My fd is about finished and I have an appointment with a tuner this upcoming Tuesday of this week. Is there anything I need to know or let the tuner know (max power or max psi). The tuner has tuned a lot of rotary before, but its been a while for him since he last tuned a rotory.
Engine
Oil Pressure Regulator Upgrade
Large Street ports.
3mm RA Super Seals
XS Engineering Cast Manifold
XS Engineering Apex'I core Intercooler
GT4088R .95 A/R
Supra Fuel Pump
875cc Pri and 1680cc Sec on JG Fuel Rail
GM 3 Bar Map Sensor
B&M Power Pack boosted Coil voltage.
AEM Boost Solenoid
50mm HKS Racing Wastegate (Open vent)
91 Octane Pump Gas
AEM EMS or Power FC (tuner prefers Power FC, so I'm bringing him both)

There has been no strengthening done to the engine.

I'm thinking about telling him no more then 475 whp and/or no more then 16psi.

anyone have experience with a similar set up?

 

How many miles were on the motor before it was rebuilt? Who rebuilt it? and in all honesty.. I would really cancel the tunning appt. It's really important to get a good tune on the car... and nothing against the guy your going to, but wouldn't you rather seek out a well known tuner that deals with rotaries all the time? That way you can just hand him a list of parts /motor specs and he'll know exactly whats safe? Also.... 475 seems like a lot of power without a Water Meth injection kit.. Save your motor man.. you won't regret it!

 

i have had virtual experience w a setup as yours making 475.

it blew up.

reason: no AI.

or perhaps you forgot to list it?

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/making-case-rotary-powered-fd-fix-806104/

read post one.

i should add nothing personal intended, in fact i compliment you for having the smarts to ask a good pre-dyno question. if there was one thing i could impress on all it is that out motors even at stock configuration are tuned up by the factory to the Corvette ZR1 level power/displacement.

many think that middle 400s is moderate! it is far from the case... 450 rw is 517 flywheel/159 cu inches is 3.25 hp per cubic inch! not on 91 octane w no water or meth. kaboom.

howard

 

I assembled the motor. Ports and 3mm seals were done previously when I bought the car. ( I bought the car with a blown motor). Mazdatrix cleaned up the port edges for me, I bought new rotor housings, and bearings. Right now it has about 20miles on the motor from me trying to street tune (bad idea in the nice area of orange county). I put everything on the back burner for about 2 years since I haven't had time to go to the track hence loss of interest in this project and running out of funds. I kind of just want it running so its not a waste of space.

AI/ and race gas was in my plans but its going to have to be a street car now since. I can only make it out to the track about once a year now.

The tuner is Koji who was a tuner at XS Engineering, now he's at Driftspeed. I'm sure he might remember, but I just want to set limits to him just to be safe.

Is there a tuner you can suggest in southern California?

What would be a safe power / boost level. would nothing over 400whp and 15psi sound more reasonable. I have no problem downgrading my expectations.

 

hmmm well i'm sure if he's a tuner at XS he'd do fine.. I bought my car with a good tune on it, but i'd ask around for a good tuner...especially if your down in the OC. It'd be a shame to scar those new rotor housings etc. I Daily drive my car with the AEM water/meth injection kit...it's actually no hassle at all and it takes Windhsield wiper fluid... which is like 3 bucks for like 2 and half gallons or something. I'd definitely look into it though. i'm at 460 @ 16 psi with water meth right now. And I don't think it's unreasonable power to expect... I just know that it'd be a hell of a lot safer with the injection kit. I'll look around for tuners though. Also what kind of plugs are you running?

The link Mr. coleman posted above is excellent....I'd def check it out!

 

Thanks for the feedback. Now I'm seriously considering AI. I will get a retune later when I get that done.

I'm just gonna get it conservatively tuned anyways first for now so its easier to get the car moving around.

I'm running a B&M Power Pack that boosts voltage to the coil packs. It was the setup that was previously on the car. The plugs currently in the car the the factory trailing plugs in the leading and trailing position.

Thanks for the responses.

 

I'd suggest getting some different plugs for the tune... the rebadged Greddy pro rotary plugs or the ngk R7520's which is what i'm running. The greddy's are a bit cheaper if I remember correctly. Good luck and let us know how it goes!

