How Do I?

[7yphon]

How do I make a car engine rev like a motorbike I mean really high like 15G

[SDEWY5]

i dont know, but i think it has alot to do with the stroke, i heard the F1 engines can rev to like 20,000 rpm coz their stroke is something like 10mm...does anyone know this to be true?

[scathing]

Strong lightweight internals to lower your reciprocating mass while being able to handle the speeds you're putting them through.

A big set of cams to let it breathe up there.

A short stroke engine will also have less inertia since the components aren't moving as much, allowing you to rev harder.

(There'll be a lot of support stuff you also need to do, which I'm not aware of, but they're the basics)

None of which is cheap. If you want a car engine that revs and revs, you'd be better off buying a rotary.

Why this is in FI performance and not NA performance is beyond me, though.

[Sydneykid]

  7yphon said:

How do I make a car engine rev like a motorbike I mean really high like 15G

<{POST_SNAPBACK}>

Reduce it's capacity mostly by shortening the stroke, make everything smaller and lighter, particularly the valve train. Sacrifice torque for rpm.

cheers

[Dale FZ1]

All of the above.

It's worth following the literature about each year's successive efforts by motorcycle manufacturers to increase power. Generally increased high rpm durability is a focus of the engineers attention, but they DO come up with some really good ideas from time to time that helps retain linear, predictable throttle response. Check out how they control air induction, and set up fuel injection. Exhaust techniques aren't bad either.

Note that the smaller capacities attain higher rpm due to shorter strokes and lower mean piston speeds. Conventional engineering there, and also leaves them needing to be wound up to go well.

Having sold a litre-class bike to get my R33, it's interesting to see how the engineers reached their goals with the car. In some ways I see the RB25DET as more aligned with a sporting V twin (eg Suzuki SV1000) than a hyper sports I4 (eg Suzuki GSXR1000). Torque, rideability, handling, but not too likely to bite the ham fisted operator.

With vey high rpm comes special setup issues for the remainder of the driveline - esp gearboxes.

cheers

[paulr33]

i think why would u want to rev that high?

more friction, heat, stability issues etc

whats wrong with revving to 6000 ?

[R31Nismoid]

is this a serious question?

[7yphon]

Yer it is, Im toying with some ideas in my head im building a Street/Track race RB20 and I had a thought and asked thats how you learn things.

[Bluprint]

Realistic answer - you can't do it.

[ylwgtr2]

fzr/cbr/gsxr/zxr250 motorcyles rev to like 19000....but they go like shit...... revs are not the important thing!

[rev210]

Put a motor bike engine in the car that revs to 15,000. It won't go very fast though. Ask a stupid question as they say

[pnblight]

  7yphon said:

Yer it is, Im toying with some ideas in my head im building a Street/Track race RB20 and I had a thought and asked thats how you learn things.

<{POST_SNAPBACK}>

Well for street/track your handing in the wrong direction, a quick street car you want torque and good width in the power band and preferable a nice linear power delivery. To get through and out the other side of the corner as quickly as possible. A high revving car is not suited to track work and the only time i have really seen high revs used is drag, that is mainly to try and gain the max power from a engine plant for a short period. But still to do this you require some of the dearest engine components imaginable.

If you were concidering a street/track rb20 i would personally try a rb24 combo rb20 with gtr crank and rods with tomei rb24 piston. This combo will actual produce as much or more torque than a rb25 because of the stoke and i believe in relation to other combos with quality forged pistons and upgraded rods (gtr) it would be the cheapest bang for buck going.

pete

[R31Nismoid]

^^ what he said.

Impossible i'd say without spending the most stupid amount in the world to get an RB doing that.

[Dale FZ1]

High revs are also the reason why bikes went to 6 speed gearboxes while cars were still running with 4 and 5.

You're going to want DEEP pockets, and have some pretty special driving capabilities.

If you're serious about motorsports, have a really good look at what other people are doing first.

[scathing]

If you're building it for track work, unless there's a specific reason why you need to use an RB20 I'd just f**k that motor off and put in an RB26DETT or bigger. It'd be a lot cheaper, and a lot more effective.

And if you have to run something in a 2.0L class, and money is clearly no object, put an SR in. Same power (mod for mod it might even be better) with less weight, with a smoother power delivery, and its shorter so it brings your centre of gravity closer to the middle. It also allows you to run a V-mount in an engine bay designed for an RB.

As the old racing adage goes, "Horsepower sells cars. Torque wins races". There's no point having your engine revving to 15,000RPM if it only develops power from 12,000RPM. In circuit racing you want a wide band of torque. It doesn't have to pull off-idle, but around half your rev range should be usable.

If you have a look at the video of the Mine's R34 "Ultimate GT-R" video that all the BMI guys almost shat themselves while driving, while the car is pretty doughy under 4000RPM (or around half of its rev range), once it hits that point the thing has power and response all the way to redline.

Even the F1 cars have a nice wide torque band. Sure they rev to 19,000RPM but they'll still pull from below 10,000RPM. And for a 3.0L NA motor that revs as high as a 250cc sports bike, it still makes a good amount of torque from low in its rev range.

[7yphon]

Well it was a thought, Thanks for your imputs.

O BTW I dont think this was a stuped question because you dont know unless you ask.

I do like the RB20 but I was also thinking about saving up for a RB26, I dont really want to go rb25 plus my mate is dumping one in anyway so I dont want to follow in his footsteps.

I'll Talk to hyperdrive about the whole RB24 if you say it will create better torque then a 25 then I guess that is the way to go until I can save to get that RB26 in.

[scathing]

Considering how much it would cost for you to do the bottom end of your engine, I'd just save the cash and use it to save up for an RB26 instead (unless you're planning on doing it yourself).

Its not worth doing internals unless you've broken something and need to do it anyway, or you're planning on keeping the engine. It would be financially silly to rebuild a motor as a "stopgap" measure while waiting for an engine swap.

[7yphon]

haha True well I have a few mods I want to slap on first im in no rush for the RB26 also I need the engine afterwards me and my mate are going to be building RB20DET Dune Buggies Fun!

Edited December 17, 2005 by 7yphon

[Johnny Cash]

As a matter of reference, fully built Honda motors (which are known for their high rev-ability), rev out to around 11,000 RPM, and at those revs, you can actually hear God talking to you!

With the RB20, being a 6-cylinder 2.0 litre motor, it is imaginable that, running naturally aspirated, you would be able to get around 8 - 9000 RPM with decent internals and tuning, but don't expect anything around 15,000 RPM!

Don't bother with the idea of a motorbike engine either, they rev high and put out good power, but have no torque. Which is okay if your car weighs 100kg!

You might be better of buying an already high-revving engine, and tuning that up. But not many car manufacturers outside of Europe bother with these sort of motors. They either force air in, or built a big motor. Rev's are out, unless you're Ferrari, or to a Japanese extent, Honda.

That said, you're more than welcome to try. Just watch the wallet!

[7yphon]

haha yer I dont want to be waisting money anyway thanks for your imputs guys. Looks like im saving for a RB26DETT