quicker steering ratio??

[DutchBlackNsx]

Just a quick thought,

Since the tractioncontrol has feedback from steering angle, i wonder what the the tractiocontrol will do. Might be a non issue.
FYI, the angle is measured direct from the steeringwheel, and not from the wheels.

 

[710]

Just a quick thought,

Since the tractioncontrol has feedback from steering angle, i wonder what the the tractiocontrol will do. Might be a non issue.
FYI, the angle is measured direct from the steeringwheel, and not from the wheels.

Good point.
When I started this, I checked and there are companies that make other angle sensors because I thought we may need a different one. And I was told that the stock unit could be modified. But it turns out we won’t need to.

On my car, when I tested the test rack (about 2.8 turns lock to lock instead of the 3.6 stock), the traction control reacted the same as with a normal steering rack.

The idea is this:
The TC senses that the inside road wheel is going slower that the outside wheel so you must be sideways heading for a crash so it activates the brakes to try to save you.

But this very same condition also occurs when you are turning sharply around a corner, say in an intersection. But in that case the TC should stay quiet and not activate the brakes because you are just turning, not crashing.

How does the computer know if you are sliding and crashing or just turning sharply?
The steering column angle sensor tells the computer the angle of the steering wheel.
If it says the steering wheel is straight ahead but at the same time the computer gets the message that the outside wheels are rotating faster than the inside wheels, then something is very wrong and you are heading for a crash. So it activates the TC, namely the brakes and possibly the throttle (timing?) and tries to save you by applying the brakes on one side.

So, say you have a quick rack installed. You turn sharply round a corner, say in an intersection. The wheels go very different speeds and the computer thinks you are sliding and crashing. The steering column angle sensor says you are NOT going around a sharp corner (because you didn’t turn the steering wheel so much), so the computer knows for sure you are crashing and that it must apply the brakes.
But you are only going around an intersection, not crashing, so you don’t need to be saved.

But this did not happen on my tests, the TC lamp on my dash did not flicker. The car did not react differently. The brakes were not applied. The throttle timing was not altered.

So I suppose the difference in the speed of the inside and outside wheels is not enough when compared to the angle given by the steering angle sensor to activate the TC. That, coupled by the tolerance of the steering angle sensor must cause the computer to suppose it is still within tolerance of normal driving.

Probably the TC is made to activate when you really extremely bollucks it up and it is not really that sensitive.

Anybody have any other theories or other numbers or measurements or opinions on this? I would appreciate more knowledge about Traction Control with regard to the steering angle. Before I blow thousands in money on this project.
Thanks,
Peter

 

[j14nsx]

I don't think the TC works in the way you describe.

It works out from the steering wheel angle how far you have turned and therefore what to expect the wheel speeds to be. If it finds from the wheel speeds that you are not cornering as expected it reduces power to the engine.

As you have a quicker rack, maybe it will think you are turning more, for a given input from the wheel. Great, no problem, you are cornering no need to cut power.

I'll PM you about a rack rebushing, it could be where the noise in may car is coming from. You can measure my rack up then for a RHD.

 

[L8apex32]

I have just a couple of thoughts on this.

The $1900 doesn't sound right for a steering rack. Especially when the Toyota one is $300. If we can't put a low-tech steering rack together for, say, double the cost of one for a Toyota, then maybe this isn't the right way to go about this.

I mean, if a brand new rack at full retail price is $700 to $1000, how does a rebuilt one get up to $1900? It seems that starting with brand new you could beat the $1900 price.

I think an ideal price range would be to match the new OEM price with the upgraded rebuilt price (after core charge). Then you are head to head as far as sales opportunities for everyone who ever needs to put a steering rack on an NSX. Plus, those of us who are considering upgrading can feel good that our upgrade is "rebuilt" to high levels (gets us a refresh) plus the quicker ratio, versus buying an OEM part.

No, I'm not in the auto-business and I don't own any businesses anyway. Just hoping for the best, I guess.

Also, I'm the guy who says that headers, no matter what they are made of, aren't worth the two to three-thousand dollars some charge. Not all NSX owners feel this way.

 

[Scin]

I am highly interested in this, please keep us updated.

