Want dyno run data of your engine

[1QuickS]

I am working on an updated venturi selection chart that is similar to the Weber published chart (below) but that has data that is specifically adjusted for our flat six engines. The popularized "Bruce Anderson" formula has been around for decades and predates publication in his book; as such it is a good starting point for venturi selection. It is however only a guideline formula and actually selects main venturis which don't match OEM selections; for example the formula selects 30mm venturis for the 2.0 911S which was delivered with 32mm venturis. The attached chart correctly sizes 32mm venturis for the 2.0 911S engine with HP developed at 6600 RPM however it appears to be fairly aggressive in venturi selection for larger displacement engines.

I keep track of what good dyno reports I can get but would like to flesh out my updated chart with more good data. If I can get the following data from your dyno run for your carburetted engine then I can "tune" my chart accordingly. I will publish my updated chart on this forum for all to share/discuss.

I would like to get the following data from your dyno run(s):

engine displacement
RPM @ peak HP
main venturi size


Thank you in advance.

Paul Abbott
info@PerformanceOriented.com

[John Z Goriup]

Here's a copy of the graph of the final set of runs with Ruprecht on Holleran's dyno.

Below, the data you requested:
____________________________

A. 3.0 liter, '80 SC motor, - modified with large-port, large valve '78 heads, further modified with porting and contouring, WebCam 20/21 cams, J. Woods modified all-centrifugal distributor, SSIs, opened-up & modified ( but not gutted ) Dansk OEM replacement stainless muffler changed to 2 in / 2 out configuration, and 40 IDAP3C Weber carbs mounted on perfectly port-matched PMO manifolds, and K&N rainshields ( at the time ) of the dyno-tests.

B. 244 HP ( at the rear wheels ) @ 6300 RPM.

C. Main venturi size = 35.8 millimeters.

JZG

[gled49]

This was a while ago. 3.0 race motor, 50 PMO with 43mm V, 300 HP @ 7400 rpm. Gordon

[ttweed]

My '73RS-look car that went to Sweden several years ago had a 3.4L in it at the time, PMO 50s w/ 42mm venturis, "Otto"-grind WebCam, and made 284 RWHP at 6800RPM on a Dyno Dynamics.

TT