nyelectrify

Put wife's 98 on Dyno Saturday. Very disappointing numbers!!
These are the mods
Blackwing
VRAM over radiator
Non screen maff
Bbk throttle body
Brand new stock injectors off crate motor
Zo6 over axle
And a tune
315 rear

365 at the crank
Held good till 5800 dropping off at 6000
Top speed was 158

Thought the numbers would be better by around 30 horse to 40

I know with ls intake and 243 heads and headers and heads it would be up there, but for a baseline???

I drive it and doing 75 it's getting 27 mpg!!
It only starts to dump a bit more fuel at around 5200 rpm

Shouldn't it get richer around 36 or 4200??

Any comments or input would be great

NukeC5

Ya thats strange. Auto right?

My 99 auto based at 320 with only a k&n and ls6 intake and a axleback exhaust. Are your spark plugs good? Wires? Running good fuel?

Before all the rear end work I was getting 31mpg at that speed..

nyelectrify

Plugs, wires, injectors all new because the car has 65k on it

nyelectrify

Yep automatic

steven31371

LS1 or LS6 intake mani?

If the former, that seems about rught to me...stock autos usually dyno around 290 to the wheels

steven31371

BTW Nuke...you called it almost spot on with my H/C/Tune

ended up at 426 RWHP and 401 RWTQ ;-)

nyelectrify

Still ls1 intake. But with all bolt ins so far at wheels was only 285

steven31371

has it been tuned?

If not, you will need to disconnect the battery and drive it for a day or two for the PCM to relearn....everytime I added bolt ons without a tune it took a good 4-6 hours of driving in various conditions before I really felt a signifigant differance in power with the but-o-meter.

steven31371

nevermind, just read that it had a tune...hmmm

onspeed

stock intake and exhaust manifolds is your problem.

And 315 rear, you mean 315 tires or 315rwhp? Cause 315 tires would take some HP away too

RonSSNova

3.15 rear gear. It was an option for the A4 cars.

nyelectrify

That's the rear end gear ratio. 315

chaase

The only thing you added that would increase HP was the Blackwing. I would expect numbers ~10-15rwhp over baseline with those mods, so 365bhp would be about right.

pewter99

....IIRC stock C5's dynoed 292-296 rwhp


so you are telling me you dynoed less than stock?

chaase

The OP needs to clarify. I think he ended up with 365bhp starting with 285rwhp in stock form. If that is the case, then the outcome is what I would've expected.

pewter99

I'm kinda lost...glad its not just me

Black 02

None of those mods really do anything so that sounds about right for me. If you haven't done plugs and wires yet, that could be a good start. When I did fresh plugs, wires, and long tubes I felt a huge increase.

nyelectrify

The outcome of Dyno with all that was done gave me 285 at wheels and 365 at crank

chaase

What were the numbers before the modifications were made? Was it a Dynojet or a Mustang dyno?

NukeC5

You also have to consider the dyno that you were on. The 285whp number is very normal power on a dyno that is not 10-15% corrected. (Which most dynos are). IE dynojet, mustange, etc. Most power figures you read on here are from dynos that have a percentage "corrected" for. I dont know why its that way, but they do.

I go to a tuner who uses a "Dynolog" dynomometer and have dynoed the same setup on a dynojet too. On the Dynojet Im at 340whp, on the Dynolog I am at 310whp. This is an uncorrected dyno and IMO, the most accurate. Its a heart breaker dyno, but when you think about it, its the most realistic.