The NSX steering is way too slow. When I first started tracking my car my instructors used to get mad at me for changing my hand positions for tight corners; until they realized how slow the NSX steering was and that it was required (when they didn't have to do this in their own cars).

It is especially frustrating when you need to counter steer and you end up having to hand over hand very quickly.

 

[stuntman]

I am highly interested in this, please keep us updated.

The NSX steering is way too slow. When I first started tracking my car my instructors used to get mad at me for changing my hand positions for tight corners; until they realized how slow the NSX steering was and that it was required (when they didn't have to do this in their own cars).

It is especially frustrating when you need to counter steer and you end up having to hand over hand very quickly.

I recommend all my students to change their hand positions for most corners (Shuffle-steering)...

You dont want to do hand-over-hand countersteering, you want to again...shuffle-steer and never let one hand cross the other.

$0.02

 

[NSXFRIEND]

After driving lambos ferraris and nsx's I can assure you most Mid-engine cars have similar steering respone, MR2 & 911(rear) being the exception because its short in length.

 

[latzke]

And then we come to the US dollar. It has gone through the floor and what seems to be reasonable price for the rest of us, turns out to be really high for you in the US. I mean €100 for us used to be about US$100. But now €100 is $150.

A few of us have noticed.
http://www.ronpaul2008.com/press-releases/71/ron-paul-comments-on-interest-rate-cut
http://www.ronpaul2008.com/articles/226/inflation-alive-and-well/
http://www.shadowstats.com/cgi-bin/sgs/article/id=343

 

[damen]

Just to add general knowledge to the pot, I will say that previous racing experiences and research on this exact topic (albeit not with an NSX) have led me to a steering quickener solution:

http://www.howeracing.com/Steering/Index-Quickener-Stealth.htm

The idea is to splice this into the steering column somewhere before the rack to realize a 2:1 ratio quickening. While I realize that this takes considerable butchering of the steering column ( plus some custom spline matching using

http://www.howeracing.com/Steering/Index-Quickener-Couplers.htm

and some non-trivial fabrication work) and would linearly increase steering effort to twice that of the original, I thought I might just mention it for those to evaluate themselves.

damen

 

[710]

Just to add general knowledge to the pot, I will say that previous racing experiences and research on this exact topic (albeit not with an NSX) have led me to a steering quickener solution:

http://www.howeracing.com/Steering/Index-Quickener-Stealth.htm

The idea is to splice this into the steering column somewhere before the rack to realize a 2:1 ratio quickening. While I realize that this takes considerable butchering of the steering column ( plus some custom spline matching using

http://www.howeracing.com/Steering/Index-Quickener-Couplers.htm

and some non-trivial fabrication work) and would linearly increase steering effort to twice that of the original, I thought I might just mention it for those to evaluate themselves.

damen

Yes, while researching this steering thing I looked at those types of things too. Thanks for the links, I had not seen that one.
In fact I would prefer a solution like that too. But unfortunately, I came to the same conclusion as you did concerning the room problems and the modifications needed to the column. It would be easier to make a new rack considering all that.
I even tried to find a rack from another type of car in the junkyards that could fit in the NSX, with some new brackets etc. Almost all cars in the world have a much quicker rate than the NSX, so it should have been easy to find one with similar shape, AND I even looked at new racks with electric power steering, that would be great for me! But I couldn’t find one due to limited time.
If any of you out there find another rack, let me know please.
I recently acquired a Ford Sierra rack (manual), better rate than the NSX rack, and Quaife make a quick rack kit for it too. One of their cheapest due the huge quantities or that car here.
But anyway the stock rate is already much better then the NSX rate so a stock unit out of a junkyard would be ok. It’s real cheap too, there are thousands here in Europe. So I will see if I can make that fit before investing more into an NSX quick rack.

How many of you would buy a Ford rack for your NSX? I’m curious. Maybe it would be sacrilege.

The other best “other” idea I had was to effectively shorten the steering arm length on the NSX upright. Not actually saw them off, but to attach another piece of metal next to the steering arm. This new piece of metal would have a conic hole the same as the stock NSX one.
It would be slightly closer to the king pin centre line thus giving quicker steering.
It would nest along side the original arm.
It would attach using the original conic hole, with a special bolt, and to one or two of the existing bolts on the upright nearer the hub.

