I went to the track over the weekend for the first time with my cam, headers and 9in from Scott @ Driveline Solutions. I was really happy with the times I turned (best of 12.32 @114.5) which is pretty good considering my tune is still off. My car is 3800lbs with me in it and has 275 nittos on it. I was launching at 4000 and cutting 1.8x 60s. I've never been able to really launch the car on the 10 bolt the way it needed to be launched. The best part is I had no fear of my rear grenading and when I was done the rear was still as quiet as the day I put it in (which seems to be an issue with some 12 bolts). I really have to hand it to Scott (1BAD86Z28) he set my rear up perfect and the driveability is no different than the 10 bolt. I think its time to spray . If anybody has any questions feel free to ask.

 

Sounds good Tom, and congrats! I've been waffling back and forth between the 9" and the 12-bolt. As it stands now, I'm pretty much set on the 12-bolt with 4.10s and some sort of posi.

I don't have a track car but I'd like to go at least once to see what kind of time I can pull with street tires. I've decided on the 12-bolt because I think it will be easier to install and make work with my car, plus I think a HD posi will be better for the type of driving I do (lots of twisties in the Northeast).

I'm curious how difficult you found the 9" to install, and if you had issues with the pinion angle? Also, can you notice a power drop with the 9" because of its weight and parasitic loss? Any issues with the torque arm or anything else you can think of?

Thanks.

 

Do you have a spool?

 

Glad to see you like it, I hope mine works just as well. I'll have some impressions with my DLS 9" w/ spool once my driveshaft comes in next week.

 

what was your best time before the 9" went in?

 

The install was straight forward. I pressed my own reluctor rings on but you could have those done if you didnt want to do it. I had no issues with pinion angle it was pretty much a plug and play.

As far as power drop I really didnt notice a drop in performance partially becuase I went from 3.73 to 3.90s so the small increase in mechanical advantage made up for the loss in efficiency. To be honest with you there is no difference in driveability. I really cant feel a difference just driving around so I'm really pleased with it. Where the difference really lies is the ability to launch the car, its really nice to drive the car hard and not worry about breaking it. I went with a 31 spline tru trac so I was able to have a strong unit with a minimum of rotating mass. Scott was really helpful in choosing what was right for my application so it kind of took the guess work out of it.

 

Nope. Tru-Trac

 

The last time I took the car to the track was before the cam and headers. All the car had at the time was a lid and 3.73s. I went 13.2 @109.

 

Thanks Tom, you got me leaning toward the 9" now. I was reading up on the Detroit Truetrac and it seems like the best of both worlds, sort of like a super strong limited-slip, and a spool when needed, no clutch plates. Too bad you can't get it with a 12-bolt.

Did you use reuse your stock driveshaft and did it fit okay? If you ordered a new DS, did Scott know what length you needed, or did you have to measure after installing the 9"?

 

BTW Tom, I see you got 3.90s (which seems to be the perfect gear ratio), are they quiet? I've heard that they're noisy, at least in a 12-bolt.

Are you saying that you almost gained 1 sec. in the 1/4 just by changing your rearend?

 

Last question (stuff keeps occurring to me), did you reuse your stock torque arm, if not which one are you using?

Thanks.

 

I missed that, "before cam and headers."

 

Yup I was able to reuse the stock shaft. You just need to put a different ujoint on the end of the stock shaft. Scott offered an upgraded shaft but I didnt want to do it yet so I stuck with the stocker. The 3.90s are noticeable but not out of control noisy. Any rear you geat you will hear gear noise. Some peoples definition of loud is different than others. I'm pretty picky when it comes to noisy gears so I think I can say comfortably that they arent to bad. The nice part is the 12 bolts seem to have an issue with getting noisier the more they are abused(ie launched). My level of noise hasnt changed since it was installed.

 

Sounds good Tom, and thanks. I've been wondering about the torque arm situation. I've heard that if you used an aftermarket one that there's not enough clearance. You using the stocker or aftermarket?

 

HAHAHAHA You know when the tru trac locks Good choice. Ive seen to many people in my club bitch how they broke a 12 bolt and my 9' is still rolling strong

 

I'm using the stock TA.

 

Yeah I love the tru trac. I never thought that I would be able to feel how well a posi, spool or locker worked but if really does feel amazing

 

BTW I would reccomend doing Control Arm Relocation brakets when doing the rear. They help alot. I chose UMI but there are others that are as good.

 

Tom, thanks for the replies.

It's looking like a 9" with 31 or 33 spline (not sure), 4.10s, Truetrac, maybe just stock TA, and either stock or upgraded DS (not sure). I really want a Truetrac--sounds great! Is a Truetrac the same as a Trach-Tech (as listed on another site)?

BTW, did you go with stock wheel studs (12mm) or 1/2"? Any thoughts about that?

Thanks again!

 

Do you mean if the car's lowered, or either way? Is that to adjust the pinion angle? Damn, there's so many details to think about.