quest for 10,000+ rpm red line

[S13/R32]

sup?
i own 89 s13 with a ca18de (yes its not a turbo) it got a few mods from the previous owner like a 3" cat back system, hks airpod and a front strut brace, after that i started modding adding a 3 piont harness, two racing seats, 5" monster tacho, lightwight flywheel with heavy duty clutch and i finished off the exuast by adding extractors and a hiflow cat (makin a full 3" system), l8ly i've been trying to make the engine as responsive as possible so i added a after market trottle body it didn't seem to make any difference so i think i've wasted my money a bit. i was wondering if i went out and got some lightweight inturnals and a aftermarket ecu woudn't i'd not only make it more responsive but push the red line up to 10,000 rpm seeing that ca18's have good vavle trains?

plz correct me if im wrong and if u differ to wat is said here or have any other opions i'd love to hear them or if u think i should upgrade something other than the engine

[requiredoption]

As a rule, less resiprocating mass means a higher rev limit. With some engines, people do make aftermarket titanium peices to lighten up the valve-train, I'm not sure about nissan engines, but i'm willing to bet the parts are out there.

Also, with high rev's you need to be worried about the balance of the engine, it is entirely possible for one side of the crankshaft to be a smidge heavier than the other, or one con-rod or piston to be out of balance with the others, this is where machine shops and aftermarket tuners come in. A machine shop will be able to balance your engine as well as take a little weight off as well through knife edging, shaving ect. Aftermarket tuners can sell you already lightened crankshafts, hollow con-rods, light-weight pistons, but all of this is fairly expensive.

The last thing I can think of at the moment is the stroke of the engine, or, the distance the piston travels in the cylinder. This is a function of the crankshaft. If you wanted more low end torque you would put in some sort of "stroker" kit which is a crankshaft that allows for longer piston travel and all of the neccessary peices to go along with it. You want higher rev's which would dictate a shorter than stock stroke, I still havent seen an aftermarket crankshaft that provides less travel, but i'm sure if you had the funds you could get one built out for you.

All in all a 10k rev-limit might be a possible thing, but the costs and time involved in it might be a little disuasive. Also, your talking about "more response" which i'll take to mean more umph down low. Generally with a high rev engine, all of your power is going to be up top in the rev range, you would have a fairly guttless low end, due to the cam profiles and stroke/bore ratio that you would be running.

Anyways, Some suggestions
- Change your exaust to a 2.5 or 2.25in. diameter, 3 inches suits a turbo car that doesnt need backpressure, but with an n/a your loosing alot of response right there.

-Lighten the flywheel

-Cam's, fully tunable management systems, deck the head ect.

-Regarding the intake (your throttle body), bigger is not always better, if you lower the velocity of the air into the intake ports you degrade your low end. You will get more air into it for an over-all higher horsepower, but you cant change one factor of an engine and not affect the others.


Hope this helps
- John

[S13/R32]

yeah that helps alot thanks man. i wasn't planing to stroke but i was going consider stroking to 1.9L not much i kno but apprently it dose good for ca18's (make their bottom end have a bit more as they are kinda of gutless down low) ... well so i've heard...

yeah about mapping and blue printing the engine (balancing) i figured i would have to do that, also i was thinking of using machined alloy pistons and lightend conrods and balenced crank for the bottom end. Do u think that i might have problem with alloy pistons?...

And i can see wat u mean about the throttle body by going back the carby's venturi, not only dose it creates a low pressure area but speeds up the velocity of the air thanks for that

but one thing i don't understand is y go down to a 2.5" or a 2.25" exuast system as dosen't backpressure degrade ur engine performance. Hence if would as to unbolt ur extuast system from the end of ur extractors u like run the quater mile in 0.01 to 0.02 quicker

any way thanks for that John

[Darkstar]

To put it simple - NA cars need backpressure, as it provides a bit of low end torque. Turbo cars don't need it, as the more spent gases can be flown through the exhaust, the smaller turbo lag is. 3 inches is a size adequate for a high-powered (300 flywheel?) turbo engine, and not a torque-lacking CA18.

[requiredoption]

Yeah, Darkstar got it right.

For a well rounded n/a engine the exaust is an important point, it needs to have enough backpressure to provide low end torque, yet be free flowing enough for top end power. In your quarter mile example, the reason it may be a little quicker is because your always in the top portion of your rev's on a drag strip, while on the street and autocross and drift and everything else, you use more of your engines rev range, so to achive the throttle response you were talking about, you may sacrifice a little top end, but you'll walk away with a much more rounded engine. It all has to do with the gas velocity's that I mentioned previously. Bigger is not always better.

