How to fix a nose dive while braking.

[DemonNeno]

although i understand the theory behind the biasing unit out back, i never liked it. I'm going to run a proportioning valve for the rears and try running slightly larger brakes out back. I'm non-abs'd and feel plugs wouldn't help me much. As you brake, this plunger reduces fluid and encourages more weight momentum. Sure, it helps you not spin out in certain situations, but a vehicle that brakes flatter will sustain more control anyways.

This isn't to say that weight shift will go away, that's certainly not the case. Helping control that weight shift a bit more wouldn't hurt though. Then again, we're talkin SHOs here!

 

[1993MTXSHO]

sou you're saying get the bias plugs? I do have the 11/6" kit already.

 

[LeddZepp8687]

IDK I had shitloads of nose dive under hard braking for a while. Turns out the biasing valve was F'ed up so I replaced it with a later model unit off of an 02 taurus and its solid now.

Or just get bias plugs and keep it flat.

 

[NJSHO]

Is there any documentation anywhere on putting a gen 3 subframe into a gen 1/2?

 

[SHO92]

Re-welding some mounting points is required to get the Gen 3 frame into the V6 cars. It's not just a bolt in affair.

 

[1993MTXSHO]

is there anyway to check to see if the rear valve is working?

 

[Shoaz]

Re-welding some mounting points is required to get the Gen 3 frame into the V6 cars. It's not just a bolt in affair.

You also need the aluminum knuckles from a GenIII.

Not every attempt at this conversion has been successful, btw.

 

[DeaconBlue]

SHOAZ is right - just don't ask me how I know that the Gen III aluminum knuckle will not work well with the Gen I/II front suspension. You can NOT mix and match these pieces/parts. You need to do the full conversion; SF, Knuckle/hub, steering rack, LCA, ball joints, outer tie rod ends.

I have the complete Gen III SF, ZF rack and brand new Gen III aluminum knuckles/hubs ready to be installed in my '95 very soon. KirkD dropped off the modified SF over the weekend. Been waiting to do this now for two years.

Not sure about the total weight difference is for all the components – I will need to weight the two loaded SF to know the differences for sure. I do know that the Gen III aluminum knuckles/hubs weigh in at 13.7 lbs, while the ’94-95 iron knuckles without ball joints weigh in at 14.9 lbs and with the ball joints weigh in at 15.5 lbs – so the difference there may not as great as some think.

As far as front brake dive is concerned, there is not much you can do with the Gen I/II strut rod design other than going with a stiffer front spring and struts with a firmer compression valving and rear struts with firmer rebound valving. Not sure if additional positive front caster will help or not. The Gen III true LCA design’s geometry does offer much improved anti dive characteristics (as well as other benefits) compared to the Gen I/II strut rod design. There were further slight improvements made on the so-called ’01-04 Gen IV Taurus, although I am not exactly sure what Ford revised in the design to improve the anti dive characteristics. But the changes were made so as to work better with the now standard 215/60-16 tires and the softer 100 in/lbs front springs that were used to both improve handling and the ride quality at the same time.

Personally, I would NOT drive on the street with the plugs installed unless the ABS setup was functioning properly - so I would not recommend that modification on the '89 SHO.

As always YMMV

 

[K-Dawg]

Where did you get the new Gen III knuckles?

 

[DeaconBlue]

A couple years ago someone was dumping them on eBay for a ridiculously low price.

Like I said, I have been planning this modification for quit some time now

 

[JEM]

Couple comments:

It should be possible to bolt the ZF rack up to a Gen 1/Gen 2 subframe and suspension, at least in trial-fitting off the car it fits fine. You cannot mix and match Gen 1/Gen 2 subframe and Gen 3 suspension.

Based on some testing done by someone who knows what he's doing the vehicle-speed pulse-count output from the Gen 3 ABS box that feeds the SARC box for steering-effort control pulses at the same rate as the Gen 1/Gen 2 VSS. The SARC box generates maximum steering assist up to about 30-32mph and then backs it out; by 38mph you're running minimum assist.

Junkyard tip - the offset-tab Bosch-injector type connector used on the Servotronic PWM solenoid on the rack is identical to that on a lot of Mazda fuel injectors...

As far as I'm concerned the Gen 1 non-VAPS rack, at least, is a defective design; almost every one I've driven (and every one I've owned including the black '91 owned from new) has a big loose spot on center. IMO it pretty much ruins the driving experience (he says, fifteen years later) and if it weren't for the prospect of the Gen 3 rack I'd get rid of the car.

