Just Bought 3.73's! A Few ?'s

[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!

[99blueZ]

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]

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]

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]

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]

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

[98T/Aformula]

I just got my 3.73s put in yesterday :burnout: 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]

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

[Hawk241]

I just got my 3.73s put in yesterday :burnout: 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]

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]

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]

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]

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

[slims00ls1z28]

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]

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

That seems about right for labor

[greatwhiteZ28]

yea thats cheap i got 400 for my estimate

[0rion]

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]

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]

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

[clg82]

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?

[clg82]

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.

That is exactly what my car does!!!! Only i didn't get any gears put in i just had my transmission rebuilt with a 9 clutch package and shift kit. would this also cause my car to do what you said, "If they're to far apart it may cause the car to "hunt" for shift points or it'll bang the limiter."

[0rion]

is your car shifting at different points or is it hitting the limiter everytime? If it's just smacking the limiter on shifts I would just move the shift point or limiter depending on where you want it to shift at and where it's actually trying to shift.

[clg82]

is your car shifting at different points or is it hitting the limiter everytime? If it's just smacking the limiter on shifts I would just move the shift point or limiter depending on where you want it to shift at and where it's actually trying to shift.

You can actually (well i can my wife is blind to it) tell the car is finding where to switch sometimes i'll be just driving downtown going 25-30 and it will just downshift for some reason then when i push on the gas it feels like i am towing something like it is in a really low gear. And when I am really racing it once it hits the rev limiter it bounces off of it until i let off and push the gas again. Then it will finally shift.

[0rion]

to be honest with you I'm not sure of the effects of rebuilds. I would assume that unless it's built to stock specs you could run into some shifting issues that would need to be tuned out. Have you had the car tuned at all? I also wouldn't make a habit of bouncing off the rev limiter if you can help it.

[clg82]

to be honest with you I'm not sure of the effects of rebuilds. I would assume that unless it's built to stock specs you could run into some shifting issues that would need to be tuned out. Have you had the car tuned at all? I also wouldn't make a habit of bouncing off the rev limiter if you can help it.

Yeh i definatley don't make it a habit but it sounds exactly what you explained in the thread above. I do need to get a tune asap as soon as i come back from leave (i am in the military) and so i am going to get a dyno and tune as soon as i get back. Do you think this will be able to help me?

[0rion]

yep, that should fix you right up. Make sure you tell the guy that's tuning it exactly what's going on and make sure you get a full tune and not just a WOT dyno tune.

[clg82]

yep, that should fix you right up. Make sure you tell the guy that's tuning it exactly what's going on and make sure you get a full tune and not just a WOT dyno tune.

WOT? Yeh I will make sure of that it is gonna cost me $500.00 for the tune and dyno. Sound about right for a full tune?

[0rion]

I see those costs vary a lot but $500 is a number I see quite a bit. The dollar figure isn't as important as the tuners experience. I would search around and find some people that have gotten tunes from the same tuner and see if they were happy with the results. WOT= Wide Open Throttle. Ideally you want a balanced tune. Someone that does your idle, part throttle, and then wot on a dyno with a wideband. Since you're an auto you'll want someone to set your shift points, firmness, and shift duration along with taking out torque management.