ZR-1 Net Registry Forums  

Go Back   ZR-1 Net Registry Forums > C4 ZR-1 > C4 ZR-1 Prototypes

Reply
 
Thread Tools Display Modes
Old 11-21-2014   #11
Hib Halverson
 
Join Date: Jun 2005
Location: CenCoast California
Posts: 899
Default Re: ’89-10 Dana 60 rear end

I am skeptical of Killebrew's information.

Back in the day, I spoke with Corvette development engineers about the 3.54 vs 3.45 debacle, one of them being my old friend, Jim Ingle.

All during development, the 3.54 axle had a noise problem. Chevrolet believed it would be a customer satisfaction problem once cars went on sale and pressed Dana to fix it. Turns out that the noise was inherent with the 3.54 ring-and-pinion's tooth count and, thus, could not be eliminated. Further development discovered a 3.45 ratio, with a different tooth count, could provide virtually the same performance but without the noise.

The idea that 3.54 axles went to countries with noise restrictions is ridiculous. Not only were rear ends with the 3.54 ratio noisier, but cars equipped with them would have noisier exhaust, too, because for a given vehicle speed, engine rpm would be higher.

No saleable ZR-1 was built with a 3.54 axle. Only the prototypes and some pilots got them, but that included some of the cars the media evaluated during the first round of magazine road tests, many of which were done with the '89s.
__________________
Hib Halverson
Technical Writer
former owner 95 VIN 0140
current owner 19 VIN 1878
Hib Halverson is offline   Reply With Quote
Old 11-22-2014   #12
Corvettes White
 
Join Date: Dec 2003
Posts: 466
Default Re: ’89-10 Dana 60 rear end

Well. I got the rear back from the shop. Replaced the constant volocity half shafts with standard ones. Removed the prototype cover and installed a regular prodiction item. 3:54 in an '89. So no complaints. Cross that off the list. Back to the soap and water. George.
Corvettes White is offline   Reply With Quote
Old 11-22-2014   #13
Hog
 
Join Date: Jul 2010
Location: Woodstock, Ontario, Canada
Posts: 1,275
Default Re: ’89-10 Dana 60 rear end

Quote:
Originally Posted by Hib Halverson View Post
I am skeptical of Killebrew's information.

Back in the day, I spoke with Corvette development engineers about the 3.54 vs 3.45 debacle, one of them being my old friend, Jim Ingle.

All during development, the 3.54 axle had a noise problem. Chevrolet believed it would be a customer satisfaction problem once cars went on sale and pressed Dana to fix it. Turns out that the noise was inherent with the 3.54 ring-and-pinion's tooth count and, thus, could not be eliminated. Further development discovered a 3.45 ratio, with a different tooth count, could provide virtually the same performance but without the noise.

The idea that 3.54 axles went to countries with noise restrictions is ridiculous. Not only were rear ends with the 3.54 ratio noisier, but cars equipped with them would have noisier exhaust, too, because for a given vehicle speed, engine rpm would be higher.

No saleable ZR-1 was built with a 3.54 axle. Only the prototypes and some pilots got them, but that included some of the cars the media evaluated during the first round of magazine road tests, many of which were done with the '89s.
The loading of the engine also contributes to exhaust noise, which would be reduced with a lower gear, not rpm/speed alone.

But 3.54 to 3.45 no human ears would be able to tell the difference. __________________
__________________
peace
Paul

ZR-1 Net Registry Member #1494
Hog is offline   Reply With Quote
Old 11-22-2014   #14
WVZR-1
 
Join Date: Oct 2004
Posts: 1,889
Default Re: ’89-10 Dana 60 rear end

Quote:
Originally Posted by Hog View Post
The loading of the engine also contributes to exhaust noise, which would be reduced with a lower gear, not rpm/speed alone.

But 3.54 to 3.45 no human ears would be able to tell the difference. __________________
I can understand an axle ratio change regardless of how minor for "noise abatement" where required. A ratio change is as simple as you or I being able to drive out of drone. The vehicle is evaluated at a specific spec determined by the country of destination. Export exhaust was seldom the same as production for many US productions heading elsewhere.

Maybe substantiating Hib's comments was the change to 3.33 ratio in the M6 cars during C4 production in '89. '90 L98 cars got these also. Hib's reference to noise I'm sure had nothing to do with noise abatement but a drive-line issue as he mentions a tooth count issue. The Corvette 3.54 was a 46/13 combination but years later the 3.55 as a 39/11 tooth count returned to the Dana 44HD. Seems to maybe hint there was likely an issue with the original 3.54.

GM SPO shows axle codes in '90 only for the 3.33 and the 3.45 but then mix '91 & '92 production codes into one chart and again mention 3.45 and 3.54 but no 3.33 references. '91 & '92 3.45 CQR(GM3) and 3.54 CQX(GH0). An SPO error? Maybe.

Last edited by WVZR-1; 11-23-2014 at 03:11 AM.
WVZR-1 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:37 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ZR-1 Net Registry 2020