just wondering if there are any BMWs out on the road that can achieve 10k rpm???:offwall

There are tons of guys who have over revved their motors. :D

they do all the time... its called moneyshifting ;)

but seriously i have been curious about this too, i see valve train kits with titanium valves, retainers, and those nifty dual valve springs that say they are capable of 9k to 10k but ive never heard of anyone actually making a reliable 10k redline on a street motor.

Valves are only one part of the equation you're gonna need to do a lot more in order to achieve a redline sustainable above 8k rpm

making the valvetrain and bottom end take that is not horribly difficult, just expensive. The other issue is wear. a 10k rpm motor will have a service life of a few hours.

i just LOVE the sound of high(er) revving motors!!!
unfortunately, not everyone does >>> :cop

the e46 m3 gets close wit 8600rpm redline.. Most of thos high revers are dirty old m10 4cly... Hand grenades..

Change your mill for a Suzuki Hayabusa engine and gearbox with turbocharger. 7,000 RPM will be a thing of the past :)

the e46 m3 gets close wit 8600rpm redline.. Most of thos high revers are dirty old m10 4cly... Hand grenades..

I have seen a E46 M3 go to 9200.... then do it again in the next gear then again once we slow down and go WOT again....

It happens but you have to remember more rpms less life in the long run.

You could probably do 9,000 rpms with a frankenmotor. A moderator over at Bimmerwerkz.com is building one to drop into an e30. His process is being documented in the e36 section because he's using a few different pieces. I bet Robstah on here could also do it.

well, I've seen a Ferrari F40 at 10,000RPM either on youtube or streetfire but that certainly isn't a BMW, I have not seen or heard of a 10,000RPM BMW but then again I haven't been really looking for one....

i'm sure the new rs4 and the new gt3 can hit 9000 with a new tune and i'm sure there are some crazy bimmers out there that can hit 10k in like swedan or something

Question is will you be actually getting any useable power out of these engines with that bandwidth?

Question is will you be actually getting any useable power out of these engines with that bandwidth?

^ I was thinking the same thing. Im guessing no.

just wondering if there are any BMWs out on the road that can achieve 10k rpm???:offwall

Probably a well built S14.

Question is:

Guys with built Supras are stroking to 3.4 and revving to 9,500 on top of that. A recent video shows one going to 10,500rpm. With giant gt47-88 and larger turbos, the power band goes up there. So if they can do it, why can't we? :smoke3

Everything is possible depending on how much you are able to pay for it. Generaly speaking any engine is designed to reach a certain rpm, take the 600cc 4 cyl motorcycle engine, it's easy to reach 15500 rpm because every moving mass is small and have a small displacement to acheive, as mass increase like the liter bikes, RPM capability decrease. So basicly to reach 10000 RPM and remain practical, a complete redesign is in order, since we aint gonna cast aluminium in our garage to make custom blocks we have to use what we have. 10000+ RPM will be very costly and unrealistic in matter of bang for the bucks. I just think that it's misusing the great BMW inline six. Take it there and you end up with miscalculated bore and stroke, too long runners, too wide combustion chambers that can't burn fast enough, overstressed ultralight but still too heavy components, valve springs strong enough to grind your cam to 0 deg in a matter of hours, etc..
But hey I agree that it would sound great combined with a loud turbo whine :buttrock

Question is:

Guys with built Supras are stroking to 3.4 and revving to 9,500 on top of that. A recent video shows one going to 10,500rpm. With giant gt47-88 and larger turbos, the power band goes up there. So if they can do it, why can't we? :smoke3

compare the rod/stroke ratios of each engine...that should give some insight. Maybe they have a shorter stroke and bigger bore.

Slightly off-topic but....

http://www.youtube.com/watch?v=v9fMRlY6L-Q

There's a few more videos out of it but the engine is still sort of a mystery. It's a V8 and one guy says:

"It's a 1990 320i with a Flossman Bodykit and a Judd Lmp 675 Engine (3,4 V8, over 550 HP, RPM max. 10500)"

Either way you can hear those RPM's screamin and I'd bet money it's hitting 10k...but then again its not an I6 either ;)

or a bmw engine

I think the best bet would be a s14 with an m10 crank, if its forged

The new V10 I think would be the best engine if you are trying to get to the 10k RPM mark its redline is set at 8,300

Question is will you be actually getting any useable power out of these engines with that bandwidth?

