Has anyone modified the steering system on their C5? My C5 coupe with F45 just doesn't give me a solid feeling between the wheel and the road. I was thinking that it was suspension, but now I'm thinking that it's steering feel more than anything.

I recently upgraded my sway bars and end links to Z06. I was considering upgrading the springs and shocks to Z06 as well. However, after some time on twisty roads with the new setup, I'm finding that the handling of the car isn't the problem. It stays flat on the corners with very little body roll. It seems that the responsiveness of steering wheel input is what's missing.

I've searched the forums and haven't found a single thread on this. Any suggestions would be appreciated. Thanks.

 

This is a common complaint of C5s. The C6 has remedied this a bit but not completely. I've never heard of a cure. Perhaps you could look into reducing the amount of assist through the power steering to provide more "feel" from the tires.

 

What kind of tires are you running. I had a set of BFg's G Force kd. They gave me a better feel on the road. Tire pressure can also affect steering lag.

 

Talk with some of the guys that track their cars. Setting up the front and rear geometry for different conditions can help a bit. But as with everything else, there may be some trade-offs, such as increased inside tire wear with more neg. camber settings etc. You might also try changing the tire pressures between the front and rear, increasing the front pressures while decreasing the rear pressures may help produce the turn-in that your hoping to find. You should be able to find a set-up that you can live with that produces the feel your looking for. Maybe some of the track guys will see this and respond.

 

Not sure what responsiveness you are looking for. My 97 was damned responsive and my 03 Z is the same. If yours isn't what you hoped for I would get a Z06 alignment. Make sure the shop sets it accurately and doesn't use the wide tolerances in the spec to just get close to it. You should feel the car turn in pretty quick then. I always found that on street tires the C5 was tail happy and really responded to a little throttle as you go through a turn.
Bill

 

Use the GY Runflats with extra air in the front (32lbs to start). Since you already have Z06 sways, I think that's about as good as it will get, assuming your alignment is otherwise accurate. (Note to fellow CFers - I am NOT advocating the use of GY Runflats in general, JUST noting it as a tire that will turn in fast due to very stiff sidewalls. Kumho MX's RULE ).

 

The Magnasteer II system is made to provide more feedback with additional tire load and lateral load, so you can do two things to directly effect the system: get more grip, or drive harder. I prefer both!

 

Let me guess... you are running non-runflats in factory size up front. How did I do?

If this is in fact your situation, it is normal. Despite their shortcomings, Runflats have very stiff sidewalls, providing excellent steering responsiveness. If you want to ditch the runflats and retain turn-in response, you'll likely have to go with larger wheels up front (i.e., larger wheels allow shorter sidewalls), or go with a Z06 setup (same size rims, but wider and w/ lower profile tires).

 

Thanks for all the suggestions.

To answer some questions.....I'm using Nitto NT555 tires all around (the car came with them when I purchased them). Running them at 30psi all around as recommended.

Also, for a comparison, I had been driving a 1995 M3 for 4 year prior to buying the C5, and a 1995 RX7 prior to that. The steering input on those cars seemed much more precise -- it seemed like you could "feel" the road, the cracks, and everything. When you turned into a corner, the responsiveness through the steering wheel was a much more "connected" feeling. To me it feels like the C5 is probably a better handling car than either, but just harder to control since the steering feedback is somewhat vague.

I'd love to just "turn down" the magnasteer effect, or, better yet, swap it for a steering system that has very limited assist. What do folks that race C5s use for steering systems? I was surprised that none of the vendors out there offered some sort of aftermarket steering product, or someone hasn't done some reprogramming of the magnasteer code.

I'd prefer not to mess with the alignment at the expense of abnormal tire wear, if at all possible.

I like the suggestion to go with runflats if that equates to stiffer tire and steering feel. I would sacrifice some traction for better steering feel. That's something I think I'll try next -- folks on the forum seem to hate the runflats though. I see alot of suggestions to "get rid of runflats to improve handling."

Finally, I guess I should test drive a Z06 to see how a stiffened suspension and wider tires impact steering feel.

What about going with larger aftermarket wheels? Would putting on 18/19s have a similar impact?

 

My Z51 Coupe with 245/45x17 stock run flats on the front felt vague in high speed sweepers and when I changed to Z06 265/40x17s (9.5" stock wheels) it felt much better. I don't run sticker pressure, I run around 35 psi in the front. I ran 38 psi with the run flats (what ever keeps the high pressure warning off when they heat) and it did feel better.
Try increasing the caster, it will make the car more stable at speed and Caster does not affect tire wear. I haven't changed caster on my C5 yet as I'm not unhappy with the feel. I've increased caster to max on one of my cars and it totally changed it's driving personality from a darting dog to a joy to drive. Make sure the caster is the same on both sides. I do it myself with a portable caster camber gage.

 

Did you have the R1 package on your RX-7? Grassroot Motorsports said the feedback on the R1 was so effective you could run over a dime and know what year it was minted!

Are your tires RII's? The RII's will have stiffer sidewalls, and better for the twisties, possibly the hardest cornering street tire available.

