Ok, got my purple pearl 93 dyno tuned last Friday (May 14th).

Dyno Sheet Here

Mods are: GM Hotcam Kit, Ported heads (reportedly flow 260/200@.550), Mac Headers, Mac ORP, Flowmaster piping with a dynomax muffler, K&N CAI, Holley Airfoil, SVO 24# injectors, Mezier WP, vented opti conversion.

Power just seems a bit low to me. I would have expected to be at about 360ish at the wheels. Everything is running fine, and the car feels great (FWIW, it's got a 3.23 rear and a 95 M6=undergeared), but I just feel like it's not making enough power. I'm thinking the car needs a better cat back and a 52mm TB. Under the previous owner, it went 12.69@105 with a 1.74 short time and a shot 2-3 clutch pack in the stock A4 with a 3200 Vig TQ convertor.

Thoughts???

 

Looks a little lean after 4K

 

Nope. It's dead at 13.0-13.2. It's just the way the graph looks.

 

Those headers aren't helping you any, a bigger TB would make a difference. With sketchy head numbers, it's hard to say if there's any issue.

 

Well, according to the previous owner, the heads were done by a buddy of his who's a pretty reputable ported.

I DO NOT think the headers are holding me back at all. 12SCNDZ is running his car with MAC's and I KNOW he's making more power than me.

I honestly think it's either a TB/cat-back choking point.

 

prove it? everyone ALWAYS throws out those comments but never has any proof to back it up!

 

1 3/4 flows more then 1 5/8 period. Law of physics.
52-58mm TB flows more then 48mm period. Law of physics.

If there's anything else, let me know.

 

LMAO, thanks for putting that in a fashion i can understand!

now do you have any proof that says he has restrictions somewhere?

NEVER BEEN PROVEN that a larger TB will help performance (especially on a stock cube NA motor)
nor larger diameter headers or LT's

when you can prove that those items are restricting the potential of his motor (or any similar), by all means "let me know"

just cause the law of physics says it flows more due to larger diameter does not mean his motor needs it or will perform better with it

 

There is no concrete proof. Dyno #s are subjective. But time and time again, I've seen dynos on cars producing 350+ hp N/A on an LT1 gain from the addition of long tubes (over midlengths), a bigger TB, or true duals over a catback.

 

maybe you should explain that to steve quinn

he runs a naturally aspirated 370ci LT1 with ported stock heads.
ET: 9.900 MPH: 135.16

those 1 5/8 headers really seem to hold him back.

 

time for true duals?.....of course

 

I will lay $50 down, and if anyone has a set of 1 3/4 long tubes around that they'd let him borrow and dyno, that says his car would dyno more with 1 3/4 long tubes.

Note: Steve is a great showing of how the RIGHT combination of parts makes a car fast. He's definetly got his stuff together.

 

It not the headers. I have a similar setup - hotcam, home ported heads, edelbrock headers and catback, ultraflow muffler. I dynoed 363hp and the edelbrocks have 1 1/2 & 1 5/8 primaries.

What muffler do you have? I don't think its the throttle body because I did not see any reall gains from my 58mm BBK. If yo have logging software, check your MAP values at WOT at max RPM to see if you start to pull a vacuum. Also what is your airflow reading from your MAF? I generally pull around 330-340 gm/sec in 80 degree weather at 500 feet above sea level.

I don't hold a lot of value in dyno runs anyway. Take it to the track and see how it does. I've run a best of 12.5@112 with my setup if you want a benchmark for a similar setup.

 

some dyno tests ive seen show that a larger header primary will make more torque down low, but a slightly smaller primary will make more power on the top end (peak power) which is where you spend most of your drag racing time.

 

there doesn't seem to be anything wrong with the parts you have selected or with fueling/ignition noting the steady AF ratio. How much do you know about the heads you have? I've seen people pulling 320rwhp just with the HOTcam no heads, so your heads may not be doing much for you...can you contact the people that set them up?