2002 blue z28

iTrader: (1)

I actually gained 65 rwhp. Last time it was dynoed was with exhaust and intake only, it put down 344 rwhp. Pretty good gains for a mild heads/cam combo.

Now I'm contemplating adding 1 7/8" headers into the mix, but from what I've read I'll lose some low end torque. Idk, I'll probably end up keeping my 1 3/4"s.

spicebird98

iTrader: (10)

sounds like good numbers to me, you have a lot of little tweaks that could add up to a good amount of power left. Dont have to RPM that too high with that little cam either to preserve the 4l60e. i would have even gone with a smaller combustion chamber on those heads since you wont have to worry much about PTV clearance with that cam. 62cc's with a .040 gasket would pick you up even more. Interested in track results for sure.

sabersaw30

iTrader: (10)

Street tires i would say mid 12s. Drag radials you would get in the 11s. My guess. You need a little more stall.

MikeWS6

Very strong. I would def get rid of the cats and get a cut out. You would probably be very close to 420rwhp. Your current headers are fine.

kinglt-1

iTrader: (26)

Thats a myth...besides you have a stalled a4, low end tq is not really much of a factor.

2002 blue z28

iTrader: (1)

I went with cats to keep the exhaust rasp to a minimum. As it sits right now there is some rasp, but you have to listen for it to know it's there. How raspy does the magnaflow get without cats?

Kingc8r

iTrader: (21)

If you're worried about rasp then add a nice merge to your y pipe.

My 3" into 4" flowmaster merge into a 4" cutout pipe necked down to a 3" cb has little to no rasp thru my Hooker CB.

Kingc8r

iTrader: (21)

Oh and decent numbers through your auto with those heads and baby cam.

MikeWS6

My buddy ran that setup without cats and it was fine. If you wanted to keep the cats maybe run a cutout before the cats, right after the headers. Ive seen that done before but the ground clearence was pretty bad.

2002 blue z28

iTrader: (1)

Could running a cutout that close to the o2 sensor cause it to malfunction?

1BAD98LS1

iTrader: (33)

Do the 1 7/8"s headers, you will not regret it and I strongly disagree with whoever said you will lose low end torque. Take a look at my sig and tell me if you think I lost any low end torque LOL.

2002 blue z28

iTrader: (1)

Little bit of an update, I was changing the diff fluid today and discovered that I actually have 3.73 gears. Could this be a potential problem since I told the tuner I had 3.90's?

1BAD98LS1

iTrader: (33)

Your speedo may be slightly off a bit but that's about it.

2002 blue z28

iTrader: (1)

Finally got down to the track today. I was leaving off idle with street tires. DA was 2900.

Best run of the day:

R/T: .578
60': 1.961
330': 5.350
1/8: 8.127
1.8 mph: 87.87
1000': 10.553
1/4: 12.591
1/4 mph: 110.69

I kept having issues with 2-3 shift, it would bounce off the limiter and the car would nose down. I don't know if that's tune related or somethings wrong mechanically. Anyway, let me know what you guys think.

Macs98Z

iTrader: (16)

The dreaded 2-3 shift fail. It might be your 3-4 clutchpacks going out--a weak point in these transmissions. Do you smell any burnt fluid on the trans dipstick, and has it ever done this before?

Mine had a 3-4 clutch pack go out, and it would be fine up until the 2-3 shift, when it would bounce off the rev limiter until I eased my foot up a bit on the gas and it would slide into gear. It progressively got worse until I completely lost 3rd gear. That took about 3 months though, so you might have some time.

It could be the issue with the wrong gear ratio in the tune, but I'm unfamiliar with what the computer uses to calculate shift points so I will stay away from that and let someone else chime in on that.

2002 blue z28

iTrader: (1)

It was my first time at the track and it only happened to me under WOT, it shifts fine driving around town. I never smelled burnt trans fluid, but I never thought to pull the dipstick. So should I avoid the track until I can get a built tranny?

DarkblueTA

If the non-shift issue did not happen before the tune, then it is tune related. Have the tuner replace the upshift/downshift tables to correspond with your 3.73 gear set.

If the trans still continues to not want to shift, then I would say it is your clutch pack.

2002 blue z28

iTrader: (1)

I checked the trans fluid about an hour after I got home and it didn't look burnt and i'm not sure what burnt trans fluid smells like. Also, not sure if it's related as my dad told me my car nosed down because i was floating the valves, but could that be from the tranny slipping?

Macs98Z

iTrader: (16)

Burnt trans fluid looks darker on the dipstick and smells like burnt clutch material. You'll know it if you smell it.

I would go ahead and correct the tune for your gears, as you should for your odometer anyway, and see if that fixes the problem. If it still doesn't shift 2-3 under WOT, then its your trans going out. FWIW, mine only didn't want to shift under WOT. Any other time it acted fine. Gradually, it got worse to the point that it would do it under any heavy acceleration.

2002 blue z28

iTrader: (1)

I'm bumping thread for opinions on swapping headers.

I'm changing my setup this spring and i'm debating on swapping out my Hooker 1 3/4" and catted-y for Kooks 1 7/8" with an ORY. So, my question is will the gains justify $1k price tag?

Current changes will include:
-Tick SNS Stg. 2 cam
-Cometic .040 head gaskets
-Milling heads from 64cc to 62cc

Any insight will be greatly appreciated.
Thanks