After weeks of trying to troubleshoot issues with my rough idle, throttle tip-in, and blobs of white smoke, I'm thinking it is time for a rebuild. However, I want to explore some options about what to do with the engine.

One possible scenario: 8.5:1 rotors and run more boost.

I've been reading some content on compression ratios, and it appears that more mid-high range power is possible (on pump gas) with lower values at the cost of the engine's natural power. Though, I've not seen anything that explains how exhaust gas flow is affected which would also affect turbo responsiveness. The low compression rotors are also heavier, so I figure throwing on a much lighter flywheel may help offset the moment of inertia of the power plant.

Is this a crazy idea?

If so, I'll probably just get the irons streetported and be done with it.

 

what are your a/f and vacuum at idle?
do a compression test before you pull the motor.

 

if you start messing with the weight of the internals, make sure you get the entire thing balanced, and yes, check your compression before you pull it, what other mods do you have done? and what do you plan on doing while the motor is out?

 

There really is no need for the lower comression rotors, do some more searching. I think tuning and technology has come a long way over the last couple years and plenty are making great numbers on the 9.0:1 rotors.

 

Get the port and be done with it.

Maybe do an RX8 e-shaft (.4lb lighter) and balance the assembly.

 

11 afr. Attempts to raise the AFR stalls the engine. I couldn't say what the vacuum is at idle, but it is pretty low.

Motor is out already, and there's oil everywhere on the block and turbos.

 

Yeah, from what I read it's not always enough to stick with OEM parts as they vary in weight distribution.

Other related mods: Full intake, aftermarket IC, 3" dp/mp/cb, PowerFC, FPR, injectors (was 850x4, looking at 550/1300).

I plan on overhauling the system, making sure all of the sensors, actuators, and wiring is in good working order. If there's an opportunity to change something while I'm in the motor, it would be nice to know what could be done.

 

I've read that the weight difference is not very noticable. Of course, since it's cheaper than the FD one, it doesn't hurt.

 

you could buy my fresh rebuilt pineapple racing engine only 3700 shipped to your door lol.

 

Agreed. I would think that it would be difficult to notice w/o isolating that one component since that isn't practical. I understand the balancing can make a difference in smoothness of the engine but no direct experience.

Someone on the other forum shared some info on it if you haven't already seen it.

 

That looks tempting, but I'm wanting either stock ported irons or maybe a light/mild street port. I will be autocrossing 99% of the time.

 

I think I could take care of you on that If you plan to auto cross mostly I wouldnt worry much with porting. Im pretty sure the stock ports will flow plenty and exhaust porting isnt going to help with spool up which you dont need if you are still running sequential.

 

The low compression rotors have a better casting. Search Carlos Lopez and low compression, I believe there are some pics of rotor cut aways showing the casting imperfections in FD rotors. You can have them ligthened and rebalanced by someone such as Carlos, Racing Beat, Mandeville.

Jack

 

I picked up a 2-ton crane lift to assist my efforts.

Engine right after I lifted it out:



I removed many of the accessories beforehand for clearance. Removed the cross-member as well.

The fuel system is still sealed. I imagine I'll have to take it apart anyway when I install the 1300cc secondaries. Moving it and the power steering out of the way made less of a mess than I expected.

I opted to keep the transmission in the car. I don't have enough room in the garage to remove the engine/tranny combo from the front.





Fashioned a home-depot desk for this task. Not bad for $50 in parts.



Things I noticed right away when disassembling the motor:
* The passenger side motor mount is completely destroyed. The thing crumbled off when I moved it by hand.
* Turbos are leaking oil somewhere. There's a thin even coating of oil on the bottom of the exhaust manifold.
* OMP leaking oil from the main seal.
* One of the OMP lines broke off right at the primary injector location. I noticed this before I removed the engine.
* There's some oil on the knock sensor and near the bottom of the housing, though I think most of the oil on the spark plug side of the motor came from the dip stick hole. Sometimes during autocross, it would spit up a little.
* Wiring harness needs work. I wouldn't trust putting it back in its condition.

 

I'm waiting for a few "things" I ordered this week before I crack the flywheel nut off. I took a peek at what I could through the exhaust ports.

So far, everything looks surprisingly clean. This is wierd, I've must have fouled half a dozen plugs over the last 2 years. The apex seals are in place, and when I turn the flywheel, I can hear that the housing is air-tight.

I'm also going to stick with the stock rotors. I'm still interested to see how changing the compression ratios will work out, so I'm going to piece together a separate block with S5 rotors. It doesn't make much sense to mess with the core I already have when the only thing I have to suspect is the coolant seals.

Data acquisition is going to be a big part of this project. I ordered a cpu/mobo combo plus a neat little USB monitor.


http://www.mimomonitors.com/products/mimo-710

$200 for computer+monitor.

The computer will likely end up in one of the rear storage bins (opposite of the battery relocation), as there's barely enough room for the wideband o2 gear behind the radio console.

 

Touch screen monitor?

 

The 740 is sold out.
http://www.mimomonitors.com/products/mimo-740

I settled for the 710 (mainly cost). I plan rig a keypad in the ash tray location, and program an interface to the apps.

Of course, when I need to whip out the keyboard I have one of these:

 

Very interested in your computer set up. You running the PFC?

 

Yes, I have a PFC.

 

motor mounts are not cheap btw.

and just premix and be done.

 

I'd recommend polyurethane motor mounts, stainless steel oil metering lines, and an oil pan reinforcement brace. We install all of these on most customer motors......PM Ihor/rotary experiment seven if interested, I believe he has it all in stock.

 

I have a set of stock motor mounts on the way, and I am between getting the SS lines for the OMP vs blocking it off.

How does the oil pan brace help?

 

I am a big fan of keeping the stock Oil Metering System. Why block it off? I premix in addition, about 4 oz's for 1/2 tank fuel.

Oil pan brace? it's been beaten to death, basically it helps prevent oil pan leaking. That along with the Moroso stud kit is something we install on almost every motor.

 

Flywheel is off.

Since I did this by myself I needed to hold the motor down:



With this:



Actually, it wasn't too difficult once I realized I could bolt down the flywheel.

 

Smart idea on bolting down the motor. I was trying to do this same thing a little bit back and couldnt figure out a way to get the motor to stay still by myself. Finally realized I could just bolt a piece of angle iron to two of the pressure plate mounts.

If your interested in having no turn around time for doing your motor I have a Rotary Performance rebuild I am selling. Just under 10k, 3mm seals, new rotor housings, lg streetport, good comp and vac. I made 362whp and 300 lb/ft at 14.5 psi on an apexi rx-6 single. Pm me if your interested.