IFS Technology - No Limit Sniper IFS

[RobNoLimit]

A big part of our goal is drive quality, and there are many parts to that. Ground clearance and wheel clearance are big factors. Wheel and tire clearance can be unsettling to say the least. If you turn the wheel sharp on an Auto-x course and hear the tire rub, it's bound to throw you off, and next time around you won't enter the corner so hot. No matter if the car can handle it. We noticed that when most F-body's have enough caster to make them turn, the tire is in the back of the wheel opening. We used some pretty cool digital measuring equipment to model up the fender area in 3d, then put it in to 2d layers, and then set the position of the suspension components to accurately center the wheel at all times.

On the underside we paid close attention to the scrub line. If you looked over the pictures from the OUSCI last year, you would have seen a number of pictures (Rodney) showing 1rst and 2nd gen Camaros throwing sparks out from underneath. Usually that was Headers and Oil-pans. We shaped the subframe crossmembers so that the oil pans (stock depth) would be protected by the lower crossmember skid plate. For LS swaps, the OE camaro pan will fit. Then we tested headers to find some that didn't hang down as well. Bump stops were added to stop the subframe from ever dragging the pavement.

The headers in the picts are Dougs #d333. We also tested the StainlessWorks 2nd gen ls header. It looks like most headers built for a 2nd gen will fit.

[RobNoLimit]

OK, lots of questions about how the car sits, tire size, backspace, ride height.....so here goes.
Of coarse, ride height is adjustable, but within a range. Then, tire height comes in to play.

We mounted up 315/30/18 Falken tires on 18 x 11 rims. Spec tire height is 25.4, but honestly, with 25 psi they measure at 24 7/8".
With this tire the spindle pin CL is 12.25".

For this suspension design, we want the spindle pin to be in a range of 7.25" to 8" above the bottom plate of the subframe. That's the sweet spot. Right now, Velocity is sitting at 7 3/8" from the spindle CL to the sub plate. So with a 315 tire, the bottom of the subframe is 4 7/8" off the ground. The range would be 4 1/4" to 5" at RH with this tire.

At the 4 7/8" sub plate height, the top of the wheel arch is 23 7/8", covering about 1" of the top of the tire. And the bottom of the rocker, behind the front wheel opening, is at 7 1/4".

** We are using a solid body mount kit that was on the car when we started, these measure out to be appx 3/8" shorter than the OE mounts. **

We had the car sitting about a 1/2" lower and it looked sweet, but until we get a set of inner fenders with more room, this RH is more reasonable.

Backspace on the wheel, 18 x 11 is 8 1/4". For narrower wheels, take the width off of the inside. As an example, an 18 x 9 wheel would need 6 1/4" backspace.

[Nothingface5384]

We have looked into that. At the moment we are busy with 1rst and 2nd gen F-body subs. While the suspension geometry and components are adaptable to the A-body, the subframe design is not. This would require a new front sub assembly that would have to be installed onto the chassis. So there's the catch. How many A-body owners would be willing (and able) to cut off the front of their chassis, say just behind the OE steering box mount, and fit up and weld on a new front section? Now for reference, we make a front snout for 49-51 Mercs with our Wide-Ride IFS, and these guys don't think twice about getting out the sawzall. I also personally think that a clean 66/67 Chevelle with 315's on all corners, updated suspension and brakes, LSX and 6 speed would be a great Power Tour or One-Lap car. But the big question is, would enough guys do it?

if ots priced right, i dont think cutting and welding up a section of tje frame would be a big deal

[RobNoLimit]

One of the keys to the packaging, allowing us to set the scrub radius in the desired range, was the Hub design. Due to the bearing and spindle snout they don't look like any other hub, with the outer bearing set 'inside' the hub face. The 2" I.D. bearings on the short snout spindle provide more than 400% more stability as compared to the common "A" or "F" body spindle and bearing. This huge reduction in spindle and hub flex/distortion leads to superior brake feel, reduced pad knock-back, lower rolling resistance, and improved driver feel.

From the hub to the rotor, we machined an interlocking step into the rotor adapter. This step put the brake load into the hub through the machined interlock rather than through the mounting bolts alone. The rotor adapter shown has two rotor mount patters, 12 x 8.75" (Wilwood) and 12 x 8.5" (Baer). We also have a rotor adapter available with an 8 x 7" (TBM and Wilwood) and 8 x 7.5" (Speedway)

The spindle nut is a "True-Lock" unit, with a threaded thrust washer and billit locking nut. This assembly allows precise load settings with the ability to be locked every 7.5 degrees of rotation of the spindle nut. As compared to every 60 degrees of the common castle nut and cotter pin.

On the back side, the hub is machined with only .001" interference fit for the grease seal. This fit provides a snug but easy press for the grease seal into the hub. A snap ring is then used to secure the grease seal. For bearing service, this allows you to remove the snap ring and push the seal out with the inner bearing. The you can service and re-pack the bearing and re-install the seal.

[andrewb70]

I am digging what you're saying about the bigger bearings. There is a reason that Koenigsegg uses helicopter tail shaft rotor bearings on the front of their cars.

Andrew

[DJW32]

Rob,
Will you be adding down bars to the existing cage/front sub? also, how much does the front sub weigh?

[RobNoLimit]

Rob,
Will you be adding down bars to the existing cage/front sub? also, how much does the front sub weigh?

We will be adding a 3-bolt mounting ringon each front rail top to receive a down tube. We may offer bolt-in down tubes in the future.

