Hot Rods Horsepower minimum, got a number?

yeah, you need to build it to run on 87. Then you'll put more miles on it

 

How much timing do you have in the chevy ll ?

 

I'm hoping for 350-400 in the 327 motor refresh in the coupe. I'll really never know, unless someone offers a dyno session free. But my seat-of-the-pants dyno will probably confirm.

The current setup is the cure for insomnia. Smogger heads, HO 305 Cam, flat tops TH400 with that tall first gear and 3.08 rear. It's gotta be a major improvement despite the numbers. I have a 700r4 under the bench and I'd like to switch to 3.42s at some point.

I want it to be snappy, but also reliable and drivable, so I picked the biggest cam to use with a stock converter, CR should be manageable on pump gas with the aluminum heads.

 

Too bad my exwife stole the car from me. But I drove it daily even in the ice and snow. Throttle control, and different sets of tires for the different seasons was key though.

 

All of it.

Around 20 initial, 36 all in. But I can bump it up a bit if I really need to go faster.

I run 85-87 on road trips, and 91-93 when racing.

 

Enough to leave a pinch mark in the seat.

480hp and 520lb ft on engine dyno should be enough for my falcon project to be quick without having to grab it by the short and curlies. (even though that only translated to 299hp at the tires when it was in my old car on the chassis dyno

-rick

 

Will be lucky to get around 100 hp with my flathead, but the speedster should be around 1,500 lbs. Actually went to a dyno place here in Ottawa this week to see about getting it dynoed, and they had shut down, but their website is up and running. When I showed up at the place of business, it was obviously closed, but thinking they had moved I called the number listed on their website. A female answered, and I then asked if this was International Dyno Authority, she promptly hung up on me. Lol!

 

10:1 WEIGHT:HP RATIO
With the right powertrain on a good track that will put you at 12 seconds in the quarter mile. On the street, any more than that will just result in lots of tire smoke and wheelspin...
...not that that's a bad thing.

 

Not according to folks on the street brawler thread.

 

That statement says that you're one of the fellas I described at the end of my post:

You are confusing torque for power at low rpm. Having lots of torque on a low rpm automatically means you'll have good power at that rpm too, as long as the rpm isn't ridiculously low. The huge bigblock V8 with a ton of torque already at idle rpm must also have lots of low rpm power - even if the cute little carb, cam and heads suffer from serious asthma and can't fill those cylinders at higher rpm, killing any chance of high power numbers at high rpm.

Big, low rpm engines will have high torque numbers and low peak power numbers. They will also have the character of a tractor: lots of low rpm grunt, but no fun at high rpm. That's simply the nature of such engines, they work rather well over a rather wide range of the rpm span the engine can handle. It will have enough power at most rpms.

If you compare it to a motorcycle engine putting out the same peak power but at triple the rpm the engine will be optimized to work on high rpm, it will have a narrow power peak at high rpm and be rather dead below that. It's not a lack of torque, it's a lack of power at low rpm. Which indeed comes from not having any torque there, but it's not the torque that performs the job of moving you so that's beside the point. 100hp @ 1000rpm will do exactly the same job as 100hp @ 10 000rpm given the right gear ratio, the difference is that the engine with that power at 1000rpm will have lots of power spread over a wide rpm range, while the 10 000rpm screamer usually will only have power in a narrow rpm range, forcing you to shift gears soon.

 

Says the guy who starts a thread specifically about numbers.

 

I seem to be in the 300 range, 350 on the roadster, 330 on the F-1 and 345 on the Corvette (off topic C5)

 

It depends on a lot of things. Weight, rear gear ratio, trans type, car type. Most important, what am I doing at any point in time, driving to work, trying my luck at the local back road races or ? Anywhere of 100 to 400 works for me. I've been happy with vehicles all through that range. Favorite was a little 65 Dodge dart, 273,4bbl,4spd, 3:55 gears. Felt much faster than it really was. 235HP stock, few parts swapped with later for a claimed 250.

 

Stock Eliminator Racers are into the high10's with cars heavier than 10lbs/hp [and a controlled tyre size]
They do it with mechanical leverage [5:1 to 6:1 rear ends etc]

These things really leap out of the hole, but it is a "long day" at the top end.
It's a real "thinking man's" form of drag racing [there certainly isn't anything stock about them]

 

Not really. Consider two engines which both have a nice flat torque curve from 2000 rpm to 7000 rpm. One of those torque curves peaks at 150 ft lbs, the other peaks at 600 ft lbs.

No matter what the rest of the car is like, the one with the big numbers is going to be a hell of a lot more fun when you stomp on the go pedal.

