WHats up with the redline on the skyline?

[Hu_Dat?]

I was reading banzi (british mag) rescently and it featured a GT-R that could rev to 11,000rpm. the owner said that he had put a pulley kit on it or something, to make it rev that high. This made me think of a couple of questions concerning rpms and speed.

1. I know that skylines have been famous for there ablity to withstand huge loads of power (1000bhp), but how do they do this? I want to know
basically what makes it so different from other cars

2. excluding the pully thing, how are Skylines able to produce such a high red line in general and still have a realatively high top speed and incredable 0-60 time(high torque) together? is it just because they are 4 wheelers or what? I know the stroke is really small (something like 2.9) so how is this possible?

3. I want to own a 97 mustang cobra (and twin turbocharge it). is there anyway to jack up the redline as I am looking for better top end power right now (high rpm sounds so cool). I don't want to adjust the c.r. too much, as that can really F&%$ up an engine. besides its 3.7" (squared) so it will only change from quite big to regular big even if I modify it a lot
Thanx in advance y'all

by the way IMPORTS Rock and stangs too but unfortunetly not stang culture. I am a firm believer that there is a replacement for displacement- Its called BOOST


just to make sure I'm correct about all this redline stuff for check me:

assuming same displacement and cylinder # a low c.r. means that the end of the connecting rod must be closer to the crankshaft. This shortens the distance of the of the moment arm which directly effects the amount of force each cylinder is able to exert on the crankshaft (less torque). however at the same time this allows the crankshaft to turn at a faster rate which in turn leads to higher rpms.

simply: a low compression ratio = higher redline than a high c.r. because the engine produces less torque

Not to shaby for a 7teen year old, eh?

This is one of the best sites I have ever visited- I discovered this site at around 5pm on sunday spent till 4 am monday browsing the forums. went from 7pm - 3:30am again today. I like this site a lot

[RazorGTR]

I've not seen one rev to 11,000 though that doesn't mean you can't build one to do that. To acheive that and still make power would mean one huge turbo otherwise you will out rev the turbo(s) flow rate.

The engine is 3.386 in x 2.902 in so it is just out of square. The RB26 block is extremely strong given its overall capcity and able to produce such high hp. Bare in mind those motors making over a 1000 hp are generally filled with a liquid hard block to keep it from splitting between the #3 and #4 cylinders due to block flex.

Factory the "redline" begins at 7,500 rpm though the factory rev cut is 8,200 rpms. All of the engines producing higher revs have had different conrod bolts fitted, along with main cap bolts. Usually ARP. The top drag teams launch at around 9,800 rpms or a bit higher.
Stroking the engine to 2.7 or 2.8 litres doesn't mean you will acheive any more power at the higher revs it is a combination of cams, turbo(s), head flowing etc.

Even in factory trim the engine produces peak hp at around 6,700 rpms and peak torque at around 5,900 rpms. This is with quite small twin turbos.

[SkylineUSA]

"assuming same displacement and cylinder # a low c.r. means that the end of the connecting rod must be closer to the crankshaft. This shortens the distance of the of the moment arm which directly effects the amount of force each cylinder is able to exert on the crankshaft (less torque). however at the same time this allows the crankshaft to turn at a faster rate which in turn leads to higher rpms.

simply: a low compression ratio = higher redline than a high c.r. because the engine produces less torque"

Not exactly right,but close.

There are a lot of other factors that come into play with an engines ability to rev. You do have some good points though.

Like what Razor mentioned, plus more cubes most of the time will mean less top end HP, once again like waht Razor mentioned. Hell, Razor said everything I was going to

[ZZII]

For ur #1 & 2 question, all u have to do is put a highier stage turbo on it. stage III or IV is like friggin fast. i can cause whipplash if u don't wear a brace. And skylines don't have much torque in relation to their HP. infact they have very little compared to alot os cars. Torque and HP are 2 totally different things. HP is a meaurement of power in the engine, Torque is for hualing ass.

U can also change the redline by messing with the gear ratios.( don't unless u know what ur doing!)
Gear rations dictate the RPMs, and the amount of of them needed to change gears or when the engine redlines. So basicly, the highier the redline, the highier the speed speed can be.

[SkylineUSA]

Gears have nothing to do with an engines redline, it has do with when you shift.

What is a stage III or IV, I am little fuzzy on that one?

Torque has verything to do with HP, that is how you come up with HP.

[SkylineUSA]

Gears have nothing to do with an engines redline, it has do with when you shift.

What is a stage III or IV, I am little fuzzy on that one?

Torque has everything to do with HP, that is how you come up with HP.

[R33]

Gears have nothing to do with an engines redline, it has do with when you shift.

Yup.That's rite. Gear ratios can make the engine to touch he redline faster/quicker. That's all. It won't however, change the redline. The redline can be changed if you deal with the engine, its innards, ecu, ignition etc. Not gears.

Torque has everything to do with HP, that is how you come up with HP.

Agreed too. Basic principle, if I am not mistaken is torque x rpm = power (hp). The more torque at a given rpm means you have more power at that given rpm. Theoritically, it is then possible to compensate for the lack of torque by inreasing rpm. That is why you would go for a short ratio gear box...rev up quicker means more rpm which in turn means more power although at the same time the torque may be unchanged. That is why I suppose F1 car revs up to 18k rpm...or the Type R. Even the GTRs.

Conversely, however, you can't compensate for lack of torque by changing gear ratio. I think, and I stand corrected on this, more cubes or longer stroke mean more torque. But this will, at a certain point, reduce power.

That's as far as I know. Not bad for mid life eh?

[ZZII]

Originally Posted by R33

Gears have nothing to do with an engines redline, it has do with when you shift.

Yup.That's rite. Gear ratios can make the engine to touch he redline faster/quicker. That's all. It won't however, change the redline. The redline can be changed if you deal with the engine, its innards, ecu, ignition etc. Not gears.

Torque has everything to do with HP, that is how you come up with HP.

Agreed too. Basic principle, if I am not mistaken is torque x rpm = power (hp). The more torque at a given rpm means you have more power at that given rpm. Theoritically, it is then possible to compensate for the lack of torque by inreasing rpm. That is why you would go for a short ratio gear box...rev up quicker means more rpm which in turn means more power although at the same time the torque may be unchanged. That is why I suppose F1 car revs up to 18k rpm...or the Type R. Even the GTRs.

Conversely, however, you can't compensate for lack of torque by changing gear ratio. I think, and I stand corrected on this, more cubes or longer stroke mean more torque. But this will, at a certain point, reduce power.

That's as far as I know. Not bad for mid life eh?

Look at the RB in comparison with any other car. the RB has much less torque comepared to a Corvette, but can have morer HP. and gear ratios dictaite when u shift.

[SkylineUSA]

HP = (Torque*RPM)/5252

So what does that tell you ZZII? HP is calculated by what.......wait for it........... torque. j/k

I mean in general terms they are different, but in the truest sence, HP is very much dependant on torque, because the formula need torque for the the formula to work.

All Dyno will crossover at 5252, if they do not, the dyno operators are not scaling the graph at the same on both sides, that will throw off the crossing point.

R33 is absolute correct, but you can compensate for more torque with gears. Just go to a higher gear, so instead of a 4.11, you would go with a 3.23. You can also go with a taller tire, roughly 1" of tire will drop you about .13 in gear ratio.

[IvoryJ30t]

Originally Posted by ZZII

For ur #1 & 2 question, all u have to do is put a highier stage turbo on it. stage III or IV is like friggin fast. i can cause whipplash if u don't wear a brace. And skylines don't have much torque in relation to their HP. infact they have very little compared to alot os cars. Torque and HP are 2 totally different things. HP is a meaurement of power in the engine, Torque is for hualing ass.

U can also change the redline by messing with the gear ratios.( don't unless u know what ur doing!)
Gear rations dictate the RPMs, and the amount of of them needed to change gears or when the engine redlines. So basicly, the highier the redline, the highier the speed speed can be.

are you serious? learn something before you go spreading your gran turismo bullshit on other people.

explain what a stage 3 or 4 turbo is? would that be like a t3/t4 60 trim or something like that? im kinda partial to the gt2530 ball bearing setup, know what that is?

and how exactly do you "mess" with gear ratios? explain it to me, id love to hear your reasoning. id bet there wont be a mention of "ring and pinion" or "differential"

and redline is determined by rod length/stroke ratio and the moment of inertia of the piston/rod assembly, and the inertia of the valvetrain.
but you probably have no idea what valve float is...

how do the people who know what there talking about deal with the rampant stupidity on this board. every other post here is complete bullshit.

[SkylineUSA]

IvoryJ30t,

Nice to have you post. There are a few guys on here that are very knowledgable. As for the other posts, we just have to weed through them. In that aspect it kind of sucks, but the site does have some good info, that you will not find anywhere else.

I know what valve float is. Hrydro are very prone to it at higher rpms, that why solids are SOOO good Speaking from a V8s point of veiw.

[IvoryJ30t]

Originally Posted by SkylineUSA

IvoryJ30t,

Nice to have you post. There are a few guys on here that are very knowledgable. As for the other posts, we just have to weed through them. In that aspect it kind of sucks, but the site does have some good info, that you will not find anywhere else.

I know what valve float is. Hrydro are very prone to it at higher rpms, that why solids are SOOO good Speaking from a V8s point of veiw.

very true. nice to be here, i love to get into it with people who know what there talking about. i hate it when kids flip through a magazine and watch some movies and think they know everything there is to know. its especially bad when people who are looking to expand there knowlege are hampered by people spreading crap as gospel. blatant stupidity is something i cant handle.

well, its geting kinda late over here, im headed in. catch you tomarrow.

thanks for the welcome.

[SkylineUSA]

I here ya, man.

Like I said, it nice to have someone else on here that is knowledgable. I hope you stick around. Its hard come by guys that are willing to have to weed through the other posts.

When you get a chance, tell us about your car.

My name is Tony.

[Moppie]

Originally Posted by IvoryJ30t

and redline is determined by rod length/stroke ratio and the moment of inertia of the piston/rod assembly, and the inertia of the valvetrain.

You can also include in that list the ablity of head and manifolds to flow air into and out of the engine, and the ablity of the fuel system to deliver enough fuel, then you have to have internals and a block strong enough to with stand the increased stress from increased RPM etc etc.


Most enignes, especialy mass produced ones are rev limited by a mechanical weakness, normaly in the valve train, but there are quite a few engines out there that are limited by the amount of air the head and manifolds can flow.
The 4cyl and V8 lotus engines are a great example, none of the Esprit models have a redline marked on the tach, the engine design is strong enough to handle revs well beyond what the intake, head, and exhaust/turbo(s) can provide air to reach, even the turbo engines simply just start to run out of puff long before the engine reachs any physical strength limits (when driving one it dosnt take long to figure out when to change gear, the power curve is long flat and well defined).

The RB26 revs so high because of a great combination of all of the above, its VERY strong (the block is about 3 times as big as it needs to be) and is able to surport not only a lot of parts moving at very high speeds, but also the boost needed to feed an engine spinning at very high speeds.




Welcome to the forums though, as SkyUSA said its always nice to have more brains around.

Don't let the lesser educated members get to you though, the trick is to not get angry or angsty with them, just explain where they went wrong, and most of them soon learn who actualy knows what thier talking about

[Moppie]

Sorry, just thought of more useless information to add.

Nissan engines in general have a history of being very strong internaly, and are limited in revs largely only by valve spring strength and or flow limits of the head.
The SR20 is regarded as one of the strongest 4cyl engines ever build, its bottom end is capable of holding very high revs, and or boost provided the right work is done to the head (cam lobe size is quite limited on many models).
Even the nissan version of the old A series engine is almost indestruvtable. Used in the 100a, 120y and early versions of the bluebird in 1.0, 1.2, and 1.5L versions I have personaly failed to destroy one with high revs, and know of several people who have done things like stu=ick a brick on the pedal and leave the car revving flat out in nuetral till it runs out of gas (thats several hours), then fill the car up and driven it to work when sober.