hey everyone, i need to get my hands on some custom pistons for the block but i'm unsure of some measurements.

i was told i need to give atleast the following:

block height, gasket thickness, bore diameter, combustion chamber volume, stroke and connecting rod length

i know the bore is 84.7mm and the stroke is 75mm, anyone know the rest? and possibly any over information that could be helpful? this is for custom Wiseco pistons of the same compression as stock *10.5:1*. the rods i'd like to be using are the CRWR rods we all like so much, hopefuly they are the same length as stock.

the idea is for a 1NZFE build to be reliably turbo'ed as if it was built that way in the first place from the factory. kind of like the Nissan SR20DET...

any help would be GREATLY appreciated!

 

why are you using such high compression pistons?

 

"the idea is for a 1NZFE build to be reliably turbo'ed as if it was built that way in the first place from the factory. kind of like the Nissan SR20DET"

i explained it right there, but for a more basic idea. i'm oing a reliable turbo settup. something that the vehicle can be reliable with for 50K + miles and not have a worry about anything. the 10.5:1 custom pistons are to keep the stock compression to keep most of the mileage and low end power the vehicle already has. having low compression pistons will hurt the mileage and of which is something i don't want to do.

this is why i need the listed information. the closest i can get is 10.0:1, but i'd rather have 10.5:1 to keep compression the same on the low end and keep mileage near the same.

 

When boosting an engine you should lower your compression.

 

yes you SHOULD, but i have no need to being i don't need to worry about it. it's a longevity settup, not a race settup.

instead of aurguing the fact that i SHOULD get lower compression, i would rather just get the measurements and you all can see what i mean later down the road.

i've already said i don't want to lower compression due to the fact that i will loose mileage and low end power *low end power for daily city driving*. having normal stock 10.5:1 compression will work just fine as long as i keep it around 8-9psi and no higher. i need the measurements so that i can have custom forged pistons made to go with some crwr rods. telling me i need lower compression isn't helping when it's not what i'm asking for.

 

Don't know what block hight could mean. I would assume they mean deck hight.
Deck hight is how munh the piston is above or below the deck at the top of the stroke.
Depending on the piston, you may need to mill the block for 0 height or cut the piston for 0. In some cases you would need a special spacer head gasket or a thicker head gasket if there is a problem cutting the pistons.
I would think that around 8-9 lbs w/10.5 even with 91 octane, as your fuel, 10.5 is a little on the high side. What you gain in compression may be lost in IGN timing being pulled back along with more fuel being used to cool down the EGT. 10 might work better for you. that .5 doesn't look like much but it realy is on these small engines.
Just a thought,
Steve

 

think there would be much change on the lower non turbo effected power range and mileage?

 

Yes.

 

theoreticaly speeking, i'm guesing i'd see about a 5% diffrence in both low end *out of boost* power and mileage. would this be about right?

theoretical method: comparing 10.0:1 compression to 10.5:1 compression

10.0:1 devided by 10.5:1 = 0.9525 *rounded up*
1 *reference to 100%* subtracting 0.9525 = 0.0475
0.0475 would translate to 4.75%, 5% is assuming another smaller 5-10% diffrence being it can't be a perfect theory.

Theoretical results:
33mpg hwy turns to 30mpg
30mpg city turns to 28 mpg

low end diffrences upto 3k rpms shouldn't be noticeable, specialy after a simple addon like a lightweight pully.

 

Winter, you are on the right track, however the fuel grade would make a difference & .5 for most people is not noticable ( the DD guy ). With no boost there are so many variables which makes it hard to determin where you would use more or less fuel. The driving range, from say 2200 to 3000 may not cahnge at all, not as much ign would be pulled back with higher compression. This is a kind of 6 of 1, half dazen of the other.
If the ign was limited to only a few deg's your numbers would work. The good old mechanical days. The Idea of running the compression as high as it is in the "lean burners" of today is to make as much power as possible. Once you add boost these engines, they realy come to life. BUT..... the internals will get hurt at anything higher. With an SC on this XB i actualy see a little improvment in mpg @7psi. All stock OE internals.
That said, I'm betting on the ECU making an overal change at the high end under boost less the .5. A turbo will make bigger numbers at the top with the right tune. Using the OE ECU, no pig, you would see some of that power, at low boost.
On the other side, lower compression 8.5:1 w/higher boost, 14psi, will make more power than 10:5 with 8.
There's more but life is short,
Steve

 

this i understand, i'm not really looking for pure power gains, but more around of just a volt more energy. i want more umph from the xB and thus why i really wasn't looking forward to lowering compression. i would like to hit around 150whp/wft-lb but i don't want to change much of the internal compression so that out of boost it's not much diffrent from stock cruising *atleast noticeably*.

 

http://en.wikipedia.org/wiki/Toyota_NZ_engine

 

Winter, is there someone that lives near that has an SC car? This would be something you would want to drive. The SC won't make the big numbers that can be had w/turbo but will give you what you are looking for as a direct bolt on ( auto only - 5 speed WILL need a clutch ).
itsme, good link. This somewhat explains the "Atkinson cycle" - VVT, but not for forced induction w/ more than 10lbs of boost. There are some inherent problems with head flow that Atkinson has addressed to increase combustion efficency. 20 years ago you could never build a 100+ 1500cc engine without lots of work ( look at SCCA FP cars - they do make more than 100hp but at what cost ).
I hear Weapon is about tomake a production manifold for the NZ that will add 30hp....
Steve

 

actualy, thats the bad part. noone in the area has a FI system of any kind except for one guy and i've only seen him once. everyone else is "looking" to get one.

 

winter, you said you only want to reach 150whp/wft-lb. Is that how much you are looking to get from the turbo alone? Or are you just looking to get 150whp/wft-lb out of your car in general just to get a liitle more kick?

 

just in general

 

ok then why would you go turbo? I think some boltons should do the trick. On my XA I have the redline power chip, AEM intake, and a custom 2.25" exhaust and I'm pushing close to 150whp.

 

i will never touch a redline chip, they don't give the adds they claim to add and i've never heard anything good about them. i always hear about people nearly blowing motors just because of this chip, others have said that they don't even give an improvement worth buying.

have you dyno'ed your gains at all?

 

sorry i spaced and looked at your profile, i just don't see how a simple chip would give such a gain.

136whp
138lbs torque?

 

I had dynoed my XA before the chip that was with the intake and just the muffler no piping done. So i figured after the piping and the chip I am around 150whp. Yes, you are right the redline chip gave me about 10hp but I had a problem with it. Just 2 weeks ago I blew the first cylinder spark plug and coil right out of the head, stripped the threads and everything kinda sucked. Needless to say I took out the chip and rethreaded my head and put a sparkplug insert in the new threads. I have heard a lot of bad things about the chip but usually within the first 20,000 miles or less I got about 50,000 before i had trouble. Well I learned my lesson now I'm looking for a performance ECU any ideas?