I have 3.15 in my car now thinking of 3.42 or 3.73 ???.
2000 with Auto Trans and prity much STOCK no big Mods. :chevy :cheers:


[Modified by C5 Beans, 1:41 PM 11/21/2002]

 

you will have traction issues with the 3.73's.

But, if the money for better tires is in the budget also... go for it!

 

I went from 3.15s to 3.42, then to 3.73s. I wish I had gone directly to 3.73s. I think they are the perfect gears for an A4.

 

What RPMs you at when going 65MPH with those 3.73s? Also, what gas milage you getting highway and city?

 

I agree wholeheartedly with SilverStar. 3.73s are just about perfect. :) Traction isn't all that much of an issue unless you're talking about from a standing start. I think I see about 2500 or so around 70 but have kind of stopped paying very close attention. I get around 23-24 MPG on the highway, more like 16-17 around town. Your converter choice will have a big influence on your city gas mileage. I fully expected to drive a little more conservatively on the highway when I installed these but it turns out that it's just so dang easy to just sit in the sweet spot and cruise along at 85-90. :bb

 

I've had my 3.73's about 100 miles so far. Now, I would not want anthing higher as the revs are about 400 rpm higer for 3.73's than 3.15's. But I have yet to even kick on the AH and I have gunned it several times.

I have not inentionally brake / Jumped it off the line - of course you will spin - put just a nice stready increase in throttle and zoom - off you go.

I'm a real big gear fan - check out my post on 3.73 & 4.10 ring & pinion upgrades in this same section.

A good way to see if this is for you is to drive the highway in 3rd gear at about 65 mph with the 3.15's. That is what it will be like going 75 in drive with the 3.73's. Drive around in 3rd alot, if you like it you will like the gears.
Loud exhaust can be more of a problem with the higher revs than gas or engine issues.

Even with the great deal I got - it is still way cheaper to get 3.42's. At a minimum do that. Both Mike & I are proof that the 3.42's do not require any programming when comming from 3.15's.

I still have stock 3.15 programming with the 3.73's and no codes - go figure.

[Modified by KingTut, 5:01 PM 11/22/2002]

An interesting view of things depending from where you started:
From 2.73's to 3.42's is a 25.3% change (3.42/2.73) and significent.

Now for guys with 3.15 already the change is much less
From 3.15's to 3.42's is only 8.6%
From 3.15's to 3.73's is decient at 18.4%
Going "radical" to 4.10's is still not all that wild at 30.1% (4.10/3.15)


[Modified by KingTut, 5:27 PM 11/22/2002]

 

3.73's are great gears, no traction issue unless you launch hard, but that also depends on which TC you have installed.

 

I went from a 3.15 to a 3.42, sy3500, transgo. It looked likeit threw every code in the DIc. I set the gear to 3.42 with EDIT and cleared all the codes and that was it. It runs great. With stock tires the car will smoke the tires with no brake stall. The converter has a lot to do with it. If you get the 3.42 use the savings for a converter. You will get the launch and still have a reasonable road rpm. At 2000 rpm's you are doing 64. Go to this link for MPH/RPM calculater.
http://www.smokemup.com/auto_math/mph_range2.php


[Modified by jfpilla, 9:29 PM 11/22/2002]

 

I went from a 3.15 to a 3.42, sy3500, transgo. It looked likeit threw every code in the DIc. I set the gear to 3.42 with EDIT and cleared all the codes and that was it. It runs great. With stock tires the car will smoke the tires with no brake stall. The converter has a lot to do with it. If you get the 3.42 use the savings for a converter. You will get the launch and still have a reasonable road rpm. At 2000 rpm's you are doing 64. Go to this link for MPH/RPM calculater. http://www.smokemup.com/auto_math/mph_range2.php

 

I went from a 3.15 to a 3.42, sy3500, transgo. It looked likeit threw every code in the DIc. I set the gear to 3.42 with EDIT and cleared all the codes and that was it. It runs great. With stock tires the car will smoke the tires with no brake stall. The converter has a lot to do with it. If you get the 3.42 use the savings for a converter. You will get the launch and still have a reasonable road rpm. At 2000 rpm's you are doing 64. Go to this link for MPH/RPM calculater. http://www.smokemup.com/auto_math/mph_range2.php

 

Give yourself some time and you may think you could take even more. I have really warmed up to the increased RPM.

