4WS Preludes and Racing (Handling, Performance)

3352 Views 30 Replies 11 Participants Last post by U.K VTEC, Mar 24, 2001

marcucci

Discussion Starter · Mar 22, 2001

Howdy...

I dug through the archives and didn't turn up anything; I'm curious as to what any racers (autocross, ITx, track, etc.) think of the 4WS Preludes. Specifically any of you 4th or UK 5th gen'ers with the electronic system.

I would assume that tight, low speed tracks would lend themselves to the 4WS system, but I'm particularly interested in high-speed performance. I've heard that the 4WS system was developed with the intention of aiding parking and maneuvering in crowded Japanese and UK urban areas and I've heard VERY little on high-speed handling (other than 300ZTT HICAS-owners disabling theirs).

Anyone? Opinions?

Thanks,

Todd Marcucci - '99 Base

1 - 20 of 31 Posts

thewedge3

· #2 · Mar 22, 2001

Good question.

I recall a Motor Trend test of a 4WS and all the editors with track experience prefered the 4WS to all the other FWD cars in the group. The U.S. cars came with Bridgestone S0-1 tires and they got .89g on the pad, which was the best of ALL the cars.

G

· #3 · Mar 22, 2001

How much weight do you add with the 4WS system?

I think one of the main problems with the Nissan HICAS system on the 300Z's was it's reliability, but I am not 100% sure.

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Billy
North Texas Prelude Owners Group
www.ntpog.org

How long will my registration last this time?????

marcucci

Discussion Starter · #4 · Mar 22, 2001

Unfortunately figuring out the weight would require weighing the parts, the trim levels of 4WS and non 4WS models varied a lot, as well as engines (at least in the US). My guess would be in the <100 lbs range as the only "new" items would be the rear rack, cabling, and computer. The rear tie rods are already there, subframe members, etc.

I'd suspect it to be about what the difference in the base and SH 5gen models are, maybe even less.

I've yet to hear of any 4WS failures, electronic or mechanical. On paper it looks like a great system...

G

· #5 · Mar 22, 2001

I know you wanted to do this a while back. Thinking about doing it again? It would make a killer project. Let me know, I am willing to help as much as I can (sorry, can't help monetarily

), especially since my project is stalled right now.

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Billy
North Texas Prelude Owners Group
www.ntpog.org

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marcucci

Discussion Starter · #6 · Mar 22, 2001

No, just making conversation : ) Seriously, it's *always* been in the back of my mind, but I've yet to find any real "pro's" to it from a track racing standpoint. See how many replies I've gotten? It seems no one with the 4WS actually races.

I haven't driven the 4th gen, but I drove the 3rd and I think the 4WS was a great addition to it in tight corners at low speeds. I unfortunately didn't have the opportunity to toss it around very much or very hard.

If anyone's interested, I can share my research into a 5th gen 4WS conversion- <$2k for used parts from the 4th gen, and the systems are identical as far as I can tell.

G

· #7 · Mar 22, 2001

Yeah, but I think you should do it. $2k isn't that bad. Especially since you can get the parts from the UK, that has to be easier than getting them from Japan. What about buying a service manual from the UK? That way, you can see all of the stuff on the 4WS system for the 5Gen.

Besides, that would be a seriously unique 5Gen.

I am good when it comes to spending other peoples' money!

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Billy
North Texas Prelude Owners Group
www.ntpog.org

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marcucci

Discussion Starter · #8 · Mar 22, 2001

You should actually read my posts : ) The parts can all be had in the US from the 4th gen lude, the system will swap over. If they made any changes they should be transparent to the 5th gen.

Check the thread on the Chilton's manual, looks like the Helm's isn't readily available over in the UK.

G

· #9 · Mar 22, 2001

How can you know with 100% certainty that the parts are the same without direct comparison?

One would say that the oil pumps on the 5Gen Preludes would be the same, but the 97 and 98 Preludes have different part numbers for the oil pumps.

Also, Honda has to have some sort of "factory" manual over there. If not, what do the Honda techs use?

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Billy
North Texas Prelude Owners Group
www.ntpog.org

gLudeous

· #10 · Mar 22, 2001

Do you suppose if you put the 4WS on an SH it would become as uncontrollable as a Corvette with Chevette wheels?

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marcucci

Discussion Starter · #11 · Mar 22, 2001

Interesting question, it's actually not possible. At least, the SH and the 4WS share a few sensors and would almost have to be mutually exclusive.

But no, I don't think so- I'm sure you can get a 4WS in Japan with LSD. Or used to, I notice the Prelude has been dropped from all but the US web site...

G

· #12 · Mar 22, 2001

I suppose if the parts are "close enough." That would work too. Another point is that the 4Gen swap would probably be the best way to do it.

Just do it, and let's figure it out!

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Billy
North Texas Prelude Owners Group
www.ntpog.org

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gLudeous

· #13 · Mar 22, 2001

If you were worried about high speed stability, I thought at highway speeds and up the rear wheels turned in the same direction as the fronts, giving the car a sort of "sliding" motion rather than a rotating motion like when the rear wheels turn opposite direction at low speeds. That's how it works, isn't it?

