Just Bought 3.73's! A Few ?'s

**CWW17** · 04-25-2007, 09:26 PM

Alright I just got a great deal on some Strange 3.73's on eBay. Should I go ahead and have them installed now or wait until after I get a TC? Also what else should I have done along with the gear swap (tune ect.)? Any and all help is appreciated! Thanks!

**99blueZ** · 04-25-2007, 10:17 PM

Originally Posted by cww17

Alright I just got a great deal on some Strange 3.73's on eBay. Should I go ahead and have them installed now or wait until after I get a TC? Also what else should I have done along with the gear swap (tune ect.)? Any and all help is appreciated! Thanks!

you can install the gears before the TC. You will need it tuned because the gears will throw off your speedo. I would wait on the tune though until you get the TC - why pay for it twice?

**CWW17** · 04-26-2007, 09:18 AM

so the only reason I will need the tune is because it will throw off my speedo? I can just do that with a handheld right?

**Silver Streak** · 04-26-2007, 09:27 AM

Your speedo WILL be off... and a tune will fix that... not sure if a handheld is able to fix that or not... but most places charge a fixed amount for a bolt on tune.. then only dyno time for everything after that... call them and find out. But I agree.. do a few things to take the most advantage of the tune first. But the gears will really wake up the car if its an auto.

**CWW17** · 04-26-2007, 11:14 AM

Is a dyno necessary to do the speedo tune? because I do not know of any shops around here with a dyno besides up in Chicago... which is a good 3 hours away...

**99blueZ** · 04-26-2007, 12:13 PM

no you don't need a dyno to change the speedo.

98T/Aformula · 04-26-2007, 02:58 PM

I just got my 3.73s put in yesterday

but I just set my speedo with my Hypertek cp3, and it seems to be on, I have a radar gun that im going to check it with but it seems like its right...I cant wait to open it up im just tryin to break them in slow before I do so, but everyone said it will be a whole other car !!!

**CWW17** · 04-26-2007, 05:12 PM

how much did the install cost you? I got quoted at $200 I believe...

**Hawk241** · 04-27-2007, 09:24 AM

Originally Posted by 98T/Aformula

I just got my 3.73s put in yesterday

but I just set my speedo with my Hypertek cp3, and it seems to be on, I have a radar gun that im going to check it with but it seems like its right...I cant wait to open it up im just tryin to break them in slow before I do so, but everyone said it will be a whole other car !!!

Hey whats your tachometer at 60 mph?

**greatwhiteZ28** · 05-22-2007, 04:03 PM

if you need to change any of the needls on your guages there a cheaper way by removing the guage bezel leaving just the cluster and remove the needls on the cluster till you think everything is perfect.

cheapest way i know of

**SteveC** · 05-25-2007, 05:47 PM

The main reason you need the speedo recalibrated is that the computer shifts the vehicle by MPH not RPM, so the vehicle won't shift correctly until the correction is made.

SteveC

**greatwhiteZ28** · 05-26-2007, 02:40 PM

not to argue but the first time i installed some white faced guages i screwed up big time and place all the needles soo far off. i had to have a friend drive next to me and see how fast i was going cuse like at 40 it said iwas doing like 120 mph. its still shifted fine. it was on a 99 TA and you could be correct but i didnt have any problems with shifting, it might go with someother sensors soo just saying my story.

**Silver Streak** · 05-26-2007, 04:13 PM

Mine didn't have a prob shifting.. but it was 13% off what it should have been reading till I got it tuned.....

**slims00ls1z28** · 05-26-2007, 06:49 PM

Mine is way off going from 2.73's to 4.11's and the shifts come in way too early if I mash it. I'm taking it to the dealer to see what they can do they told me they "should" be able to do it will let ya know then.

**john5632** · 05-30-2007, 01:28 PM

Originally Posted by CWW17

how much did the install cost you? I got quoted at $200 I believe...

That seems about right for labor

**greatwhiteZ28** · 05-30-2007, 02:34 PM

yea thats cheap i got 400 for my estimate

**0rion** · 05-30-2007, 11:37 PM

the computer looks at mph AND rpm before it will shift. Both parameters have to be met before it will shift. If they're to far apart it may cause the car to "hunt" for shift points or it'll bang the limiter. With a gear swap in an f-body you'll want to get the speedo corrected. Vette's don't have the same problem because their speed sensors work off the axles and not the driveshaft.

Putting the needles back on incorrectly won't effect shift points. The pcm looks at the speed sensor not the gauges.

**LETHALxLS1** · 06-01-2007, 07:39 PM

Does anyone know what the gas milage would be in a a4 with 373 gears installed? Also at 50mph what will the rpms be at? Thanks!

**Silver Streak** · 06-02-2007, 12:05 AM

With hard drivi9ng I get around 18-19 combo driving. And 50 is just shy of 2 grand.

**clg82** · 06-02-2007, 12:41 AM

Originally Posted by CWW17

Is a dyno necessary to do the speedo tune? because I do not know of any shops around here with a dyno besides up in Chicago... which is a good 3 hours away...

Where you from in illinois?