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Old 07-04-2017, 07:29 AM
olddog olddog is offline
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Join Date: May 2006
Location: St. Louisville, Oh
Cobra Make, Engine: A&C 67 427 cobra SB
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Brent - I apologize if I over generalized and painted with too wide a brush. Obviously some builders are looking at how to get a flatter torque curve or I would never have read it in a book.

In my quest to understand how to tune my EFI, I took a deep dive down that road. I was surprised to learn how much time the OEMs spend trying to perfect the low rpm torque curves on engines. They are also trying to find MBT at every driving condition, as that is how you get the best fuel economy. Well they are concerned with fuel economy, when they are at light to moderate driving conditions, where emissions matter. Once you get to WOT, they dump extra fuel and back off on the timing to assure the engine will not detonate with crappy fuel. They are quite willing to give up Hp to make sure they do not have to replace engines. I think I am rambling around again. I guess my point is that the OEM are spending a great deal of time at the opposite end of the spectrum from a performance guy.

Anyway, it would be hard to get into trouble with bring the timing in a tad too quick in a Cobra. Your only going to roll into the throttle hard at low rpm in a low gear. The tires cannot hook up huge torque numbers anyway, and even if they did it will only be there a second or two. These engine are not likely to ever pull hard at a low rpm for a long period, like a truck pulling a trailer. Most guys are going to down shift before they hammer it anyway.

2bars - Take Brent up on the offer to help you with your cam and purchase it from him, if that doesn't kill the deal you have with your builder. Honestly I'm surprised your builder didn't try to steer you away from that cam. It shouldn't bother the builder if you do this. He just has to make sure he has piston to valve clearance so he needs to know before he assembles the short block. Then he has to get the valve geometry right. I don't see the cam change as a big deal.

Last edited by olddog; 07-04-2017 at 07:37 AM..
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