2000 Z28 A4. 2.73 gears. 275 tires. I cannot spin the tires. Is this normal for the gear ratio? Not sure what I'm doing wrong? If they do spin it hooks up after a couple seconds or a chirp. Thinking of doing a gear swap?

 

Hello, This isn't normal even with 2.73 gear. How long since last good solid tuneup? Oil, filters to include oil, air, and fuel. Plugs and wires? My 2002 with same set up would literally put tires up in smoke. I would address the basics first, then see where you are. Is your car stock, any known issues? CEL lights on?

 

Thanks. I just done all of this. Had it on a dyno at 275hp and 315tq. I am turning the ASR off.

 

OK, great. Did anyone log your run, trans may be going downhill. Check your fluid color, if its burnt then there's the answer. Sorry man can't be more help to you, I'm sure someone will jump in with better answer. Hang in there!

 

 

Two of my four LS1 F-bodies have been 2.73 A4 cars and they both had zero issues breaking the tires free - even good quality, fresh 275mm tires. From a stop it could be done with relative ease, and even from a very slow roll (<10mph) I could shock them free. So the gear ratio is not the problem IMO.

That dyno sheet certainly isn't the prettiest, but the peak numbers aren't terrible for a totally stock A4 car - maybe on the lower end of normal though. Without knowing mileage and history of the engine, that might be a perfectly fine number.

It could be that the fuel pump is getting weak under the load of actual street acceleration (which might not be as evident in the early stages of failure on a dyno, as it still provides load but not quite the same as the street). You could try a WOT run with a fuel pressure gauge hooked up and make sure that pressure stays in the 58-60psi range. Otherwise, the pump could be weak or the filter could be partially blocked. Checking the trans fluid wouldn't hurt either, as mentioned above.

 

Thanks. The dyno run was from a dyno day right after i got the car. I have since changed the fuel filter with the rest of the tuneup items. The car has a little less than 50k miles on it. All stock motor except for a SLP lip that was on it when I got it. I will check the trans fluid this weekend and look into the fuel pump. The carfax showed the car didn't move much for the last 10yrs so the fuel pump would make sense.

 

Never have this problem with a manual transmission...

 

My 2000 SS had trouble spinning tires most of time. After a mail order tune that reducing torque management it would spin very easy. Also went from 14.0 to 13.4 at the track. Highly suggest a mail order tune for any auto car to reduce TM and adjust shift quality, for about 100$ it really makes a diff.

 

My '02 SS spins the tires with ease. The original 275/40/17 BFG's
It made 332 hp on a dynojet.

BTW the tires aren't 275mm.

 

Mine were. I replaced the stock 16x8/245 setup with a 17x9/275 setup on both cars in question. They still spun with ease even when everything else was stock, other than the air lid.

 

Why spin em? Perfect, now take it to a track..

 

Mine didn't with the original 2.73's on stock 245/16's. The car was a turd until my first mod, which was a 3.42 upgrade.

 

Over the years I remember a small handful of folks posting about the inability to break the tires loose even on stock 3.23 cars, and this goes back to when these cars were much newer and generally in a better state of repair. I remember going through a check list of possible issues with those members as well, yet nothing obvious was the culprit - I specifically remember one of them being a WS6 car with stock 275s (the factory tires were VERY easy to burn on my WS6, even when they were brand new).

I've had an even split of 2.73 and 3.23 cars (two of each), and there honestly wasn't much difference in dead-stop traction between any of them when stock. No issues getting them to break free regardless of the gear or 245mm vs 275mm (all tires being normal Z-rated; competition level tires were a different story).

 

Thanks for the responses guys. I checked the trans fluid again today. It still looks pretty new. I will need to track down some help to check the fuel pressure.

These tires are definitely 275s. I've never heard of the brand before "Fierce UHP" is on the sidewall. A 420 treadwear rating so I don't expect them to be super grippy.

 

What you need to do is put a fuel pressure gauge on the fuel rail then find a way to capture what its reading when your trying to put the engine under a load. I used zip ties, a good light to light up the gauge under the hood and my phone. You should have around 58psi on the rail and it should not drop more than 3-5 psi when under a load.

 

As in post #14, never had a problem breaking em loose with stock convertor, 3.23s', and with both 245s' and 275s'. I've driven Zs' with 2.73s' and never had a problem with those either.

 

I ordered a fuel pressure gage. Supposed to ship out Monday. Hopefully I will have it before the weekend.

 

58psi is fine, but if it drops 5psi from there under load I would consider that a potential warning sign of weakness. Anything in the lower 50s is not ideal and might suggest a blockage or weakening pump. Or, it could just be a less-than-trustworthy gauge. But if the car seems a bit down on power with no other explanation, then I would suspect the fuel system if readings drop to the lower 50s under load.

 

This sounds like my car, but its a 6 speed, 3.42s. Lid, cat back, full tuneup. No cats. It's felt underpowered sense I bought it with 50k on it. Gotta get pretty aggressive to get it to break free. Even in the wet it doesn't. Just feels lethargic under 3-3500rpm. It's almost comical cause my old tpi 5 speed bird would light e hides at will. Sounds like I need to chase fuel too