 

maintaining straight rotor housings has alot to do w plugs. specifically the heat range.

unless you plan on just idling your FD you should run 10 heat range. hotter plugs retain heat around the spark plug boss which leads to warpage in the area. colder plugs conduct the heat to the coolant supporting straight housings.

the NGK EGV plug is available in half heat ranges and is excellent/cheap for everyday blasting around. tracking and dyno NGK6725 10.5s work well.


hc

 

From personal experience on a turbo around this size...

Set trailing split to 15 degrees in most boost areas. Those bigger turbos just don't seem to tolerate low split, not at boost levels that high and pump gas. With that octane, set leading advance to 10 degrees max by redline if you plan to go over 15 pounds. For that octane and power level, take a look at this map:





A lot of people would consider that pretty damn conservative map. Few aftermarket tunes run that much trailing split (more split = more conservative), but hey Mazda has been running 15 split just fine on both turbo and non turbo factory calibrations. The old rules of thumb are "15 degrees leading at 15 psi, with 10 or 12 split." Well that rule of thumb doesn't apply so much to big horsepower builds. The more air you cram into the engine (a function of the turbo, the porting, boost level, etc) at a given rpm, the less timing advance you run.

Of course every engine is different, and there is more than one method for building a timing curve. I've been running 17psi on a T04R/T67 (a bit smaller than a 4088) with a leading map slightly more aggressive than that one above. Compression ratio is 8.5:1, porting is large streetport, octane is 93. No AI at that boost level. Four BUR9EQ plugs. Once I adjusted the timing the car hasn't given me any trouble with knock.

Keep AFR's anywhere from high 10's to mid 11's. It's going to fluctuate a bit with the weather anyway. In my experience, the timing is more important than the AFR for controlling detonation (up to a point anyway). You can run race plugs if you want, but they are expensive (Greddy etc) and sometimes pains in the *** (stupid thinwall socket). They can also hurt idle quality. 9 heat range is a VERY cold plug. Recall that the factory leading plugs are a 7. Most turbo piston motors will run a 6 from the factory with maybe a 7 or an 8 on heavily modified applications. And you'd be surprised how much heat turbo piston motors generate. Lots of turbo piston motors get preturbo exhaust temps almost as hot as a rotary, 1600+ degrees F.

 

what size jet are you guys using??

keep us posted with what figures you make.

 

Update for everyone who cares to know.

Got the car to the tuner yesterday.
There was a few things the tuner preferred.
So there is some work being done to the car before it goes on the dyno.

I brought him both and AEM EMS and a Power FC. Gave him the option to use either and he preferred the Power FC since it was more tried and true system.

Greddy Racing Plugs 9 and 11. We were trying to get 10 and 11 but greddy is out of stock on the 10's so going to tune on the 9 and 11 and probably going to switch them out to 10 leading if I make it out the the track.

Electronic boost control. I had the boost control hooked up through an AEM solenoid though the stock ECU. So I ended up buying a greddy profec b. I wanted the ability to run high or low boost. This makes it much easier to change and a simpler boost control system was suggested, as one stray boost spike can blow the motor.

The fuel temp sensor and wires are being added back in. Since the power fc has the ability to use it might as well add it back in. So my fuel rail is being welded with a bung for the fuel temp sensor.

My throttle body had the gasket reversed. You can tell if the extra gasket sticks out in the front corner, it is supposed to go out the back corner. It looked all the same to me but after careful examination the gasket has a slight raised edge on the side for the air passage. It may look the same but it is not, and will cause a leak once you get into boost. He told me this was a very common mistake.

My throttle body has the dashpot and thermowax removed. The tuner felt more confident with a dashpot and thermowax and I had an extra throttle body, so that is going back on. They never removed those before when he was at XS so he was unsure about it. Unless someone can chime in and let me know that the power fc works and has settings to compensate for the removal of dashpot and thermowax. I still have an ISC motor.

That pretty much a summary of what went on. Over all he was pretty nice about everything. Most of the above were just his suggestions and I had the option of doing them or not.

