Going to start a flame 3.73's!!!!

[jaynutz]

Ok y doesnt everyone go with 3.73's? I love these gears....i still have top end acceleration and my low end is acceptional. My speedo is off about 10 mph so i top out to say about 110 mph. I can see wear the car lags but what is the negativity about 3.73's.

[DominusEtDeusNatus]

Why doesn't everyone go with 4.10s? I love these gears. I'm going to try 4.56s if I can get them used.

[wickedties82]

I love my 3.73 to is you car an auto mine is

[Seal]

well, if i get 3.73s, and i have an a4, the mpg will kill me :mad: if i had 4.10s there would be mpg anymore on the highway :D

i am still thinking between 3.73s and 3.42s... but 3.73 on a highway car might be too much for an a4. if i had m5, i'd get 3.73s no questions asked

[Seppo Kaitainen]

<blockquote>quote:</font><hr>Originally posted by jaynutz:
Ok y doesnt everyone go with 3.73's? I love these gears....i still have top end acceleration and my low end is acceptional. My speedo is off about 10 mph so i top out to say about 110 mph. I can see wear the car lags but what is the negativity about 3.73's.<hr></blockquote>

It depends on what gears your car came with as to how much top speed you'll lose.

3.42 to 3.73 = 9%
3.23 to 3.73 = 15%
3.08 to 3.73 = 21%

3.23 to 3.42 = 5.8%

mpg, incorrect speedo, and higher mileage than car actually has are all valid reasons.

[marco]

You can always get SLP's Speed processor and correct the problem. No biggie.

[NSolano]

what is that speed processor?? I am planning on getting 3.73 gears too, but i hate the fact that it will kill top end speed, if there is no way to fix this then i will go for 3.42's. Will the speed processor fix this, where could i get it?

[jaynutz]

i have an A4 w/ a Torque converter and stage 3 shift kit. I had ruined the rear end and tranny at the same time so i did a full drivetrain re-build. I am wondering if to get that speed proceessor too. does it add any HP? or does it just correct the speedo.

[12secondv6]

You have top end???
I've had almost all the gears.
I started with 308's and went to 410's then went to 342's and finally had 323's
4 10's had no frigin top end, I know from experience.
373's can't be much different.
My 323's are giving me a 1.630 60 ft
In the drag racing section there is a 0-60 calculator.
My 0 - 60 is 4.04 seconds
410's my speed limiter came on at 85 mph
342's I passed the end of the 1/4 in overdrive at 103.5 mph
Now with trapping mid 107's on a 245 50 16 tire I pass in overdrive.
I either had to go to a 308 gear or taller tire. I went with taller tire.
For me with 308's:
4 10's are 25% off
3 73's are 16-17% off
3 42's are 10-11% off
3 23's are 5% off
Change gears and you have a speedo off, record more miles on odometer, speed limiter comes closer, and if it is an auto shifting is sooner.

Nuff said [img]tongue.gif[/img]

[Only4U]

so when the speedometer is recalibrated...let's just say from 3.08's to 3.42's, then will your top end STILL be 10% or so less? i understand that the actual speedometer will read the accurate speed once it has been recalibrated, but will the ACTUAL speed be affected (compared to stock) after all is reprogrammed? i mean, i know there's a lot of talk about this all the time, but no one really has ever made it clear if getting the speedometer recalibrated with new 3.42's puts your top speed limiter back at 117 like it was with the stock 3.08s??? all i ever seem to hear is that the speedo will be off by 10%, so i just assume that no matter if you get your computer reprogrammed or not, your top speed will be about 100 (from 3.08s to 3.42s), but if you don't get the cpu reprogrammed then the speedo will be off as well; am i wrong or right here? sorry, that's been on my head for a while and i've never seen an appropriate time to ask that without having an admin yelling at me to do a search...so i figured now was probably a better time than ever...

[12secondv6]

Well there are several ways to get the pcm reprogrammed:
1, find a dealer who will take someone elses vin # and program it in there. Most will not do this because technically it is illegal.
2, jet SCU (speed control unit) tried it and didn't work
3, SLP recalibrator, i haven't tried it but I know no one who has any success with it
4, ed wright, superchips, hypertech, all of them can not access the speedo to recalibrate it. superchips adjusted my fuel mix, timing stayed stock, speed limiter was removed but that is it

OK, now getting back to your question.
Let's just say the car came stock with 308 gears.
You then bought and installed 342's
We know the speedometer is off (reads higher) by about 10-11%
When you are cruising at 100 mph your speedo would say 110-111mph.
Stock speed limiter is 118 mph
With the gear change the speed limiter will come sooner because the speedometer is reading higher
With 342 gears in a 308 gear programmed car you would hit the speed limiter at 105.02 to 106.2 mph.

If you could find a way to recalibrate your computer to adjust the speedometer to read correct then your speed limiter would be back at 118 mph.

Make sense?

[CamaroBill]

Top speed should not be affected that much if you get your speedometer corrected. Reason being, horsepower to overcome wind resistance is a very serious factor with regard to top speed, and swapping out rear end gears does nothing to affect wind resistance. The percentages stated in above post would only apply if you reached the rev limiter in top gear which our cars will not do unless you are on a dyno (no wind resistance).

[AMinor65]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
Well there are several ways to get the pcm reprogrammed:
1, find a dealer who will take someone elses vin # and program it in there. Most will not do this because technically it is illegal.
2, jet SCU (speed control unit) tried it and didn't work
3, SLP recalibrator, i haven't tried it but I know no one who has any success with it

If you could find a way to recalibrate your computer to adjust the speedometer to read correct then your speed limiter would be back at 118 mph.

Make sense?<hr></blockquote>

I hear ya, those speed calibrators are BS. I have one, so I'm gonna keep mess around it a little more, but I wouldn't buy one if I didn't already have one I tell ya that. I should've listened to everybody else, BUT NOOOO!! I wanted my speed correct.

One of the problems is that, it fixes the speedo, but the RPMS are reading "accurately" for your new ly calculated speed, which screws up the stock PCM. It starts thinkin' your tranny's slippin' and throws that P1870 code. It's like the speedo problem is addressed, but not the increased RPMS for the gears! Got it as soon as I got to rolling on the highway. Unintentionally removed it after mechs. got water in it. Haven't had the problem since. My stock gears were 3.08, gonna set it to 3.23, and see if that works. No joke, learn to live with the speedo being off.

Oh yeah, I would've gone with 3.73s if I didn't drive on the highway so much. And without correct speedo calibration, you will have less high end. I would get 3.73s if I was doing other things to justify custom programming or could get an HPP3.

[Seal]

ill be getting 3.42s, and luckily i know a techninian at a GM dealer, and he can probably do the reprogramming for me [img]smile.gif[/img]
(hopefully heh) he has a 95 camaro BTW maybe i should try getting him to the boards [img]smile.gif[/img]

[Only4U]

so besides the hpp3, there is really no way to get it recalibrated. i just called chevrolet and the comp technician said that putting another VIN in there is pretty risky because a lot of things they have that you don't or vice versa will cause SES lights gallore and you'll have hell trying to fix them all/find out what they are. i was planning on getting new gears, but don't really want to at all now because if i ever need to sell the car, no one is going to want a car that has a speedo off and no one will believe me that the odo is off as well. are there no other ways around this? hpp3 didn't make a comp recalibrator for my year car either :( any help or advice plz...