Cobra power, how much is enough?

[Silverback51]

Originally Posted by patrickt

Excellent. Are you now going to go back to this thread: Best way to adjust rear coil overs for proper height on my SPF and report that Patrick and Jerry C. were indeed correct all along?

WHAT!!!!?

Admit that you were right about something?


Let me drink a few more beers and think about it.

[Silverback51]

Well Patrick, our weather here in the not so great northwest has sucked big time. Cold and wet for the most part, with 3 of the first 7 days setting records for rainfall.

I put my wife on a plane this morning for Houston, so I'm hoping that tomorrow will be nice enough that I can take it out and be by myself so I can push it a little.

Forgot to mention this. I passed 200 pounds when I was 13 and have never looked back. Don't think me getting down under 200 is in my near future.

[Bruce M]

My Contemporary has a 502 BB with 505 HP on Dyno running 93 octane on Hoosier tires and Watts linkage. This combination puts the power on the ground and is more fun to drive.

[tirod]

Balance in the way I meant it isn't about weight distribution, it's about relative grip of the front and rear tires under power.

Since the rear tires also have to deal with torque, the point of the 427's poor handling was that those cars - on those tires in those days - would break loose the rear.

You all know the traction circle diagrams for road racing - a tire only has so much frictional capability, and if it's already on the edge of adhesion, suddenly adding another 200-300 foot pounds of torque means the rear loses grip and slides out.

It's not necessarily caused by jumping on the throttle - but poor linkage design that tips them open in a geometric increase can create it. Nobody talks about how to finesse the linkage to work the power output in a way that creates a linear response.

The 427's had a well deserved reputation on the track of suddenly letting go of the rear end - were all those drivers throttle dumping boobs incapable of controlling it? No. It just took a lot more driver skill than the average Joe buying into the ride.

Raise the hp levels, add some more grip, finesse the throttle and suspension for 40 years, things are going to improve, but the basic problem is still there, just at a much higher point - it's more power than the average Joe is used to.

As specifically said by many, they started out with a "small" hp motor and grew up with it, learning the car, and then moving up if and when they felt more comfortable in their ability. Maybe they didn't say it that way, but that's what is happening.

I wouldn't recommend a 550 hp car to any new driver, or one who's been in cookie cutter commuters most of their life. It's a big step up, and all too many will make a mistake that will crunch the car.

It's moving from a snail like 10 - 12 pounds per hp to 6.5 as it is, jumping into the sub 5:1 ratio is another significant step up. It's simply not allowed in most racing leagues to drop a driver into that kind of transition without a lot more under their belt, and shouldn't be recommended for a street car used on public roads.

Drive closer to the edge, it's a sharper break point.

[patrickt]

Originally Posted by tirod

I wouldn't recommend a 550 hp car to any new driver, or one who's been in cookie cutter commuters most of their life. It's a big step up, and all too many will make a mistake that will crunch the car.

There's merit to that statement. Now suppose, and I'm not saying he did, the OP worded his question like this: I don't plan on racing my Cobra, in fact I probably will never even autocross it in the high school parking lot, and I have never even been in a 500 horsepower car, and the only sub 2500 lb. car I've ever driven was a VW bug back in high school, so do you think just a 400 horsepower Cobra will be ok for me on the street?

I say a 400 horsepower Cobra would be just fine.

[twin turbo]

On my car I have found 550-600 rwhp is the sweet spot (limit) for reasonable street driveability with fresh drag radial tires on good roads during warmer weather. If someone is having problem with spinning their tires at 70 mph running 500 flywheel hp (approx 420 rwhp), then it might be time to look at upgrading tires or checking suspension settings. When I first got my car I had 420 rwhp and had no tire spin in 1st when rolling into the throttle (I had 3.08 rearend gearing at the time). Cheers.

[Obsessive]

Originally Posted by PHC1

What do you guys think is the "sweet spot" for powering a typical Cobra replica? If the car is to be enjoyed mostly on the streets and driven semi-aggressively on back roads, how much is enough to keep the car fun to drive and feel you have neither over-powered or under-powered the car with the choice of engine? Bragging rights aside, being realistic and keeping driveability in mind for your answer!

Horsepower is fun, especially when you can put it down! Driving a Nissan GT-R with 535HP and 0-60 of 2.8 sec with all wheel drive, dual clutch tranny and launch computer is nothing like driving a Cobra replica with the same HP! Of course the GT-R can't compare to the raw and exciting experience the Cobra brings either...

So then, would most agree that between 400-500HP is more than enough? Or do many feel between 500-600 is where the sweet spot is? Perhaps below 400 or above 600 for some???

This thread could go on forever. While there is a lot to address here to answer your question, I'll simply tell you what has worked for me. I've built a couple of these but never for racing. My first build was purely an experiment with a 428 FE. It went like stink but I never put it on a dyno to see the numbers. The 2nd build was a 427 that I stroked with a 428 crank. I really got carried away with the pursuit of high HP numbers and over did it. My current Cobra has a combination that feels perfect as I drive mine on the street and love to drive (too) fast. Here's what I find to be the best for me:

427 SO block, 428 crank, Ford "Sidewinder" dual plane intake manifold, custom grind cam shaft (.507 lift with 274/284 duration and 110 lobe separation), Edelbrock RPM Performer heads with 2.19 intake valves, Comp Cams roller rocker kit (with end posts), Holley 850 DP 4150 carb, Edelbrock water pump, Canton 8 qt oil pan, -12 oil cooler, Melling (non-HV) oil pump, ARP bolts and modified sidepipes.

