I'm thinking about installing 373 gears in my rear end. Does any one have them already? If so, what kind of changes will I see in acceleration and rpm's at highway speeds?
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I'm thinking about installing 373 gears in my rear end. Does any one have them already? If so, what kind of changes will I see in acceleration and rpm's at highway speeds?
I run 3.73's in our car. The general rule of thumb is A4 cars should upgrade to 3.73's and M6 cars to 4.10's. I honestly cannot tell you what RPM our car runs at down the highway, but it isn't bad at all. Stock tire height is something like 25.6" and you can either math it out or go to an on-line converter that will tell you the RPM.
I have 3.73:1 gears in my 01 Z28 (Sara) and the rpm difference from the stock 3.23:1 (GU5) was 500. I did not notice that much of a difference in the pickup until I had a Y3000 stall (should have gone to 3600) Yank converter installed ;)
SteveC :)
I went with a 3,200 stall -- also should have jumped up to the 3,600. Live and learn.
I have a Yank SS 3,600 stall and 4:10 gears. On the highway doing 70 MPH the RPM's are at 2,500. I am very happy with my gear choice!
I would go with the 4.10's over the 3.73's because of the overdrives in both the M6 and A4 cars. I am waiting to break my 10 bolt so I can get a 4.10 9" from Strange.
I considered something steeper than 3.73's, but have no complaints. As cpop posted, he went with them in his car and they appear to also work great with an A4. Hell, he might even be able to edge by me at the track... at about the 100' mark and then all I see is his tail lights!
I've also read this quite alot, is there a particular reason for this?Quote:
Originally Posted by pajeff02
Out of interest, has anyone used 4.10's with an A4?
I am. Read post #5, I'm very happy with 4:10s and a A4. Lots of fun on the street and not to bad on gas on the highway.
I use 4.10's with an A3, does that count? :DQuote:
Originally Posted by SS Camaro UK
I think the reason you read it quite a lot may be due to this generation of people that have gotten attached to their overdrives, and aren't used to buzzing the engine down the highway. Honestly though, I think the 3.73 or the 4.10 with an A4 is a good combination that still has excellent highway manors and good acceleration at the same time.
I personally wouldn't even squabble at any gear with an overdrive tranny in front. But if you drive quite a bit and don't frequent the track so much, and like loafing down the highway at high speeds, maybe steeper gears aren't a good idea.
Like Jeff said, decide what you might be comfortable with as far as rpm cruising goes.
It's good to know that.
Is the car's top speed affected as well?
Don't know. How fast do you want it to go? These 4L60's will shift into overdrive at full throttle, with that said, I would think they would still go as fast as you care to go.
Here you go, play with this. You can change the gear ratios, transmission ratios, tire height, etc...I've found it to be accurate with my stuff.
RPM / Speed / Gear Ratio Visual Calc
I ran a test for you,,,,
With 3.73's, shifting into overdrive (.70 ratio with automatic) at full throttle and only running it to 4800 rpms with a stock 26" tire you'll be going 140 mph and there is still room to spare. I'd say that's fast enough (I know I'll never do it anyway)
I was just being curious. :) I wouldn't risk my car being totalled, not after waiting for so long for it.
:uk:
How do you go about finding out what the gear ratio is without dropping the cover? I have a six speed & at 70mph in sixth it tacks 1600 all day long hills and all, it will do 85 in 3rd near redlineQuote:
Originally Posted by pajeff02
all 6 speeds got 3.42's. 70 mph at 1600 sounds right on the button for 3.42's.
3.73, A4, i get 3000rpms at 75mph. still get 25mpgs/hwy though.
Quote:
Originally Posted by kingls1
FBJ posted an answer... but if you ever need to verify a rear end ratio it is easy to do. Block the front wheels and support your rear axle on jackstands. Place the transmission in neutral and then make a mark on both the driveshaft and nose of the differential that line up with one another. Also place a mark on the inside of your tire that you can easily see and that points straight down. Now, simply rotate the driveshaft as many times as it takes to turn the tire one complete revolution, counting the turns of the driveshaft as you go. A 3.42 ratio rear will require you to turn the driveshaft just under 3-1/2 times to get one full tire revolution as the number of turns corresponds exactly with the ratio.
that sounds easy enough, I'll give it a tryQuote:
Originally Posted by pajeff02
my 98 c5 vette has 342 stock gears. ive ordered 800 hp clutch stage 2 tranny rebuild, and now looking for advice. ima change gears in the same job so ima do it all. whats stock cv shafts hold up to? and would it be better and easier on the rear end to get like 373s and upgrade cv shafts for bigger tires n launch?Quote:
Originally Posted by kingls1
with the A4 going to the 3:73 gear, whats it worth in e.t. / and just street driving
With track wheels and tires, exhaust, a tune, plus a few suspension pieces, our car went from 13.3 to 12.8 in the quarter after swapping out to 3.73 gears. On the street, it'll pull a bit harder and have a snappier feel -- or just bust the tires loose quicker.
both my ws6 and SS have been 12.9 with street tires, exhaust, and all the bolt on suspension parts you would normally do with these cars, what type of gain might I see with just the gears, still only drop to 12.8 maybe 12.7
Depends. The WS6 and SS would already have 3.23's originally if equipped with an auto. Still a 3.73 gear is a fairly noticable difference and could pick you up .2 to .3 tenths with all other things being equal. Where you would see a bigger difference is a Z28 or TA that has 2.73 rear gears.Quote:
Originally Posted by 01SsRacing
I went to 3.73's in my wifes 6 speed SS which had 3.42's originally. Even that small change was very noticable in that car. Without popping the clutch, it went from stabbing the throttle in first gear and being lack luster and just waiting for the engine to climb, to now hazing the tires and fishtailing through first gear, with tires spinning and the rpm climbing much quicker It happens quick enough that sometimes banging the rev limiter set at 6700. It would never spin the tires like that with 3.42's, I had to get the clutch involved for any tire scratching.
So it made her car much more fun to drive. Haven't been to the track since the gear change but I would expect a mild pickup. With the 3.42's and on stock rubber, I went 12.70's at 112 mph, and that's shifting to 4th right at the finish line which was killing me. Trying to stretch 3rd to the finish it would just hit the limiter 3-4 times at 6700 and trap 110 mph doing that. So that car needed a rear gear badly so I could utilize 4th gear. However even the 3.73's aren't enough for this car for optimum 1/4 mile assults, but a welcomed improvement anyway.
Great post thanks! Yeah idk looks like right now I'm going to swap to a T56 in the SS and build that up, and just leave the Ws6 alone but want a nice gear for the strip being I wont drive it nearly as much as the SS.