We learn something new everyday! I hadn't heard about that ratio and neither had my dad who used to be a mechanic and race car builder. It must be a newer term and way of thinking. I do see how it can affect the engine and to be honest I wouldn't try messing with that. Toyota engineers have probably gotten that ratio to it's peak for all around performance and unless the engine was being built for out and out competition shouldn't be messed with. It will be interesting to see what parts and modifications become available. How far can the NZ be pushed? what is the most power/torque that can be squezed out of it?

we don't know the limits of the 1NZ-FE engine yet, but i'm sure someone is going to find out soon enough. new advanves in engine design and building are always popping up, which is why you see 1500cc cars with 110hp. there are tons of bigger engines with a lot less power. or how about the old vw beetle engine? those had around 36hp, and had enough power to get people around. i think 110hp in a light car is a good starting point to make a fun, quick little car. top end will never be like a big V8 or 4 cylinder with 2.5l or more, but with the low weight, you can really get the scions to fly. i think it just requires good engine design.

there are civics running 10 second quarter miles with normally aspirated engines. how do the guys running 12 second supercharged V8 mustangs explain that?

Hey , my Focus is 2.0 liter with a 110 hp. The only good thing about it is its 125 tq. But its an overall BAD design , it only has 8 valves!!

I had a feeling Randy would post something like this......... :lol:

Thanks eric for the breakdown on the engine info!

and thanks to everyone for the feedback too!

this give me a lot to read about to learn more about my xB....

Engine performance upgrade
 

Truth is, "There's no substitute for cubic inches." Install the engine from the Corrolla or the 1.8 from the Celica!
I'm quite satisfied with my 1NZ-FE engine with the AEM cold air intake, TRD axle-back exhaust and oil filter, Royal Purple synthetic motor oil and gearbox lube to lower friction. An engine is simply an 'air pump'. Make it's job of pumping air easier, with less restriction, and it'll breathe deeper and give more flexible power.
I'm looking for a larger throttle body!

Actually overdrive isn't an extra gear it is a device that is added to the transmission before the connection to the driveshaft. it feel like and extra gear but itsn't.

Re: Engine performance upgrade
 

kind of. you can't just go balls out on the intake and exhaust of a N/A engine though. it won't be as efficient. you have to design it to bring in and exhale a specified amount of air to get the power and efficiency you want. that's why there is continuously variable valve timing on the intake cam. on a turbo engine, you can have a 1" intake and 1" exhaust to and from the turbo, but on our car you cannot do that, even though you could consider that "less restriction". anyway, everyone is talking about putting the 1.8 engine in the scions, but i have yet to see pictures. i wish people would stop talking about how much better it would be, and just start doing it. it's always the people who aren't online who do the coolest stuff to their cars.

Re: Engine performance upgrade
 

BURN...on me

damn you meanie

Re: Engine performance upgrade
 

i'm online too.

Re: Engine performance upgrade
 

Remember we had that talk awhiles back and this totally suits us now.

Me too... :P

Adding a longer rod simply won't increase displacement. To increase c.c. you need a longer throw ( or crankshaft stroke.) There has been lots of article on rod ratio advantages and disadvantages, certainly it would effect the way an engine "feels" but I have not read enough to understand all of the science behind it. Also keep in mind if you do switch to longer rods you will need new pistons with a shorter compression height ($) and you will need to rebalance everything. There are also ongoing studies on (rotating assembly) Center Of Gravity location and the affect on engine performance.

Quench area is also very important to cylinder combustion. does anyone have any pics of the head or the pistons? I would love to see them.

I personally think a good valve job is worth its weight in gold, I have only seen better flow and power gains from proper backcuts. How do the Toyota valves look from the factory?

10.5 CR is a bit too high for much more than 5psig boost without proffesional tuning. In the future, will Scion release a motor designed for higher boost? (like the turbo vitz?) With a lower CR and wider ring gaps?

I/H/E mods will be great for this car, but I wonder if a larger cam will ever come out for it? As any change in duration will require new programming.

HP and torque
 

http://www.remus.dti.ne.jp/~pochiinu...411NZ-EGSC.jpg

http://babelfish.altavista.com/babel...eSpecCurve.htm

even Ford mustangs have had returnless fuel lines, since 1999

Uh, not really.

"Overdrive" simple means that the last gear on an automatic, actually lowers RPM instead of being a multiplier of the final drive, i.e. 1st-4th take the final drive and are multiples of that ratio. a 1:1 would mean that if your final drive is 4.11, then in that gear what you're getting is 4.11, where as overdrive might give you effectively a 3.90 or something like that.

Another advantage of returnless fuel lines not mentioned yet is that by keeping fuel cooler, they increase it's density slightly. That's better for making power. A mariginal difference, but it matters. Notice that drag racers and other performance applications will actually super cool their fuel before a run. That is why.

Same principle as cooling the intake charge, it increases density of air or fuel which means more mass/volume. More air + more fuel = more power.

I've even heard of people modifying their cars to make the fuel lines returnless. One reason they use the return is it's supposed to help the engine warm up faster, but I'm not so sure about that.

Ah.. I got it. :idea:

I was thinking of the lockup torque converter on an automatic transmission. That would make sense in the context you are using. You are 100% right about the manual transmission overdrive being a mechanical unit bolted to the rear of the transmission, it will reduce the engine speed by about one-third, while maintaining the same road speed.

what if i changed the diff. gear ratio to about 4.355:1 with 5th gear @ 0.815 that should bring the final drive down to about 3.55:1 wouldn't that also help with the MPG???

Making the gearing # lower would in ideal increase MPG. There is a point though where you could gear tranny to low & that would cause more bad then good. I found out earlier today that JDM xA has a 185/65-15 Tire. So by the american market putting a 185/60-15 changes the gearing a little. So just by running a taller tire you lower your gearing a little. Also by changing your gearing you increase the overall time it will take you to get to speed. I read in this thread that @ 60mph the engine is at 3,000RPM!! I drove a v6 stang & that was at about 1,800RPM @ 60. I got near 3,000 when doing 85 in that thing. I know the Stang has more HP & more so TQ. So if you could change the gearing so the engine does about 2,200 @ 60mph that would be a drop of 800RPM of engine work. Might only raise gas milage by like 2% but every bit helps. Sorry for the very long reply to such a simple question.