Don Terrill’s Speed-Talk

I would think the camshaft will depend on what the heads flow and where. If your flow maxes out at 0.500”, then a cam much bigger than that won’t get you anything. If your heads flow well to 0.700” and your cam tips over at 0.500”, then you are leaving something on the table. That said, its about h...

i would think you would need to reinstate the chamfer on the rod BE (unless your crank is fundamentally different ot the BMW one) and thus likely maintain the relationship between the bearing shell and chamfer in the thickness direction of the rod

In an effort to gain additional rod length after going after additional stroke. If one used thinner piston pins such as going from 22mm to 19mm and/or moved the piston pin up in the piston. Are there any specific rules or guidelines or gotchas? What about going after rod length or additional stroke...

The IVC is an indication of trapping efficiency and at low rpm on a street engine this provides some good indications of the relative torque production at rpms before the engine comes on the cam or the intake runner is in tune etc this would be say sub 3,000rpm provided nothing else in the setup is ...

Stan, That was my understanding of the testing, LSA was a conclusion not a reason for the testing. The tests were done to gain information about cam events. Well you would hope the people conducting the tests approached the tests without any preconceived ideas/notions etc. But the question remains ...

Because almost everyone has a compression gauge and almost no one has an F1, NHRA Pro Stock, or NASCAR budget or tools to work with. Stan Stan, We’re not building 900rpm air compressors and a good enthusiast builder can even understand that. Bob, While no one here is building an air compressor, mos...

Tuner, Do you have anything actually useful to add to this thread....or is this your way of getting even. speaking of useful, so if the LSA is the most important thing, how would one design and conduct a testing program to identfy or verify that this is indeed the case? If I remember right that was...

Geoff2 wrote: ↑Mon Feb 26, 2024 2:11 am Tuner,
Do you have anything actually useful to add to this thread....or is this your way of getting even.

speaking of useful, so if the LSA is the most important thing, how would one design and conduct a testing program to identfy or verify that this is indeed the case?

Tom68 wrote: ↑Sat Feb 24, 2024 6:38 pm

digger wrote: ↑Sat Feb 24, 2024 6:20 pm

Tom68 wrote: ↑Sat Feb 24, 2024 5:54 pm

632 with 11:1 comp cranking 160 psi.

and?

Should make good bottom end, not good for it's capacity, but still good fun.

i guess thats the point, not good for its capacity, so if you dont happen to have 632ci and have half or even a third of that then that's going be a bit crap

Tom68 wrote: ↑Sat Feb 24, 2024 5:54 pm

digger wrote: ↑Sat Feb 24, 2024 5:49 pm an engine with low cranking compression will never make good bottom end

632 with 11:1 comp cranking 160 psi.

and?

an engine with low cranking compression will never make good bottom end

Warp Speed, I was referring to the 19000+ cam dyno tests that D. Vizard did while contracted to Crane Cams. You have tested a few hundred? Well you have only got about 18000 to go to catch up to DV..... I have NEVER mentioned the number 500,000. Someone else did....I also find the number incredible...

steve cowan wrote: ↑Fri Feb 23, 2024 4:49 pm I am sure the zero gap deal works otherwise they would not make them.

When you consider there are infact infinite events on the valve(s) lift profile(s) it seems to be a bit useless to say one is the most important. As a minimum i would try and get more than one of them pretty close to optimal

Still learning about camshafts and understand on a basic level duration , lsa , lift , overlap etc. So - on the same camshaft when you advance it say 4 degrees what is actually happening to increase low end tq and why? Duration lift and overlap are the same so its obviously related to do with when ...