I bet actual running duration changes 5-10* from spec’ed just by virtue of system flex.Roundybout wrote: ↑Mon Mar 18, 2024 1:06 pm That’s pretty close. I wonder if any perceivable difference would be even measurable on a dyno between those two specs. Probably within the margin of error to be even picked up.
Search found 2618 matches
- Mon Mar 18, 2024 4:03 pm
- Forum: Engine Tech
- Topic: My CompCams Cam Card ECL Question
- Replies: 15
- Views: 417
Re: My CompCams Cam Card ECL Question
- Wed Mar 13, 2024 8:02 pm
- Forum: Engine Tech
- Topic: Pushing the limits of a BMC A series head - max effort circuit race
- Replies: 17
- Views: 953
Re: Pushing the limits of a BMC A series head - max effort circuit race
Split Weber or single on a manifold with bends?KnightEngines wrote: ↑Wed Mar 13, 2024 6:20 pmNo idea!Erland Cox wrote: ↑Wed Mar 13, 2024 6:18 am How much less hp will an engine with dual SU carbs give?
Erland
All the ones I've dealt with have run a Weber.
- Wed Mar 13, 2024 10:07 am
- Forum: Engine Tech
- Topic: Anyone been able to reach Isky Cams lately?
- Replies: 30
- Views: 2046
Re: Anyone been able to reach Isky Cams lately?
Hi. I’ve contaded them by email and on their facebook-page 3 times for about 6 and 3 months ago, without any reply. Asked for help with a part number. In the end I figure it out, but I still invested my cash in Jesel- parts instead. Email and social media are probably the most unreliable ways to co...
- Wed Mar 13, 2024 9:22 am
- Forum: Engine Tech
- Topic: Pushing the limits of a BMC A series head - max effort circuit race
- Replies: 17
- Views: 953
Re: Pushing the limits of a BMC A series head - max effort circuit race
How much less hp will an engine with dual SU carbs give? Erland According to the builder I know, 145bhp or so is the limit on those carburetors. That includes all the tricks: thru-boring, etc. He did a big cam development round and was stuck there, changed to the FI and the differences showed thems...
- Tue Mar 12, 2024 9:40 am
- Forum: Engine Tech
- Topic: Honda CBR1000RR stock valveseats.
- Replies: 4
- Views: 274
Re: Honda CBR1000RR stock valveseats.
Mike, have you mapped out the valve timing on these yet?
Not surprised by some of this. Bikes, even racing, run under a lot of part throttle time, and would be focusing on mixture motion for better part throttle combustion quality vs outright flow / max WOT power.
Not surprised by some of this. Bikes, even racing, run under a lot of part throttle time, and would be focusing on mixture motion for better part throttle combustion quality vs outright flow / max WOT power.
- Mon Mar 11, 2024 9:25 pm
- Forum: Engine Tech
- Topic: Road Race Build .. input required
- Replies: 12
- Views: 619
Re: Road Race Build .. input required
E85? . I would go 3.48 to keep c/r reasonable. If it has a big enough tire and the best passing is coming off a slow corner a 406 might be hard to beat . Just to be different, a stock block 350 with lite wieght parts will be about 50lbs liter than a 406. E85 is a “how long is a session and how big ...
- Mon Mar 11, 2024 5:15 pm
- Forum: Engine Tech
- Topic: Road Race Build .. input required
- Replies: 12
- Views: 619
Re: Road Race Build .. input required
I don't think I would run pump gas under those conditions. AV gas might be a good solution. Plenty of SCCA classes require pump gas, and do fine. Most amateur endurance road racers use pump gas because of costs. Almost all FIA race series in Europe require 94-100 octane fuel. I think OP needs to be...
- Sun Mar 10, 2024 8:43 pm
- Forum: Engine Tech
- Topic: Most aerodynamic Muscle Cars?
- Replies: 69
- Views: 6064
Re: Most aerodynamic Muscle Cars?
From a pure driving experience stand point, a manual is the most rewarding / fun. If the car is a fun toy, and you’re not worried about consistency for bracket racing and or have some kind of physical handicap, a manual is absolutely the way to go. Do I judge when I see a cool car with an automatic?...
- Fri Mar 08, 2024 9:47 pm
- Forum: Engine Tech
- Topic: Pushing the limits of a BMC A series head - max effort circuit race
- Replies: 17
- Views: 953
Re: Pushing the limits of a BMC A series head - max effort circuit race
Can you lift the valve to .700in or more safely? I only know them and other similar BMC / BL style heads to take 0.625” or so. The valvetrains are wet noodles on all these engines. Small journals, missing a cam bearing for the oil pump / dist drive, long pushrods, and because of their displacement,...
- Fri Mar 08, 2024 3:59 pm
- Forum: Engine Tech
- Topic: Most aerodynamic Muscle Cars?
- Replies: 69
- Views: 6064
Re: Most aerodynamic Muscle Cars?
AC Cobra 67 Vette From personal experience, both of those had dangerous lift at speed. A family friend / mentor raced a 289 Cobra back in the day. Plenty of lap records, 2nd to a newer psuedo factory backed ‘69 Vette at the SCCA National Championship in 1970… they were bricks. Corvette was more sli...
- Fri Mar 08, 2024 11:15 am
- Forum: Engine Tech
- Topic: Pushing the limits of a BMC A series head - max effort circuit race
- Replies: 17
- Views: 953
Re: Pushing the limits of a BMC A series head - max effort circuit race
What are you expecting power wise out of that? Looks great! I know a builder who got similiar numbers out of those. Here is what it did with a camshaft Mike did for him, and fuel injected: DFFDBE05-32F4-4B9D-B134-9DCF7706F575.jpeg A handful of flowbench tests, including Longman and Swiftune heads: h...
- Sun Mar 03, 2024 10:37 am
- Forum: Engine Tech
- Topic: valve timing events??
- Replies: 53
- Views: 7290
Re: valve timing events??
The exhaust valve isn’t stopping the flow, rising cylinder pressure does. If you do it right, at peak power, the the port flow is nearly stopped by the time the exhaust valve closes. The port is already beginning to slow down before BDC. To quote the late MadBill from like 15-18 years ago, “if gass...
- Sun Mar 03, 2024 7:40 am
- Forum: Engine Tech
- Topic: valve timing events??
- Replies: 53
- Views: 7290
Re: valve timing events??
I'm referring to air/fuel movement established into the cylinder and the inertia it has, not the state of the inlet port at valve opening. Do you mean the Inertia from the accelerated fuel and air in the runner when the piston is reversing after BDC and the inlet valve is starting to close? Erland ...
- Sat Mar 02, 2024 7:21 pm
- Forum: Engine Tech
- Topic: valve timing events??
- Replies: 53
- Views: 7290
Re: valve timing events??
Honda measuring droplet size as it enters the cylinder. Measured vs simulation: Hondaincylinder.jpg Hondaincylinderagain.jpg Different port lengths and two different injector types (low pressure and high pressure). This is 20 year old stuff. They can do much better now. There is a lot to take away h...
- Sat Mar 02, 2024 7:11 pm
- Forum: Engine Tech
- Topic: valve timing events??
- Replies: 53
- Views: 7290
Re: valve timing events??
Here is a (lawnmower) carburetor at 28,546 fps:
You can see the fluid inertia keeps it flowing between pulses, but it's only being distributed when the intake valve is open.
You can see the fluid inertia keeps it flowing between pulses, but it's only being distributed when the intake valve is open.