1 2
Ed Higginbotham
Ed Higginbotham Associate Editor
5/22/17 10:25 a.m.
feature_image

On May 21 we held a special dyno day at the Mach V Motorsports facility. Lots of cool cars showed up, but who ended up making the most power? It was a 2009 Audi S5. These cars came from the factory with a naturally aspirated 4.2-liter V8 rated at 354 horsepower. This one made 431 all-wheel horsepower thanks to a JHM supercharger kit based on a Vortech unit.

Read all the latest amateur motorsports stories in your mailbox eight times a year. Subscribe to Grassroots Motorsports now.

Read the rest of the story

jstein77
jstein77 UltraDork
5/22/17 1:03 p.m.

431 was the highest? I guess nobody showed up with a Hellcat.

Keith Tanner
Keith Tanner MegaDork
5/22/17 1:14 p.m.

That's a cheat. Really, you want the car with the greatest percentage improvement. This Audi scores 21.8%.

The Miata I drove to work today is about 270% over stock.

APEowner
APEowner Reader
5/22/17 1:45 p.m.
Keith Tanner wrote: That's a cheat. Really, you want the car with the greatest percentage improvement. This Audi scores 21.8%. The Miata I drove to work today is about 270% over stock.

I like that idea but if you use that scale then you need to class engine mods and engine swaps differently. My Camaro is at %456 but it's got a 496 stroker motor in place of the wheezing 307 that GM put in it originally.

Keith Tanner
Keith Tanner MegaDork
5/22/17 1:52 p.m.

Doesn't matter, you can't walk into a showroom and just buy one. There's no such thing as a Showroom Stock class at a dyno day

Don't forget that a jump from 50 to 100 hp is a 100% gain, not 200%.

Daeldalus
Daeldalus New Reader
5/22/17 1:58 p.m.

431 ain't terribly impressive for a dyno day. my old rx7 had more than that.

SVreX
SVreX MegaDork
5/22/17 2:03 p.m.

I'm with Keith.

By that standard, my work truck would have annihilated everyone there.

dculberson
dculberson PowerDork
5/22/17 2:05 p.m.

Nah, overall power wins at dyno days in my book. Percent improvement will spark up conversations and a good pat on the back, but the final number rules!

Daeldalus
Daeldalus New Reader
5/22/17 2:16 p.m.

a 350hp 1.8 miata is much more impressive than a 400hp v8 in my book.

Driven5
Driven5 Dork
5/22/17 2:20 p.m.
Keith Tanner wrote: That's a cheat. Really, you want the car with the greatest percentage improvement.

That's like saying the "greatest percentage improvement" in time should win the race.

That being said, I'd probably find greatest percentage improvement more interesting at a dyno day, in much the same way that I find PAX more interesting than raw times at autox.

Trackmouse
Trackmouse SuperDork
5/22/17 2:39 p.m.

I'm with Keith. But I think if you're handing out awards it should be one for each category. % gained, highest overall, and then a third category: one that is a disbelief category. As in "I can't believe this engine made that much power at all and is still running."

Cotton
Cotton UberDork
5/22/17 2:45 p.m.

I've been to a bunch of dyno days and no one ever did percentage of improvement....top dog was always the highest peak numbers.

Keith Tanner
Keith Tanner MegaDork
5/22/17 3:41 p.m.

Oh, nobody ever cares about percentage of improvement - but this is GRM. It's not about just going out and buying a Hellcat so you can "win" a dyno day. It's the creative and high-effort stuff that's more interesting. Since GRM is declaring this particular winner, then they can set the rules to whatever the hell they want them to be!

And actually, "greatest percentage improvement" does win races. That's what classification does.

Driven5
Driven5 Dork
5/22/17 4:03 p.m.
Keith Tanner wrote: And actually, "greatest percentage improvement" does win races. That's what classification does.

Really?...I'm pretty sure that since no two racers are perfectly equal out of the box, but are merely considered close enough when running within the same rule set to be classed together, that the originally faster one will still win with with the same (or even slightly lower) percentage improvement. It's only when the originally slower one manages to beat the faster one that the greater percentage of improvement won.

Again, while the greater percentage improvement may be more interesting, it still does not necessarily 'win'.

HapDL
HapDL New Reader
5/22/17 4:21 p.m.

Obviously, this whole gig is a boosted car paradise. Want more power, turn up the boost. Personally, I have more respect for engine builders and more importantly, engines, that can make big horsepower without boost.

Robbie
Robbie UberDork
5/22/17 4:34 p.m.

