What steps can be taken to safely raise the redline with the stock bottom end?

Why would you want to do this? Unless you are going FI theres really no point there is so much power/torque drop off after 6.5K that it feels to me as if it were trying to start rolling in 3rd gear.

Please forgive me for being a newb, but what does FI stand for? The reason I'm looking to rev higher is because I'd like to try and offset the hugely short final drive with more revs. Also, more revs = more power if you have enough air and fuel right?

FI = forced induction

the reason torque drops off is due to how HP and lbs/ft are calculated (notice that at 5250 hp and torque are equal. that happens to all motors...)

plus the gearing isn't made for higher revs...

you can change the gearing...

Want a better gearing? Find an Echo Transmission, Switch out the Final Gear(or all of em :P)
Also more revs does not equal more power. More Air and More fuel equal more power(Oversimplified statment there).
I'll tell you now that if you do you will lose some acceleration and not gain any top end(unless you remove the speed restrictions).
I owned an Echo and I can tell you stock the xA accelerates faster, and both top out around 118 when the restrictor cuts on.

How would changing the gears change the redline? I thought your gearing affected your acceleration.

all motor cars like foruma 1 cars and NHRA import all motor cars run better at high RPMs because the engine benefits from the higher revs. if you notice when driving the car around 5800 will fall flat on its face.

more revs dont really equal more power unless the parts in a car can work with such a mixture

what restrictor? my xB doesn't have one. the hp and torque starts to curve down, but I think that there would be more at 7000 than 3500(where he would shift too)

How would changing the gears change the redline? I thought your gearing affected your acceleration.
the reason the redline is there is to prevent the Engine from tearing itself apart, Toyota's are overengineered however I am a firm believer of "It was put there for a reason". Even if you were to change the redline to 8K you still wont get anything out of it without changing Internals, or doing other stuff. the redline has absolutly nothing to do with HP. Have you seen the Power Curve on a 1NZFE?

Boombox, the computer controlled top speed, is the restrictor I am talking about

I don't have any restrictor on mine, there is nothing that bumps me back down like my moms camry(125)

No I never have seen the power curve. Where does the engine make it's peak torque/hp? Do you have a link for a 1nzfe dyno chart?

http://www.remus.dti.ne.jp/~pochiinu/001Vitz-TechInfo/Taco/0411NZ-EGSC.jpg
http://www.overboost.com/picture.asp?a=1209&i=Scion%20xb.jpg
If you look at the second one just past 65K youy can see the dropoff I was talking about.

...If you look at the second one just past 65K...

Wow! 65K RPM! :)

The limiting factor in RPM is the fatigue life of the reciprocating parts, primarily the rods. As the RPM goes up, the stresses also go up. As the stresses go up, the parts will not last for as many reciprocating cycles.

The stock rods will have infinite fatigue life at 2000RPM. Raise that to 4000RPM and the life becomes finite, but is still longer than the life of other engine parts. Go to 6000RPM continuously and the life is shortened to a number of hours. At 8000RPM, fatigue life is reduced to minutes.

How to raise the red line? Well, it can't be done on a stock lower end! You can raise it if you replace the crank, rods, and pistons with items designed for a longer fatigue life. Be prepared to spend $$$, though!

George

xb's do not have a speed limiter , but do have rev limiter. , (just clearing things up in case people didnt understand)

...If you look at the second one just past 65K...

Wow! 65K RPM! :)


George
I could swear there was a . in there, should read 6.5K

xb's do not have a speed limiter , but do have rev limiter. , (just clearing things up in case people didnt understand)

exactly, what car doesn't?

xb's do not have a speed limiter , but do have rev limiter. , (just clearing things up in case people didnt understand)

exactly, what car doesn't?

there are plenty of cars that do not limit the speed....they just gear the car to top out at that speed in sted of making the ECU do it...

thats not what I asked read again, it sais that they have rev limiters, and I said what car doesn't

alot of older cars dont , trust this , lol , that and you could easily remove them via distributer , lol

What steps can be taken to safely raise the redline with the stock bottom end?

If its more HP you want than why don't you nos it out and not worry about the redline? :D The motor will destroy itself if the redline is rasied higher than what it's set at. So to answer your question.

There are no safe steps to rasing the redline. Sorry :(

to raise the redline you would need to build the head , and change rods , and change crank bearings. so a fully built motor.

One more newb question (for now)...

I'm not sure how exactly to read where the power band starts and ends according to a dyno chart. Could one of you tell me? Thanks!

well from that chart it looks as though it starts around 1100 and stops gaining power by like 5900 or 6000 , it's the more uphill band , lol

What steps can be taken to safely raise the redline with the stock bottom end?

If its more HP you want than why don't you nos it out and not worry about the redline? :D The motor will destroy itself if the redline is rasied higher than what it's set at. So to answer your question.

There are no safe steps to rasing the redline. Sorry :(

gabe's not joking about that nitrous. if ur thinkin about it, keep at real low at least. from my experiences its a no-no on these motors :no: ...they just cant handle it. a 35 will be ok. but dont go to any extremes.

Raising the RPM band or changing the cams will actually have negative effects on your car~~ Daily drivabilty is worsened, and you can even risk internal damage to the engine!

The engine was specifically designed with narrow-angle twin cam heads for a torquey punch at low RPMs. Modifying the internals will prove to be a very difficult task~ i.e. forced induction, camshafts, etc

damn piece of chit motor.

http://www.remus.dti.ne.jp/~pochiinu/001Vitz-TechInfo/Taco/0411NZ-EGSC.jpg
http://www.overboost.com/picture.asp?a=1209&i=Scion%20xb.jpg


Look at the lower line that peaks out in the 143 range.
Once the RPMs (r/min on the graph) hit ~4200 the torque is peaked. After that it drops. After ~5000 there's a DRAMATIC drop off in tq.

