FC Compatibility questions
 

So I have been looking to build up an 1988 fc se I bought recently. The paint is slightly shabby and she has 74k miles. Rebuild kit, bridge port, exhaust, coolant (rad, pump, etc...), removal of ac and air pump, painting, and fixing the dash should be done by the middle of spring. My step after is to up the intake, which brings me to my first question.

Will an FD lower intake manifold and three section throttle body fit on my NA FC? I am aware that the manifold I am looking at and my engine are both 4 ports, however I'm not sure if the bolting patterns are the same. If someone has experience with this please let me know.

The other main question is Is the stock ECU capable of being re-mapped or should I get a new ECU? Again, please let me know!

James

FD lower will not fit the engine wiuthout major modification.
Anyways the Throttle body would point the "other way" so really if you are staying N/A then the intentions you have it for would not be useful to do.
The ECU is NOT mappable unless you get it "modified" to an RTEK..(digital tuning, inc.).

and lastly your engine is a SIX port..not 4.

Don't.

Unless this car is a track only car in a racing style where a Bridgeport will actually be a benefit (mainly road racing, or I guess as the kids call it these days, "time attack", or any style of racing where the engine is operated mostly in a narrow high RPM range) then I would not suggest an NA Bridgeport.

In order to make any power from an NA Bridgeport, especially a 6 port bridge, you need a very unrestrictive exhaust and intake. Which is going to generate noise like you have never thought you could experience. It will fit most definitions of "not streetable" due to the exhaust volume. Bridgeporting a 6 port engine also has the effect of moving the powerband up around 7000 RPM due to the already huge port area now having 100% overlap. You'll need to have the engine balanced, swap to a lighter flywheel, and to be safe install a scatter shield on the transmission.

Let's say that you use a butt plug to quiet the car down for street use, and then uncork it when at the track.

Now you have a car that makes only a little more power than a street port on that engine would, but now gets 8-10 MPG in the city (on a good tune!). Because of the ambiguous vacuum signal created by a bridge, tuning is rather difficult if you don't have experience with such a thing, so even getting the car to start reliably and not run basically random AFRs at light load might be an issue.

The short answer is no. FD engines are 4 port. Your engine is a 6 port. 2 more intake runners on your engine. Also even if you did bolt the FD lower intake onto your engine, your upper intake wouldn't fit. And your throttle body is very similar to the FDs anyway with multiple stages (all EFI Mazda throttle bodies have shared the same basic design characteristics since '85).

The longer answer is...you could make the lower intake fit if you welded up some cavities in the flange, port matched it to the NA engine, welded on some excess material to the bolt hole area then re-drilled the holes to match the engine. Why you would want to do this I don't know. At that point you then need to either use an FD upper intake, or modify perhaps an S5 NA upper intake to fit if it doesn't end up hitting the hood. Or fabricate something from scratch.

Now it is true that with radical porting the NA intake sucks. So instead use the TII lower and upper, which is much easier to fit. Still 4 port, but easier to modify.

Porting The 4 Port Turbo II Lower Intake To Fit The 6 Port NA Block


If you Bridgeport the car, you need a full standalone or...gag...a carburetor.

Thanks both of you! I need to do some more reading obviously... I had thought the 6 port and 4 port were the other way around. I did want to run a turbo eventually, maybe a t70 kit or something. I am aware that I would need a new upper intake manifold and was also looking at new throttle bodies as well. my problem with the manifold is I can't find an upper intake manifold!!! Would it be safe to weld an upper intake together with stainless tubing and cnc flanges? Would a street port be better for the rebuild and bridge with turbo? Or just keep the street port? Are the turbo II manifolds worth the 250 Usd used I found those for?
I was going to get rid of the air pump, A/C, and go through with an mr2 P/S conversion from a thread I had read previously. My mechanical knowledge is vary narrow right now, but I love to learn more. Any thoughts on those would help as well!
Thanks!

James

Does the car need to be street legal, and if so does it need to pass an emissions test?

