DISI-MZResponse

[Tokay444]

Can't have shorter stroke AND shorter rods...

[Enki]

Compression height 2 inches; SCR of 2:1...probably wouldn't even idle, just slow roast some coffee beans.

[Mazdazilla6]

I dug up some numbers from back in the day when I was doing calcs on making a big displacement DISI. The number I calculated for deck height was 230mm. I'll try and confirm when I go into the machine shop today.

[Mazdazilla6]

Just got to the machine shop. Measured 9.127" so right around 231mm but I think 230 is a more round number.

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[mituc]

9.127" = 231.8258mm

[SNOW_QN]

I think he's suggesting that Mazda would use a an even number like 230, instead of 231. I could be wrong, but it makes sense to me.

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[Enki]

Except our rods are 150.55 mm. Fuck is that shit.

[Mazdazilla6]

Originally Posted by Enki Except our rods are 150.55 mm. Fuck is that shit.

Here's one of my calcs:

MZR 2.3 DISI -
Stroke/2 = 47mm
Comp height = 31.75mm
Rod length = 150.65mm
Theoretical deck height = 229.2958mm

Note: This doesn't take any deck clearance into account, if any (top of piston to deck).

[Easter Bunny]

Originally Posted by Enki Except our rods are 150.55 mm. Fuck is that shit.

150.55 millimeter = 0.029 935 178 557 perch

[Easter Bunny]

Originally Posted by Enki Except our rods are 150.55 mm. Fuck is that shit.

Technically just as precise as 150.00 just seems worse.

[Enki]

Got an email from HR today, being forced to take a shitload of PTO. Might tear down the Mazda in December...Hopefully I can get at least some shit going by then (at least the transmission stuff, if not the engine proper).

Also, does anyone know the weights of the stock valves + retainers? Trying to find out how much weight can be shaved off with titanium/hollow stem parts.

[ItsNox]

Poor guy. Forced PTO.

Sent from my big ass Note 4 using shitty Tapatalk.

[Enki]

Originally Posted by ItsNox Poor guy. Forced PTO.

I'd cash it in if I could... I have 232 hours worth (or would if I take none by Dec 31st).

In other news:

James, The only possibility to lighten the valves is to use the regular MZR valves that have 5.5mm stem. This will save you 12-13% of weight but this is not much to allow you to get to 9000 rpms with the factory springs. You will still need a stiffer spring. Maybe by using custom made Titanium valves, as these will save you about 40% in weight but they are expensive, close to $ 100 each and not ideal for turbo applications. Best regards. Willy Tagliavini Supertech Performance Inc.

I'm under the impression most of the spring "upgrades" available to us really aren't. Discuss?

[Enki]

@anavrinIV;

Any luck shipping that crank yet?

[Mazdazilla6]

Originally Posted by Enki I'm under the impression most of the spring "upgrades" available to us really aren't. Discuss?

Are you referring to the thread where someone measure stock springs to be stronger than a good amount of our options?

There are a few that are stiffer. I know for sure that someone makes a double spring option for us and a couple make some really stiff ones (like 80lbs). IMO you're best off with a double spring if you're gonna rev 9k+ since you're much less likely to get coil bind at those high rpms. I believe the Greek guy with the awd ms3 is running double springs or at least stiffer ones.

[Dano]

Here is his quote Post #213

Originally Posted by RE-ACTIONENGSPEED3 supertech single i run and i will install double spring supertech 90lbs if i remember correct.

[Enki]

Next question will be what kind of strain that's going to put on the VVT actuator and camshaft itself...will lobe/follower wear increase?

[Dano]

I don't see a way to answer that question on paper...run it and see what happens the subbie guys don't have too much trouble with theirs (AVCS nor tappets) so I don't know why ours would be any more trouble.

Sit back and see what happens to Teo's setup.

[Enki]

OK next question:

Any detriment to valve life running the smaller stem valve? More likely to break the head off with high force springs? I'd assume that Supertech would know what they are talking about...

[Voltwings]

Im not intimate with the inner workings of a VVT system, but i know a lot of the big cam 5.0 guys will delete the cam phasers because they cant quite keep up or something. Its not something i have really looked in to, but just food for thought.

[Easter Bunny]

Originally Posted by Enki OK next question: Any detriment to valve life running the smaller stem valve? More likely to break the head off with high force springs? I'd assume that Supertech would know what they are talking about...

Its a matter of material strength. Our stock valves are sodium filled to help with heat dissipation so there may be a minimum size necessary for that to work correctly.

[xfeejayx]

Originally Posted by Easter Bunny Its a matter of material strength. Our stock valves are sodium filled to help with heat dissipation so there may be a minimum size necessary for that to work correctly.

