Advice please

[thelimpingwhippet]

Collected my Targa from Scotland a week ago and have now put 500 additional miles on the clock. What an amazing car! However I need some advice. I get an occasional loud rattle/vibration from the middle of the dash, about 4 bps, which stops abruptly when I put on the heated screen control. Sounds like a fan motor rather than a bearing. I am sorry if this is a common problem which has been featured before.
The only other problem is the hesitant turn-in which probably needs the front end stiffening a bit, but this is where the fun starts!
Bob
proud owner of L33 NSX (reg available!)

[AR]

What do you mean by hesitant turn in?

[thelimpingwhippet]

On a neutral throttle, without trail braking the first third turn-in is a bit heavy and rather vague. Second third up to apex requires progressively more steering input. Exit with power on is neutral but tending to understeer. Compared to my 928 the turn-in is a little hesitant and imprecise. Camber adjustment may help but might compromise the normal road manners and straight-line stability. Advice from experts is always very gratefully received.

[Senninha]

Hi and Welcome,

Are there any records in the vehicle history of it having had the factory setting alignment done within the past couple of years? If not, I would start here before you start fidling/changing. Todays road conditions can often mess up the sweet handling of the NSX.

Not sure where you are located. There a few well respected centres around the UK that know what there doing.

As for sharpening it up further then I'm happy to share my thoughts if you've not found them already on how I've tweaked my Targa over the years.

Factory alignment will satisfy most owners unless of course like many of us you simply enjoy personalization :)

regards, Paul

[thelimpingwhippet]

Paul
Thank you for your kind welcome to the NSXCB. I have just found your excellent articles on suspension modifications for the Targa to improve the turn-in. Before embarking on chassis stiffening I really need to check the suspension geometry on my car. Do you have the factory settings for camber, caster, toe-in - I suspect ride height and corner weights are not adjustable with the standard spring dampers? I do have chassis set-up equipment left over from my racing days.

Any ideas about the loud tapping/ rattle from under the dash - could it be a solenoid?
regards Bob

[gumball]

Also check for wear in the steering joints, I've recently changed trackrod ends and inner rack joints, although mine is rather long in the tooth.

[NSXGB]

You can find geometry settings on nsxprime, either in the wiki or the online service manuals which are very handy.

Sounds described can be hard to diagnose but two common faults are the ABS solenoids sticking or the air vent flaps sticking. I think I'd put my money in the ABS solenoids. Lots on here and prime to read up on. :)

Welcome!

[Hagasan]

Hi Bob,

I have a Targa too. There have been a few nae-sayers (is that the spelling) regarding Targa dynamics but I think as a road car the differences are negligible.

I've made quite a few changes recently to my car which I think for fast road driving at least, have resulted in what I feel is a well balanced set-up.

I've replaced all four shocks and springs. Main reason was having not driven the car for a whilethen when I jumped back in it just felt soggy. Being a 96 car with the original shocks I thought they were probably past their best. Car has done ~54K miles.

Looking for something compliant yet sporting I went for the KW Varient 3 NSX specific coilovers. They are adjustable in compression/rebound and obviously ride height.

To give the suspension half a chance of working well on the front I have fitted the NSX-R front and lower chassis bars and a "carbing" strut tower base. In addition I also have the front compliance pivot clamps with will limit bump steer & toe changes under heavy braking.

In the rear I changed out the rear beam bushes and the rear-toe links. The rear beam bushes are stiffer than the factory ones and the toe-links are also solid doing away with the rubber compliance bushing. All this again to limit the rear toe changes. You may have noticed a kind of "float" before the rear end settles into a "set" as you enter corners? These rear end parts do away with this sensation.

One of the problems with lowering the car is that inevitably you end up with more negative camber. My car is not ridiculously low but is lower than standard. This situation can result in the situation where you can't adjust the camber back out to get standardish setttings. This may be fine for the track but it won't help roads tyre longevity. The rear beam bushes I have have an eccentric/non centred hole through them so the camber can be corrected. This is done by rotating the bush ever so slightly "pulling in" the lower arm and allowing camber settings within factory ranges. The rear toe-link stops the dynamic rear toe changes.

As for settings, I have left castor settings as standard. These adjusters seem to seize regularly anyway so if yours are within standard limits just leave them as they are. I'm running a bit less toe-out on the front and also a bit less camber than standard.

One the rear, again camber is a bit less than standard as well as the toe-in being reduced due to the solid rear links.

I have also replaced the front and rear rollbars for stiffer items.

I'm running standard sized wheels & tyres. They're actually 2002+ wheels so these are 17" front and rear. The tyres are quite high performance Yokohama AD08's

I think with the combination of ride height/alignment/damper-spring settings/arb uprating/chassis stiffening and tyres designed for performance I have achieved for me what I believe is a nice handling set-up. It all feels direct, no slop, firm but not jarring. There is no tendency to snap into any oversteer. The tyres are very grippy and even driving briskly I don't expect this is likely happen. I haven't pushed it hard in the wet and wouldn't do so anyway to the point of being silly. Even with slight provocation in the wet the tendency is to slightly understeer first so it's a good warning not to go too crazy.

As for track driving I cannot comment on it's suitablility other than to say that I believe it would be quite a bit better than a stock set-up. Any looseness in a road car set-up is going to be markardly shown up on the track. I know for sure it won't roll or pitch & dive anywhere near the old set-up would have done. I would need to upgrade the brakes though...

As for the tapping noise. The screen is not heated so I'm guessing you mean pressing the demistor button on the heater control? If so then quite possibble you may have a snagging heater motor flap which is being continually driven by the servo motor until you change settings? There is a CCU system self check which may flag up a servo issue? I think if you either search on here(one of Kaz's posts) or on NSX Prime you'll find out how to run it. It's in the work-shop manual if you have access to one. They can be found on line...

Cheers,

Gary

[thelimpingwhippet]

Gary
Thank you, this is fantastic help. I have just gone over my NSX geometry with rather aged gauges. Camber - Front Rt and Lt = 0.1 and 0.2, rear 1.3 and 1.2: caster front Rt and Lt 8.0 and 7.6: toe - front 0.1 toe-in rear 0.2 toe out. Yes, the adjusters have seized! As recommended I have sourced a workshop manual and linked up with NSX prime consequently I have much reading to do tonight - still better than watching the F1 at Silverstone.
I shall now run the auto diagnostics test on the climate control system.
thanks again
cheers Bob

[Nick Graves]

It's an exaggerated characteristic with the -T, but it's still an NSX characteristic, that slow turn-in.

It's partially a corollary of the slow steering, mid-engined layout and the compliance pivots. Mainly the ME thing.

I tend to drive round it by trail-braking slightly into corners, to get a bit more bite to the front end. I have to remember NOT to trail-brake when back in the S2000, of course - that's rather different!

But a precision geo. check to make sure things are as equal & opposite as possible is a good idea. Especially if your rears are toeing out at the moment - that could be scary. Also less front toe-in tends to help turn-in too.

Also remember the Honda setup has quite a lot of passive RWS from bounce to compression & on/off power. So a slight lift & re-apply of power mid-corner is a neat way of trimming the line. I have the S2000 set up with chassis braces & minimal rear toe, so it does that trick remarkably well for that Walter Mitty F1-type feel.