I'm going to post up a build series of the sub, them the weights and specs. - some lighter, some heavier.

[RobNoLimit]

Constructing the subframe to achieve all of the goals meant doing things different. Bent and sectioned rails wouldn't fit in, formed rails flex too much, so an integrated set of parts is needed. Four different material thicknesses are used in the subframe. 3/16" is used for the lower sub-plate, rack mount plate and LCA mounts. 8ga. (.164") is used for the outer rails, main cross ribs, rear inner rails, LCA bracing and UCA mounts. 10ga. (.135") is used on the forward inner rails, rail tops and cross rib bracing. 11ga (.120") is used on the rail bottoms and sub caps and covers.

The set of parts here is for one subframe, and a few parts are not shown. It takes 87 different pieces to build one subframe.

The built table is laid out with locating holes, and using milled spacers the rear rails and sub plate are bolted to the table. The LCA mounts and rack mount plate are set in place on a different fixture. Every piece fits together with locating tabs and sockets. The clearance for each tab/socket is .005". This type of construction helps to keep the assembly accurate.

[RobNoLimit]

The big pieces go on next. The cross ribs which include the upper coil over mounts and the engine mount locators drop into the sub plate with indexed tabs. Then its the outer and inner rail sections. The rails are spaced using blockers, which are tabbed in to the outer and inner rails, and to the cross ribs. The interlocking assembly helps to force the components into the correct alignment. Machined cross spacers help to hold the rail width. All of the internal blockers and spacers will be welded from the inside and stay in the subframe. These parts are essential an reducing subframe flex.
The larger cross tube, the furthest forward, is temporary. It is in place of the sway bar, and is set in place to keep the sway bar mount locations true. Different material will be used here in the final assembly.

[RobNoLimit]

The rail tops including the front sub mount are installed next, and more welding starts. Then the front inner rails, mid mounts, and the bracing for the rear LCA mounts. Welding is kept to specific areas to limit distortion. At this point there are 18 locators holding the subframe in place. - not to mention all of the interlocking parts of the sub itself.

[RobNoLimit]

At this point with some of the welding done we move back to the front side of the sub. A formed brace is added between the front LCA mounts, and then trussed out to the rails. The tubing that was in place to center the Sway bar pivots is removed, and short pieces of DOM are inserted. The tubes will be T.I.G. welded and sanded flush. The secondary front rib is put in next. It may not look like much, but this rib added a ton of rigidity to the sub.

[Kenova]

Will you be offering a "weld it yourself" kit?


Ken

[nicks67camaro]

Wow looks awesome. Hard choices ahead for which aftermarket sub to use.

[RobNoLimit]

Will you be offering a "weld it yourself" kit?

Ha, the table might be more than the crossmember.

Wow looks awesome. Hard choices ahead for which aftermarket sub to use.

Thanks nick

[RobNoLimit]

The UCA mount integrate with the cross ribs and the rail tops. That makes the placement easy. A small notch marks the assembly center line. The interlock with the cross ribs sets the width. Once the UCA mount is in place the ends are gusseted to the rail top. Internal gussets are added to the cross ribs in the motor mount area and to close out the upper shock mount. Then the welding starts.

[RobNoLimit]

Finally, a fixture is used to set the motor mount tubes. From the OE position they are the same elevation, 1" back and 3/4" to the passenger side. The trans mount is also offset to the passenger side. Driveline angle is set at 3 degrees. This mount set will accept LSX, SBC, and BBC. "Stock Position" adapter plates are needed for LSX installations. The trans crossmember and slide plate mounts will adjust enough for TH-350 on the short end to T-56 on the long side. Then the cart is rolled over to a T.I.G. station and the rail blocks, spacers and sway bar mount tubes are welded in place. After it cools off overnight, the sub is pulled from the surface plate and the bottom side of the rails will be capped.

[dhutton]

What accessory drive options is this being designed for? Will it be limited to a few aftermarket versions and exclude any factory versions? Factory LSA might be one to consider since aftermarket versions are limited to Concept1 as far as I know. Factory LS9 is another one for the Stielow wannabe's.... :>)

Don

[RobNoLimit]

I had a chance to take these today, so I thought I would share this with you. This is a 69 Camaro with a stock sub (modified) and the usual aftermarket upgrades. With the current geometry and wheel and tire combo there is appx 3 1/4" of scrub radius. So how does that affect the suspension? Well, take a look. As the wheel turns in or out, the contact patch of the tire is being pushed forward, or pulled back. First, this action is at a different rate than the tire is rolling and forces the tire to 'drag' against the pavement, and makes the contact patch "un-happy" - loss of traction. Second, from the pictures it is easy to see that the wheelbase is changing. The outside tire is moving forward, making the wheelbase longer. On the inside of the car, the wheelbase is getting shorter. This changing of the wheelbase takes mechanical load off of the outside front tire and allows the tire to 'skip' on the pavement. or, "Push".



Looking at these pictures helps to understand why Scrub Radius is so important to a true performance suspension design.

[RobNoLimit]

What accessory drive options is this being designed for? Will it be limited to a few aftermarket versions and exclude any factory versions? Factory LSA might be one to consider since aftermarket versions are limited to Concept1 as far as I know. Factory LS9 is another one for the Stielow wannabe's.... :>)

Don

Don, i'm working on a complete list (or as complete as I can make it) of compatable drives. We did get most of the OE assemblies to fit.

[lxss350]

What steering rack are you using with this subframe?