I run a Lakewood bellhousing with a wide ratio toploader and 3.08 rear end gearing. The car sreams and I have never felt the need for more power. Even with the high gears, the car drives just a little faster than I can think but not so much that it scares me. Too much. I am still playing with the ingition so no advice from me on this.

Horsepower and torque numbers? Not sure but it feels like 500/550ish. With the modified pipes it sounds like even more.

Have fun.

[Hydramada]

As much horsepower as your skills allow you to use effectively. I have seen Dennis Olthoff dominate with a 400HP Cobra against 600HP cars. My car has more horsepower than I can effectively use but I am smart enough to recognize that and respect my car.

[Mdman352]

Not sure how much is too much but I have 480 HP and 580 TQ at the flywheel in a FE SO 454 inch motor with Avons and it did this with an off idle launch.......



In previous attempts with drag radials the results were a bit more dramatic.....

[patrickt]

Originally Posted by Mdman352

Not sure how much is too much... [/IMG]

Well, for those parts at least, I would say you did indeed stumble over the threshold of "too much."

[PHC1]

A lot of great replies with various viewpoints on this topic. Thanks!!! It is pretty obvious that choice of tires, suspension differences between the replicas as well as setup makes a big difference in how well any of these replicas can put the power down.

I originally asked the question because in my opinion and it is just my opinion, a replica car made of fiberglass with virtually zero safety measures built into it such as traction control, stability control, ABS, no airbags, virtually no protection from impacts on any side of it... etc... etc... should be powered in a way that would not break traction and result in wheel spin at the tip of the gas pedal in just about any gear.

Driving even semi aggressively on the back roads in performance cars with HP numbers in excess of 500HP and some 1,000+ lb difference over the Cobra replicas as well as running state of the art street tires, it is still NOT uncommon to see the traction control and stability control to be quite busy.... With them off, all hell breaks loose in a blink of an eye as well. That's in a modern performance car with chassis and suspension designed and built with the best of the current technology and engineering for street driven cars. I'm talking about cars that come from the best of the best from Germany and Italy as well as USA...

Yes, I've been on the track, yes, I drive with "enthusiasm", yes, I have experience with over 500HP cars and yet I'm thinking that somewhere in the range of 425HP or so would be more than enough for me in any of the Cobra replica.... If I am wrong, I will just have to live with a boring Cobra for a while!

Thanks for all the replies! Would be interesting to hear even more opinions on this!

[Silverback51]

Originally Posted by PHC1

I originally asked the question because in my opinion and it is just my opinion, a replica car made of fiberglass with virtually zero safety measures built into it such as traction control, stability control, ABS, no airbags, virtually no protection from impacts on any side of it... etc... etc... should be powered in a way that would not break traction and result in wheel spin at the tip of the gas pedal in just about any gear.

Sounds like maybe you better stick a little 120CI Chevy 4 popper in it and call it good.

It's been discussed a number of times, but these cars are flat out dangerous. And it can be argued as to whether a motorcycle or a Cobra is worse and both sides will have a good argument.

If you are looking for safety, consider looking a Corvette. And I don't mean that in a nasty way. There are lots of people that just have to have a Cobra, get one and then find out it's not for them.

[patrickt]

Originally Posted by Silverback51

There are lots of people that just have to have a Cobra, get one and then find out it's not for them.

John's right. The most recent debacle was Tin-Man's. That was just a few months ago, in fact. I think you should do some more research, let some time go by, and maybe reconsider the whole thing.

[crASH]

Originally Posted by PHC1

...should be powered in a way that would not break traction and result in wheel spin

This can be achieved with as little as 150HP in a 90" wheelbase car of this weight... with just the wrong choice of tires. I spun one around and went through the woods backwards.

There is no substitute for caution, and little forgiveness for error with any performance vehicle of this variety lacking correct tires, ABS, traction control, etc.

I still want one.

[REAL 1]

Anyone who claims they need more than 400 to 500 hp in a 2300 lb with a short 90 inch wheelbase car for the street or even for open track is to be taken with a grain of salt, a polite smile and then as you walk away

Ken Miles and Shelby's other top drivers and many privateers had a hard time taming the 427 beast with 475hp to 500 hp.

All those here that think they can handle a 427 Cobra better then Ken Miles please step forward and identify yourselves.



Anything beyond what these cars did originally is simply for bragging rights and is removed from what these cars ever were.

[RodKnock]

In your original post, you never mentioned whether you were thinking of building a SB or BB replica, but you ought to consider building a nice simple 302 like Tim built for his SB ERA.

ERA 2136 Build Log

SBF's are cheaper to build and make good power. I'm sure Tim's car scoots well. And someday if more power is desired, you can upgrade to a bigger SBF (stroked Windsor) or a BBF (385 or FE).

