Just got dyno'd....

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Originally posted by jayfotos
I'm a little weirded out by this dyno chart, is the rpm supposed to decrease after 3500rpm then slowly rise?
Watching the dynocomp guys, it was a steady rise on acceleration threw each run(4-5 runs)...are there different ways of running a dyno test?

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The RPM is a steady rise, but the HP generated by Anita's VX (all VXes?) does seem to start climbing again after 4000 RPM. What we are most concerned with (and why I own a PV cat-back exhaust) is the max HP. 20HP increase over stock at @ 3500 RPM... yee ha!

http://www.alpine-developments.co.za...2L%20dyno.jpeg

Looking at the dyno chart from Alpine's site (I hope they don't mind me borrowing it), the HP gain after adding a supercharger would just about double that of the PV mod. Plus, it looks like the max HP comes at higher RPM.

Man! I've got to start saving my pennies! :goof:

wow 200hp 200 lbs to teh floor.
is this on a 4w dyno?
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Striperella live

I'm having a little trouble figuring out these graphs. Maybe someone more knowledgable can help explain a few things. First of all, how is it possible that torque decreases while hp is increasing (after 4000 rpm's)? Apparently there is not much difference in either one between a SCed and nonSCed vehicle at 3000 rpm's? What does Jay's first graph measure?
Finally, Jay, why was it necessary to get dynoed in order to determine if you had the correct air/fuel mixture? Did they install an extra O2 sensor in your exhaust or just use the built in one? (Hopefully they plugged any holes.) Just wondering; but any answers would be appreciated. Thanks.

I'm new to the whole dyno thing and my main concern was testing the feul/air....because I was told by my shop to run a feul regulator on any turbo or SC....I tested fine.

What I recently found out was my stock air box can't take the suction(without any modification) of a 5psi....and I think this is the problem, see this post.

http://www.vehicross.info/forums/sho...&threadid=4573

I plan on installing a cold air intake that should take care of any power loss....at that point I'll dyno it again and I'm sure I should see a meager improvement.

Oh, the first graph measures psi..as you can see 4psi straight across....and I have a 5psi pulley(not certain on that still have to install the new cone, at that point I'm having everything measured)....the other is the air/fuel, witch is steady.

Thanks Jay. I found my own answer to the question of the difference between torque and hp. If anyone else is interested here is a link.
Though, I still don't see why you needed the dyno to measure air/fuel. Couldn't you just install an air/fuel gauge and then drive around? I was curious about AWD dyno testing myself until I found out the price. Decided I wasn't that curious. Hope it didn't set you back too much.

I did 4 or 5 runs and it cost $140. Along with seeing how my air/fuel I wanted to see if they noticed anything wrong while running it, all was good(except boost)

Jay

I too had my VX tested at Dyno-Comp, several times last year. I can't seem to find my printouts, but as I recall I maxed out at 196 HP. This was with a 4 lb. pulley and a two filter after-market intake. A second test session yeilded 184 HP. This time I was running 4 lb., a Cal-Mini cone filter and it was considerably hotter outside, which probably retarded the timing a bit.

The August 2004 Sport Compact Car magazine has a test of 4 wheel dynos. Some very interesting information comes to light in their article.

First and foremost, no two dynos measured the same horsepower. Not even two of the same manufacturer. Secondly, the difference between 2 and 4 wheel horsepower ratings were anywhere from 5 to 30% different. In all cases the 4 wheel numbers were lower.

The most telling info, in regards to this thread, is that the Dyno Dynamics dyno had the very lowest horsepower numbers in both 2 and 4 wheel drive. The worst case was a deficit of 54 horsepower when compared to a Dynojet in 4 wheel mode. The dyno at Dyno-Comp is a Dyno Dynamics unit.

Another interesting fact was that the Dyno Dynamics dyno produced the most consistent numbers from run to run, which would seem to indicate that it was actually the most accurate at measuring.

The Dynapack dyno, which I believe was the unit the PV muffler and Alpine charts were generated on, measured almost identically to the Dynojet units. This would translate into about a 50 HP gain over the numbers generated by the Dyno Dynamics machines.

Moral of the story... Dynos are really only useful if you get a "before and after" measurement. If you want bragging rights, go find a Dynojet dyno to produce the highest numbers.

Yeh, I don't take dynos to seriously......only when they tell me I'm not running at the boost I was supposed to and I think thats something you can mess up on a dyno(getting a boost reading)

J