Is the car's main purpose going to be drag racing, autocross/road racing, or drifting?

If you plan to race competitively, which class rules do you need to follow?

What is your budget for this car?

More importantly... why do you have a 10 and 5-year rotor and I have a 15-year rotor? Can I trade my 15-year rotor for three 5-year rotors so that I can have a 3-rotor? LOL

Street/drift, no it does not need to pass emissions, and the budget is adjustable. Intake/fuel delivery I'd like to spend around 2k not including the t70 turbo. The rebuild kit I'm not skimping on, I'm getting an overhaul kit from Atkins. These plans not going to be completed anytime soon (with the exception of what was in the first post... 'rebuild, exhaust...etc). However I'd like to learn more about the best port for what I want to do before I decide on that.

Triple that budget. If you want to run a large aftermarket turbo you need a full standalone, upgraded fuel system, 4 larger injectors, intercooler, upgraded radiator, and all the little things that really eat into the budget.

My recommendation would be to start with a j-spec 4 port TII complete engine. Rebuild that with a street port. Swap into the car.

Of course, remember that you will need to upgrade the entire drivetrain for the power levels that a large turbo will provide. Easiest method of that is to swap in the TII drivetrain. You'll need an upgraded clutch & pressure plate.

Is there some reason that you are really attached to that car? For example, does it have an extremely expensive paint job, fiberglass body work, or something else of high value that is not removable?

The reason I ask is because you are going to need to replace so many parts that you are better off selling the car and buying a Turbo II, especially if you can find one that somebody modified with aftermarket parts that you like. This would most likely save you over $10,000 and several months of labor. I have seen Turbo II cars with $20,000 worth of mods selling in the $5,000 to $8,000 range.

As far as attachments to the car go... I had an 85 gs that I fell in love with but had to get rid of because of the frame. The budget was based on some hardware. I know I'd have to get a new ecu. This is not an all at once buy so much as an over time build. I'm getting a practice car around the time this will be finished (running and rebuilt) that I will have plenty of help building. I'm buying an e21 with an 8.8 rear end and a 1jz-gte swap, welding in a cage and bump guards so it can be a missile car. That will be immediately after the 91 firebird I have is sold (converting the 305 to a high rise carburetor setup to bypass the broken vats before selling). I know a little about a lot and am continuing to learn.

A’PEXi SuperAFC would it be worth the buy? or should I save for a haltech? Really I'm trying to get what I want as a base for more serious mods down the line. Right now, street port, exhaust port, full rebuild, tii intake (for when i turbo it down the line) ac delete, air pump delete, power steering relocation, bracing, small electrical mods, tires, and the ecu. Thoughts so far?

(after these are complete, I will be saving for isr coilovers, angle kit, and turbo)

James

It is hard to help when you are so incoherent. Not that there is anything wrong with that, but I think you should just go with whatever you happen to fancy at the moment, as that seems to be your personality.

The best platform to start on is the car itself.
Better Brakes,tires,suspension and new bushings,etc.

After that you could start on the power aspect of the build and Frankly it does look like you are up in the air over exactly what you want.

I'll just comment on the ECU part of it and say that if you intend to visit both aspects of the engine(N/A and then Turbo) then get a programmable unit that can cover both engines.
This would be along the lines of a Haltech or similar unit.
I say this as it will not limit you to just ONE side of the engine spectrum.You can go from N/A to Turbo by modifying the maps in the ECU...That is IF you are familiar with tuning a Rotary..otherwise you get a Blown up Lawn ornament.

Thanks for the advise, my ideas started getting ahead of me. I have looked into turbo ii engine swaps. the apexi i found is compatible for both. I asked a couple of other local tuners to help me with a plan. If there are any pieces of advice as far as the s4 models go, that would be very helpful. Thankfully, I also found another 2 people in my city who have fcs that are modifying this year, so I have local troubleshooting and problem solving, which is nice.

The build log will be started after much more reading is done on the manuals, and after selling my firebird.

James