Finally got started modding the car!

[ScreaminRedZ]

Well, I was off yesterday, so I decided to stop slacking and get started modding the LT1. Nothing crazy, but I swapped the stock 2.73 rear end out for a 3.42 rear end from a 2002 Z28. I also swapped in an LS1 driveshaft and a 1LE elbow. Changed the oil with Royal Purple and used Royal Purple in the rear.

Like I said, nothing crazy, but the fun factor just went through the roof with the car. It actually does a burnout like a real muscle car should and even kicks the ass out sometimes on the 1-2 shift.

I was worried that the shift points might be off (I've heard that that can happen when gear ratios are changed on these cars). The car seems to shift about 200 or so rpm higher (around 6000 or 6100) but doesn't hit the limiter and feels strong, hitting the next gear with a kick.

The only thing is that the speedo is quite a bit off since I have no way to fix it as of yet. That should be fixed in the next couple weeks.

I also have a set of Nitto drag radials ready for the next time I go to the track (I'd have them on already, but they are on 16" wheels and I don't want the car to look rediculous).

My previous best time is in my sig and I don't think the car will have any trouble cracking into the 13's on the Nittos now.

[YZF]

Nice! That gear swap is equivalent to the M6 cars swapping to a 4.10. So as an M6/4.10 owner, I can understand how that would really wake up the car.

[BLOWNDFIZ]

2.73 to 3.42 swap made a huge difference in the fun factor of mine. Believe it or not the fuel mileage stayed the same. I'd go ahead and have your PCM tuned by PCMforless of whoever you choose. Bryan can increase the line pressure, adjust shift points, and correct your speedo.

Have fun!

[bricez28]

is the kick that awesome? i have 4:10s sitting in the car, i hope its worth it!!!

[KissMyWhtSS]

You'll gain some power from the LS1 Driveshaft being lighter but it's not as strong so if your running DRs at the track I'd highly suggest a DS Loop. (Granted your suppose to have one with DRs anyway.)

[BLOWNDFIZ]

is the kick that awesome? i have 4:10s sitting in the car, i hope its worth it!!!

Gear swaps make a huge difference. I can't remember if you are A4 or M6. In my experience 4.10's are good for a NA M6. When I had 4.10's in my car I felt I had to shift way too much. I went back to 3.42 with the blower, then settled on 3.73 with the 12 bolt and T-trim. The A4 car of mine I have 3.42 and being I drive 22 interstate miles during my commute 3.42 is as low as I think I would ever go. I'm 2500RPM @ 75 with 3.42. I think generally 3.73 for A4 is the norm, 4.10 for M6. I'm more in the 3.42 A4, 3.73 M6 camp. Just my opinion.

[KissMyWhtSS]

What do you 4.10/M6 owners get on the highway? Just curious.

[ScreaminRedZ]

Yeah, I had 3.73's in my old 1994 TA and they were fun, but for what I want with this car I'm gonna stick with the 3.42's. The 3.73's definitely wind out more on the highway.

For the driveshaft, they are slightly weaker, but there are plenty of people beating the hell out of them with 400+ rwhp 6-speed cars on slicks and they aren't breaking left and right. I'm sure my mild LT1 A4 won't break it. The driveshaft loop is definitely a good idea though (both for safety and in keeping within the rules) and I'll be getting one in the near future.

My friend has the laptop, program and cable needed to adjust my speedo, so I may save my money for now and fix it that way. I do like the idea of getting a bit more hp out if it though. It shift very firmly, so I'm not sure if the line pressure needs to be upped, but I'm sure they know what it needs better than I do. What does it cost to have PCMforless tune it?

I did end up setting up a race between my LT1 and my stock G8 again and the LT1 definitely hangs with it better down low, but the G8 just runs away once the LT1 hits 3rd gear. We did 2 1st gear rolls and 2 2nd gear rolls. With the street tires it just blows them off from a dig in the cold weather. Once I get the drag radials on I want to do it again from a dig and I think the LT1 will pull the G8 out of the hole. I'll be curious to see where it catches up again.

Next up I'm debating whether to go with the Thunder Racing performance pack or a Mac Cat Back. Someday I'd like to put a supercharger on the car, so a CAI doesn't really make sense, but it's such a good deal that it's hard to pass up. On the other hand, I would like to get the Mac catback just to have something different.

[BluBeaSSt]

Very nice man congrats, but watch it...it's addicting ;)

Also food for thought, you might wanna just run some straight GL5 with friction modifier in the rear end, or your clutches will wear out prematurely.

Also about the comment about the LS1 driveshaft, there's many car's with LS1 drivelines in the 11/10 range.He should be fine,and it's an auto so deff no worries.

[ScreaminRedZ]

I'm running Royal Purple gear oil with the GM posi additive in the rear. It's an LS1 rear though, so it has the worm gear type posi. I don't believe there are clutches in that setup. Thanks for the advice though!

As for it being addicting, I think that the crap gearing is what was making me not care about modding it. Now that it's so much more fun to drive I'll be looking for the next mod every chance I get. I feel like I did a few years ago with my 1994 TA. It wasn't the fastest car ever, but it was fun as hell to mod it up and then go looking for some races!

[ScreaminRedZ]

Well, I'm sure plenty of people have done it before, but I weighed my LT1 driveshaft and my LS1 driveshaft that I just installed in my car. The LT1 shaft weighs 16.5 lbs and then LS1 driveshaft weighs in at 11.5 lbs. That's gotta be worth a couple rwhp.

[dafhturbo]

when you change your spedo you need to change your shift points. i went from 2.73 to 3.73 in a a4. the car did ok for the drive home. after fixing speedo car shifted very late. the transmission uses rpm & speed for shift points. both settings have to be met in order to shift.