But I did the calculations on bump steer and it would significantly change the bump steer because the tie rod would have to be way shorter.

The NSX handles so nice now the way it is, I would not want to change the bump steer, especially introducing more bump steer (which the NSX has very little of, effectively, and that is very very good thing).

Also, such a device would have to be mounted slightly higher or lower than the original tie rod end mounting point. Thus changing the bump steer again, and slightly changing the Ackermann characteristics.
Also it would hit other things slightly during full lock or bump.

And I don’t see many of you out there buying such a modification…there would be too much fear that it would break the steering arm or something.

Do any of you have any other thoughts about such a thing?

I am currently looking from outside the box and so:
What about someone casting (or otherwise fabricating) a new upright with a removable steering arm? Many other cars have removable steering arms. Them a slightly shorter arm could be used achieving quicker steering.

And fabrication could be done with laser cutting steel (or alu) plate and welding together. An original NSX bearing or more standard bearing could be used, to reduce the price of replacing that ridiculously expensive Honda hub.
This would also be good for RHD and LHD cars, same hub. And it could be the same hub for left and right side, just different mounting points.
Steel or alu? Suggestions?

If anyone has a front NSX hub, please send it to me and I will digitise and measure it up, put it in 3D, do FEA on it and then get the parts cut.
I don’t know where I would get one cast, so welding fabrication (like on race cars) would be the way I would do it.
I could easily build a jig for an upright.

Then different length steering arms could be easily and cheaply made, lots of different lengths from easy parking slow steering “Pussy long” (Type P) to quick steering “Real big balls short" (Type R of course) and everything in Between (Type B).
Even steering arms that give better wheel Clearance (Type C), by sloping them inward slightly. Although this would alter the bump steer, but some people with really wide tyres don’t care about handling, it’s the looks that they are after, so altered bump steer wouldn’t matter to them. IMO most NSXes with wider wheels have already seriously compromised the handling, even really messed it up in some cases. No problem, each to his own...handling is not important to some. New hubs with removable steering arms would help those owners too.

This idea could be cheaper, look cool like on a racing car, and cheaper considering the RHD and LHD investments.
They would fit power steering and manual cars too, every model NSX.
I could even have 2 attachment points for camber. Lowered cars use one setting, stock cars use the other. That alone might be a reason a buy the hubs.

So a survey:
How many of you would buy these uprights if I had them for sale right now? Price? $800 per upright? That’s only €550, peanuts.
I’m only guessing the price at this point, might be cheaper (yeah right).
Would it be possible to produce a hub for a few hundred dollars? Anyone?

Peter

 

[710]

Or, easier yet, does anyone care to machine the stock steering arm off the stock upright, leave a nice flat area, machine 2 holes in, and make a slightly shorter steering arm?
This will achieve quicker steering.

 

[710]

there it is



should be possible to change the steering arm
or make a new upright...

anyone have any photos of the steering arm area?

 

[robfenn]

Hi Peter,

We've spoken on the UK form a while ago.

I am still interested in getting a shorter rack myself, but unfortunately it's low down the priority list ATM... With our car being RHD is a problem for you guys, but hopefully it will save time if you don't sort a short rack before i do! I guess the advantage is i live half a mile from Quaife and will be able to monitor the project regularly.

Keep us updated.

Cheers,

Rob

 

[nimdivino]

Hello Peter,
Just want to say a few things regarding your previous statement in the last page. I really want a quick steer kit but I don't think I can justify to pay more than $500 for a rack and pinion piece. In all honesty, $500 is very steep, but hey we got an exotic car right, so I would understand the mark-up given by Quaife. With that being said, please don't take this as an attack, its just my opinion and sort of trying to help to lower the cost of this future product.

The reason I thought of you sending your rack unit to me to rebuild was because I didn’t think many people could rebuild the rack.

---I think this is a good idea, there are some people out there who would rather have the vendor install their parts for them. But you should sell the rack and pinion alone because any mechanic can work on it. This will be a less burden for you, less work for you. The manual rack housing on our NSX is old technology, it doesn't need a special mechanic to work-on it. Take a look at this picture, its an exploded view of the NSX manual rack from the service manual. There's nothing special about this.