I hope to have my Gen 3 subframe in the car in a month or so, and I do plan to make the Servotronic work. Once you've been driving around in any of the Euro or even occasional Detroit hardware with Servotronic, you get awfully used to it.

The Gen 3 subframe bolts right up to the Gen 1/Gen 2 mount bushing locations, but the engine mount locations are (mostly) different and it takes some fab work to build a depression into the LH subframe rail to clear the MTX-IV. There's some dispute in that world as to what's the right Gen 3 subframe to start with and how to do the engine mounts, so I won't comment on my choice and what I've done to it until it's in the car and working.

 

[thecrew2999]

hmm someone made mention of the sturt rod design not helping for the nose dive, now is it because the rod bends at all?

possibly the bushings give some? and would stiffer bushings help this ? not to mention the ingalls adjustable strut rods?

 

[SHO Dude]

Couple comments:

It should be possible to bolt the ZF rack up to a Gen 1/Gen 2 subframe and suspension, at least in trial-fitting off the car it fits fine. You cannot mix and match Gen 1/Gen 2 subframe and Gen 3 suspension.

Based on some testing done by someone who knows what he's doing the vehicle-speed pulse-count output from the Gen 3 ABS box that feeds the SARC box for steering-effort control pulses at the same rate as the Gen 1/Gen 2 VSS. The SARC box generates maximum steering assist up to about 30-32mph and then backs it out; by 38mph you're running minimum assist.

The difference is the ratios. The early model SHO ('89-'92) non-Vaps has a 14.1:1 ratio. The later VAPS racks are 15:1 (SHO or base Taurus). Then the late model ('96-'99) SHO ZF racks are 16:1.

Personally, I don't mind the higher steering effort at low speeds. It gives a more consistent and more accurate steering feel at speeds and when turning.

As far as I'm concerned the Gen 1 non-VAPS rack, at least, is a defective design; almost every one I've driven (and every one I've owned including the black '91 owned from new) has a big loose spot on center. IMO it pretty much ruins the driving experience (he says, fifteen years later) and if it weren't for the prospect of the Gen 3 rack I'd get rid of the car.

I disagree. I believe that the high rate rack and consistent boost pressure is much better for a performance street car or a race car. If you've felt that looseness on center, it's most likely the lower steering shaft or where the lower steering shaft connects to the top of the pinion shaft. But then again, I've only seen a few of these cars.

I hope to have my Gen 3 subframe in the car in a month or so, and I do plan to make the Servotronic work. Once you've been driving around in any of the Euro or even occasional Detroit hardware with Servotronic, you get awfully used to it.

The biggest difference is that the Gen II VAPS system uses a stepper motor to control the bypass orifice. As the speed increases the orifice is opened boost is reduced in 4 steps. After about 45mph, it drops to minimum boost. All in the name of steering feel. In the ZF Gen III rack, it's a variable force solenoid and regulates boost in a linear fashion, not stepped.

The stepper motor stays where it is until commanded to change. So if you unplug the controller while the car is stopped, you'll get max boost all the time. If you roll the tires past 50mph and then unplug the controller, you'll get minimum boost (don't do this while driving).

 

[JEM]

If you've felt that looseness on center, it's most likely the lower steering shaft or where the lower steering shaft connects to the top of the pinion shaft. But then again, I've only seen a few of these cars.

That's a different looseness and I've been through that, in fact back when my black '91 was still under warranty the first servicing dealer couldn't/wouldn't fix the problem even though I told them what it was - "that's normal play".

Went through three dealerships with that car and not one of them had a service department that could find their corporate ass with both hands and a flashlight. Fifteen years later and my wife still wouldn't tolerate buying a new Ford (even if there were anything worth buying) because of the incompetent service we got with that car.

 

[JEM]

hmm someone made mention of the sturt rod design not helping for the nose dive, now is it because the rod bends at all?

possibly the bushings give some? and would stiffer bushings help this ? not to mention the ingalls adjustable strut rods?

No, none of those things have anything to do with dive. The rods don't bend, the bushings flex some but that's a good thing up to a point.

Broadly speaking anti-dive geometry is defined by the height of the front control arm pivot above the ground (which in the Gen 1/Gen 2 is the strut-rod front bushings) vs the height of the control arm rear pivot above the ground. Lower the front pivot or raise the rear and you get more anti-dive. Downside is you also lose some ride compliance. Tall front-drive cars without much weight in the back like the SHO are a tough case. I'm not convinced the car has a real dive problem; what it does have is a whole lot of back-end lift and resulting forward weight transfer.

The best case would probably be to move more weight to the trunk and figure out a way to make the rear brakes do just a little more of the work.

