Went to my local dyno shop today for some power-runs on their Sun Road-a-Matic XII dyno. First run (in red) is stock, second run (purple) is with K&N cone filter and third run (black) is with K&N cone filter + Hypertech Power Tuning (non-RFG).











Plots show calculated numbers at the flywheel. Power at the wheels is as follows:

Baseline (all stock): 249RWHP @ 5,457rpm
K&N cone filter : 265RWHP @ 5,553rpm
HPPIII : 267RWHP @ 5,337rpm

Car seems down on power (esp. for the first run, all stock) and last run has very eneven power/torque curves. This may well be due to swapping components and not allowing time for the fuel trims to adapt.

All runs were performed in 3rd-gear with the TC unlocked. Coolant temp was approx. 196f and ambient was approx. 72f.

Here's how the filter and HPPIII affect baseline power and torque:

Filter: Additional 16RWHP / 16RWTQ
+HPPIII: Additional 2RWHP / 18RWTQ

It's worth mentioning that although the HPPIII only gained an additional 2RWHP peak power, it added 25RWHP at 5,000rpm when compared to stock tuning.

The K&N cone filter ($55 shipped) added power and torque throughout the rev range... amazing what just an air filter can do! The dyno op was speechless!

What is interesting when looking at the plot is how smooth the stock curves are in comparison to the K&N and (especially) the HPPIII curves. I am assuming this is due to the PCM making crude realtime adjustments to fuel and spark. I would anticipate that, after a period of learning, the curves would even-out and, maybe, I would find more peak power/torque.

What do you guys think? For those that have seen several dyno plots for other C5's or have first-hand experience of dynoing stock and modified C5's, how do these plots look?

The one thing that is very strange is the sudden jump in RWHP/RWTQ between about 4,800rpm and 5,000rpm for both the K&N and (especially) the HPPIII curves. Can someone offer a credible explanation?

Cheers,
Ian.
:cheers:


[Modified by i_york, 11:24 PM 9/24/2003]

 

ttt anyone?

 

I can't see the plots!

 

Hmm... that's strange, I can see them fine :confused:

Do you see the other pics?

 

I can see it fine too. Getting my car tuned tomorrow, crossing my fingers.

 

Ian,
HP #'s seem 30-40 low for a stock C5.What kind of TQ #'s did you get?You should be somewhere near 295-310hp.It just might be the Dyno,comparing to Dynojet or Mustang and converting to #'s comparable.
jerry

 

Hmmm, aren't the hp & tq #'s supposed to cross at 5250? Its seems that they cross at different points on each run. :skep:

 

The first problem is the HPP.I know he's in the UK but probably should have used a Predator,since he's not able to use LS1 edit.The only good thing a HPP is good for is a paper weight. :yesnod:
jerry

 

ya, 5250 is where they should cross... this looks like a fishy dyno to me.

:crazy:

 

This is probably because the plot you see here is one I cobbled together in Photoshop from the 2 separate scans I had (1 for HP and 1 for TQ). I may not have been sufficiently accurate with overlaying the torque curves.

Cheers,
Ian.

 

Well, looking at the raw numbers from the dyno, I don't see how the HPPIII has harmed anything... I mean, +25RWHP @ 5,000rpm! Regarding the Predator, see my sig... it's on the way :yesnod:


[Modified by i_york, 11:10 PM 9/24/2003]

 

Ok, I've replaced my Photoshop montage with the individual power and torque sheets that I got from the dyno. A little easier on the eye, too.

 

Something that may explain the low readings... this dyno (Sun Road-a-Matic XII) is a load-bearing dyno. The power is measured by applying a constant braking force to the rollers. In my case, the load applied was 400rpm. Not sure what this means, exactly... but, I'm pretty sure it means the readings will always be lower than a true inertia-type dyno (DynoJet??)

Cheers,
Ian.