 

injector staging is completely different on the AEM EMS and will probably be more trouble to get right. There are a lot more idle control options on the EMS.

changing the leading plugs may affect the idle tuning.

there are two boost options in the Commander... you can set one for high boost and one for low boost. I have option one as around 15psi and option 2 as around 17. The Power FC will cut fuel in an overboost condition if configured properly. This can be configured whether you are using the Profec or the PFC itself. The fuel cut boost level is the PFC boost setting + .25 kg/cm^2 , at least nominally. Sometimes it will kick in at a little lower boost than that. See this post: https://www.rx7club.com/single-turbo-rx-7s-23/long-term-testing-power-fc-single-turbo-boost-control-900599/

Settings 2 INJ vs Fuel temp table. Just remember that when your fuel temps are high, your air temps are probably high too. So you have at least two correction tables to deal with now in the event that engine heatsoaks.

Pressure testing before tuning is always a good idea.

You will really notice a lack of a dashpot if you have a lightweight flywheel. The revs drop faster than stock and the dashpot and ISC, if properly adjusted, will reduce the chances of the engine stalling if you pop the clutch in quickly. If you raise the PFC "F/C" speeds, that may help make up for a lack of a dashpot. But I don't see much of a point in removing the dashpot in the first place. Many throttlebodies from that era have dashpots (3000GT Vr-4 for example), there is nothing unusual about the FD in that way.

Removing the fast idle system saves you a little bit of plumbing. Without the fast idle you may have to hit the gas pedal a little bit to get the car to start consistently every time. One way to mitigate this problem is to advance the cranking ignition timing.



See this post: https://www.rx7club.com/showpost.php...4&postcount=34

 

good post arghx. One of the more informative ones on this forum.

 

Very excellent post. thanks for all the information.

Yea it was similar to what Koji told me. I guess when I get everything back its time to sell the EMS

Hopefully not by too much. As the car is there and I'm running out of options. I don't like my car to sit idle at someone's shop taking up space. I should have started asking questions and did my research earlier. My fault and I'll just have to deal with it. Or maybe I'll buy a datalogit and make the adjustments myself =X.

I never got a commander with my power fc. But still great information if I end up getting a commander later on. I'm going to hold on to my MAC solenoid.

Probally unnecessary but I guess this doesn't hurt then.

there a lightweight flywheel in there.

I'll call the tuner now and let him know. Save him the trouble of hooking up the coolant lines.

Is there a setting in the power fc for cold idle speed or is that completely accomplished by the fast idle thermowax.

 

They're about to flood the used market. Apex'i released a new Commander and a group buy recently went down, so you should be able to get the Gameboy-looking Commanders for cheap. I adjust my boost settings with the Commander, it only takes a few seconds when you know what to do.

That's still up to you. I think you will be happier with the fast idle hooked up unless you trailer the car.

There are a couple aspects to idle control. There's ISC duty cycle (completely controlled by your ECU), idle ignition timing (controlled by the ECU), and your throttle plate opening angle which is controlled by the mechanical fast idle system.


On the PFC there isn't a separate target idle speed setting for warm up conditions. The way it works is that your warm up idle ignition timing is determined directly by the IGL and IGT maps until water temps reach about 60C. Idle air is determined by throttle plate opening angle and the air adjust screw. Then the PFC enters closed loop idle control over about 60-62C. In that mode the idle ignition timing is

base idle timing (determined by accessory loads) + closed loop correction value.

See this post: https://www.rx7club.com/showpost.php...0&postcount=27 . There is also an ignition retard warm up setting in the PFC which is 15 degrees by default but many tuners set that to 0. A little bit of ignition timing retard during warmup sometimes helps to reduce popping sounds and little misfires.

The AEM EMS has much finer control over warm up idle speeds and ignition timing. So here is a base target idle vs coolant temperature table from one of AEM's crappy FD basemaps:



then here is the base ISC duty vs target idle lookup table:



The ISC duty feedback engages on top of that. You can adjust the feedback speed to reduce oscillations as well as set a "deadband" where feedback is disabled.