Really? Now I want to go find one to cut apart.

[MD1032]

Most valves these days have sodium cores because it's lighter and dissipates heat better. The 130 HP 1ZZ-FE from my 2005 Toyota Corolla had sodium valves.

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[Easter Bunny]

Also the smaller valvestem would theoretically increas flow due to the smaller obstruction.

[Voltwings]

Now, this is me just splitting hairs but ... are you just splitting hairs at that point, or could it actually be an appreciable amount? In theory it makes perfect sense, but im just wondering.

[Enki]

I really don't think it's going to make as much difference as just having lighter valvetrain will...Besides, I can always turn the boost up.

[Easter Bunny]

Originally Posted by Voltwings Now, this is me just splitting hairs but ... are you just splitting hairs at that point, or could it actually be an appreciable amount? In theory it makes perfect sense, but im just wondering.

You would have to look at cross sectional area of the port at the valve stem and then determine the percentage increase. I would expect around 1% increase in flow area.

When you are rethinking every part of a motor to make just under 400 Hp every little bit matters.

[Enki]

With the bigger (hotside) turbo and minor headwork combined with the destroke, 400 should be pretty fucking easy and at lower boost than I was hitting.

[Easter Bunny]

Originally Posted by Enki With the bigger (hotside) turbo and minor headwork combined with the destroke, 400 should be pretty fucking easy and at lower boost than I was hitting.

If you do too much work you are going to end up running 0 psi of boost and 380 Hp.

[Mazdazilla6]

I guess it also depends which valves you plan on replacing w/bigger ones. The exhaust are the sodium filled ones, hence why they are ~$50ea. The intake valves are just whatever ferritic material they're made of.

IIRC stock is a 6mm stem and Supertech is 5.5mm because duratecs use 5.5mm stems. I wouldn't expect to see any quantifiable gains by moving to a smaller stem nor any detriment to useable life. How much bigger were you planning on going with the valve size?

[Enki]

I'm not. It should be fine with the destroke as far as flow goes.

[Mazdazilla6]

Well if your pursuit is less weight then IMO that .5mm is not worth the amount of money it will cost as well as the work to replace all of the valve guides in the head. The Supertech exhaust valves may not even be lighter if they aren't sodium filled.

There might be some weight savings if you can get an aluminum exhaust sprocket or possibly hollow cams. What is your main reason for wanting a lighter valvetrain? Faster revving?

[Enki]

Mostly for valve control at high RPM. Looking at titanium retainers as well.

[Mazdazilla6]

Hmm well chopping weight at the stem certainly isn't bad but I highly doubt you'll see much of a noticeable difference since that weight is so centralized to the valve.

Honestly I feel like proper cams and strong springs should do you just fine for high rpm use. Only other thing I would do is get the cams pinned and the crank keyed. Other than that you should be just fine.

[Enki]

Yeah that's already the plan.

[Tomas]

Intake valves are 50g each. Exhaust valves are 45 gs each

Obviously you don't need to lighten the IN valves to less than 45 gs unless you also change/ lighten the EX valves.
If you are going for a high RPM engine and hais the dorrah I would recommend titanium wrist pins with a cassidian or DNC coating. If you need a minimum order quantity let me know the price via PM. I might order 4 with you just for the lulz and potential future failz.

http://www.tricktitanium.com/forms/WRISTPIN%20BLANK.pdf

[Mazdazilla6]

Not sure if it's been covered or not but have you chosen a piston material yet?

Most forged are made from 4032 or 2618. If you're going for high rpm and don't want to rip the gudgeon our of the piston then 2618 will be a lot more safe, it also is much more tolerable of detonation. Downside is that it has a much higher thermal expansion rate so you'll have to run a higher PWC so it won't run as good while cold.

I haven't really checked out other materials but I know some companies have their own proprietary stuff that they use.

[Enki]

In truth my piston speeds will be significantly slower from the destroke, so I shouldn't necessarily have to worry about piston damage from rpm (especially considering people are already spinning 8k with OTS Weiscos.

[Realgib3]

I've run as high as .0048 PWC with zero piston slap or noise at all on cold start, etc.

The only thing piston wise I'd tell you to look into is the wrist pin. Our pins are very thin by turbo industry standards and I've seen plenty bent pins when disassembling engines. You should be fine since you'll be so low on overall power/Torque, but just as RPM plays a big role in rod bolt choice, it also makes life harder on the pins when the stroke starts pulling the piston back down the bore.

[Mazdazilla6]

Ah yea I forgot you're going to have a retarded high (compared to stock) rod/stroke ratio so that should keep piston speeds down. I'm pretty excited to see how this turns out.