange. Fitting these rims, the outside dimension will be 60” + 7” – 2x27mm (are you still with me?) = 1.650mm = 65” wide. Sounds pretty good to me!
I was previously calculating with 10” wide wheels, but these 7” ones with a little wide tires on it should give a nice look, I think.

[img]http://i.marktplaats.com/00/s/NzY4WDEwMjQ=/z/SlkAAOxyTjNSkNdT/$_85.JPG[/img]

Please tell me my calculations are correct. This would mean no shortening of axles, LCAs, or anything. Hurray!
 
Cheers,
 
Hugo

Nealing systems were my speciality. I got pretty good at making them work. Still like the Wabco stuff we used back then. We built some pretty wacky protos and used to race them on the narrow roads behind the factory, "to test stuff". Too bad the company went bust, pure missmanagement.

And I was the only person in the comany the could drift (like counterstear oversteer action) with an articulated bus. Ours had the drive in the rear section, pushing the rest. I did so unvoluntarely one morning when the roads had iced up, but it sure looked good the bystanders told me. I was happy to get out and have a cup of tea...

Hugo

Thanks! Then these should work too, right?
http://www.actionmachineinc.com/ami3-28-97.aspx

I know 3" axles are a bit wide, but I am going to mod pretty much everything anyway, so I think I can manage.

Cheers,

Hugo

tyrellracing wrote:

Nice drawings Hugo W but in the drawings with the airsprings, how would you fit a differential in there?

 
The idea is to fit the bags behind the dif. And the shocks in front. I will make a top view drawing as well, when I get to it.
 

tyrellracing wrote:

The big problem I have with air springs in a performance application is when you lower the ride height by dumping air the springs get softer. This gives the vehicle a mushy ride that is way too soft to go around corners effectively.

tyrellracing wrote:

The bright side of this is that rolling lobe air springs are affected least by change in ride height by change in air pressure.

 
Eh, no. With equal load, the height of the spring is determined by the amount of air in the spring. Not pressure. Pressure is a result of the surface area of the air bags (the top and bottom disk, in my case) and the load. So unless the Mrs. stuffs her beauty-case in the back of the truck, the pressure in the bags stays the same regardless of ride height. Vice versa is true, too. If I don’t change the ride height and the Mrs. puts the case in the back, the pressure in the bags is adjusted, not the ride height. I worked a lot with these valves:
 

 

(Not my car, pics googled)

I used three of them, one in the centre of the solid rear axle of the vehicle, and one per front bag / wheel. So the front is kept level with the road. The rear is only on the correct total height, not necessarily the right height per wheel. These I have always used in full load applications, not as assists to coil or leaf springs.

Thanks, good inspiration.

I have not chosen any specific bags yet, I just found these on e-bay:
http://www.ebay.com/itm/Two-NEW-STANDARD-2500-AIR-BAGS-1-2-NPT-PORT-Ride-Springs-Bag-Suspension-fbss-/261281352364?pt=Motors_Car_Truck_Parts_Accessories&hash=item3cd5950aac&vxp=mtr
They are 6" in diameter, extended 8" and compressed 3" height. Should be plenty of movement. The 6" seems very small to me, I fear it is only the top and bottom plate, not the overall width. Loading of 2500lbs per side should be plenty, even though the arms set-up will probably half that efficiently.

Cheers,

Hugo

Hi,

Any progress on this build you can share? I am planning the same on an earlier Chevy truck. Can you share some dimensions on used tube and bushings?

Cheers,

Hugo

Hmmmm, OK, probably not the right place to ask, but I cannot find a better one;

Is there a drawing / template available of the bolt parterns of the Jaguar IRS?

I have bought an old Chevy truck which I'm going to convert to a hot rod, and I consider using the Jaguar IRS as it is easily available here in Europe. (I'm also considering a Ford Crown Vic front set-up, that is a lot harder to come by, and irrelevant to this forum).

Cheers,

Hugo