When you cam the S54 with a new intake manifold you do make power up past 8000rpm.

compare the rod/stroke ratios of each engine...that should give some insight. Maybe they have a shorter stroke and bigger bore.
m52 = 84x84
2jz-gte = 86x86

Key is square engine so I have to look at other components but not sure why a built m52 can't rev super high as well. Now the stroked 2jz-gte version of course has much more than 86 stroke but still has 86 bore I believe. The more the stroke the harder it usually is to up the redline but they are going to 10k with even more stroke than 86mm.

pistion speed also becomes a problem with more stroke

When you cam the S54 with a new intake manifold you do make power up past 8000rpm.

But were talking 10k. Not 8k, big difference.

m52 = 84x84
2jz-gte = 86x86

Key is square engine so I have to look at other components but not sure why a built m52 can't rev super high as well. Now the stroked 2jz-gte version of course has much more than 86 stroke but still has 86 bore I believe. The more the stroke the harder it usually is to up the redline but they are going to 10k with even more stroke than 86mm.

Over-square is even better for high RPM, there is less side-loading on the piston.
The thing about this, is that a street car is not in some race class where we have to make the most out of certain constraints. Super high RPM is the hard and expensive way to make power, and also the most life decreasing to the motor. There is an advantage to increasig it some, but the same power can be had through other means that are less likely to decrease the life of the motor so drastically, like increasing flow and efficiency.
To build a high RPM motor, a key part would be using the WPC treatment on the bearings, rings, pistons, valvetrain etc. It decreases friction alot, while increasing internal parts ability to retain oil, and increasing the amount of load bearings can safely withstand. It uses ~10-20 micron super hard particles hitting the components at super high velocity, leaving non-directional peaks and valleys, which is excellent at retaining oil over the standard tool mark grooves left in say, a piston. It was developed for 24 hours of Le Mans, but is now used by everyone form club racers to OE manufacturers like Honda on factory cars.

Is there something to be said about the layout of the engine and how it affects its natural balance and the weight of the crank. v8's need heavy counter weights, i4 need balance shaft. I6 needs none but has a long crank and many bimmers are undersquare. I wish bmw would make a flat plane v8.
I'd attempt to take a s14 to 10000.

Could someone explain the differences in forces on a turbo engine compared to a NA engine. I'm sure it has to do with speed and not pressure.

Question is:

Guys with built Supras are stroking to 3.4 and revving to 9,500 on top of that. A recent video shows one going to 10,500rpm. With giant gt47-88 and larger turbos, the power band goes up there. So if they can do it, why can't we? :smoke3

Supra motors are WAY beefier then our's. I have one of my s52 blocks next to one of our 2jz-gte blocks at the shop. I'll take pics of them together and post them when I get back to the shop on tues.

I'd say more smaller cylinders reduce mass/speed load.

boost helps in terms that the increased backpressure and intake pressure actually cushion the piston rising applying a certain force (small in compared to the rotating mass) on the piston on the 2 tension strokes (rod). Compression remains about the same but exhaust is further from free folwing and the piston "see" this pressure thus reducing the upward deceleration force close @ overlap.

Supra motors are WAY beefier then our's. I have one of my s52 blocks next to one of our 2jz-gte blocks at the shop. I'll take pics of them together and post them when I get back to the shop on tues.
Yeah they are way beefier. I've seen both in person. Better HG seal with Supra too. But what does the beefier block have to do with high rev?

Beefier blocks means you can bigger rod and main bearings to deal with the loads. Most sportbikes have a bore to stroke ratio of 1.5:1. The short strokes help keep piston speeds reasonable. Remember that the forces exerted on the parts go up with the square of the speed. Ke=1/2MV^2. F1 cars were approaching 20K RPM, but to make them last 2 weekends, that had to drop the rev limits.

I heard if they went to 8 cyl from 10, they could easily appriacg 24k in F1

I got the answer

The bmw p84/85 engine revs 19,000 rpms.

