Mike M

My 93 Fd has 42K original miles and everything works, including a/c and cruise control. I replaced various components with stock except improved materials- silicone tubings, metal AST, and reverse vented (99) hood. I am now thinking of replacing my PFS cat back with a stock cat back. Why: The car was engineered to work best when stock. Doing anything to ramp up hp is like giving your car steroids. the whole system is stressed.

Plus, it troubles me to see more and more modifies Fds and Supras, and fewer and fewer stockers. Which, by the way look pretty elegant-by design.

Herblenny

iTrader: (13)

I don't think replacing your catback will reduce that much stress. I acturally think you might even create more stress by putting your OEM catback.

If you have stock pre cat, you might want to replace that with DP to reduce so call stress.

WaLieN

Agreed. Components like the pre-cat do nothing more than help you with cold-start emissions testing and retain heat in your engine bay.

coolvette

Maybe if you were selling it you might get more$ for it stock.But some of the oem parts like cb,main cat,ic precat are so inferior to the aftermkt.They weigh more,less flow, and are very inefficient.my car runs faster,cooler, and better mpgs with my bolt-ons.

Mike M

Have you ever seen the RX 7 hardback book? A lot of real world testing was done by smart guys. Circa 1990's. Mazda had the rotary since 1957 and had plenty of time to work out details including 2 previous generations. Of course a car is a mass produced machine that must meet all sorts of contrary standards and still be fun to drive. And yes in 1994 a few changes were made. The car isn't perfect stock, just unique.

cabaynes

iTrader: (4)

if i were in your shoes, and thinking like you, i would probably put on a downpipe (if you still have the stock pre-cat) and then buy a Racing Beat Dual Tip exhaust, to keep that stock appearance. There are a lot of classy FD's left, if you want to be one of them, then be one but you dont have to be 100% stock

mibad

The 1993 brochure for my car mentions the cat being a high flow cat. Having said that, I would never choose the stock muffler over those beautiful RB Dualies. I will keep all my stock parts for the future owner. Provided I'm not buried in the car.

moconnor

iTrader: (14)

The car was engineered to work best at a particular price point when stock. Like almost everything it was also designed under deadline constraints and had to meet a whole host of noise, emissions, and mpg regulations.

In stock form, it is arguably one of the most unreliable cars to come out of Japan in the last 20 years.

The stock FD is seriously compromised in a multitude of ways. To mention just a few things: the cooling system in inadequate (can you say AST), the downpipe is a heat trap, the twin turbo system has way too many failure points, a significant number of components have a useful life of 50-70k miles (e.g., suspension bushings, oil pressure sender), and the damn thing chews up engines every 40-80k miles.

WanKeL FD RX-7

iTrader: (7)

i agree, you can do all the reliability mods ... even keep stock catback if you want, but things like the stock ast and downpipe.... it wouldn't be a good idea to put back the oem downpipe ...

but that's just my opinion.

Max

MrRx

iTrader: (1)

it does boil down to how to drive

My father had nearly 140,000 miles before he blew out this back rotor

my car had 90+ on the first motor 15K on my motor and 0k at the moment on my third

FDNewbie

iTrader: (10)

Mine's a '94 with 89K original miles, and everything still works (don't have cruise...R2). I think that's considerably more impressive, given that my FD is heavily modified. So I'm not quite sure where you're going with that point.

Mike, it seems like you're seeing one end of the spectrum (an extreme, if you will), by looking to these wildly modified FD's, and to counteract it (so to speak), you're saying you're gonna be an extremist as well, and return to 100% stock. That's not a smart thing to do. Extremism is extremism, both in excess and in inadequateness.

As for your comment re: the car being engineered to work best when stock, that is absolutely false (with all due respect). Mazda had to buy back a multitude of cars as "lemons" in 94 and 95 due to a whole host of problems. A lot of that was due to poorly trained technicians who had no idea how to troubleshoot or diagnose boost & vacuum leaks. But some of that came from plain inadequacies of the stock FD.

For example, it's a proven fact that the FD has a good number of weak links in stock form, many of which aren't potential - they're definite problems, and it's only a matter of time.

- The stock plastic AST is notorious for cracking at the seams. With all the heat generated in the engine bay, the AST plastic doesn't stand a chance. And if you flush your coolant system under any kind of pressure, a failure of the AST's seams is almost inevitable. Having your AST crack and losing all your coolant in a matter of seconds is not an inconvenience; it spells disaster.