On top of the closed loop ISC control, there is closed loop idle ignition control on the AEM EMS just like the Power FC. But in some ways the AEM EMS gives you more control:



The AEM EMS gives you a lot more direct control over ISC behavior in the event of deceleration or when the A/C is put on, two situations that are prone to idle sticking and surging on the PFC.



And yes that is pretty complicated. That's why cable driven throttlebodies suck. They are just a pain in the ***. Drive-by-wire eliminates much of the adjusting and other hassles you have on these 90s EFI systems.

Getting back to AEM vs Power FC: there are tradeoffs between the two. The PFC is the easier solution definitely, but it doesn't have as much fine adjustability nor does it have switched outputs. The big thing the PFC has over the AEM EMS (besides much wider support) is the injector staging. It is duty cycle based on the PFC like on the stock computer, while it is RPM and boost based on the EMS. It doesn't take that much work to get the injector staging to work decently on a PFC. There are only a couple settings to mess with (and you can usually use everybody else's settings) as opposed to having to tune a full 3 dimensional table. I would only recommend the EMS to the experienced DIY tuner who wants to put the extra time in to take advantage of all the little features and maps in the EMS.

 

Okay its done.
I failed.

Only getting 2 pulses from the front rotor. Engine has either a stuck or broken side seal. The tuner didn't detonate the motor at all. He barely got it into boost and it started misfirng and hesitating. At first he thought it was an ignition problem so moved and re grounded the ignitor back to the stock location. But with the run afterward the power significantly went down. Thats when we knew something was wrong mechanically for sure.There's a few possibilities. I might have messed up on the side seal, or it maybe the lack of breaking in the motor. Car still starts and idles okay. Chances are the seal was stuck and then broke when he started increasing the rev.

The car is being towed back today. And I should have the engine out today and motor tore down by tomorrow. And I'll update with what exactly happened, where I screwed up. At least now I have a drivable tune on it so I can break in the motor next time around. Depending on how bad it is or what caused it, I might venture to getting someone else build the motor this time around.

 

Well what did you clearance the side seals to?

 

clearenced to .004 in
I've put together stock motors and ones with small street ports before but never something like this that has work done by someone else before. Never had and previous problems but a large port big turbo engine, seem to be totally different. Never trust an unknown port.

Talking to Howard it might be because of the port job on the motor previously. But we will find out for sure once he gets the motors and torn down. Maybe he will inform me of anything i did wrong my self and make the wall of shame. hahaha

I've decided to just send the engine and an extra block (for spare parts and new ports) to Howard Coleman to get built.

Its was fun working on stuff but I just want a good running car now.

 

You are in great hands shipping your motor to Howard... ask me how I know

I just got my engine back from Howard and throughout the whole process he has been very helpful as far as parts suggestions as well as I know my motor is being built right based on the experience and knowledge that Howard has. Build it right the first time around. Get AI and don't cut corners and you won't have to go through this again.

I am also in CA and as you know, there aren't really any knowledgeable rotary tuners in the area. When the time comes, I may even ship the car to Howard for him and his tuner to work their magic...that's how much trust I have in them and I know my car is in good hands.

It's been a long process, but it will all be worth it once I can drive my FD again! Good luck my friend.

 

Here are some pictures of the motor that died.

 

If you ship it to howard and soak up every bit knowledge that he throws at you, you will not have to worry about having a non reliable rotary. I rebuilt my motor twice in a month and got so frustrated that I almost went to a v8. But I got in contact with Howard and shipped him my engine. I took a trip to green bay to have his tuner Luke do his thing and I came out of there with an extremely reliable 466rwhp street rocket. I gaurantee you will not be disapointed.

 

Damn, those ports look horrible

 

I didn't know for sure. I thought they looked kinda off so I consulted with known rotary shop in so cal and they told me it was okay, I guess they just wanted my money for lapping those irons. The previous owner also told me they were good also. Should have went with my gut instinct or checked here on the forum here first.

 

I've never been happy with Mazdatrix's port work. If they signed off on those ports after they 'cleaned up the port edges' then it only cements my opinion.

 

You can see where the side seal was catching on the port face closing, especially in the 4th photo. Those ports really are rough.

What shop told you the ports were ok? If you don't want to share I understand, but I cannot imagine a well know shop saying those are OK.

Good luck getting her back together.