The bushing needs to be replaced too, the stock bushing in the NSX is very weak, it wears out very quickly and all the NSX racks I have looked at (in running cars too) need a new bush. Then a replacement bush has to be found, can’t buy one from Honda.

----What bushing are you talking about? Is this the bushing (highlighted in yellow).

If this is not the bushing, please tell me what bushing it is. If that is the bushing, I find it very hard to believe that Honda wouldn't be producing this part. The fact that there's a section on how to overhaul a manual rack in the service manual (page 17-22) tells me that every single part in that exploded view image above is available in the Acura parts department.

As far as the price being high, it is because of all of the above and I have to order a minimum of 25 racks. That is a very low quantity for Quaife. So the price per rack is very high.
A Corolla or Sierra or Escort rack is a few hundred dollars, maybe not even $300. Because there are thousands made and sold.
Peter

-----Just want to say that when we started the group-buy for the corolla, there was NO quick-steer kit available from quaife. My friend went through the same thing as what we're doing now, and yet we paid just about $280. Well I got it cheaper because my car was kind of the guinea pig. And also, its not like Quaife made 100 units, or 1000 units either. We sticked with 40 orders. In order for Quaife to run a production again they require about 20 people (corolla guys are in the process of having a GB again).

I also want to say that some corolla owners were trying to be picky, they want a customed rack where there's more teeth cut in the rack. The reason behind this is so that they can use this "angle spacer" that will give them massive angle for drifting. Quaife tried to fill that request, I believe Quaife did cut but the sample didn't work with the spacer and so they never produced it.

I really think there's another way to do this, easier and cheaper way. You have your own design and you have done the research already, that's awesome man... Shoot, I haven't even looked under the car yet, so I may be 100% wrong. I'm basing all my knowledge now from the service manual and my experience working with Quaife and working with a manual rack which is VERY similar to the NSX rack. I am not a mechanic so I really don't have much credibility but I have worked on a rack before and I'm telling you, if quaife can make a modified rack and pinion for our cars, that piece will be worth $400 at the most. The rest of the installation is 2-4 hours depending on your mechanic's ingenuity.

I don't want to step-in by creating a new thread or whatever. What I'm going to do is step in the side-lines and continue my research. I'm going to uninstall my manual rack and see what problems I may face, and make a list of what I need to replace. I really hope that you can finish this project because it is a great piece and people will love it. But I also hope that it won't be that expensive as a nice set of headers or something.

Good luck.

niM

 

[710]

Good post niM, thanks. I am going to contact Quaife again and see their current situation about the price / quantity etc. and see about selling only the rack and pinion.

The bushing that wears out is inside the tube at the arrow. It is a sort of nylon bush in a steel holder.
It is difficult to get out.
The Honda dealer here said I needed to order a whole new steering housing but he couldn’t get it anymore so then he said I needed to order the whole steering complete, everything.
Ridiculous just for a €1 bushing.

The bush is pressed into the tubing, it holds the shaft in the place marked with a big red arrowhead in the drawing below.

When it is worn, the shaft rattles around in the bush (which is pretty hard) and that makes a noise in the tubing, a noise that you can hear and feel.
While the steering still feels tight with no play, there is still that annoying “something is loose” feeling in your hands on the steering wheel as you go over rough roads.
If you grab the lump inside the boot and shake it with a lot of force with your hand, you may feel it move inside the bushing.
You don’t need to remove the boot, you can feel the "lump" through the boot. Be careful not to to tear the boot, although it is pretty strong.
But if you remove clip/strap thingy and slide the boot along the tie rod, you can see the “lump” (it is actually the ball joint) in the drawing. Stay clean, don’t get any dirt in there. Your hand will get greasy from the grease inside the boot.
Peter

 

[nimdivino]

Hey Peter,
Thanks for showing me where that bushing is. I now remember that I had to remove a bushing also before, sort of a nylon too. But I know I didn't have to replace it, so maybe that's where the design differs? Darn! Good catch.

As for the tie-rod, for a 17 year old car, that is meant to loose. Most people will have to replace that. I just hope there's an aftermarket somewhere you can buy because I bet tie-rods in the dealership will cost an arm.