- The stock precat (in the downpipe) is known for clogging up (and it doesn't help that FD's run so rich in stock form), that MANY "premature" engine failures on STOCK FD's were a direct result of this. In fact, Mazda was in a Catch-22 when it cames to this because it couldn't get the FD's to pass emissions w/o a problem by removing the precat, but keeping the precat meant premature engine failure. Pick your poison. They did; no more FD's in US markets The lack of sales wasn't because the car was too expensive or ugly; it was because the car was notorious for being a hoopty lol (but a fast and beautiful one nonetheless)

- The stock radiator is utterly pitiful. I have one in my garage, and a friend of mine came by and saw it the other day. He couldn't believe his eyes. If you see how thin it is, and couple this with the FACT that rotaries run so hot, PLUS being turbocharged only adds to engine bay heat...it's not exactly smart to skimp on the radiator.

- The intercooler is wimpy too, and it's ends are plastic!

- The various hoses and pipes are plastic and rubber, which are great for splitting and causing boost leaks. Needless to say, hardpipes are much more reliable (ignoring the fact that they flow better)

- Putting a high flow catalytic converter or exhaust does not work the engine harder. It's the exact opposite; since the exhaust system flows much better, there is less backpressure, reducing temps upstream. Basically you're letting the engine breathe better - which is why you'd want to get rid of the stock downpipe with the clog-prone precat. That's a reliability mod any way you look at it. As someone else said, if you want to remain stock-like, get the RB dual tip. Quiet, and flows better than stock.

- Stock, the car never came with a boost gauge. Anyone who knows ANYTHING about FD's will tell you a boost gauge is the single most important instrument for you to have to ensure and maintain the health of your FD. You can't diagnose a multitude of problems without it. In fact, in later years, Mazda did away with that inaccurate oil pressure gauge, and replaced it with an inaccurate boost gauge hehe

- We're all experiencing problems with engine bay temps - it's a part of the territory. Doing the fan mod (any one of them) is a smart way to keep temps down and help the longevity of even your plastics in the engine bay. That is a reliability mod.

- 93s came with 1.3 bar (19psi) AST caps. They should be replaced with 0.9 bar (13psi) caps, as was done in 94 and 95. An overly pressurized coolant system which is flammable is probably not a good idea

- The stock temp gauge is useless. It only tells you cold, hot, or dead. Re-linearizing it, replacing it with a more accurate one, or adding a water temp gauge to the car is advisable.

These are all the ones I could think of off the top of my head. So in short, although stock is good, it's good to a point. Keep in mind even Mazda was on a budget (in fact, they were on a VERY tight budget), which is why you'll see that MANY of these issues were addressed in the later years, as RX-7's got a horrible rep for being so unreliable. Heck...Mazda even simplified the sequential setup with the infamous "99spec black box"! So trust me...those improvements over the years weren't accidents; they were Mazda making up for it's earlier inadequacies.

They key here is moderation. Sure, some power mods decrease the reliability of your FD (such as a midpipe), but it just so happens that some modifications (such as the ones listed above) that may give you a bit more power actually increase the reliability of your FD as well!

~Ramy

dgeesaman

iTrader: (7)

IMO, a cat-back is a rather small hop-up. As for disturbing the balance that was designed by Mazda, the pre-cat does not belong - only in the US, where start-up emissions were being measured, was the pre-cat installed. Everywhere else the downpipe was empty. Since precats are known for puking and clogging, and generally roasting the engine bay when they are working correctly, I see no reason to keep it.

Dave

ErnieT

iTrader: (2)

I say put a single turbo on and build a 600hp monster!

Not like its a collectable and appreciating in value. Hell I have a CYM and you can only get a little bit more for that.

njstreetrx7

well jd has STOCK RADIATOR, AST AND 500 RWHP and he never has cooling issues!!

TT_Rex_7

It's not that the stock radiator and AST have cooling issues, it's the fact that they're plastic. The factory AST is seriously prone to cracking. However, i've never personally heard of an issue with the factory radiator end tanks cracking. Either way, I wouldn't wan't either of those factory components in my car once modified.

-Alex

1QWIK7

iTrader: (33)

car is gonna break down regardless, even stock..the chances are not as high when stock but at least having high hp will be an excuse to why it broke lol..

might as well have fun with the car, not saying go crazy but its a car, if it breaks, it breaks..

alberto_mg

I understand what you're saying here. I have a FMIC in my car and I was looking at it the other day and thinking the FMIC didn't look as cool as it used to.

However, I'd sooner replace the PFS with an RB dual that matches the stock exhaust nicely and sounds better (imo).

dubulup

I've got a very stock looking FD, only a mild attitude.

black93RX7

IMO the stock system is a total POS.

Just too many failure points and poor design.

I don't car how long Madza has been building rotaries, they screwed up on the FD mechanically. The styling Is great, but everything else is garbage.

I decided to go with Ernie T's suggestion!

Heavily modifying a car is not bad if done correctly and can be more reliable than stock.