Without changing timing, air/fuel, and probably the cams, you wont get any more power from raising the redline.

What really helps drivability is "power under the curve." How many seconds does the engine spend at 6K rpm? .5? 1? How many seconds does it take the engine to get up to 6K rpm? If you improve the power the engine makes before 6K, you'll notice it a lot more.

Make sense? :)

damn piece of chit motor.

Depends on what you're looking for, doesn't it? In most cases, 1.5L engines aren't built for speed and power. They're generally built for economy.

damn piece of chit motor.

Depends on what you're looking for, doesn't it? In most cases, 1.5L engines aren't built for speed and power. They're generally built for economy.
yes but i'm saying these cars deserve toyota spending an extra 300 and charging us an extra 1k for a 130hp 1zz

http://www.remus.dti.ne.jp/~pochiinu/001Vitz-TechInfo/Taco/0411NZ-EGSC.jpg
http://www.overboost.com/picture.asp?a=1209&i=Scion%20xb.jpg


Look at the lower line that peaks out in the 143 range.
Once the RPMs (r/min on the graph) hit ~4200 the torque is peaked. After that it drops. After ~5000 there's a DRAMATIC drop off in tq.

Without changing timing, air/fuel, and probably the cams, you wont get any more power from raising the redline.

What really helps drivability is "power under the curve." How many seconds does the engine spend at 6K rpm? .5? 1? How many seconds does it take the engine to get up to 6K rpm? If you improve the power the engine makes before 6K, you'll notice it a lot more.

Make sense? :)

Very much :D

But what external mods will actually make for low RPM HP? I believe only internal mods will actually to do just that, but you'll be sacrificing much drivability in terms of fuel economy, top speed, and ultimately engine life.

The engine is developed by Toyota, somehow I seriously doubt we can actually improve on something they took years in developing :P

yes but i'm saying these cars deserve toyota spending an extra 300 and charging us an extra 1k for a 130hp 1zz

Not familiar with 1zz. Is that a toyota motor?



But what external mods will actually make for low RPM HP? I believe only internal mods will actually to do just that, but you'll be sacrificing much drivability in terms of fuel economy, top speed, and ultimately engine life.

Usually things like headers will bump up the lower rpms, but most of the time small engines can enjoy some midrange power from intakes/exhaust and other bolt ons. From what I've seen on this site, intake/exhaust will bump up the the midrange a little and top end of these engines, too.



The engine is developed by Toyota, somehow I seriously doubt we can actually improve on something they took years in developing :P
I agree, but I bet this engine would take to timing like a champ. You'd have to use higher octane gas, but I'd bet Toyota kept the timing pretty mild.

Not familiar with 1zz. Is that a toyota motor?
Yup~ 1.8 liter 16 valve aluminum engine with VVt-i. Same engine that powers the 00' Celica GT and MRS

Seems like a feasable engine swap with the right people and money, and can accomodate F.I. much easier than the 1NZ-FE engine ever could! ^.^

Bolt on mods so far have only been dyno proven to increase HP in mid to high RPMs where air flow is important, however this is at the sacrifice of low end torque due to the loss in back pressure.

Sadly, the 1NZ-FE is highly developed and purpose tuned powerplant. Squeezing more power out of it would be a time consuming task :(

the 1zz also comes in corolla's ,in both regular and matrix for m argurably better than the 180hp 2zz because the 1zz has more torque and can be used with forced induction , my ideal is the 1zz with a trd supercharger . the zz motors bolt up to our tranny but will require an additional engine mount to be fabricated. if i were to do the swap it would be trd supercharged 1zz with a celica gt 5 spd , our tranny's bolt up but do not have a stong enough cluth and have pretty chity gear ratios for a higher hp motor , the 1zz starts at 130 stock and with trd supercharger and header / exhaust will have approximately 190whp but more tq than a 2zz ever would . think about that say 165whp maybe more all depending on mods . that would be nice power with tq . a lil rocket think high 13's

Good info, thanks hotbox.

Cloudnine:
I think there may be a few ponies stored up, but not a whole lot.
The sticky thread shows some power gains from the intake setups. I haven't seen any graphs in the sticky, though. I saw an article (not sponsored by AEM?) that showed a decent bump in power from the AEM CAI.

The magnaflow website (of course) shows a bump in midrange (slight) and some up top.

http://www.magnaflow.com/05news/magazine/importr.asp

As far as the power loss below 2K rpm...if you're "racing" and you floor your 1.5L and your revs are below 2000....you've already lost. :doh: :wink:

You don't want to raise the redline much for 2 reasons,
1. unless you have cams that are made to make power higher up the rpm range then its not helping.
2. I had a Integra type R with a lot of mods including cams(Crower 403's at the time, the Toda spec B's weren't giving me as much power as I wanted) I had upgraded my valve springs but believed people's advice that the stock retainers would work. Well on the drag strip at 9600 rpm(my new redline, 8500 is stock) I threw a valve and punch a hole in my piston, sent metal shavings through the motor. The head was damaged beyond repair, I had to have the block resleeved and of course new valves, titanium retainers and new pistons. I ended up boring the cylinders slightly over and put in higher compression pistons so $6000 and 3 months later (yes it took 2 months to find a new type r head even the dealer couldn't locate one in the US) later the car was better than ever but just a lesson for those wanting to up the rpm with out prper precautions.

^^^ good advice... you definetly need to upgrade the head... and maybe get some oil squirters for if they are gonna go through some really high rpms...

ouch 6 grand since you didn't spend 400 bucks on new retainers?
also installation and break in is a key factor to why your valve gave...