Thanks for the new info man. Keep us updated here.

Good luck

niM

Good post niM, thanks. I am going to contact Quaife again and see their current situation about the price / quantity etc. and see about selling only the rack and pinion.

The bushing that wears out is inside the tube at the arrow. It is a sort of nylon bush in a steel holder.
It is difficult to get out.
The Honda dealer here said I needed to order a whole new steering housing but he couldn’t get it anymore so then he said I needed to order the whole steering complete, everything.
Ridiculous just for a €1 bushing.

The bush is pressed into the tubing, it holds the shaft in the place marked with a big red arrowhead in the drawing below.

When it is worn, the shaft rattles around in the bush (which is pretty hard) and that makes a noise in the tubing, a noise that you can hear and feel.
While the steering still feels tight with no play, there is still that annoying “something is loose” feeling in your hands on the steering wheel as you go over rough roads.
If you grab the lump inside the boot and shake it with a lot of force with your hand, you may feel it move inside the bushing.
You don’t need to remove the boot, you can feel the "lump" through the boot. Be careful not to to tear the boot, although it is pretty strong.
But if you remove clip/strap thingy and slide the boot along the tie rod, you can see the “lump” (it is actually the ball joint) in the drawing. Stay clean, don’t get any dirt in there. Your hand will get greasy from the grease inside the boot.
Peter

View attachment 38663

 

[ftuhy]

A few comments on a quicker steering ratio. I also would like a slightly quicker ratio on my '96 NSX. But, you need to think about where you will use the car. I also have a 1984 Z51 Corvette. That has very quick steering. Its a delight when driving on winding back roads. But, if I'm taking a 3 or 4 hour drive on a fairly straight interstate higway, the quick steering ratio is downright tiring. The slightest twitch or the hand on the steering wheeel and the car changes 2 lanes. So, think about the majority of your driving when choosing a steering ratio.

As to changing the length of the steering arms. I had a 1964 Corvette that had two sets of holes on the steering arms (factory standard configuration). The car was delivered with "slow steering", but all it took was a few minutes to pop out the tie rod ends and move them to the other set of holes, check the toe-in alignment setting, and you had quicker steering.

I have a feeling that making new suspension pieces could be more expensive than making a quicker ratio rack and pinion. And I'm not sure which one would be quicker to install. Perhaps someone could come up with an adapter for the present suspension pieces, but it would need to be both low weight and rugged.

In any case, I'll be watching this post for creative solutions.

Frank
'96 NSX-T, red/tan

 

[PaulL]

food for thought ..

The NSX requires 3.1 turns lock to lock, I believe?

I have another car with the same turning radius, yet it requires only 2.5 turns lock to lock to achieve it (almost the same wheelbase), and it feels quite comfortable in different spirited driving situations.

So, a steering increase of 25% would get us in the 2.5 turns area.

... just some ballpark numbers to well on.

 

[710]

Some more numbers:
It’s not just the turns lock-to-lock, it’s also the angle of the road wheel turns for a certain movement of the steering wheel.
You might have noticed the NSX has big turning circle. That means the angle the road wheels turn on full lock is not much.

So for the NSX, 3.25 turns lock-to-lock to turn the wheels “not much” means the NSX has a really slow rack, similar to a Daihatsu Charade…!

For example, here are some of my cars I measured while looking into the rack. The degrees are how far the road wheel turns from straight ahead to full lock.

Daihatsu 16V (yes, embarrassing, I know)
4.1 turns lock to lock
39 degrees one way
18.9:1

Daihatsu GTti (ok, but it goes like hell)
3.5 turns lock to lock
35 degrees one way
18.1

Mondeo station Wagon (is like a boat)
3 turns lock to lock
37 degrees one way
14.6:1

Cosworth Escort (has variable ratio steering)
2.5 turns lock to lock
36 degrees one way
12.5:1

Escort MK2 Rally car (Quaife quick rack)
2.5 turns lock to lock
36 degrees one way
12.5:1

NSX
3.25 turns lock to lock
31 degrees one way
18.6:1

The ratios shown here are known as the overall steering ratio (not the “rack ratio” BTW).

