Quote:
Originally Posted by xb-60
Max revs, or change up revs, or 7000, and max power at ....whatever...6500?....
And at the bottom end, able to take 3.08 gearing at 1500prm ideally. That doesn't mean real grunt at 1500, it means at steady speed, level ground, no driveline snatching. If acceleration required, or slight hill encountered, the a change down to third. Oh, and the weight I'm anticipating is 2350lb
Thanks for your continuing interest guys, I though this one might have died a while ago. I AM actually learning stuff here. Appreciated.
Cheers,
Glen
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I think I know what you mean by driveline snatching....we call it "bucking". You would have that with an engine cammed to make horsepower at 7000 while trying to cruise at an off-idle rpm.
Ok guys.....listen up.
I'm not saying that it's not possible to make horsepower at higher rpms. I'm not saying that torque rules the roost.
I am saying that with this particular car, this particular transmission, and this particular rearend, an engine that peaks at 7000 isn't a good match.
If you'll look at some of the engines that I build for myself (when I have time), you'll see that I like them a little on the revvy side. Most of my engines peak at 6400-6500. I like that. HOWEVER, I don't pair them up with rearend gears that will make them total turds...
I normally have at least 3.70-4.30 gears. This goes for my Mustang, my Cobra, etc.
I've also owned some of the modular 4.6L engines that Olddog was talking about. Sean Hyland doesn't need large durations and large lifts because the engines are very small. The 4.6L started out as only 281 cubic inches! You don't need 350 cfm flow numbers to support that. However, these engines made decent horsepower, but they had no torque. My '02 Mustang with the 4.6L was a complete turd at lower rpms, even with 260hp and 305 lb-ft of torque. It received a 4.10 rearend. My dad has a '97 Mustang Cobra with the DOHC 4.6L. It was a turd at lower rpms with the 3.27 rearend. It too received a 4.10 gear so that it would have some lowend grunt and pull to 7000. The 4.6's will also rev easier because they have no pushrods....everything is overhead, so you don't have to worry about valve float, etc. They also have extremely small bores and strokes so the rotating assembly is light. Not really an apples to apples comparison here.
That is what I'm getting at.
You will not find a 302 that makes power at both extreme ends of the powerband. That's not the way engines operate.
So if you want to go that route, you need to make sure that the rest of the car's combination will help you in the best way that you can.
Also, if you have an ERA FIA car, you will find that it will weigh closer to 2600 lbs, plus driver, plus fuel.
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