hwnd 3rotor build
 

I want to provide some details into the build up of my 3rotor.

Car Details
- FD R1 BB
- 50k miles

Engine Details
- 3rotor
- David's shaft :)
- 13B-REW housings
- Stock Subframe!
- Forced Induction

Goals:
- None

I'm 80% sure that I'll be staying with the Wolf EMS unit. I'll probably upgrade to v500. I've had a pretty good time so far with the v4 unit, didn't find too much trouble configuring it.

I am interested in feedback on a few things:
- Lightweight Rotors?
I'm 100% sure if I would even want to run these. A few reasons why I do are (1) less stress on the shaft in terms of flexing. (2) Less wear on the bearings.

- Porting
This is an area which I know little about at this point. I've read that larger ports can hurt the performance as well being too "under ported" can also hurt.

I'm open to ideas :)

Lightweight rotors increase your throttle response and they also benefit in the 8k and upper rpm range. If your going to rev that high, you will need to consider some oil mods, some ceramic apex seals, doweling, and a small diameter clutch set-up. For a street car, I would be more concerned with balancing the rotating assembly. This is how you really save the bearings. ;)


Porting depends on your power goals. The stock porting is plenty large and will easily allow for 500+hp. Since your using the rew housings, you don't have to worry about the sleeves.

I will run ceramic seals, no doubt.
As far as oil mods... outside of running a dry sump, what I know to do are increase the oil pressure on the front and rear regulators, tap the center iron to increase oil flow to the bearing. thats about it as far as i know.

i'm not a fan of doweling the engine but I will be using the Guru-Stud kit.

my shaft was balanced to 10k rpms, Cam said if my rotor weights are very close then thats about all I'd need. though he did warm me about not having enough oil past 8k rpms - so i'm hoping that increasing the pressure and modding the center iron will allow me to spin that high (should the build go that route).

Can anyone shed more light on tapping the center iron to increase oil flow to the bearing?

Bakanced to 10,000 Rpm
 

If I may, I'd like to clear up some things about "Balanced Shafts"

Unless You have the actual CW's (Counter Weights) both Fr. & Rr. that were originally on this shaft when it was spun balanced, and ....
additionally know the actual bob weight value used during the balancing process for the "Specific Rotor Weight" that was planned to be used for this rotating assembly during the balancing process, then:
You DO NOT have a balanced shaft.
Not to 10K or 1K or even 1 revolution. All You have is a 3 Rotor shaft.

For a balance assembly to be correct, one starts out doing a Static weight adjustment to all rotors regardless of how many to match the weight of the lightest one.
Then you do a Dynamic spin to each Rotor individually and correct for "Core Shift" and balance out the heavier corners (Apexs)
Procced to calculate the weight of all Seals, Springs, O Rings, and Oil.
Come up w/ a "Bob Weight" value in grams.
Build and affix the Bob Weights specificlly designed for Rotary engines on the E- shaft in critical locations relative to the Rotor's Center of Rotational Moment.
Finally, spin the Rotating assembly and correct for out of balance of the COUNTER WEIGHTS accordingly.
Some times "Heavy Metal" may need to be added to the CW's for balancing or correcting for CW's out of tolerance.
Some times CW's need to be adjusted for a given Rotor Weight,
And for "Light Weight" rotors, sometimes it's nessesary to use different series of CW's and even sometimes re-shape Counter Weights to adjust for index of location.

It is not an easy process.

If you are building is a "Street" 20b engine and will not be spinning past 8.4K,
the factory CW's originally out of a runing of 20b will work OK for a Rotor Weight of 4360 grams including bearings +/- 50 gr. in either direction.
As long as ALL ROTORS USED IN THAT ROTATING ASSEMBLY ARE WITHIN 20 grams of the lightest.
We like to see 1 gr.

Only Cosmo, REW, or GTU Rotors, will balance, and be within tolerance with OEM 20b CW's originally balanced by Mazda.

Any Rotor other that those mentioned above or any lightened Rotors of any series, or Rotors outside the weight tolerance previously stated, if used then the complete Rotating assembly must be Dynamicly re-balanced.
Obvioully, for real race engine, a "Fully Balanced" assembly is in order.

Last, any shaft that's been re-balanced, should have the Rotor weight, CW weight, and index angle relative to TDC engraved on the CW's for the next time a Rotor may need replacement in that specific rotating assembly.

Tolerance of our "Balanced" rotating assemblies:
Actual weight of the Rotors are balanced to < than 1 gram. to the lightest.
Actual Rotor out of balance to < .5 grams
"Complete Rotating Assemblies" balanced to < a tenth of a gram. (0.010 gr.'s) at each end.

CLR Motorsports.

Thats exactly what David told me a while back.

I didn't know how much went into a correct balance job. I've changed routes in light of this information and will be sending the shaft,rotors,clutch & couterweights out for balancing.

regarding rotor-to-rotor weight... is it common to see 1gram or less in weight across all 3 rotors? My mindset is having all rotors matched within one gram.

