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rb torque


ridin_Z_alb

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Ok, here's a good one for you...

 

Dynos (you know, those things that measure the HP of an engine of a car) don't measure HP... at all. They measure torque.

 

Torque is actual power, HP is how much work can get done with that power.

 

So 200 torque at 2000RPM is 76HP

 

but 200 torque at 4000RPM is 152HP.

 

The basic calculation is Torque multiplied by RPM, divided by 5252 (5252 is the RPM at wich the calculation comes out identical, which is why you'll always seen HP and torque touch/cross at this RPM on a dyno graph)

 

It looks like this in math terms:

 

Tq * RPM / 5252

 

So torque is the given power, but you can't get HP until you know what RPM that torque number is at.

 

Again, HP is how much work actually gets done. The reason torquless motors feel powerless is because they don't have HP in the lower RPM when you're getting the car off the line, which is why they need higher gearing, to make better use of the higher RPM.

 

So if you give me ANY engine spec as far as Peak HP and Torque and told me at what RPMS both those numbers occured I could give you a rough estimate what kind of power curve that motor is going to have. A low torque number and a high HP number tells me right off the bat that PEAK power comes above 5252rpm, where a peak torque HAS to be lower than HP.

 

In a motor where peak torque comes in low, and the HP peak is a good 3krpm higher, than I can tell you it's going to have a very broad HP curve and a torque curve that starts falling off by 4k or so.

 

It's basic math because they're related and/or the same thing depending on how you look at it.

 

Torque doesn't make power.

 

RPMs don't make power.

 

The two combined make power.

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ill say this once more, those numbers were FAKE made up numbers off to give an example of hp. tq. differences with import engines in general. 550 ft. lbs isn't weak but what good is a 1 bagillion million hp car if it can't push numbers like that in tq. does it help trap speed or something? i'm all for learning new things.

 

btw numbers i was looking for were more in the 450 range for both hp and tq. if that clarifys anything. thanks for all the help guys keep'em coming

 

its a 77 280z btw weight on the door says 2700 lbs.

 

That caculator is pretty close give or take a couple tenths..

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Here at Hybridz its all about personal preference. You do what you want to do and whats going to be fun for you. I picked a RB because I wanted to keep it nissan, 6 cyl, and wanted to go turbo. I love the sound of them and the power you can easily make with them. Now if your looking for a motor that will be easy to build, RB is not for you. The parts market in america is growing but no where near a v8 product or even a sr20. RB's are EXPENSIVE! You can easily build a v8 or l28et to around 400whp for the amount of money I have spent into just getting the motor in my car and getting it to run right. Not to confuse anyone about that last comment but that is based on the amount of money I have put into my car and from what I have seen other peoples costs for say a l28et build. Now if you build a ls1 with all the latest and greatest parts then yes you will spend more but thats not the point. Personally this thread could have been finished in the first page. Yes a RB will make plenty of power for you to beat vette's and stuff like that. But you can also kick ass with a l28et, v8, or sr20, or 2jz. The point is what you want to do and how you want to stand out from the rest of us.

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  • 4 weeks later...
gonna kinda sound newbie

which rb series engine has the most torque output to horsepower? i wanna know before i sell/buy anything i heard of rb26dett making over 600hp on stock internals but does it have 600 ft. lbs. of torque?

 

I can't believe no one even tired to answer the first part of the question.

 

RB30 would make the most torque to HP. It doesn't flow as well as a rb26 and is larger, More cc's= more torque, less airflow less HP. Obviously boost or displcement make torque. You run enough boost on any lower cc engine and it will make decent torque, although not with the power band of a turboed V8 or on pump gas.

 

 

Soapbox.

 

For 600 rw/tq on a 3l engine, expect to run 30+ psi and expect to spend $6.60/ gal to have that torque and a horrible steet car power band. If 600 rw/tq on 91-93 octane pump gas is your goal then run to the V8 section on here and don't look back, you'll thank me later :burnout:

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I used to be about peak tq when i was building my Starion, the 2.6 4 banger in that car makes huge tq..in stock trim 188hp 235ft pounds @ 2500 rpm ...problem is , the motor runs out of steam around 5000-5500 rpm..:( Before just blinding wanting tq be sure you know what type of car you are building..If you have a light car a lot of low rpm tq can be your enemy..Theres a couple of Honda guys local that spanks vette all the time, and those motors don't start making good tq( if there such a thing) until 5-6000 rpm...Rule of thumb..If your light 500hp 400ft pounds If you are heavy 400hp 500ft pounds....

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I used to be about peak tq when i was building my Starion, the 2.6 4 banger in that car makes huge tq..in stock trim 188hp 235ft pounds @ 2500 rpm ...problem is , the motor runs out of steam around 5000-5500 rpm..:(

 

I have a 88 Starion, I know the feeling..... I wish I had that kind of power, low down in the rev range with my RBZ.

 

My Starion gets with it instantly, but poops out fairly quick. Its a stocker though....

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