My baseline dyno happened a while ago and the 2002 Z28 only had around 13,000 miles on the odometer. Check out the dyno graph below:



At around 46,072 miles and still completely bone-stock, I brought the car to Atco for a baseline quarter mile run. Here were the variables:

- The car had a full tank of gas.
- Each tire had 30-31 psi air pressure.
- Elevation was at -158 ft.
- Temperature was 54 degrees F.
- Relative Humidity was between 76-78%.
- Dew Point was 46.7 degrees F.
- The barometer was 30.09 inHg.

First run was 13.567@103.62; 2.095 60'
2nd 13.512@103.39; 2.107
3rd 13.804@101.84; 2.171
4th 13.687@101.92; 2.126
5th 13.540@101.80; 2.079
6th 13.679@101.84; 2.102

Is my car retarded or something? Why are my dyno numbers so low and why are my quarter mile numbers so horrible? Should I get a dyno tune? At less than 8,000 miles, the dealership replaced my transmission's pressure control solenoid, because I was getting a P0748 code. (The car was intermittently shifting too hard.) The car shifted fine afterwards. Could replacing the solenoid be related to my low power and slow times? Thanks in advance for the info.

 

idk but that sounds about right... most auto's dyno near 290 or 300.

 

my 98 dynoed 305 to the wheels stock with 75k on it

 

It doesn't look so bad to me...you just didn't get a freak of a car I guess. Nothing to worry about. Its still pretty damn fast. Get those 60' times down to soemthing respectable and you'll be gonig low 13's...which is right on par for a completely stock car. Who care's what the dyno says anyhow? How quick the car goes is really what is important, right?

 

Mine only dyno'd 288 HP / 307 TQ a couple months ago with the setup in my sig. Your #'s may be on the lower side (the MPH reflects the RWHP) but it's not that far off what the average LS1 runs.....your times are good, and the 60' time shows you need a little more traction. I'm resolved that I didn't get a "factory freak", and you're in the same boat, that's all. 280 RWHP is still better than 260 flywheel HP that Mustang GT's are rated at!!

 

Bone stock with just over 3k, after the first oil change, mine dynoed 285/300. With the mods in the sig, it did 310/326.
Times are about the same as yours. I only have 8 passes on the car, so practice would be a big help.
These are just numbers. Unless you make a living racing the car, it's just for fun anyway.

Relax and enjoy the car.

PJ

 

At 47k miles your plugs could be misfiring, you could have a little carbon in the combustion chamber, and or your fuel filter could be plugged up if it hasn't been changed. I've heard of the stock plugs misfiring at only 30k miles on a well-maintained car (Patman's vette is an example). I changed plugs and wires and ran that cleaner through at 70k, and the car seemed to feel a little more responsive. Change the plugs and fuel filter and run some GM Top Engine cleaner through your car then get it dynoed again at the same place. I bet you'll put down better numbers. Also, the dyno you were on could be a tad off as well.

Jason

 

I've been thinking about getting the plugs changed, but would you still recommend that after you read the following update?

Just recently, I had the local dealership (where I bought the car from) replace my fuel filter, clean my injectors, and drain and fill my transmission with a new ATF. Now, I just got back from a 4 hour roundtrip drive from Performance Specialties in Pottstown, PA, for 3 dyno runs on a dynojet with air fuel ratio monitoring. The weather this time around was cool with low humidity (unlike the first dyno that took place in a hot and humid day). Note that the first dyno took place at Cartek and the car back then had around 13,000 miles. Now, the car has a little over 46,000 miles. Here were the results:

Max Power = 285.1
Max Torque = 302.0
Air Fuel Ratio was 11.9.

The car seems to have gained 4 hp and 5 ft-lb. of torque just through mileage alone. Ray, at Performance Specialties, mentioned that the car was running fat and could gain 15 horsepower through dyno-tuning. Could my air fuel ratio be the reason why my car is dynoing lower than other stock f-bodies? Also, regarding my times in my original post, I forgot to mention that 5 of the 6 passes were done when the transmission was engaged in overdrive. Does that make a difference? Thanks in advance for the info.

 

Yes, change your spark plugs and get some NKG's like mine, preferibably the Iridium version instead of the Delcos. Also, get a can of GM Top Engine Cleaner from the dealership and run that through. If you're familiar with Seafoam, this is basically the same except it comes in a spray can. After driving the car warmed up, disconnect both AIR hoses (right by the coil packs) and spray a can of this stuff into the throttle body while the engine is running. Let the car sit for at least 30minutes and start back up. Your car will blow out huge amounts of smoke from burning off the cleaner and carbon. What this does is clean out your combustion chamber and prevents any hot spots that could cause pre-ignition. With this and a plug change, you should dyno in the 290's.

Jason

 

I know everyone is going to call blasphemy, but not EVERY ls-1 dynos over 300 in bone stock form.

 

Was this done on a dynojet?

 

If your runs were done on a mustang dyno...your numbers would be VERY GOOD...especially for an A4. That would be around 310rwhp or more on a dynojet...very good for an automatic car.

I agree...something must be wrong for an 01-02 ls1 car to dyno 280 at the wheels on a dynojet...that is even on the low side for a 98-00 a4 car.

 

[QUOTE=damon_Z]My baseline dyno happened a while ago and the 2002 Z28 only had around 13,000 miles on the odometer. Check out the dyno graph below:





First run was 13.567@103.62; 2.095 60'
2nd 13.512@103.39; 2.107
3rd 13.804@101.84; 2.171
4th 13.687@101.92; 2.126
5th 13.540@101.80; 2.079
6th 13.679@101.84; 2.102

QUOTE]
Not sure why it would trap so low . The times where not bad for a stock Auto but your Trap speeds are low for an LS1 . I dont think I have ever seen one trap less then 102 on a good run . Dunno man , Hope you figure it out . A 13.5 isnt a bad quarter time though .

 

My numbers in my sig. are from a lid and a muffler I had on.

I hope those two things didn't give me much gains because that would mean mine would have dynoed lower than average if it were stock.

 

[QUOTE=robb4964]This was done on a dynojet, but I think I might have it figured it out. I'll engage the transmission on D the next time around and, before running any more drag strip passes, I'll get my factory spark plugs replaced. Another issue is the rich 11.9 that I'm running, because I know I'm losing a little horsepower from that. I'm not going to dyno tune the car just yet since it's only in bone-stock trim.

I did some research on LS1.com regarding the stock AC Delco and even the sometimes come-from-the-factory NGK-TR55 and I realized that at 46,000 miles, those plugs have probably gone bad. I'll also run at least half tank (of gas) to maybe save me at most 50 lbs. from the rear end.