Bone-stock 2.0 911E dyno numbers
 

I got some baseline numbers for our untuned 2.0 liter 911E,

at the wheels in 4th gear: 124.3 hp, 107 lb.-ft. of torque.

for shiznits and grins, I removed the airfilter and snorkel off the stacks, gaining 3 horsepower and about .5 in torque.

We'll be using a air/fuel meter to dial in from there...dyno sheets will be uploaded this afternoon to the project car page.

Per
http://www.classicmotorsports.net

curves
 

Curves are posted.

With about 10% for drivetrain losses you're right on the money for a 69E. The 69E has a published HP figure of 140. The other thing to keep in mind is that porsche's Hp figures are a minimum and not an everage so it's very possible that you've got potential for more there.
With some tuning left to go it'll be interesting what you'll end up with in terms of HP figures.

DIN vs SAE
 

It gets confusing trying to convert wheel hp to crank hp...and then you've got the issue of the 69 being rated at 140 DIN, where a few years later, it was SAE net, which accounted for some parasitic loss (alternator, etc)...but not tranny/tire losses.

We've been using the estimate of 15% loss from SAE net to typical chassis dyno numbers for most of our articles in Grassroots Motorsports, but at some point, I think we're actually going to test a car and use it as an example.

Per

Ya that can be confusing and I frankly don't really know a whole lot about it but I think anyway you slice it your engine is pretty close to the rated Hp of your engine.

In comparison, my '69T (apparently with E cams), managed a whole 108hp at the wheels.

http://forums.pelicanparts.com/showthread.php?s=&threadid=61152&highlight=bosch+d yno

This might help as a Webers vs MFI data point, although my T has less compression too (and smaller ports?).

(edit - I just reread my old post - although I mention "third", the dyno run was done in 4th.)

One of the biggest differences between chassis and engine dynos is the length of time the engine is loaded. When manufacturers rate HP, they do it at steady state--i.e. RPM, air/water/cooling temps, etc not changing. The engine must maintain this for one minute.

As heat for the most part decreases the power of an engine, those engines most affected by heat (i.e. turbo/supercharged) appear "under rated". Add in the effects of inertia and it's not an easy percentage conversion between them, even though people like to do so.

With all that said, seeing these old cars on dynos is interesting. I'm sure a wideband and some MFI tweaking will provide some nice gains, especially in the midrange.

Have fun!

Anybody else have any small displacement (2.0-2.4) chassis dyno numbers?

Per

I've been planning on finding a shop to dyno mine on once I've got the webers better tuned...

Its a 2.0L with S cams from what I've been told. No clue at all what kind of power it makes, but it moves pretty quick when you get above 5k. (Plus it sounds sooooooo nice, sucks I get about 15 km per gallon at that rate. :) )

Here are the factory spec's which curiously were not included in the factory shop manual like the 2.0S's and the 2.0T's.

After thinking about it, that is pretty impressive to have an essentially flat curve from 2500 RPM up to almost 7000 RPM. Looking at your curve and comparing to the feel of my car ('69 2.0E with S pistons and the stock MFI), your curve almost seems to be TOO flat. Where your curve has a hole at 4500 RPM my car's engine actually comes on cam and seems to be developing peak torque. Maybe there's still something to be found in that old engine.

I have a 2.0L with S pistons and E cams.

Webber 40IDA carbs with 30mm venturies, on the dyno with the ARF at 12.6 - 13.2 it maxes out at 152hp at the crank at 6400 rpm

The power curve look very similar to the 2.2E graphs that the factory issues in the factory manual.

I have had the car on 4 different Dynos and in 4th gear I have had figures on RWHP ranging from 78hp - 130hp. Guess it has a lot to do with the setup of the individual dyno.

Here is the (hard to read) graph from my run.

The nastiness around 2-2.5k revs is, I think, because the Webers weren't tuned that well. They are sold, so not a problem I need to fix.

http://forums.pelicanparts.com/uploads2/911T_e_cams_dyno1061418499.jpg

John, I agree, the curve seems too flat, or rather, there's a slight dip where there should be a peak. This car has not seen a 4-gas, and I've been "tuning" by smell and feel. I think it's a bit rich right in the mid range and needs to be leaned out a bit....but I don't want to go too far in that direction w/o the meter.

Anybody have stock 69 2.0S numbers w/ MFI?

Per

Per;
I've got the 69'S numbers, but due to home network problems stemming from some recent thunderstorms, I won't be able to post them for a few days.

John, at the wheels or the factory ones? I've seen the factory ones, and am curious what that equates to on a modern chassis dyno.

Per

Per - I was going to post the factory charts, but you've got them already. I'd agree, it would be great to see if anyone has dyno'd a stock 2.0S on a chassis dyno.

But then I'd love to dyno my 69E 2.0 with S pistons just to see what sort of a difference they make. I just haven't seen anyone having a dyno day up in this part of the country.

John, might be a good thing to see if we can find a few people locally who want to do that and find out if a local shop would give us a break... once I've futzed with the timing/points/carbs and eliminated this popping problem I've got, I want to do the same thing, to see what having non-S pistons with S-cams does to the power curve. I'd be particularly interested in seeing your 2.0 with S pistons next to my 2.0 with S cams...

Dyno time in this area is $80/hour. One hour is enough to strap the car down and do 2-3 pulls, typically, with a few small (mixture) adjustments between each pull.

Here's a blatant plug, you might want to get a hold of the cover story for the 5/2003 Grassroots Motorsports, gives the lowdown on what to expect at a dyno and how to test.

Per

Been there -- bought that. BTW - I love both of your magazines, especialy GRM which have formed a significant part of my reference collection. SmileWavy

Good Idea Dotorg. See my new thread...