Beefier blocks means you can bigger rod and main bearings to deal with the loads. Most sportbikes have a bore to stroke ratio of 1.5:1. The short strokes help keep piston speeds reasonable. Remember that the forces exerted on the parts go up with the square of the speed. Ke=1/2MV^2. F1 cars were approaching 20K RPM, but to make them last 2 weekends, that had to drop the rev limits.
actually that's kinetic energy, not force.... kinetic energy comes from net force times the distance it's applied, it's closer to momentum than force....i'm a physics geek, sorry.... that squared comes from the circular motion of the crankshaft, thus centripetal force:
Fc=mv^2/r
So, for instance, at the same rpm, if r (stroke) is decreased by .5, v would also be decreased by .5 (v=rpm x 6.28 x r), then v^2 would be decreased by .25, and F would be decreased by .5 (.5 x .5 / .5). then you have to account for the loss in displacement, which is (1/2 bore)^2 times r (stroke) times 3.14... because volume = 3.14 times r(in this case half of the bore) times height (stroke)....so to retain the same displacement while decreasing the stroke by a factor of 2, the bore would need to be increased by the square root of 2. now, assuming the piston is the same material (therefore same density) and same depth, the mass would increase by the square root of 2, because the volume of the piston is being increased by that amount. now, you have two engines, with the same displacement, and at the same rpm, but one with half the stroke of the other. let's say that in the original engine, the one with the longer stroke and smaller bore, the size of everything is 1. stroke is 1, mass is 1. so F is 1 because 1 times 1^2 divided by 1 is 1. now in the engine with the shorter stroke, the mass is going to be the square root of 2 (1.41), the stroke is going to be .5. and we said v would be .25, so 1.41 times .25 divided by .5 is .705, which is the force on the bearings, connecting rod, etc.
Cliffs: if the stroke in an engine is decreased by 1/2 while increasing the bore to keep the same displacement, at the same rpm, the force on the components would be 70% of the force on the original engine.

I heard if they went to 8 cyl from 10, they could easily appriacg 24k in F1

They went from 3L V10s to 2.4L V8's this past season. Rev limits went up slightly over the course of the season, but the vibrations from the V8 design meant that you were playing with fire if you went much over 20k RPM from what I saw.


I could see wanting a slight increase in RPM over the stock rev limit, but such crazy increases are usually very expensive and like others have said, really take a toll on engine life.

Damnit...I saw a video from some Euro guys (not sure which country but prolly a Swede) revving the hell out of his BMW. It looked like a 325 guage. Needle pointed straight down when he revved it. I will try to find it again.

oh yeah, that thing about there being a big difference between 8k and 10k, definately. the speed increases by .25, so you are now at 1.25 of 8k. that means the force is 1.25^2, or 1.5625. so yeah, the force increases 56% in that increase from 8k to 10k. all this talk makes me want to fix up my nitro r/c car, the 3.0 cc engine revs to about 30k and makes 1.5-2 hp.

m52 = 84x84
2jz-gte = 86x86

Key is square engine so I have to look at other components but not sure why a built m52 can't rev super high as well. Now the stroked 2jz-gte version of course has much more than 86 stroke but still has 86 bore I believe. The more the stroke the harder it usually is to up the redline but they are going to 10k with even more stroke than 86mm.

yeah, the bore/stroke ratio is 1 for both but the rod/stroke ratios are different. the 2jz has a rod/stroke of 1.65 and an S50 has a rod/stroke of 1.48. The rev happy hondas like the b16 have a rod/stroke ratios of around 1.75, which is kind of the "magic" number, so the 1.65 of the 2jz is much closer to the magic 1.75. I'll have to read up on the reasons why 1.75 is the magic number (something to do with the max connecting rod angles which have to do with the side loading of the pistons) since it was a long time since I read up on it.

JOEY

info sources:
http://www.crower.com/cat/import/toyota/pistons/pistons.shtml
http://members.aol.com/FE3N/rods.html
http://users.belgacom.net/bmw_z3/bmw_z3_coupe.htm

i've read about an 86 corola, built and everything made 276whp @ 10,700 rpms i think, which is crazy (info might be a lil off i can't remember exactly)

interesting facts of the P84/5 at 19,000 rpm:

• At 19,000 RPM the following events occur in one second - The engine rotates 316.7 revolutions, the ignition system fires 1,583 times, 9,500 engine speed measurements are made, the pistons covers a distance of 75 yards and nearly 140 gallons of air are drawn into the engine.