Timdog1650

I just drove my 93 FD back from NJ to MD today, had a lot of fun on the way down. Car runs really well, it's a relatively new rebuilt motor, 3mm seals, light street port, stock turbos in sequential, no restrictor pills. Car has some basic stuff, coolant reliability mods, ported throttle body, greddy IC piping, built automatic tranny from Level 10. There are 1600cc secondaries with an aeromotive FPR controlling fuel pressure. Car runs like STINK, TONS of fun....BUT.....

When the second turbo comes on line, the car almost immediately fuel cuts (13psi?) and does the fun herky jerky thing....I was told by the previous owner that it was fine for this car to run in the 15psi neighborhood since it had the built motor, and that a FCD would be a good move, just let it run like that without the restrictor pills in it, make slightly higher boost than normal, let the big injectors take care of fueling, and that's all it would need. It still has both stock cats, so the boost isn't going freaky crazy creeping or anything, it just doens't rev out clean in 2nd or 3rd gear because of the fuel cut. Is this good advice? i have one of those blinky little narrowband AFR guages in there and it always reads pegged rich when under boost...I'll throw my nice wideband in the car as soon as I get some time to screw around with it just to double check.

I've read that the FD really REALLY hates boost when it comes to anything over stock levels, but I can't honestly believe that on a ported motor with big injectors and an FPR that it's that bad for it. Here are the options I've been tossing around in my head:

-FCD, leave everything else alone, just let the thing run like 14/15psi boost and enjoy safely.

-MBC, turn it back to 12 psi or whatever won't cause fuel cut (loss of performance from low boost, maybe not fully utilizing engine capability).

-Put restrictor pills back in turbo lines, see what happens, end up with stock boost again, no fuel cut, but drastically slower than it is now.


I know that this may not be the way that everyone would agree to go, but there are always more than 1 way to skin a cat....I'm willing to boost this thing on these injectors, 14 psi isn't that much of boost for a turbo import, rotary or not. It's an automatic so the whole "ECU upgrade" thing is sort of out of the question unless there's a viable reflash of sorts for an automatic. I have an AFC, but really don't want to use it on this car since it's only going to add timing to the car if I pull fuel to correct for the big injectors.

So what would everyone smart do...any alternatives or other suggestions are of course more than welcome!

Thanks,

~Tim

apex_sideway

Uh, if you want that car to last turn it back to 10psi. You're going to blow that ************ up without a ECU . . . . the tru guru's will let you in on what's going to blow your car up. Good luck, she looks good!!! (P.S. if those are tenzo rims . . . please take them off, they're prolly only 7.5 inches wide anyways)

Marshall

LOL

Read the FAQs and, FWIW, PFS purple motor eater will work with autos.

How are you running 1600s on the stock ECU btw? (nevermind why with the stock IC and intake)

dgeesaman

iTrader: (7)

Yep, like the others said the mods on that are a bit out-of-order. The FD doesn't mind higher boost, as long as you don't mind shorter engine life. 14-15psi is a good working limit for the stock _turbos_, you can go higher but you'll need a different turbo to do it. Get your boost in check at 12psi - the MBC sounds like a good route for that. Fuel cut is not a good thing.

Put on that wideband and see what's happening. If you truly have both cats, replace the front cat with a downpipe. AFC is not an appropriate ECU for this car.

I would also look into a manual tranny swap, if you intend to run more power.

Dave

Timdog1650

the auto's built, so i'm not worried about that on the stock turbos...if I was planning on doing anything other than the stock twins, I'd definately put some sort of manual gearbox in there...GM...maybe mazda or something. I'll take a look at everything to make sure it is what I think it is (1600cc injectors does sound fishy on stock computer, I know).

I'll get a boost controller on there in the meantime and see if I can't find a good engine management solution that I like for the car...any really good ones out there for the auto tranny?

