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First FD modification?

What should be some of the first things I upgrade or future problems I can prevent in a stock FD? :nod:

Hard to imagine there's still a TOTALLY stock FD out there, so you may be able to skip some things. You can also search in the 3rd Gen Section for reliability mods. But regardless, here's what I'd do (somewhat in order)....
1. Replace the stock pre-cat'd downpipe with a quality downpipe, preferably heat coated or at least header wrapped.
2. Install a good aftermarket temp gauge. The stock gauge is worthless as it's not linear. Pay no attention to it. I prefer coolant temp because it's just an easier install and references are plentiful on what appropriate temperatures are under varying conditions. But some do monitor oil temps.
3. Install a good boost gauge.
3.5. Aluminum radiator and AST.
4. Clean all stock grounds...and even add an additional ground circuit...think of it as a circle, battery ground to chassis, chassis to engine, engine to battery ground.
5. Change fuel filter and spark plugs if you don't know when they were changed last.
6. Change ALL fluids, coolant, oil, transmission and diff oil, brake flush.
7. Add a quality fuel system cleaner over a couple of re-fills of fuel.
8. Change belts, being careful to not to over-tighten.
9. Replace the inadequate SMIC. There are some decent aftermarket SMICs out there...PFS, Greddy, Pettit etc. If you're really flush, a 'V' mount, but those usually require a larger budget, some fab work and even relocating things like the battery. Personally I don't recommend a FMIC for a street-driven car.
10. If your choice of IC allows retaining the stock air-box, there are simple and inexpensive modifications that can be done to have it source ambient air from the nose rather than scavenging it from the stock IC duct. Search in the 3rd Gen. section for "Cheap Bastard intake". Otherwise, I'd do my best to avoid open intakes taking hot underhood air.
11. Replace the stock intake couplers, especially the 'Y' pipe to crossover coupler with good silicone versions. OEM was rubber and prone to fail with all the turbo heat. If you've got $120 or so, look for someone selling an Efini 'Y' pipe. It was a MAZDA re-design that we never saw on North American models. But it eliminated that troubling coupler with bolt-on design...and it flowed a bit better as well.

Other things to consider down the line...
*Faster reacting Intake Air Thermosensor and/or relocating it.
*A standalone ECU. If you stay at stock boost, the stock ECU is fine, but things like boost hesitation can pretty much be eliminated. And if you CAN eliminate emissions where you live, you have to have one.
*If your boost pattern is good and you have no issues, leave the stock vacuum lines alone. BUT, if you do end up removing emissions and/or have issues, then silicone vacuum lines are a no-brainer.

All I can think of off-hand. And with the exception of the first two or three, they can be done as time and budget allows. One of the BIGGEST RELIABILTY MODIFICATIONS is between your ears. So get a copy of the Factory Service Manual, spend a few evenings reading through the FAQ sticky in the 3rd Gen. Section to learn about the car, enjoy it for a while...and avoid PERFORMANCE mods for IMO, the first year or so.

Edit: I just noticed you're in CA. so removing emissions is not an option. I think the pre-cat can still go, it does nothing really except to aid cold start emissions.

Thanks for the information, I too was wondering what should be the very first modifications done to my FD.

Just thought of something I forgot......

Quote:

Originally Posted by Sgtblue (Post 11952676)

Hard to imagine there's still a TOTALLY stock FD out there, so you may be able to skip some things. You can also search in the 3rd Gen Section for reliability mods. But regardless, here's what I'd do (somewhat in order)....
1. Replace the stock pre-cat'd downpipe with a quality downpipe, preferably heat coated or at least header wrapped.
2. Install a good aftermarket temp gauge. The stock gauge is worthless as it's not linear. Pay no attention to it. I prefer coolant temp because it's just an easier install and references are plentiful on what appropriate temperatures are under varying conditions. But some do monitor oil temps.
3. Install a good boost gauge.
3.5. Aluminum radiator and AST.
4. Clean all stock grounds...and even add an additional ground circuit...think of it as a circle, battery ground to chassis, chassis to engine, engine to battery ground.
5. Change fuel filter and spark plugs if you don't know when they were changed last.
6. Change ALL fluids, coolant, oil, transmission and diff oil, brake flush.
7. Add a quality fuel system cleaner over a couple of re-fills of fuel.
8. Change belts, being careful to not to over-tighten.
9. Replace the inadequate SMIC. There are some decent aftermarket SMICs out there...PFS, Greddy, Pettit etc. If you're really flush, a 'V' mount, but those usually require a larger budget, some fab work and even relocating things like the battery. Personally I don't recommend a FMIC for a street-driven car.
10. If your choice of IC allows retaining the stock air-box, there are simple and inexpensive modifications that can be done to have it source ambient air from the nose rather than scavenging it from the stock IC duct. Search in the 3rd Gen. section for "Cheap Bastard intake". Otherwise, I'd do my best to avoid open intakes taking hot underhood air.
11. Replace the stock intake couplers, especially the 'Y' pipe to crossover coupler with good silicone versions. OEM was rubber and prone to fail with all the turbo heat. If you've got $120 or so, look for someone selling an Efini 'Y' pipe. It was a MAZDA re-design that we never saw on North American models. But it eliminated that troubling coupler with bolt-on design...and it flowed a bit better as well.

Other things to consider down the line...
*Faster reacting Intake Air Thermosensor and/or relocating it.
*Replace the stock fan thermoswitch with a S5 (FC) Thermoswitch. This will change the threshold temperature for the radiator fans from about 226 F. (108 C.) to 203 F. (95 C). https://www.rx7club.com/3rd-generati...switch-629095/.
*A standalone ECU. If you stay at stock boost, the stock ECU is fine, but things like boost hesitation can pretty much be eliminated. And if you CAN eliminate emissions where you live, you have to have one.
*If your boost pattern is good and you have no issues, leave the stock vacuum lines alone. BUT, if you do end up removing emissions and/or have issues, then silicone vacuum lines are a no-brainer.

All I can think of off-hand. And with the exception of the first two or three, they can be done as time and budget allows. One of the BIGGEST RELIABILTY MODIFICATIONS is between your ears. So get a copy of the Factory Service Manual, spend a few evenings reading through the FAQ sticky in the 3rd Gen. Section to learn about the car, enjoy it for a while...and avoid PERFORMANCE mods for IMO, the first year or so.

This is great info for when i get my rx7 thank you im new to the forums i appreciate this information and know that it takes a long time to even type it all up and let everyone know thank you SGTblue :)

another link to some reliability mods that I've read that seem like a good idea too:
https://www.robrobinette.com/reliabiltiy.htm

My first mods were replacing the radiator (had plastic end caps) with a Koyo and replacing the AST with an alloy one (used the Knightsports one actually).

The Knightsports AST is a good choice as the stock cap works well on it, and the hose fittings are welded. The RE-Amemiya AST has screw fittings - just something else to leak and cause air in the system IMHO.

While I was doing those, I replaced the hoses to the rad, installed an aftermarket Water temp gauge, and also changed the V-belts and the thermostat for safety.

When bleeding the coolant, also check the low coolant alarm works by temporarily allowing the coolant to drop below the coolant sensor. If this doesn't work, it's been bypassed and it NEEDS to be fixed.

I managed to get all of the above done in a weekend. The best weekend I ever spend on my FD!

+1 on the non plastic AST and a better radiator. Double check your coolant and vacuum lines to make sure none of them are brittle and ready to break or rupture.