i got a 97z, 383 lt4 heads/intake, gm847 cam. Ive got a vig3200 sittin in my room waitin to go in. Right now ive got stock tires but obviously im going with some nice slicks. This will be a street and strip car. Fuel economy is the last on my mind due to not having much anyways so what the hell. Im thinking of going with 4.10s. I am not worried about a few more rpms on the highway. Im wanting the best performance. My races consist of a few 30mph runs but mainly stoplight to stoplight as well as the 1/4 and 1/8 tracks. Im going to go for high 11s i dont know what im up aganst though. Any ideas ive got a few weeks before i do gears, but im trying to weigh what people will say.

 

I'm in the same boat as you...I currently have 3.73s and go across the traps at 6000 with a 26" tire...I'm going to switch to 4.10s to bring my rpms up to 6300 with a 26" and also give me the ability to turn a 28" tire if I decide to change sizes...The GM 847 is a big cam with a high rpm peak power so I'd think that 4.10s would help you have a great top end charge...You are not running a power adder, right?

The downside besides highway cruises, which still isn't too bad with the OD trans, is the 3.06 first gear the 4L60E has...multiply that times the 4.10 rear and you have one hell of a first gear total drive ratio...meaning traction may be an issue if you don't have a good suspension/tire set up...I'd say with your cam they'd be a good choice...

My wife's 2000 SS A4 has 4.10s and an air lid and went 13.50s @ 108 with a 2.17 60' just messing around at a track rental, full weight with half her life in the thing (actual weight addition, not reduction hahaha) and Toyo tires at who-knows-what psi...Its a 12 second ride with DRs and a yard sale!

--Alan

 

I loved my 4.10's in my A4 car. With a stock bottom end LT1 with a little CC305 it was running 12.0's @ full weight. My best 60 was a 1.67 on 26" tall ET Streets. I was making a 3-4 upshift around 100 ft. before the stripe, and trapping 112 MPH with.
With the only change being a swap to 3.73, the car slowed to a 12.2.

Frank
CPT

 

nope no power adders for me, all na. i just have to fix this violent vibration from 2k up which only happens in gear not in nuetral. Sounds like a aluminum driveshaft is in order

 

+1 for A4 w/4.10's . Running STREET tires, I posted the time in my sig, and my car was otherwise stock! (with the exception of a lid and Chokemaster catback)

As long as your engine can handle spinning a little further over 6000 RPM, and/or you run a taller tire (ie: 28") to get you through the traps in 3rd, then you've got no problems, and you'll have (obviously) better acceleration.

Hey Frank, you say you let 'er shift into 4th before the line ..... is it "ok" to do a 3 - 4 shift under full power like that?? Or is it something that you'd have to have the tranny "built" for?

 

[QUOTE=Capn Pete;4366636
Hey Frank, you say you let 'er shift into 4th before the line ..... is it "ok" to do a 3 - 4 shift under full power like that?? Or is it something that you'd have to have the tranny "built" for? [/QUOTE]


Well, I wouldn't really suggest it unless the transmission is built for it. We set them up so they're capable of holding up under a WOT 3-4 upshift.

Frank
CPT

 

^ ^ that's sorta what I figured .

 

There's no such thing as toooo much

I love my 4.11's w/ the automatic.

A GM847 w/ 3.73's is undergeared.

 

Those are the same parts that I've got in my impala SS. Difference is that I've got a lot more weight (4100#) and a lot less motor (stock B-LT1). I was able to run a 12.97@102 with a 1.70 sixty foot time with completely stock internals and a bit of an ignition miss in excellent weather.

 

Too much "how"??? C'mon, don't you go jumping on the "you should probably get 3.73's for your A4" bandwagon!! I HATE stereotypes like that!!

 

I would have NEVER switched from 4.10's to the 3.73's unless I thought it was neccessary because of my future nitrous intentions.

Frank