Type NSX steering ratio into Google and you will find many articles. Most comment that the steering ratio is slow.

http://www.digest.net/alfa/archive/v9/msg11237.html is about an Alfa- Ferrari.
(Google search – ferrari steering ratio). With a little searching some more ratios will turn up.

Lotus Elise is 15.8 to 1


The overall steering ratio (12:1, 14:1, etc.) is measurable using turntables under the front wheels. Beginning with the front wheels pointed straight ahead, rotate the steering wheel one turn (360 degrees) one way, and read the turning angle of the front wheels from the turntable scales. You will have to resolve the difference between the right and left due to the Ackerman or steering toe; the usual method is to read the angle of the inside wheel, which is the maximum value. In road racing some prefer to average the two.
As an example, if your reading is 36 degrees, dividing this into 360 gives you a quotient of 10, and thus a 10:1 overall steering ratio

 

[Tytus]

I just bought a 2004 NSX and have the same complaint about the steering as many other's have indicated. I had an MR2 Turbo which I beleive had an even slower stock steering ratio but it felt much better and quicker in a hairpin situation than the NSX. It may be the smaller wheel circumference.

I am very interested in a quiker rack but it must be powered. I have no interest in going to a manual set up. Considering this is the cars' most critical short coming, I would think that lots of owners would do this modification if it were available. Considering there are possibly over 18,000 running NSXs world wide, any fraction of that number is the potential market. I personnaly would be interested in a new set up since my car has only 6,500 miles and am probably in the minority but I would be willing to pay extra to have a new electric rack converted.

The steering is the second pleasure center of the NSX after the excellerator, I'm sure every owner would want the conversion if not immediately then after it has hit the market and everyone raves about it.

PS is a must, except for the track guys, and most owners that don't have PS now but could get it along with a quicker ratio would do it, if it were available.

Put me down for a PS rack, anytime you are ready to put it together.

Tytus

 

[thouchin]

...most owners that don't have PS now but could get it along with a quicker ratio would do it, if it were available.

I disagree, I won't talk for everyone else because I know some people really like the PS, but I would never consider it. It adds wieght and complexity and you get no performance gain in return (unless your running a 24 hour race maybe). For me, there is no down side to a manual rack. I suspect that most of the poeple who would by a quicker ratio rack would also track the car and hopefully would frown at adding this extra weight.

T.J.

 

[710]

Unfortunately Tytus a quicker power steering rack is not going to be made because I don’t have the funds to re-engineer all the motors and sensors and ECU in the PS rack. I would guess nobody will do it.

The manual rack is the one that will be made, if any.

Sorry Tytus. I too would like a power steering quick rack (I'm getting old I guess).

The only way you are going to get a quicker steering rack effect with the NSX power steering is if somebody makes a kit for putting slightly shorter steering arms onto the upright.
This would then make the manual quick rack redundant and a waste of money/time. My investment in a manual quick rack would be wasted.

So I suggest this:
Could somebody machine the steering arm off an upright (leaving a nice big flat surface) and bolt on a slightly shorter arm? The arm would be steel. Two bolts is enough to fix it to the upright, or one bolt and an existing hub bolt.

This would work for power steering and manual steering, RHD and LHD too, as the uprights are the same. This one kit would solve everybody’s problem for all types of NSXes around the world.
Different arms could be economically made for people who wanted 2.5 turns lock to lock, or 2.8 or whatever they wanted.
And an arm could be made the stock length too, for those who wanted a sort of reversibility.

If somebody would send an upright to me, I would do it.
I now sort of prefer this method, unless somebody can tell me why it is not a good idea. The small difference in the length of the arm would not affect suspension geometry. Electrolysis should not be a problem. Others?

Shall I do this?

Please feel free to give me any feedback. How many NSX owners would want to buy this?
Again, it doesn't matter if you have Power Steering, Manual steering, Left Hand Drive or RHD, a circuit racer or a canyon cruiser or if you are a grand dad, any year NSX, it is all the same kit.
Peter

 

[MJK]

Please feel free to give me any feedback. How many NSX owners would want to buy this?

I still want a quicker ratio.
What is the proposed ratio and estimated price?

 

[collegeboy]

Badass. Keep us updated.

 

[powerneedy]

I am still interested any info on a product.