What is "race specs" in terms of rotary-balancing for the 20B?

^ Hah, I said something like "you need to balance the entire rotating assembly not just the shaft" and "you probably shouldn't go the Pettit route of having "close" rotor weights", not what Carlos has described. Makes me feel great I sent him my rotating assembly for balancing:)

So how exactly does one do the center oil modification work? Anyone with experience care to explain? You tap the center plate or the housing? You also have to modify the oil pedestal?

+1 Do you run from the oil filter to the middle or front iron?

David has a bit of info on this;
He did the legwork (as I should have done) and emailed some info;

I've since cleaned up my email box so I would need him to resend (sorry Dave!).

the short end of what I know is,tap the center housing, run oil to it.
Remember, "Ask a pro" who has done it professionally. :)

Basically you would use a oil filter relocation, and add a second or third outlet to it, by tapping or welding a extra fitting in. Then modify the rear pedestal to no longer use a oil filter. Next drill and tap the fat plate, there is a plug that is soft metal right in the top of the dowel pin casting. Then run the lines from the remote mount to the rear, center, and the front side plates if you want to get the most balance. This mod will help, but if using a stock oil pump, it will still be too small over 8,000 rpms. This is where the drysump will be needed.

The details, per Brent in New Zealand:

From: "Curran Brothers Racing Limited" <curranbrothersracing@xtra.co.nz>
Date: October 23, 2007 10:19:07 PM EDT
To: <david.hayes@earthlink.net>
Subject: oil mod

Hey mate,you want to machine a block that will fit under the filter housing
that you can tap into.I usally tap a 1/4 npt thread into it, to fit a -6 1/4
npt male adapter.
Tap the 20b centre housing with the same thread,you will see the factory
brass bung that seals the oil gallery,this is where you tap into.
For the front gear feed you can either feed into the factory hole where the
turbo feed is or you can tap into the side of the front plate,again you will
see the factory bung where to drill.Make sure you either replace the top
factory hollow dowels with solid units or put 12x1.5mm grub screws into the
ends of the factory dowels,this seals each gallery from each other.
This is the easest way of doing it,the next is the best.

I machine off the pederstall off the rear housing and tap both holes(oil reg
gallery aswell)to 1/4 npt.use a Peterson remote filter housing,from there
you want a peice of 1 1-4 tube with 4 -6 fittings tapped into it,these four
fittings feed each gallery.

My lastest update is...
Picked up a new turbo (ditched the T88 for an HKS T51R SPL [GT4598]).

I'm dropping in a stock 20b while we build the "20b wish list", the biggest reason for droppin in a stock 20b is it'll allow me to dry fit the subframe, wiring, etc.

My biggest worry is the custom oil pan and how much clearance it'll have.

Should have pics soon!

Photos

an old spl but an spl (big one) at that.

Some basic Garrett Turbo naming guide

http://www.limitengineering.com/GTmodelcode.pdf

Just looked thru the Garrett naming guide and ran across this:

“V” Muti Vane Variable Geometry Turbine

Do you think that's like the new Porsche variable turbo or is it limited to just diesel applications? If so, that would be bad ass. If I understand it correctly, variable vane turbos have immediate response while allowing progressively more air flow throughout the RPM band so you get the best of both worlds, quick spool up/response and max HP.

These types of turbos have been used on diesel engines for a long time but they haven't been available for gas engines until now because the high exhaust temps would melt the blades.

Here's a primer of the technology:

http://variablegeometryturbos.com/

Yep, is the same (vnt, vgt) turbo as the new porsche. Until now there weekest link was the heat from gas engines melting the pichable blades. One thing though about VGT turbos is that they make alot of back pressure leading into the turbo. Thats why they are mainly used on diesel trucks, the high back pressure helps to feed the EGR systems on the diesel engines. But, they do provide fast spool up!
I remember seeing some guy put a garret Vt37 from a 6.0 powerstroke on his STi. He said that it took awhile to get the tunning figured out(since the blades pich hydrolicly), but once he did he said it was vary impresive!

Extra Photos
 

Here is a small update;

i was unpacking the engine & thought i should grab a few pics;

Looking good Jason. What did you decide to do with the internals of the engine? Balancing? Lightened rotors, etc?

so are you gonna put a v-band on the manifold or change your turbine housing?

The plans are to send CLR a 3 rotor for my car;
In the meantime, I'd like to pick up a *working* stock 3 rotor which will allow me to dry-fit then re-fit the exhaust,wiring,etc;

Where did you source your exhaust manifold, if you don't mind me asking. What sub-frame is that?

it's all custom made - nothing "off the self";

the subframe sits the engine in the stock location (in terms of the trans). hopefully i'll have it in within a few weeks... its getting cold in oklahoma;

did you buy that subframe off of ebay? everything is looking good so far!

Any new eye candy?

Are there more of the sub-frames available?