New Dyno Numbers

[voxwagen88]

I was able to make it to the Dyno Day hosted by RPI at Kinetic Motorsport.

Here's the resullts of the 4th gear pulls.

88.3 WHP @ 5300 RPM
103 FtLb @ 3700 RPM

A/F 14.3/14.4 all the way through.

Regan


Modified by voxwagen88 at 1:35 PM 6-3-2006

[88vwFox]

thats not bad at all. i wonder what a 100% stock fox puts down?

[voxwagen88]

Quote, originally posted by 88vwFox »

I wonder what a 100% stock fox puts down?

Flipping through VWSport Tuning, I came across this.

The Caption reads
"The stock Fox exhaust system strangles the engine above 5000 RPM. An aftermarket sport exhaust will yield a 7-hp peak gain and a 14-hp gain at 5500 RPM."

[slvfox]

Quote, originally posted by mdwelsh »

Unless I am mistaken, the Bentley states 81HP stock.

True, but isn't that at the flywheel.

[Longitudinal]

Regan,

Nice. I'd love to wave the wand over your fuel system. I am sure I could find a few ponies you didn't know about.

[voxwagen88]

I wish you had been here to do that. I would have loved to pull 90 WHP and matched the MKII GTi's crank rated 90HP.
You are one of very few I would let wave a wand under my hood.

She seems healthy though. A bit rich? At this level I do not find myself saying"I need more fuel!"

[VWestlife]

Quote, originally posted by voxwagen88 »

Flipping through VWSport Tuning, I came across this. The Caption reads "The stock Fox exhaust system strangles the engine above 5000 RPM. An aftermarket sport exhaust will yield a 7-hp peak gain and a 14-hp gain at 5500 RPM."

Notice how there is only a 1-2 HP gain below 4000 RPM -- really not that much to be noticeable or useful, in the range where most people do 95% of their daily driving. This suggests that unless you constantly drive your Fox as if it had a VTEC under the hood, a more useful mod to start with would be better gearing (such as from a 9Q gearbox), since it lets you make more effective use of the engine's entire rev range, not just the extreme top end.

And remember, a Fox is quite a bit lighter than a GTI, therefore it doesn't need an equivalent amount of power to deliver equivalent performance. (For example, the 1976 Rabbit, with 1.6L and 73 HP, matched the acceleration of the 1986 GTI, with 1.8L and 102 HP. Why? Lighter weight, and better gearing!)

[BustedFoxWaGeN]

Quote »

This suggests that unless you constantly drive your Fox as if it had a VTEC under the hood,

drive all my cars like that.. especially my diesel just to keep up with traffic


Modified by BustedFoxWaGeN at 7:55 PM 6-4-2006

[voxwagen88]

By way of meaningless comparison, here is my previous dyno numbers. TT exhaust, synthetic oil, and a K&N filter were the only performance mods at this point.

By way of explainawaytion
The numbers are from a different dyno. With the PSA 5 speed. The big numbers were a second gear pull. The lower numbers generated by run 002 are from a third gear pull and are helpful in guessing what the (lower) 4th gear numbers might have been.

I found I tended to drive the car very hard when it was stock. I felt I had to to keep up. My wife however tended to shift much lower. Working with the torque band rather than the horse power band. She got much better gas mileage.

With the TT exhaust it was much more willing to stretch to 5K rpm.

Now I still like to drive it hard from time to time. But because it is fun, not just to get the car out of its own way.

Modified by voxwagen88 at 9:45 PM 6-4-2006


Modified by voxwagen88 at 11:24 AM 6-28-2009

[snowfox]

Quote, originally posted by voxwagen88 »

She seems healthy though. A bit rich? At this level I do not find myself saying"I need more fuel!"

I wouldn't call it 'rich' unless you were getting down to like 12:1 A/F.

Isn't stoichiometric 14.1:1? If that's the right number, 14.3/14.4 would actually be lean... Or is it 14.7:1? Can't remember off-hand. If stoichio is 14.7, then your 14.3 should be just about rich enough to get you near max power. Maybe you might even want to get down to 13.9...

BTW, I thought most folks did their pulls on the Dyno in 3rd. Why did you do it in 4th?


Modified by snowfox at 10:13 AM 6-5-2006

[chryco63]

Stoichiometric is 14.7:1.

[snowfox]

Quote, originally posted by chryco63 »

Stoichiometric is 14.7:1.

A-ha! I thought my first guess of 14.1 sounded a little off...

[voxwagen88]

Quote, originally posted by snowfox »

BTW, I thought most folks did their pulls on the Dyno in 3rd. Why did you do it in 4th?

My understanding is that you want to make the measurement in the gear closest to 1:1 in order to limit the torque multiplying effects of the lower gear. Second or third gear pulls tend to produce smoother curves and more flatttering numbers so they are popular.

It probably doesn't matter that much which gear the pull is done in as long as you are comparing it to one done is a similar gear. And of course these were done in different gears with a different set of gears so it quickly becomes apples and oranges with lots of room to speculate.

I'm mostly pleased the numbers are bigger. At least that would suggest it is going in the right direction.

Power on the lean side.
Regan

[snowfox]

Quote, originally posted by voxwagen88 »

My understanding is that you want to make the measurement in the gear closest to 1:1 in order to limit the torque multiplying effects of the lower gear. Second or third gear pulls tend to produce smoother curves and more flatttering numbers so they are popular.

Aaaaahhhh... I've never actually messed with getting on a Dyno, so the gear selection thing is nothing I've ever had to deal with. Doing it at or as near as possible to 1:1 gearing makes good sense though. Thanks.

[Fox-N-It]

With your AF staying pretty constant in the low mid 14's i'd say your O2 and such are doing their job.

From all the tuning stuff i've read a 13.5 to 13.9 AF is the place to be on a NA motor.

Adjust the CIS-E a bit and im sure you'd see over 90whp.