You don't have to give up low end torque to make a 600 hp engine.

btw, torque makes the car move. Power is just a calculated number.

 

@Roothawg ...If your car doesn't flatten your eyeballs and blur your vision, keep building, you ain't got enough under the hood.

 

Sure, with four times the torque at the same rpm you will have four times the power. So I'm again back at the power being the thing you want. Torque just has to be there to make that happen.

You don't have to give up low end power to make a 600hp peak engine, absolutely right, but it requires a large displacement and/or forced induction. Without those torque will be limited and the only way to get power is to multiply that small torque number by a high rpm.

Torque makes the car move, yes, agreed. But then you have torque and movement in combination, which still makes it power. Torque alone, without movement, equals a stationary car and those aren't very fun.

 

Torque turning the wheels makes the car move. You can get a lot of torque at the wheels by having mild gearing, combined with an engine with a lot of torque. Or you can have steeper gearing, and an engine with less torque, spinning really fast. Both of these methods make lots of torque at the wheels, which makes for fun acceleration.

If you want to have a lot of fun by just pushing the pedal down, nothing beats big inches (and forced induction) for making it happen.

well, if you take your foot off the brake pedal, then you'll start moving. Give it a try!

 

LOL!

 

And you will always have the most torque at the wheels, no matter what the engine rpm or engine torque is, when the engine power is highest. When you go to a lower gear and the corresponding rpm with more power you have increased the torque at the wheel. So, you probably know what I'm about to say. You need more power to make the car accelerate faster. It's the torque at the wheels that pushes it forward, but it's the amount of power that decides how much torque you can make there at that speed.

 

The torque at the wheels is always highest (in any one gear) at the engine's torque peak RPM.

But you can get the car to accelerate faster if the car is geared so that the engine is close to the HP peak RPM most of the time.

 

This thread only started yeasterday, and it's already 5 pages. So I think we like talking about Horse Power, and Torque! lol It's kinda like this. Can a girl be too pretty? or can a Hot Rod be too fast? I don't think so. But it's what can I afford? Also what am I using my Hot Rod for? I can't afford real fast. But just lots of FUN! I really like the feel, and sound of acceleration! My old jalopies are 350 to 400 bhp? So they are just FUN, and I've blew a few doors between lights over the years too.

 

Friend of mine only dated women 1.5 to 2 times his weight.

1hp to every 18 -25 pounds on my rides is about right.

 

Man all this high horsepower talk gets me all torqued up...
Ideally 400hp on an old car with old suspension is plenty for my budget & balls. Now if I had a "street brawler" add a couple hundred more and some traction upgrades or all the locals around here in Audis, Camaro's, Hellcats ect... will just plain embarrass you. Hell you might even get whipped by a "young punk" in a 25 year old civic if youre not prepared.
Ive never been on a dyno & aint building race cars, but I sure as shit want my hot rods/customs to have all the power a poor boys budget can afford.

 

personally its all about fun factor, my stock Y block makes enough power for me to be happy with it, itll smoke a tire, i do want to change the valve springs sometime next year so i can access stock redline again, not 4 grand.

 

Torque vs horsepower is always a debate. Ive built several cars and harleys over the years. Horsepower means nothing if the Torque is not in the useable range. Id rather have a 300hp engine with 400+ lb/ft of torque than 400 hp with 300 lb/ft of torque. The torque is what you feel in the seat of your pants, especially on bikes. I remember several years ago building harleys the magic formula was 100hp 100 lb feet of torque. They were streetable and when you rolled on the throttle it would just go, no downshifting. My 402 BBC made less hp in my Nova but got the job way done. the 327 was rated higher in hp but didnt have that same grunt.

 

That means the torque peak is around 5200 RPM, eh?

since HP = Torque x RPM/5252

(sorry Root)

 

Anyone remember how much @Ryan de-tuned the engine in his '38 coupe?

"Has been dynoed in one form at well over 800hp, has run 1/4 miles times on juice as low as the 11s, has ran high 12s as it sits now detuned"

 

The real meaning of torque is before you take your first morning wizz, if you push down on your Big Johnson and your heels come off the floor, you have plenty of torque.
YRMV

 

In one gear, yes, but most cars have several gears, an you'll get the highest torque at the wheels (where it matters) by using the gear that puts the engine at the rpm that gives the most power.

Let's not bore the others, but go ahead and do the math, grab data from any engine you like and calculate wheel torque at any one speed you like with one gear ratio that puts the engine at peak torque and another that puts it at peak power.
Just knowing that power = torque * rpm means that we also know that we must get the highest torque at the wheel when we insert more power - the rpm at the wheel is constant, so if the power goes up so must the torque.