[Quintum]

I have yet to buy my kit just yet. So for what its worth... Here is my 2 cents.

If you have to ask why do you need 500 hp, in a car that is only 2200 / 2900 lbs give or take. Well I'm not sure there is any answer for ya. For me I've always been a power freak. Not a speed freek, but a power. I realized it when I got my incentive flight in an F-15 D when I was in the Air Force. Fast is fun. But taking something that weights 40,000+ lbs and pushing it at Mach 1.8 and past. All the while putting it into a turn, pulling 8 G's. Now that’s power! (btw... those are not the limits of an F-15. But they were MY limits before I black'd out)

I just know that it will be a few years down the road. But I already have picked out the engine, trans, rear-end, and down to the tires. Hell I've even got the color already picked!

If you can't see yourself in the car. If you can't imagine what it would be like. You might want to ask one of your local guys to see if they can take you for a ride in such a wonderful machine. After that, if you still don't have the "Bug". Then I'd say look into something else.

Regards,
Dave.

Again Just my 2 cents.

[PHC1]

Not that it really matters as far as the discussion goes but just for the record and so you guys don't waste your time posting suggestions and such, my daily is a '2008 911 twin turbo with 560HP. It's all-wheel drive and very manageable. I can and do use ALL the power in that car when the opportunity presents itself and it is safe to do so.

I've also owned a few other cars in the past few years including the latest Ferrari 458 with 570HP and that car was a lot of fun, I could put most of the power down most of the time with the traction+stability control telling me "NO WAY" on a few occasions... Yes it sounded fantastic with that V8 behind the back screaming all the way to 9000 rpms and making the hairs on the back of your neck stand up! The sound of most Ferrari cars at WOT is unforgettable.

I've never felt the urge to upgrade the Nissan GT-R that I just got rid of and it was brand new... For the price of the Cobra, the GT-R can be easily turned into a 1100HP monster and it already does 0-60 in 2.8 sec stock with 545HP. Booooring.... Too civilized, too capable, too perfect. There was nothing it couldn't do and most of the time I drove it hard I had two things to say, it was either, "I never knew a "car" could do "THAT" or I never knew "I" could do "THAT" and live to tell about it... I got rid of it as there was nothing more or exciting I could gain from that relationship. Same reason why when I test drove the new McLaren MP4-12C a few times already, it just doesn't excite me. Maybe it's just me... I must be weird. I ride motorcycles like many others here and I am no stranger to very fast sport bikes. I like riding bikes and yes, they are dangerous! Speed doesn't scare me, the statistics do! I've seen too much, heard too much and nearly been waffled myself a few times...

So why do I even want a Cobra? Because I've always admired and loved the Cobra and because the sound of a free breathing, normally aspirated, big displacement, hunk of an American V8 iron under the hood and the mechanical, raw, feel that appeals to me. It's not about going ultra fast, it's not about seeking the ultimate back road carver or trying to impress someone or scare the crap out of myself. It's about walking into a garage and seeing that familiar shape that has always excited me and hearing that big V8 come to life with that intoxicating rumble and to row through the gears as the bold, loud and proud exhaust note bounces off nearby objects and to feel the wind in my hair. I don't want another car that feels like I am in a Formula 1 car and actually drives like it can compete with any F1 cars from a decade ago... I want a car that is more challenging, more raw and rewarding with all the flaws it has! I think you guys get it... At the same time I don't feel the need to put the hammer down and go sideways at 100mph either... I feel every car/chassis/setup has a "sweet spot" where it is fun to drive and doesn't feel over or under powered.

I also didn't post the above to somehow brag about the cars I own or have owned... I have been fortunate to enjoy a few very nice cars/toys along the way but I don't like to seek attention because of them, please don't take it that way. I'm simply trying to explain my point of view on this and why I asked the question. I'm sure there are many other members here that have many nice toys!

[RodKnock]

Originally Posted by PHC1

So why do I even want a Cobra? Because I've always admired and loved the Cobra and because the sound of a free breathing, normally aspirated, big displacement, hunk of an American V8 iron under the hood and the mechanical, raw, feel that appeals to me.

I think for many "green" people who come here to CC, after experiencing the sound and raw feel, they then sometimes will want to move on. That's what some of the guys here are saying by referring to the sad stories.

That raw feel and sound can eventually become a huge turnoff to some new Cobra buyers.

[PHC1]

Originally Posted by RodKnock

I think for many "green" people who come here to CC, after experiencing the sound and raw feel, they then sometimes will want to move on. That's what some of the guys here are saying by referring to the sad stories.

That raw feel and sound can eventually become a huge turnoff to some new Cobra buyers.

I can certainly see how a Cobra may not appeal to some... I doubt I would not like it as long as I can drive it in reasonable comfort being 6'2", which is what I am trying to determine first. Sounds promising so far based on the responses to my question about that issue but I have to go and sit in one. The rest would fall into place as I love cars with character and soul.

I have to command the guys that moved on for at least trying and not wishing they had the rest of their lives.