You've already picked up on how grippier tires will increase steering effort, which you want, so it's a win-win situation. Cheap way to upgrade is to find someone selling a set of Z06 wheels with tires. Next step up is to do the same, but just get the rear wheels, but mount them on the front too, but with a 1/4" spacer to prevent rubbing. Ultimate step up is to get a wide body kit and a mini tub kit, then get the fattest wheels and tires out there. Hell, get them in slicks, and I doubt you have problems with steering effort....just make sure you have a power steering cooler! If you can, stay away from the 18/19's. The best handling package is to go with 18's on the front to improve turn in, and 17's in the back to improve grip out of corners and drop a little weight.

The F45 was designed for a cushy ride as the GM engineers put it in their SAE report. If you want ***** out handling, upgrade the springs, shocks, swaybars, handling bushings, wheels & tires, brake rotors & calipers. Tune that suspension while dropping the ride as low as you can go while staying off the bump stops or bottoming out over road imperfections.

If you really want to improve the handling, check out this thread I just started: http://forums.corvetteforum.com/showthread.php?t=976812

It has everything I know about suspension modifications, specs, and weight reduction.

 

No R1 package on the RX-7, just the standard touring package. The 95s were supposedly softened from the 93s due to complaints. Still, that car was certainly stiff!

The Nittos just say NT555 on them....no RII.

Wow! I just checked out your new thread. That's a great resource for information. Question: If I pick up a set of Z06 wheels/tires, do I need a realignment to Z06 specs? Is there a difference in Z06 tires and wheels from different years? Any recommendations? Finally, I have the magnesium wheels on my car, and have kind of grown fond of their looks, whereas I'm not all that crazy about the looks of Z06 wheels. Are there any aftermarket wheels in Z06 size that look like, say, the painted stock C5 wheels from a recent C5?

 

Anyone(dealerships mainly) with a Tech II scan tool can adjust the steering effort(more firm or less firm) used in the Magnasteer system.

 

I've heard that putting in an underdrive pulley would make it feel more firm. You'll get more power too. Two birds with one stone. Power and more firmness. However it might be more of a hassel than a proper solution.

 

Antvette's solution sounds solid. That's a big duh for me!

I don't know about the TechII solution. It should be possible, that's what the Magnasteer system was designed for, but I just haven't heard of it before. If anyone gets it done, please post here about it.

 

Sorry guys.. I should have mentioned where I got my info. I have the factory service manuals and it states that the Tech II tool is capable of adjusting steering firmness. Hope it helps..

 

Turning down the power assist will not affect turn in. Are you confusing ease of turning the wheel with turn in response? Do you have any codes in the ABS/TCS? The magnasteer system gets its inputs from the EBTCM which determines how much steering boost is required based on the vehicle speed sensors and the steering wheel position sensor. The EBTCM does this by increasing/decreasing the current sent to the magnasteer unit. Increased current means less torque is applied to the steering meaning less assist. If you have a code for any of these sensors the system defaults to max boost all the time.

If one or both the Magnasteer actuators fails magnasteer is disabled and you get full boost. Basically, a magnasteer unit is a standard rack with some items added to reduce steering boost at higher speeds.

As for using a Tech II to change the Magnasteer programming in the EBTCM it may be able to be done but my service manual does not say it can. I doubt there is anybody but a factory engineer who knows what to change and what the impact of the change would be.

Bill

 

A more aggressive alignment (at least to Z06 specs) will help a lot, but it will never be M3 or RX7 like. Pay close attention to front toe - it should be right at zero for best response, with some negative camber and as much positive caster as you can get.

Having driven all of the above, the C5 system just does not provide as much feedback - not sure why, since most of the steering gear is very solidly mounted.

 

I wouldn't say "never". The front bushings in the control arms are the "handling" bushings, while the rear bushings are the "ride" bushings. LGM is running metal spherical bushings on their race car. If they'd sell it to us, or if someone designed something similar, even Delrin based bushings, we'd get more feedback and control while being able to keep a comfy ride bushing in the rear of the control arm. GM stated in their SAE report that they could go very hard on the handling bushing with very little loss in ride comfort. I for one would like to find out how far I could go with that. Also the rear wheels are designed to toe-in slightly with turn-in to generate a slight understeer moment. Get rid of that too, and it generate crisper, if not scarier for the unskilled drive, turn in events and sharper handling.

 

Yes. Very confused!

Not sure how else to explain it other than it's just not quite as precise feeling as the M3 or RX-7. For example, an abrubt lane change at 45mph feels a bit uncertain. I turn the wheel to do the maneuver, and the car follows. The car doesn't seem to roll much, or lose control. It just feels like the steering wheel isn't very connected to the turn. I might be confusing this sensation with suspension stiffness, steering wheel ease, magnasteer, or all of the above. I'd like to feel more road through the wheel.

Also, no apparent codes for ABS/TCS -- I would see those in the center display, right? So there's no adjustment of steering feel through the Tech II? Someone else mentioned an adjustment -- I'd like to hear more about that if that's really the case.

So far, this has been very instructional for me, and will probably save me $$$ from investing in things that won't really help with my problem. Thanks all.