Biggest percentage change is a great game for finding the worst stock engine.

Keith Tanner
Keith Tanner MegaDork
5/22/17 4:36 p.m.
Driven5 wrote:
Keith Tanner wrote: And actually, "greatest percentage improvement" does win races. That's what classification does.

Really?...I'm pretty sure that since no two racers are perfectly equal out of the box, but are merely considered close enough when running within the same rule set to be classed together, that the originally faster one will still win with with the same (or even slightly lower) percentage improvement. It's only when the originally slower one manages to beat the faster one that the greater percentage of improvement won.

Again, while the greater percentage improvement may be more interesting, it still does not necessarily 'win'.

If you're used to modern "mostly spec" racing, sure. The idea is to put all the cars that are equal at the start in the same class. Then it's all about who can make the biggest improvement. If the rulebook is really locked down, this isn't all that possible.

But seriously. We're talking about a "winner" of a dyno day and having some fun with it. Don't try to make it a deep discussion. "Winning" a dyno day doesn't mean squat.

And this is from the guy who owns the highest horsepower car ever to spin the FM rollers. And, uh, the lowest. Doesn't matter.

The0retical
The0retical SuperDork
5/22/17 4:39 p.m.

In reply to HapDL:

Blasphemy. Turbos engines are like veal. The more you force feed them the better the end result.

My personal preference: I respect more real estate under the curve than a crazy 5000 to 5500rpm peak power, because I like having power everywhere. All in all though dyno days are usually peak numbers.

It'd be fun to do a % over stock dyno day though.

Keith Tanner
Keith Tanner MegaDork
5/22/17 4:40 p.m.
Robbie wrote: Biggest percentage change is a great game for finding the worst stock engine.

So if you add 80 hp to a 450 hp engine, that's better than adding 300 hp to a 100 hp engine?

Driven5
Driven5 Dork
5/22/17 5:00 p.m.
Keith Tanner wrote:
Robbie wrote: Biggest percentage change is a great game for finding the worst stock engine.

So if you add 80 hp to a 450 hp engine, that's better than adding 300 hp to a 100 hp engine?

I wouldn't necessarily consider the lesser improvement a "better accomplishment" on on the factory higher output engine, although on an already high strung engine vs an understressed one it actually could be...But yes, regardless of improvement, I would probably still consider the engine that started at 450hp from the factory to be the "better engine" of the two.

Robbie
Robbie UberDork
5/22/17 5:22 p.m.

Well, more like how cool is it actually to add 50 HP to something that started with 4? Especially​ with an engine swap.

3.4l swapped stromberg mgbs should crush the percentage increase Dyno day, but I don't find them all that cool or impressive.

To have the biggest percentage improvement just start with the smallest number.

KyAllroad
KyAllroad PowerDork
5/22/17 5:32 p.m.
Keith Tanner wrote:
Robbie wrote: Biggest percentage change is a great game for finding the worst stock engine.

So if you add 80 hp to a 450 hp engine, that's better than adding 300 hp to a 100 hp engine?

Generally, yes. Because adding 300 hp to a 100 hp base engine (generally) results in a hand grenade with the pin pulled.

But adding 80 to a 450 base engine is (again generally) just fine and probably won't even void the warranty.

codrus
codrus SuperDork
5/22/17 6:30 p.m.

We need some other category winners. What was the lowest power output at the dyno day? Most FWD power? Highest Miata power? Most spectacular failure? Did anyone leap off the dyno and fly across the room? :)

Also, the 4.2L V8 in that Audi makes about 260 at the wheels stock (that's what my S4 turned on an AWD Mustang dyno a few years ago with the same/similar engine). The 350 hp rating is at the crank, and there's a lot of drivetrain loss in a quattro vehicle, so it's more like a 62% gain than 21%.

Keith Tanner
Keith Tanner MegaDork
5/22/17 6:45 p.m.

Here's my 39.2 rwhp baby. About 8% the wheel hp of one of my other cars This was a leisurely test.

Huckleberry
Huckleberry MegaDork
5/22/17 10:19 p.m.

A 431HP car won a dyno day? I mean... somebody could have killed that on a test drive from any domestic dealership these days. If you want trailer queens with big air pumps to come out you can't be giving out $9 magazine subs and cotton t-shirts as top swag. Even a rental... I gotta be able to cover the $92/day fee on the GT350 from Hertz Premium.

1 2
Our Preferred Partners
BgwZKecd2qTxWQYYfbq8fWkse3aDX7ADtnd6R2LwNJdaJa7RCsp56faVEQcNRyb6