Things like equal length headers are also important parts of n/a exaust tuning, while in a turbo car, header's dont make a sizeable difference - ex: the wrx.

[Darkstar]

Brrrr. Bzzzz.

Headers really make a HUGE difference in the WRX. In this particular car, every tube coming out of each cylinder has different length, what makes the no.3 cylinder overheating. It's been a common problem in the earlier Scoobies. If you swap the exhaust manifold for an equal length one (Greddy could be a nice example), then there's no problem. In a 2 liter STi GDB (the bug-eyed one you Honda guys), a Greddy TD05 turbo (dunno which one? There's so many of them ), plus a Greddy manifold, intake system and intercooler make as much as 350 flywheel horses. And without the possibility to melt a single piston.

[Parry]

So want to turn to 10k, huh?

No you don't.

Your car will drive like crap, idle like crap, burn a ton of gas, not make power until 6 or 7k. You will need to upgrade the entire rotating assmebly, or at least rods with a balanced crank and serious hardware. You might as well do pistons and raise the compressoin ratio while you are in there though. You will need headwork like a madman. Like find the best machine shop you can and put a grand into your head. Rebuild it, upgrade the entire valive train, and hog the *Censored**Censored**Censored**Censored* out of it to get enough flow to make power that high. You'll need to run super hot cams that will make so little vaccuum at idle that you'll have no power assist on your brakes when the car is not wound up and it will idle like absolute trash, just barely staying alive. You'll probably end up tuning it to idle way higher than stock, really. You will probalby end up running standalone, and spending a lot of time dyno tuning. A lot of these type motors are running ITB's as well, and without them you will probalby excede the flow of even a somewhat worked intake manifold and throttle body. You'll want fairly short runners that will help you make max power and torque, but will destroy what is left of your non-existant bottom end. You will run out of fuel probably as well, so you'll need injectors, perhaps an adjustable FPR and pump. You also start breaking wierd stuff when you turn this high...underdrive pullies help keep from frying accessories, trannies don't necessarily like it and I've actually seen clutches fail.

That was all sorta "general" info, it vaires greatly from motor to motor.

Good luck (with coming to your senses and realizing you don't drive an F1 car, because this is a pipe dream.)

[DriftingNewbie]

What perry was saing above reminds me of the S2000s when they first came out. I remember owners talking about having to launch the car (drag racing) as high as 5k because the car would just bog and you would get a horrible launch. This is just one problem i could think of when a high red line

[LexmarkX73]

Originally posted by Darkstar
To put it simple - NA cars need backpressure, as it provides a bit of low end torque. Turbo cars don't need it, as the more spent gases can be flown through the exhaust, the smaller turbo lag is. 3 inches is a size adequate for a high-powered (300 flywheel?) turbo engine, and not a torque-lacking CA18.

actually this is incorect.. backpressure is an old hotrodders myth, NA engines require an exhaust with a great enough diamater to maintain exhaust velocity which creates a vacuum that scavenges the cylinders of burnt fuel/air. Too large of an exhaust = no velocity. too small of an exhaust = backpressure. turbo cars do not rely on proper exhaust sizing due to the sheer amount of burnt fuel/air being forced from the engine.

[requiredoption]

Originally posted by Darkstar
Brrrr. Bzzzz.

Just a quick aside. When I was looking at power options for wrx's a while ago the exaust manifold wasnt the place to get it. Yes up and down pipes make a HUGE difference, but the header's that were being produced for the car wern't. Alot of the manifolds would cool the gas before the turbo, slowing the gas down, and thus affecting the turbo spool, and any header that did add power, was so pricey that it wasnt wort it.

Either way http://www.cobbtuning.com/tech/exhaustdesign/index.html
thats a good tech artical on n/a and turbo exaust tuning

[SidewaysGts]

I think someone got that a little backwards. Turbos do need a bit of backpressure, without it turbo lag would be even logner then it already is, if you dont believe me ask around or do it yourself if yoru willing to waste the bucks, without a build up of air its actually harder and takes longer to "push" the turbo.

Nas actually do better with negative pressure, or a vaccuum. This actually helps the engine by sucing the exhaust out of the cylinder. I think Bill sherwood covers this topic better, youd probably only know him if you were a 4age fan though.
___

About a 10k rev range.its fun and all but its a 8itch to do.

Basicly by all respects, EVERY aspect of the engine will need to be replaced or worked on.

