The last two weeks have been spent collecting parts for dyno testing in the coming months. So far I have two additional headers to test back to back against the MM pulse chamber header - an Ireland 1 5/8 to 1 3/4 step race header and a Stahl 1 3/4 race header.
Here is the Ireland header (black) vs the Stahl (silver)
And here is the Metric Mechanic header
I dug out a set of my old TWM intake manifolds to test against the MM intake manifold too
I spent the entire weekend machining a prototype venturi for my Weber 50 DCO carb borrowing an idea I have seen used in Formula Atlantic. This design in theory should improve CFM flow thru the carb while at the same time boosting signal strength and fuel atomization. It was worth 6-8hp on a full tilt FA engine using my same carbs so I felt it was worthwhile to try to build some. The prototype came out well but still tweeking a few dimensions before sending it to a CNC shop to machine up several copies. Besides these custom chokes, I will be testing my big 46MM Weber chokes and need to pick up sets of 42 and 44MM Weber chokes to round out the testing on the intake side.
It's regrettably been a very long hiatus for me on the 2002 board due to moving, losing garage space and other unforeseen setbacks but I'm finally starting to seriously dedicate time now to my sad, sad GT3 project.
I decided this time to start with the most exciting stuff first in hopes that it will carry me through the project to completion. The race motor has been sitting on an engine stand for several years now and at the very least I knew it needed partial disassembly and inspection. I took the cylinder head off this weekend, and the bottom end looks pretty pristine (as it should with so few hours), so my focus will be on refreshing the top end of the motor.
As some of you may remember from the picture, my motor was built by Metric Mechanic many years ago and I was very happy with the outcome. I've kept in touch with them over the years, so naturally my first call was to Jim Rowe to see what 15 years of additional knowledge and developments can bring to this build.
The original motor produced 228hp on a wet sump with weber 50 DCO carbs. My goals this time are:
Bulletproof the valve train with new custom rockers
Dry sump the motor for increased oil control and additional power
Try a new cam profile to increase power and broaden the powerband.
TEST, TEST, TEST...there is so much conflicting opinion on these motors that I just want to verify everything on my own to find the best combination for my engine. I have found a local engine dyno facility that is very familiar with the M10 and is specifically set up to dyno small bore high revving race engines. It's getting nearly impossible to find engine dyno operators who are not exclusively set up for Chevy, Ford, etc. Most import guys use chassis dynos now because it's easier but I think nothing beats an engine dyno... I plan to spend 2 full days on the dyno testing multiple headers, intake manifolds, chokes, jets, ignition timing.
In the process of collecting the engine parts right now and planning to be on the dyno late spring. I'll be sure to post videos and dyno results on the various combinations.