MAGNAFLOW - Open House / Dyno Day

[AlfaRacer75]

Bummer... looks like I'm not going to be able to make it after all.
I'm stuck working tomorrow and there's no way I can make it up there in time for the Magnaflow event.

I was really looking forward to seeing what all the other monster Alfas were putting out too.

[AlfaRacer75]

So... how did it go? I'm bummed I had to miss it.

[AR4me]

Most Alfas on the dyno were 4 cyl. My general feeling was that many recorded less than expected. Although mine was the highest output Alfa I was a bit disappointed with the measured 146 hp and 158 ft-lbs at wheels. I did watch that the boost went as planned, but didn't really have time to check everything beforehand as my 2-year old kept my busy (didn't like the noise of some of the louder cars). Though, he was very excited about all the Alfas in one place out front

I was really looking forward to seeing Chip's 24v and a 24v GTV6 that had signed up, but both cancelled

Jes

[AlfaRacer75]

That does seem low, I would have expected your car to come close to 190hp to the rear wheels. Maybe the dyno was calibrated incorrectly or something?

My old "warmed-up" 12v 3.0L put down 171hp & 169 ft-lbs on a DynoJet in HOT HOT HOT weather.

Do you have the dyno plot for your car? Should be interesting to see the torque curve on your turbo car compared to my NA engine.

[alfa-sportivo]

some photos - more to come...

[alfa-sportivo]

more..................

[alfa-sportivo]

and more...........

[High_Ram]

I wish I could of gone!!!

[alfa63]

Quote:

Originally Posted by AR4me ... My general feeling was that many recorded less than expected...

[Norman Silverma]

My 65 Spider Veloce curve was almost identical to the 1965 issue of Road & Track - actually a little higher. 94+ horses at the wheels is approx. (+/-)130 at the flywheel. Max torque just under 90 was around 4500 rpm. MPH in 4th at dyno red line was 104. Sound was smoooooth awesome.

[Bruce Colby]

I suspect the dyno was fairly close to right. The relative humidity was a bit high (this reduces air density) but air temp and atmospheric pressure were reasonable. My stock twinspark engine in a rear drive car hit 112 bhp @ 5600 rpm. My guess is that the rear drive nets a loss of 30 to 35 bhp. So, let's say it was a loss of 35 bhp; that, plus the 112 measured would be 147 bhp at the flywheel. That's darn close to the "advertised" 148 bhp @ 5800 rpm.

I think what we are seeing here is a just an example of how small seat-of-the-pants (SOP) horsepower are compared when with dyno (SAE) horsepower. It looks like it takes about 1.3 SOP horses to equal 1 SAE horse.

Now I must admit, I'm not immune to the SOP hp problem. I had expected my twinspark race engine to be showing something like 140 to 145 bhp. It didn't even get close. However, it was spitting some good sized bits of muffler baffle out the tail pipe which I'm guessing became partially blocked. Guess I should get a MagnaFlow installed!

[75evo]

Did you all get the corresponding A/F values graphed against bhp & rpm? That would be extremely useful.

[Bruce Colby]

Quote:

Originally Posted by 75evo Did you all get the corresponding A/F values graphed against bhp & rpm? That would be extremely useful.

[75evo]

At WOT, the Motronic will ignore the O2 sensor and will run on a given map in the ECU. But what's important is the A/F given by the wideband O2 sensor.

Did they use a wideband O2 sensor during dyno?

Its useful because then you can figure out where your car is running lean and where it is running rich. Then you can start tweaking the ECU a little.

For max power, I was told, 12.7:1 A/F is good. Actually using a Lambda value is better.

[Norman Silverma]

Gee Bruce, you constantly amaze me. I had no idea you were fluent in Alfabonics.