RE-Amemiya

Car looks nice. Just worried about those side pieces on the front bumber scraping EVERYTHING. That's the FEED bumber. Anybody have feedback about how low it actually sits?

manatecu

iTrader: (6)

The 1600 injectors are adding to much fuel. The stock computer is looking for 850's. Not to mention the high vs low impedence issue - there is no telling what kind of AFR's you are getting up top.

My guess is the 1600's are dumping way to much gas into the chamber and choking you out.

You really need to invest in a PFC (or other stand alone computer) and get someone to tune it correctly.

Chris

dradon03

iTrader: (2)

I can't beleive noone has flamed this guy yet. I mean it is impossible to do what someone has "supposedly" done to this car. Because in transition from leading to trailaing rotors the car should just bog out. Also runiing the boost on the type of mods you have it is almost inconceivable in my mind, blwn motor secteion here you go. Also the car has to be a VGA with that much "supposed" power and those rims/tires. AHHHH I am going nuts, like I read for two years all the forums and info I could get my hands on before buying my FD I don't understand why people don't do the same.

I'm out.

dgeesaman

iTrader: (7)

Did you mean to say "in transition from primary to primary + secondary injection, the car should bog out"?

And yes, the car would run pig-rich under boost if the 1600s were installed as drop-in replacements for the 850s. But I've never done that or analyzed a car with that setup to conjecture how it would run. There would be a lot of crazy stuff going on in that exhaust due to so much unburned fuel - if it weren't for both cats it might backfire and flame something ridiculous.

Dave

Timdog1650

hmm, okay, seems like some of what i was told by the last owner was BS. I just want the car to run well on the stock twins and be however reliable a rotary with basic boltons can be. Ordered a Halman MBC, I'll throw that on and screw down the boost a bit, I'm looking at downpipes....I'll take a look at the secondaries and if they look stock or the rail is stock, I'll just assume that they're not aftermarket and the last owner was incorrect. I don't think I want to do any ecu mods to this thing right now, so I'll just make sure I'm running within spec for the stock computer.

As for the bumper, I've only scraped it twice and that was just the lowest part of the lip...those pictures are deceiving, the car was sitting on a slant sort of when they were taking them, so it's actually a good bit higher off the ground than it looks. What is everyone's complaints with the wheels/tires? Is there something about them that is so wrong? I got them with the car, so I have no emotional attachment to them, I'd be totally willing to ditch them in favor of something better if someone could justify or explain why they're not good enough.

Last question: Does anyone have a good PICTURE (i.e. photograph, not MSpaint sketch) of where to install the MBC when I get it? I've seen the FSM diagram and a couple of MSpaint sketches, just wondering if there was an actual photo so I could be 100% sure to hook it up properly. I apologize for sounding so rotary ignorant, this car sort of fell into my lap already modded like this and I want to make sure it's running properly....I have experience with a lot of other cars, but these are a whole new bag of tricks, so I figured I'd ask here since it's the most lively board I've found.

Thanks,

~Tim

dgeesaman

iTrader: (7)

This thread should help.

https://www.rx7club.com/showthread.p...ht=mbc+install

If in doubt, just snap a photo of how you have it and post it.

Dave

Rotofire

We'll I guess I'll be the first...Welcome! You've found a good board. Although i can't help with your car...since i've only had mine for two weeks. So I don't really post much, just ALOT of searching and reading form this board...it's a good'n. Take my advice...take at least 1 hour a day and just read this forum. It's helping me! (don't let the post count fool you, I can build a first gen from the gorund up!)



Mike

Montego

iTrader: (1)

Nice car!

but it's gonna KABOOM if you don't listen to what others have said here. Read up fast especially threads between higher boost levels with the stock ECU.

willub and company

iTrader: (3)

are there any fcd's for the fd? my car has what seems like the same problem. i can only find fcd's for the fc

Timdog1650

well I know you can use a generic FCD like the turboxs one, but apparently that's a really really bad idea.