ENgine head design. valve angles, valve train in general, everh ear of "valve float"?, huge cam shafts with increase duratio nand lift, adjustable cam gears, fully programable ecu, increased copmression forged piston heads, conrods (cunningham conrods will make custom ones), dont forget conrod bolts- arp is a good bet. conrod bolts are more at risk generally then the conrod itself. Balancing your crankshaft may be enough, but not knowing the nissan engines very well a custom built forged crank shaft may in call for to sustain 10,000 rpms (This will hands down be the most expensive single part), a dry oil sump kit, a VERY well designed radiator, 4;1 header with the proper length to creat the mid-high range torque youd want. i think i covered most aspects...

Added up.. your looking about 10+ grand. but then again as with most cars this really depends on who you know and is just a "ball park" figure... either way it will NOT be cheap by any means.

Could just buy a formula atlantic 4age earlier models were built to rev up to 12k ! THeyve boucned around over the years, aroudn 10-12k. lately its been a mild 9k from what i understand.

Added: Just saw LexmarkX73 cuaght onto the exhaust thing already

[Parry]

sidewaysgts and I already had this discussion once.

I think we pretty much agreed that this was not the cleverest idea for a street car. These motors are really buitl for specific race classes and whatnot.

[S13/R32]

ummmm... maybe should go back to me drawing board?

i'll give that exuast a try i've got good extractors... or could i just change the muffler ova and get one fabicated for me that be the cheepest way? ... i'm woundering if the extuast system on my s13 would fit on my R32 GTS-t? oh well learn something new everyday, never knew extuast could be that complicated

any way im gonna go out and buy a wolf 3D sometime in the near present future i'll think i'l work me way up from there, get it purrin like a kitty kat first

thanks for ya help ppl

http://www.wolfems.com.au/home

[SidewaysGts]

Greta choice in ecu, its actualy the model i reccomend for any serious engine tuner (i plan on one for myself if i ever go the extra step for the silver top)

Raising the rev ability of an engine slightly isnt overly complicated.

For the most part some arp conrod bolts are really all thats needed. Those suckers are most at risk, if just one goes there goes your engine and all the money you dumped into it. Accompanied by some larger cams and adjustable cam gears you could have a decently tuend engine.

For moderatly higher reving engines, youll want to get some custom built or forged conrods for sure. To be on the safe side you sohuld shotpeen/balance your crank shaft which will let you go even higher.

Anything radicly over your stock revs and you WILL more then likely need a custom built crank shaft. this opens a big window in terms of how high u can rev; assuming youve got the parts mentioned before.

[Tsunami]

Originally posted by Parry
So want to turn to 10k, huh?

No you don't.

Your car will drive like crap, idle like crap, burn a ton of gas, not make power until 6 or 7k. You will need to upgrade the entire rotating assmebly, or at least rods with a balanced crank and serious hardware. You might as well do pistons and raise the compressoin ratio while you are in there though. You will need headwork like a madman. Like find the best machine shop you can and put a grand into your head. Rebuild it, upgrade the entire valive train, and hog the *Censored**Censored**Censored**Censored* out of it to get enough flow to make power that high. You'll need to run super hot cams that will make so little vaccuum at idle that you'll have no power assist on your brakes when the car is not wound up and it will idle like absolute trash, just barely staying alive. You'll probably end up tuning it to idle way higher than stock, really. You will probalby end up running standalone, and spending a lot of time dyno tuning. A lot of these type motors are running ITB's as well, and without them you will probalby excede the flow of even a somewhat worked intake manifold and throttle body. You'll want fairly short runners that will help you make max power and torque, but will destroy what is left of your non-existant bottom end. You will run out of fuel probably as well, so you'll need injectors, perhaps an adjustable FPR and pump. You also start breaking wierd stuff when you turn this high...underdrive pullies help keep from frying accessories, trannies don't necessarily like it and I've actually seen clutches fail.

That was all sorta "general" info, it vaires greatly from motor to motor.

Good luck (with coming to your senses and realizing you don't drive an F1 car, because this is a pipe dream.)

I agree totally Parry. Also with that kind of RPM's you start to sacrifice alot of reliabity. Nascar motors are only turning 9500rpm yet they don't always make it. These are motors built with the best there is, yet they still grenade. When you push a motor that hard, it's not gonna last very long. At 10k rpm your car will be totally undriveable on the street.

It'd be much easier and far more practical to spend your money on an SR20. You'll get a much flatter torque curve, more power, better mileage, and better reliability. Plus, since the SR20 is a known quantity, you'll have a much easier time finding repair parts and fixing it than if you had a one-off, high dollar motor.