I think we should start a pool on when the first code shows up. :D Best ways to reproduce them are a) long, slight inclines around 35 MPH or so in 4th and b) sustained highway speeds around 65-70 MPH, slight inclines assist here too.

 

I've been thinking about going to 3.73's (had'em on my old 5.0 and loved them), but what should I do about the t/c? Leave it stock or step up? What actually changes when you go with a different t/c from stock in terms of how the car drives? BTW, my car has the Al Gore 2.73's currently!!!

My Stang was a 5sp, so I never worried about how a t/c affected driveability.

TIA


[Modified by dads01dream, 1:10 AM 11/24/2002]

 

My concept of a TC is like slipping the Clutch in a stick. You could get your car to accellerate faster by having the clutch only partially out and having your engine rev higher. Tc is same thing.

When a clutch is all the way engaged it is like the TC is locked. While the clutch is partially out it is slipping and so does a TC until it locks up. Stall speed is how high the engine can rev before it locks up.

I only have a 2400 stall and other than when I gun it from a stop it is just like stock. Those with 3500 stall converters experience the slipping sensation much more often. Not a desirable thing for me, but many others really like it.

You need to ride in a car with a 3500 stall converter and draw your own conclusions.

For just good "stock" fun arround town, you can not beat gears. I only put in the TC for "burning rubber" once in a while.

By the way "Toppless" is have now topped 200 miles, got up to 90, and put down a nice 60' two wheel patch and still no codes.


[Modified by KingTut, 1:59 AM 11/24/2002]

 

Actually, several of us have discovered that the ST 3500 IS much tighter than the ProTorque 2400 or the SY 3500. Who would've thought?! :yesnod:

 

I do hear very good things about the ST3500. Is it being discontinued? I thought I read that somewhere else.

My car is street only and even at that often more 50 mph type 4 lanes than interstate. I almost did not get a converter at all. Mine was used so I just thought I would give it a try.

People always say "if I could do it over I would skip some steps" but taking small steps is the only way to get what you want without over shooting the target. So it costs a little more. When you do something that turns out you do NOT like - it is cheaper to reverse that decision.

 

Any one have a sight or thread of a reaend housing and torque converter change for a DIY
Thanks

 

The ST3500 for F Bodies was discontinued, it is still available for the C5s.

 

Thanks KingTut!! Your explanation makes perfect sense to me. I agree that it would be a good thing to take a spin in someone's 3500 stall car - only problem is who & where?? :crazy: I don't think anyone here in CT has mod'ed their cars like this.

Any fellow Forum members nearby Danbury, CT? Heck I'll even throw in a free lunch!!! :lol:

TIA

 

Well, sort of. The slipping clutch analogy is correct from the perspective of allowing the engine to rev faster but that's where the similarity ends.

You're better off thinking about a converter as a) a variable ratio gear or b) a torque amplifier. By that I mean that a converter is multiplying the torque produced by the engine, but only up to some point that's a characteristic of the design of the converter. Higher STR converters typically have greater multiplication effects down low but don't do so for as long. Note that a high STR high stall converter can still feel "tight" thanks to torque multiplication. That's one of the reasons Brother Gary liked his ST3500 converter.

As far as locking goes, modern lockup converters are designed to be mechanically "locked" with a torque converter clutch or TCC at low RPM for fuel efficiency. "Locked" does not mean no loss across the converter in a PWM setup like ours though. There are really three distinct phases of operation that a converter will see:

1) TCC unlocked, multiplying torque
2) TCC unlocked, no further torque multiplication
3) TCC locked, no torque multiplication and minmal slippage

For most around town driving you'll toggle between 1) and 3), at the strip 1) and 2).

King, good to hear you're not having any issues yet. One of the conditions for setting the DTC is that you're between 35-65 MPH (with the TCC locked) so although you're actually seeing a larger TCC slip value at higher speed, not throwing the code in "worst case" situations shouldn't give you confidence that you won't or can't in the area of operations defined by the test.

 

Stop giving out our secrets gary, I remember when 3.73's were to much gear for the A4 back in 00! :lol: :lol:


[Modified by wallstAL, 11:10 AM 11/24/2002]