Dare I admit that the biggest thing I'm hoping to get out of the Gen 3 subframe (aside from the ZF rack) is better ride quality? I figure the one-piece control arms and German bushings are going to provide better bump-thump absorption without funny toe changes, and I'll be getting rid of the solid SFBs at the same time.

 

[DeaconBlue]

The best case would probably be to move more weight to the trunk and figure out a way to make the rear brakes do just a little more of the work.[/QUOTE]

Moving the battery to the trunk, using rear struts with increased rebound control, installing the "brake plugs" and/or if you have large enough front brakes - the use of the 11.6" rear setup are basically the only option we have here. That combined with firmer front springs and more compression control in the front struts will also help. But please remember that all of this will make for a much firmer ride - which isn't always good on the street.

Dare I admit that the biggest thing I'm hoping to get out of the Gen 3 subframe (aside from the ZF rack) is better ride quality? I figure the one-piece control arms and German bushings are going to provide better bump-thump absorption without funny toe changes, and I'll be getting rid of the solid SFBs at the same time.[/QUOTE]

Using the Gen III rear SFB in all four locations vs. solid SFB will help with ride comfort as well. They are directional and offer much better control vs. any Gen I/II units. Again solid SFB are not always the best for use on the street.

 

[93rev2sev]

Answer to thread title:

Powerslide.

 

[JEM]

Moving the battery to the trunk, using rear struts with increased rebound control, installing the "brake plugs" and/or if you have large enough front brakes - the use of the 11.6" rear setup are basically the only option we have here. That combined with firmer front springs and more compression control in the front struts will also help. But please remember that all of this will make for a much firmer ride - which isn't always good on the street.

I don't see any reason (aside from owner sloth, which I fall prey to myself at times) for any SHO that's not a bone-stock preservation candidate to have the battery under the hood. The weight's in the worst possible place, the location makes maintenance harder and results in shorter battery life from engine heat.

I've been quite happy thus far with the Tokicos in the white car. I never liked the Konis, no matter how adjusted, and years later I now find the Tokicos do pretty much everything IMO a strut should do on a SHO. The front Konis were always too stiff in jounce, but too soft in rebound even adjusted full-stiff, and they were not a happy combination with the Eibachs. Maybe front Tokicos because the Konis suck, but rear Konis to get the rebound-adjustability for track use...

The problem with the plugs is that without the metering valve the SHO has far too much rear brake. This is, I'm sure, to some extent dependent on which front brakes you're running, but with my old 12.5in Baers and 38mm PBR calipers plugs mean lots of rear lockup. ABS is no substitute for a properly balanced brake system. Way-back-when I tried plumbing the rear brakes on the black car into a pair of Wilwood proportioning valves and bypassing the metering valve, even at full-restriction (57%?) the car could lock the rear wheels before the fronts were doing much.

Changing the hydraulic ratio might help - the Cobra rear calipers have a much smaller piston (the calipers are smaller overall) and might help, I'd just like to be able to run the things without the extra weight of the bigger-diameter rotor since even a stock 10in rotor is more than enough.

Using the Gen III rear SFB in all four locations vs. solid SFB will help with ride comfort as well. They are directional and offer much better control vs. any Gen I/II units. Again solid SFB are not always the best for use on the street.

What I find interesting is that the '98 Sable from which my subframe came had four-stud front mounts like the early Taurus in the front holes and what you call the gen 3 bushings in back. I have to conclude that there's some reason Ford did that - either compliance or steering behavior. I was planning to run a pair of my fifteen-year-old-never-used blue police mounts in the front holes and the gen 3 mounts in back once the thing goes into the car.

 

[DeaconBlue]

I was only able to get the brake bias stiffed back toward the front, after going with the 11.6" rear setup and plugs, when I upgraded to the larger C5/C6 PBR front calipers and the much larger D731 pads. Those calipers have twin 40mm pistons, like the '99-04 Cobra calipers did vs. the twin 38mm pistons in the earlier Cobra calipers. I can’t remember the piston or pad size comparing of the ’90-92 to the ’93 and later calipers.

I have run the Gen II blue police front bushings with the Gen III rears for the past couple of years. Most likely the main reason why Ford didn't upgrade the front bushings design to a directional type with the hard nylon/Derlin inserts in the Gen III cars was due to the cost. Plus the movement and level arm length with the front SFBs vs. the rear didn't dictate that the upgrade was “absolutely necessary”. They may have gotten 70-80% of the improvements desired with only upgrade the rears and that was ½ the cost of upgrading all four.