Rack and pinion..again - ZR-1 Net Registry Forums

JFFerner · 12-03-2015

I'm about to undertake determining the causes of some steering noises as they have been previously described here. Please excuse my lack luster knowledge even after reading many postings. Steering ratios, my understandings:
Standard C4 15:5:1?
C4 with Z51 option 13:1
C4 with ZR-1 option, (ZR-1 inlcudes the Z51 option)however, per my car's manual, it has a ratio of 15.73:1
I understand the aspect of a slower ratio for high speed, but what is the steering ratio on a stock ' 90 ZR-1?

If replacement of the rack and pinion is needed, will a standard C4 rebuild be a bolt in substitute without modification?

Thanks..and so it goes..Jim

batchman · 12-07-2015

I took a quick look at your prior posts, went back near a year and didn't see anything about steering noises. I highly suggest getting a trained eye on your noises before spending any money on fixes since it's easy to a) spend money quickly b) making things worse.

I am only aware of 2 C4 steering racks, "standard" and "quick". The quick rack is 2 turns lock-to-lock. I'm not sure I'd trust anything printed other than a real GM master part number book, better yet a year-by-year stack of them.

As I understand it all ZR-1s have the standard steering rack. It seems the Z51 option "changes flavor" depending on what else it is ordered with.

I'll have to look again at our Beast but I seem to recall it showed Z51 on the codes. But I can absolutely confirm there were absolutely no Z51 parts as I know and love them (from our other car) on our Beast. Springs, Rack, shocks (of course), sway bars, even the steering shaft rag joint.

Unless you need "zero down time" I highly suggest sending your rack out to a reputable rebuilder (such as Turn One in Saginaw MI) for best results. There are a lot of crap parts out there and many are "rebuilt" or "refurbished" in degreasing only, or at best by well meaning but marginally skilled or shall we say volume-oriented resources.

Good luck, and I'm sure there is help here to be found with your noises.

Best,
- Jeff

JFFerner · 12-09-2015

Thanks.

And so it goes...Jim

12-03-2015	#1
JFFerner Join Date: Jan 2012 Location: Dallastown, PA Posts: 189	Rack and pinion..again I'm about to undertake determining the causes of some steering noises as they have been previously described here. Please excuse my lack luster knowledge even after reading many postings. Steering ratios, my understandings: Standard C4 15:5:1? C4 with Z51 option 13:1 C4 with ZR-1 option, (ZR-1 inlcudes the Z51 option)however, per my car's manual, it has a ratio of 15.73:1 I understand the aspect of a slower ratio for high speed, but what is the steering ratio on a stock ' 90 ZR-1? If replacement of the rack and pinion is needed, will a standard C4 rebuild be a bolt in substitute without modification? Thanks..and so it goes..Jim

12-07-2015	#2
batchman Join Date: Jun 2009 Location: I live at Devens, one run at a time Posts: 455	Re: Rack and pinion..again I took a quick look at your prior posts, went back near a year and didn't see anything about steering noises. I highly suggest getting a trained eye on your noises before spending any money on fixes since it's easy to a) spend money quickly b) making things worse. I am only aware of 2 C4 steering racks, "standard" and "quick". The quick rack is 2 turns lock-to-lock. I'm not sure I'd trust anything printed other than a real GM master part number book, better yet a year-by-year stack of them. As I understand it all ZR-1s have the standard steering rack. It seems the Z51 option "changes flavor" depending on what else it is ordered with. I'll have to look again at our Beast but I seem to recall it showed Z51 on the codes. But I can absolutely confirm there were absolutely no Z51 parts as I know and love them (from our other car) on our Beast. Springs, Rack, shocks (of course), sway bars, even the steering shaft rag joint. Unless you need "zero down time" I highly suggest sending your rack out to a reputable rebuilder (such as Turn One in Saginaw MI) for best results. There are a lot of crap parts out there and many are "rebuilt" or "refurbished" in degreasing only, or at best by well meaning but marginally skilled or shall we say volume-oriented resources. Good luck, and I'm sure there is help here to be found with your noises. Best, - Jeff __________________ [I]91 ZR-1 #1840, autocrossing in SCCA BSP. FIC S/S's DRM chip/Watson/Borla/lid/LW batt&headlights, springs, shocks, pads & lines, quick rack & Turn One, camber brace, 32/22mm sways, A/C halfway deleted 17x11 & 12 CCW's, 315 & 335 Hoosier A6s [/I]

12-09-2015	#3
JFFerner Join Date: Jan 2012 Location: Dallastown, PA Posts: 189	Re: Rack and pinion..again Thanks. And so it goes...Jim