i have a 2002 z28 A4 with 3.42's. would i notice any difference if i upgrade to 3.73's. my car is completly stock except for a flowmaster muffler.

 

Get a converter instead, at least a 3200. You will notice a difference! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Get a Super Yank 3500. That will give you 5 times the gains a gear swap will for double the price <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

yeah you're probably right guys, i was thinking of a converter too.are they good for street driving or mostly for drag racing though. i'm not really the car man i wish i was so please excuse my stupidity. do you feel the difference only off the line or if you were just driving or rolling and hit the gas would you feel anything. i don't think this will make sense to anyone but please try to help.

 

They are a blast for street driving. The SY3500 is made for the avid street racer with 3.42's <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

See my sig...

 

i agree, get a convertor, I went from 3.23 to 3.73 and cant tell much. convertor was way better!!!!!

 

BTW, if your car is completely stock, you have 3.23 gears

Get a converter and good tires. HUGE difference. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

i thought i had 3.23's too, but i gave my vin to the parts guy at my dealer and he said i had 3.42's...go figure....maybe i got lucky.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Es02'zee:
<strong>i thought i had 3.23's too, but i gave my vin to the parts guy at my dealer and he said i had 3.42's...go figure....maybe i got lucky.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The parts guy is probably just as knowledgable as the salesman. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> Just look on the inside of the driver's door, and that will tell you which gears you have. GU2 is 2.73's, and GU5 is 3.23's. A4's do not come from the factory w/ 3.42's.
I also agree that you should get a torque converter. It's nothing to shave off .5 from your 1/4-mile time, and this is with the mildest of setups! An aftermarket converter will help you all around, whether launching, racing from a roll, etc. It will eliminate those dead spots from when you hit the throttle and it leaves you at the bottom of 2nd gear. It will make the car a LOT more fun to drive as well. The best street converter is definitely the Super Yank 3500. It has a high efficiency and a low stall torque ratio (STR) of 1.6:1 (i.e. it won't hit the tires near as hard when launching), so it's the perfect street converter. I ran this converter in my '98 T/A for a while, and it was LETHAL on the street with drag radials! I had a lot of fun racing from stoplights. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> If you're wanting a converter that's a nice street/strip setup, then a Yank Super Thruster 3500 or Vig 3200 would be a nice choice. It will hit harder off of the line compared to the SY3500, so you will net better 60' times with full traction. Neither of them have the efficiency of the SY3500, but the ST3500 is close. Efficiency will help you in MPH, which is what wins street races. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Just to give you some info, a "looser" converter is going to require more throttle to get the car moving. So, you're going to notice more RPM's driving around until the converter locks up. Lockup typically occurs at 40-45 MPH on cars w/ the stock PCM. Your highway gas mileage will be unchanged since the converter is a lockup unit. You won't notice any increase in RPM's while cruising down the road. The higher stall means that your RPM's are going to stay higher up in the powerband when you're at WOT. You won't drop NEAR as much on the shifts (shift extensions) with an aftermarket converter as you would with the stock unit, so it uses the power you have MUCH better. An aftermarket torque converter will not add any HP, but it will add torque. A torque converter multiplies the engine's torque, and that's how A4's with minimal mods can pull such great 60' times. The higher the STR the more torque that you'll see at the rear wheels upon launch. A high STR is great, but you'd better have some sticky tires to hook the car up with!

 

With 3.23's I am at 2500 RPM at 80 mph.

<img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> Steve

 

i checked the door and i have frekin 2.73's. that parts guy is an idiot..thanks to everybody for the help. you really cleared up a lot for me trev.

 

You should be turning 2,000rpm @ 80 with 2.73. In that case you'll need the Super Thruster 3500.

 

so now that i know that i have 2.73's, should i go with the 3.73's and the converter?

 

A good converter will make 2.73's even look good. My car came factory with 2.73's and last year with nitto's, 2.73, lid, cutout and a vig 2800 I ran a 8.03 @ 89. Not the fastest in the world but a heck of alot faster than the 8.9 @ 82 it ran with just a lid <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Actually after my torque convertor(vig 2800), i saw @20rwhp almost across the band accept @5500 when i ended up lossing 5 hp by @6k, though at the track didnt see any real mph gains only et improvements....

 

If it were me, I'd do the gear swap. My friend has a '94 Z28 w/ 2.73's and a Yank 3200. I could not believe how loose the converter felt w/ those gears. It felt very similar to my 4400 with 3.73's! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> With stock internals, you're not going to see much improvement with 3.73's over 3.23's. I'm living proof, and there are quite a few other guys that have had the same results. Going from 3.23's to 3.73's had no effect on my 60' times, and I'm not alone on that either. You could swap to a set of 3.23's for cheaper, and you could even get the speedo re-programmed at the local dealership since you can get a car from the factory w/ the 3.23's. 3.73's will make a converter feel tighter compared to 3.23's on the street, so that's something to consider. My 3.73's make my PT4400 livable on the street for me. I did lose 2-2.5 MPG on the highway from the gear swap, so that's also something to consider.

If you do decide to swap to a set of 3.23's, let me know. I have my stock ones for sale for $50 shipped, and they're in excellent shape with only 5,000 miles on them. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />