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

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.

"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:)

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.

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.

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.

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? :p

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? :p

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.

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.

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.

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,

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.

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.

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 :smokin:

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.

Okay, i stand corrected. U can not change an engine's redline, but u can change the engine's topspeed, by "messing" wit the gear ratios. And Ivory what i mean by this is setting them to what u want, and when u want them to shift, changing the speed u get to when u shift, wether it's highier or lower.

And as for all that "Gran Tourismo" Bullshit which i doubt u know the true meaning of, i know everything about turbos. u ask & i'll know. What they are, how they work, how to use turbo lag to where it has no affect on ur car, what they will do to ur engine with too many of them, and their disadvantiges.

There are a lot of guys that read the contents of these pages, without posting. I try to make it a point to know what I am talking about, at least give it some forethought. ZZII, you might want to do the same.

I'll give you a little quiz. What is the diffence of the 2510, 2515, 2530, 2540 HKS Turbos?

Also the word is you, not u.

Okay, i stand corrected. U can not change an engine's redline, but u can change the engine's topspeed, by "messing" wit the gear ratios. And Ivory what i mean by this is setting them to what u want, and when u want them to shift, changing the speed u get to when u shift, wether it's highier or lower.

And as for all that "Gran Tourismo" Bullshit which i doubt u know the true meaning of, i know everything about turbos. u ask & i'll know. What they are, how they work, how to use turbo lag to where it has no affect on ur car, what they will do to ur engine with too many of them, and their disadvantiges.

ok, then explain to me how you change gear ratios. manufacturers chose gear ratios for a reason. if you have a narrow powerband, and you nuerically decrease the final drive ratio to gain more top end speed, you will increase the rpm difference between gears and effectively land out of the motors powerband on the shift hurting your cars performance in more than one area.

ok, lets say i have a 3.0 liter 6 cylinder engine and i want to utilize a single turbo setup. ill be encountering a max pressure ratio of 2.75 while flowing 48 lbs/min of air. what turbo would land me in the efficiency range for those specifications? what is a flow chart?

oh, and while were at it, what causes lag? not what is lag, or how a turbo works, but why turbos lag and why a cam profile optimised for high rpm operation decreases efficiency at low rpm's?

oh, and if you know everything about turbos, what is the effiency range of a gt2530, and what is its airflow in lb/min at approx. 80% adiabatic effiency with a pressure ratio of 2.5-2.7?

OOOW OOOW Mr Kotter, OOOW OOOW Mr Kotter........:) In my best Horshak voice.

Can I answer that?

Hey just as a side note where do you, IvoryJ30T and SkylineUSA, get youre info. I eventually want to own a Skyline. But want more info turbo and car info. in general. I like this site but do not like the amount of BS that is posted so I want to be able to weed them out myself. When ZZII either makes himself sound dumb or smart I would appreciate some helpful links to expand my knowledge and answer some of the questions you asked him. Thanks and sorry for the interuption.

ra227,


Dude I am glad you posted. My question was not nearly indepth as what J30t did.

I have worked years on cars, and done a lot of research at a lot of different sites. Its a love for cars, when it comes down to it.


As long as you ask a question it is fine, but when you post stuff that is completely incorrect, or not presented in the correct format you desire to be ridiculed:)

ra227,


Dude I am glad you posted. My question was not nearly indepth as what J30t did.

I have worked years on cars, and done a lot of research at a lot of different sites. Its a love for cars, when it comes down to it.


As long as you ask a question it is fine, but when you post stuff that is completely incorrect, or not presented in the correct format you desire to be ridiculed:)

no problem. if someone asks a question or show that they want to learn, i help them out as much as i can. if someone shows blatant ignorance, you better believe there gonna get shit for it from me.
basically, i started learning about motors and the basics in highschool. i had a great teacher who taught me a great deal about engines, transmissions, ect ect. i also spend a great deal of time learning about as much as i can. if theres something i dont know or understand i strive to learn it. alot of car performance is engineering and physics, which i love. also, my uncle is a retired foreman for Con-Edison [electric company] who taught me about electricity at an early age. i can make my own printed circuit boards and design electronics [working on learning how to use microcontrollers]. also, ive worked in many repair shops, the last of which i was the electrical systems specialist. Pretty much anything technical interests me and begs me to understand it. to top it off, i have a CDL, drive tow trucks, build/fix computers ect. ect.

basically i try to learn how everything works and why. im just crazy like that. if theres something i dont know, i dont act like i do and push incorrect information. if theres something im wrong about, by all means tell me. i want to know.

I am with you. If I post something is that is wrong, let me know. I doubt it though, because I am all knowing;)

Thanks guys its nice to actually talk to people who don't like to just gossip. I read alot of things on the internet but still can't even begin to answer the question Ivory asked. I still want to see if ZZII can- if he doesn't where can I get in depth detail on turbo's and other car stuff. Not from howstuffworks, they are ok but not to in depth. I work on my car a little and have helped w/ an engine swap and other various stuff. But just to try to stay on topic I want ZZII to post his comeback.

Hey just as a side note where do you, IvoryJ30T and SkylineUSA, get youre info. I eventually want to own a Skyline. But want more info turbo and car info. in general. I like this site but do not like the amount of BS that is posted so I want to be able to weed them out myself. When ZZII either makes himself sound dumb or smart I would appreciate some helpful links to expand my knowledge and answer some of the questions you asked him. Thanks and sorry for the interuption.

ok, basically my line of questions to ZZII was to show him he doesnt know everything and he should shut his mouth because from what i have seen, he has very little real world knowlege.

basically, i have never owned a skyline, or ever will. the reason im here is that i have a little project lined up and im trying to figure out what people in the field have had the best experience with. i have had a toyota MR2 [1st gen], an 11 sec DSM [1st gen AWD] an Acura Legend [2nd gen], and my current project that im researching- I have a white [ivory quartz pearl] Infinity J30t that i want to see w/RB26DETT RWD. [not to mention the 5-speed conversion]

if it has been done before, then its only a handful of times [less than 10, if that ever] and i want to be the builder/owner of that extremely rare combination. 4 door luxury, and blazing speed.

Why go with the RB26?

Its a very expensive engine. That is why I am going with the 351W for my project GTR. It will put out MORE power, and be cheaper.

basically, the j30 comes with the VG30DE. now, before you guys say "just slap the 300zx motor in there" the steering shaft is so tight, the j uses a driverside exhaust manifold that is actually recessed slightly to clear it. [mainfold slightly wraps around the steering shaft] the turbo would optimally reside where the steering shaft intersects.
now, the rb is inline, giving me more space than the 60 degree VG v6. also, i want turbo, so that on the street i can lower the boost and not go pouring gas down the monsters throat. also, the sound of the 351 would quickly give it away. one of my friends has a 89 notchback mustang w/ a 351 from a 94 lightining [sp?] pickup. has a vortech blower pushing 10 lbs. its a monster. ran 11.6@126 mph [can you say wheelspin] its an excellent motor, but its not what im trying to do. its more of the exotic nature of the RB [i live in the northeast US] that entices me. that and the ability to fill that bad boy up with 116 octane every one in a while and boost the crap out of it. its more of an exotic project than a speed demon.

oh, and if you know everything about turbos, what is the effiency range of a gt2530, and what is its airflow in lb/min at approx. 80% adiabatic effiency with a pressure ratio of 2.5-2.7?

after he makes a fool of him self trying to answer the question, ill explain how to read flow charts and what that crap means.

Poor ZZII, so clearly out of his depth.



You guys might want to have a look at the Automotive articles section: http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=1202

Have a read of the threads by Texan, a very very smart man, should answer a lot of the questions above.
He still floats around the forum, and I know is always interested in discussions with like minded people.

oh, i know the answers to my questions, i just wanted to see what our self advocated expert has to say.

after he makes a fool of him self trying to answer the question, ill explain how to read flow charts and what that crap means.

Yeah I was hoping that you would.

ok, well obviously hes not going to respond to this so here goes-

how to choose your turbo-

if you have ever seen a flowchart, they are confusing as hell if you dont know what your looking at. you know, those funny charts with the isolines and pressure ratios, and flow in lbs/min?

ok, the pressure ratio the the boost your gonna be pushing on your motor, [duh] but its measured differently. the reason its not measured in psi, is because 14 psi of boost at sea level is not equal to 14 psi of boost at 6000 ft above sea level. how you get pressure ratio is you take your atmospheric pressure [sea level =14.7 psi] and add the manifold boost pressure, then divide by atmospheric pressure. say, at sea level, i want to push 22 psi of boost. [22+14.7] / 14.7 = 2.5 if you take the same boost pressure at 6000 ft ASL, [approx 12 psi] you would get [22+12] / 12 = 2.83 as you can see, those are different places on compressor maps, so that must be taken into consideration.
forgot to mention the equation-
[(atmospheric pressure + boost pressure) / atmospheric pressure]

the flow in lbs/min is ROUGHLY equivalent to 1/10 horsepower. aka 44 lbs/min can push ABOUT 440 hp @ wheels. also varys with volumetric effeciency of the motor, so its not a constant, just a nice guide [as a guide the hks gt2530 turbos flow about 33 lbs/min of air, and are rated for 320 whp]

and the isolines for percentage is the adiabatic effeciency. this is the clincher. when air is compressed, it heats up. we all know that, and there is no way around it happening. the greater the effeciency the less excess heating occurs. as you move out of the effeciency range, the turbo does more heating of the air than it does compressing, which we all know is bad, because hot air is less dense, having less molecules of oxygen per given space than air that is not as hot.

you want to pick a turbo that can flow the amount of air that you need, at the pressure you need, at a high effeciency

note- twin turbo motor- figure your needs, and choose a turbo that FLOWS HALF of those needs. remember you are using two.

J30t,
I have never had that explained to me, thanks. At least now I know what I am looking at.

no problem. yeah, thats the "proper" way to size/flow a turbo setup. the first time i saw one, i was like "what the hell does this mean" its so much easier if you know the info in them, takes the guesswork out of "will that turbo be good for that boost on this motor?"

The way I have been doing it, is just looking at the whole engine combo: Turbos, Cams, injectors, port work, flow characteristics, dyno runs,etc. I would just store all that in my head, and figure what I could do from that. Now, I can just look at the maps. :)

I still have some questions. I'll post them when I get a chance.

oh, i know the answers to my questions, i just wanted to see what our self advocated expert has to say.


Not my intention at all, I was merely pointing to an existing resource here that might either prevent you doing some unnessacry explaining (since someone else already did the hard work), or that even better, you might be able to add to.

AF's a big place, and keeping all the really informative stuff in one place is an almost impossible task, the trick is to let all the smart guys know where the other smart guys have already left thier mark. :sunglasse

just gave me a reason to type.

anyway, where can i get a top mount twin manifold setup for the rb26? rb parts are hard to come by in the states

sorry, i kinda messed up the question. i meant a distributor/web site i can get the manifold.

Not my intention at all, I was merely pointing to an existing resource here that might either prevent you doing some unnessacry explaining (since someone else already did the hard work), or that even better, you might be able to add to.

AF's a big place, and keeping all the really informative stuff in one place is an almost impossible task, the trick is to let all the smart guys know where the other smart guys have already left thier mark. :sunglasse

oh, no its ok. i tend to get out of hand on my ridicule. as displayed...

www.takakaira.com

Is the place that sales a lot of stuff.

What size are you looking for? I heard a lot of good things about the Apexi units, but I do not have any personal experiance with them.

I know of a unit that for sale in www.gtr.co.uk for sale section a while ago, I am pretty sure it did not sale.

I can follow up on it if you want.

www.gtr.co.uk/forum/upload/showthread.php?s=&threadid=14761&highlight=apexi

Here you go, this at least will give you something to compare it to when you're looking at other kits.

Thanks for the explanation IvoryJ30t. I will probably have to read it a couple more times to understand it- have been reading that 350Z sucks post- man its long- and kind of burnt out on the reading. As another side note- if things go well in the next few years with my new job I want to start seriuosly looking at an R34 vspec II- does anyone know the price RB motoring sells it for- I looked at the site and they dont have it.

thre selling them for like70 - 80,000 i think. out of my range, thats why i wanna do a swap.

Hopefully thats true- is a little better than Motorex at like 95K although it has come down from about 105K- or maybe the car was newer. 70-80K is still very high thats why I have to wait and see- I doubt I will be able to pay it off right-off. I'll just make high ass payments. We'll see... its some years away but I'm patient. The only reason I'm asking here is because you guys have been cool- I know other skyline owners, not you IvoryJ30t you said you don't have one, here are tired of answering these types of questions unless they know for sure your going to get one soon.

yeah, im more into building projects than laying out an incredible amount of money just to have a car that i paid twice its value and its still stock.

i would much rather put the effort into something than pay to have it done.

seeing as how i cant make a skyline comply, i wont be having one.

http://files.automotiveforums.com/gallery/watermark.php?file=503/649Turbomap_007.jpg

I understand about the pressure on the left.

I understand the impeller speeds, the blue line with the dots

One thing I do not understand, is how they have 15psi in two seperate places on the graph? One at 2.1, and the other around 2.45. These is where I get lost.

I look at the bottom of the graph, and I automatically try to coralate that to the out psi of the turbo, which I know is wrong, but I still do it.

yeah, im more into building projects than laying out an incredible amount of money just to have a car that i paid twice its value and its still stock.

i would much rather put the effort into something than pay to have it done.

I know exactly what you mean thats why they are my last option, I want to buy it in Japan and ship it over here but you know how all that goes, I'll look into this and ask around- not really here though because they all get pissed because this topic has been beat to death. I really want the car but really don't want to pay 2x the original amount of any car...but then again I love the car. Like I said its some time in the future I'll see what happens. Thanks again for the info.

http://files.automotiveforums.com/gallery/watermark.php?file=503/649Turbomap_007.jpg

I understand about the pressure on the left.

I understand the impeller speeds, the blue line with the dots

One thing I do not understand, is how they have 15psi in two seperate places on the graph? One at 2.1, and the other around 2.45. These is where I get lost.

I look at the bottom of the graph, and I automatically try to coralate that to the out psi of the turbo, which I know is wrong, but I still do it.

heres whats confusing you, a title on the graph would be good, because in that picture, there showing the effect on flow due to a change in elevation. the 15 psi at the higher pressure ratio is at a higer elevation.


here, watch- [x=atmospheric pressure]
[2.1] {(x+15)/x=2.1} [x+15=2.1x] [15=1.1x] [15/1.1=x] [13.64=x]

[2.45] {(x+15)/x=2.45} [x+15=2.45x] [15=1.45x] [15/1.45=x] [10.34=x]

i definatly feel what your saying. im just not even gonna get wrapped up in the hassle of it all, so im settling for the skyline motor in a non skyline car...

I gotcha. I have been doing some more reading. After I read what wrote, the light went on. Thanks.

I never thought I would get it.

i put the equation to the problem in the last post. as you can see, x=atmospheric pressure [just algebra]

Yeah, whats happenin yall, i have recently heard bout this forum and he info supplied by some members is sufficient. so.... i wanted to ask about buying a R32 GT-R skyline Japan spec. This includes:

1989 Nissan Skyline R32 GTR Twin Turbo
5 speed
Grey
100,000 kms (odometer is showing 33,000 kms due to the fitting of an aftermarket meter)
Engine was completely overhauled 20,000 kms ago
260 degree TOMEI cams
TOMEI 1.1mm metal head gasket
TOMEI cam pulley
N1 oil pump
N1 water pump
R34 GTR turbos
Intercooler
Airpods
Exhaust
MINES fuel pump
HKS racing suction kit
PFC street pad
TOMEI master stopper
HICAS cancel switch
Front and rear strut tower bars
HKS EVC3 boost controller
HKS turbo timer
MINES computer
HKS gauges
Nismo front bumper
Trust sideskirts and rear skirts
Eat Bear aero bonnet
Aero side mirrors
N1 lights

this will cost approx imported and on the road $25 000 aus dollars.

i wanted to know what other mods except bigger turbos can i do and what are the runnong cost of GT-R's in australia and dyno tuning?
also will it cost double for modifyin due two twin turbo?

Thanx for your help guyz

u guys r sad

I think this thread has done its time, its starting to attract low quality life forms.