Well I know this answers varies but lets say on the average here. I have a '95Z a4 and Im getting a h/c setup installed and it will push aroun 375-380 rwhp. I also have a 3200 stall TC along with some et streets for the track. I know breaking the rear is mostly from launches so how should I approach it. I mean is 400hp to much for a 10bolt? Or could I be fine as long as I dont launch to hard.I cant afford a 12bolt right now so, thats out of the question.Thanx.

 

Kind of a difficult question. I know people who did high 10 second passes on stock 10 bolts and others that broke them on mid 11's. However A4's are very forgiving on the rear end so if you can avoid wheel hop I'd say you can run ok with your 10 bolt. It's the 60' time that makes the big difference. If your pulling 1.6's it'll be fine. Most automatics I hear of breaking the 10 bolt is either because of bad wheel hop or some 1.5 or better 60' times under tremendous HP and torque.

It's really amazing how far an auto can take a ten bolt compared to how easy M6's can break them. But then again they get all that friggin MPG on the highway and thier tranny can handle a lot more power then ours can. You'll probably need a stronger tranny before you need a stronger rear end.

Good Luck

 

You're probably in the breakage zone now. I'm probably putting down the same amount of power, and stock 10 bolts with big converters in front of them generally start to fail at low 1.6 60's. Although I've seen a stock 10 bolt with 3.42 rear gears and a TA stud girdle hit a 1.48 60' before.

 

Had 670 runs on my 10 bolt with 4.10's in it before I took 4 teeth out of the ring gear And that doesn't include all the street abuse it had A lot of it will depend on how well the gears are set up (backlash, etc.). I'd have to look at my log book to figure out how many runs this second set of 4.10's has on them, but so far so good!

Oh yeah, the stock A4 had a lot more runs than that on it before it finally need rebuilding. It still worked, just getting sloppy.

 

On my original rear I averaged 400 passes between breaking it.

 

i think u may want to start being careful with it now. i think high 11's/350+RWHP with an auto is when it is starting to get weak

 

get one of these to make your 10 bolt last. Spacer

My best 60ft is a 1.54 and I drive my car every day so it gets it fair share of street ragging too.

 

i rarely goto the track, so I cannot say how many passes. my best ever on the stock 3.42 rear was a 1.69 60'. best pass i made was a 1.97 60' on a 11.4@124mph pass. when the rear finally gave, it was at like 50mph on the street powershifting into 2nd with BFG DR's. the ring and pinion still looked really good, but the spider gears on the posi itself were destroyed!

 

mine lasted about 2 weeks after the 17" nittos went on broke the spider gears.. mine is a m6 though and a A4 is not as hard on the rearend.

 

How those that spacer help, and what would it do. Also where does it go? Thanx

 

another member of my car club just informed me that his spider gears were gone in his as well. he broke his 2 weekends ago at bragging rights. his was a 3.42 and had 3 passes on it when the spider gears went. he has an LS1 auto with only a lid, headers, cutout, and stall. he ran 11.9X with 2.73's, and was hoping to better his time. he had 3 passes of 12.0X before his new 3.42 rear gave out.

 

They go on the pinion shaft in place of the "crush sleeve" as you can imagine putting a lot of abuse on the ring and pinion makes it want to push the ring gear back. And when Hook up good all the time this tends to crush the "crush sleeve" which makes it sloppy.

The Solid pinion spacer is "solid" so it won't move over time like the crush sleeve will.

Most guys rear ends will start to howl when this process starts to get bad and not know what to do about it they keep running it hard until there is to much slop and it rides on the edge and breaks off the teeth.

 

Ive know some guys that busted them stock....and ive seen some guys runs 11's for quite awhile til they busted

 

this goes to show that there is no telling how long one will last. some last only the first trip to the track, some last a long time. it is a gamble you take when you flog an F body rear end!

 

A4 here I have had a best of a 1.44 60ft with mine and have seen no problem with it.

Here is a pic of one of the launches

www.illinoisracing.net/jucin2.gif