93si4ws

· #14 · Mar 22, 2001

i have the g4 4ws trim. its very hard to lose the rear on tight corners even at moderate speeds. i try to do it almost every day on my way home, even when its wet. and thats with bald tires on the rear. on those turning overpasses i can take them [dry] at 70, i could probably go faster but i wont try until i get my new rear rubbers.

i'm setting up for autox at camden. im told i'll be in street modified due to my motor, etc. im also told the g4 prelude vtecs are highly competetive in solo events, and im very interested to see how my 4ws affects the handling.

as far as 1/4 i haven't run with the new motor as im not entirely done hooking up the vtec. with the old motor i wasn't able to better my 15.4 before i snapped my crank in half. im VERY anxious to get her finished and see what she does.

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don't touch me . . .
aim:jR93si4ws

93vtec4ws

marcucci

Discussion Starter · #15 · Mar 22, 2001

I can say it because I am the man. I guess you don't remember, I spent QUITE a bit of time on this- I'll email you my spreadsheet on the conversion.

Looking at the 4th gen manual and all the 4WS hardware, controls, and diagrams, the only "difficult" part would be the steering angle sensor in the rack. I still need to tear apart a 5th gen rack, but I believe this sensor will swap into the 5th gen rack w/o a problem.

Other than that, the steering input sensor on the SH has the same electrical output as the 4WS unit. The rear subframe from the 4th gen 4WS (needed to mount the rack) has the same bolt pattern (mounting) as the 5th gen subframe. The stationary "tie" rods in back are replaced with the 4th gen 4WS tie rods. The rack bolts up. All wiring to the controller is independent of the ECU other than the fail line (the ECU and controller signal failures to each other). The system is actually very simple in terms of hardware.

I've got prices and details on the spreadsheet. I'll email it to you when I get home.

Keep in mind many p/n's change due to supplier issues and improvements. I'm running a '98 MAP on my '99 which happens to be a different p/n - no problem yet.

<font face="Verdana, Arial" size="2">Originally posted by 71dsp:
How can you know with 100% certainty that the parts are the same without direct comparison?

One would say that the oil pumps on the 5Gen Preludes would be the same, but the 97 and 98 Preludes have different part numbers for the oil pumps.

Also, Honda has to have some sort of "factory" manual over there. If not, what do the Honda techs use?

</font>

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marcucci

Discussion Starter · #16 · Mar 22, 2001

You are correct. I'm curious, though, how that "feels." I haven't felt that yet on the road. I'm sure you'd get used to it, but I'd like to know if it would ultimately be an improvement or not.

<font face="Verdana, Arial" size="2">Originally posted by gLudeous:
If you were worried about high speed stability, I thought at highway speeds and up the rear wheels turned in the same direction as the fronts, giving the car a sort of "sliding" motion rather than a rotating motion like when the rear wheels turn opposite direction at low speeds. That's how it works, isn't it?</font>

Pork Chop

· #17 · Mar 23, 2001

It sounds interesting, but I wonder how the 4WS is set up. I know that the rears turn in the opposite direction as the fronts at low speeds, but at higher speeds, they turn in the same direction. What is the crossover speed at which this occurs? Maybe it's speed dependent (at really high speeds, maybe it turns minimally).

Another thing you'll need to consider is the fact that the 5th Gens are stiff enough that they pick up the inside rear wheel on hard cornering. What effect will this have on the 4WS? If there's a wheel-speed sensor on that rear wheel, what will happen if that particular wheel slows down? Will the system turn the wheels in the opposite direction? You've already got a wheel in the air and traction at the rear is entirely loaded on the outside rear. A drastic steering correction by the 4WS would be the last thing I'd want in this situation.

gLudeous

· #18 · Mar 23, 2001

I would bet the transaxle speed sensor for the speedo would serve to tell the 4WS which way to turn, so rear wheel pick-up wouldn't affect it, wheelspin on the other hand, but if there is enough wheelspin to really alter the rear's steering angle, I'd imagine you'd be having more problems than just wrong steering angle. I can undertand how if you transitioned from one side of the crossover speed to another while in a corner, it might be abit surprising, I suppose it's done gradually over 10 mph or so.

DirtyLude

· #19 · Mar 23, 2001

Everything I've seen, heard, and felt says it's not very good for road courses. 93si4ws, I don't know what your suspension setup is, but on H23_4ws' (should post on here sometime) car, we can easily jerk the back end out just by letting off the throttle too much in a high speed turn. It's twitchy and difficult to control in highspeed corners.

This was a topic along time ago and it was pretty much a consenses that it did not help out.

Doesn't the SH have a steering angle sensor, as well? You should be able to use that if you're converting.

------------------
DirtyLude
My Car
Toronto Prelude Club
www.hondaprelude.to

marcucci

Discussion Starter · #20 · Mar 23, 2001

First, the 3rd and 4th gen systems are completely different. The 3rd gen uses a speed sensor to determine the crossover point. The 4th/5th gen system uses the steering input sensor (same as is on the SH), measuring the steering rate, to determine the crossover point. If you juke it hard (and not very far), they turn together. The slower and further you turn the wheel, they start turning with each other.

Second, I'd like to see what suspension setup people have (with 4WS) that their rear end stepped out. On mine I've dialed in toe out in the back, have a 450/380 spring "split" and keep my Konis dialed in full stiff in back. If I load up the rear outside tire in a corner I get good oversteer, but not much "lift throttle" oversteer at all.

I'd suspect with 4WS you'd need to make the car as neutral as you could- maybe even toe in the back a little, or soften it- to allow the 4WS to "do the work for you."

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