LemonR1

I have a 93 R1 with a DP, HKS FMIC, 3 inch full exhaust with RB catback, K&n filters, stock ECU. The guy i bought the car from said he gutted the cat where the midpipe would go. I dont like the idea of this from all the bad things people say about midpipe and stock ecu. Should i replace the gutted one with a stock or high flow? Also just any advice on what i should do with my setup to be the safest and i would greatly appreciate it. Thanks

rx7f4n4tic

It would really depend on your goal of the car. If you plan on keeping it near stock levels I would replace it with a reprogrammed ECU and get a high-flow cat because otherwise you arent going to pass emissions. If you plan on going all out, leave as is and get a PFC.

It's not so much of the fact that a midpipe isnt good for the ecu, its the fact with a midpipe or "gutted cat" in your case, that the stock boost control system wont hold boost at the stock 10 psi and cause overboost which will cause the engine to run lean. You could also get an SAFC and a good boost controller and limit to 10psi if you wanted to.

There are a few options you could take, but all depend on your goals of the car. Good luck!

LemonR1

Thanks for the input. My goals with the car at this point is to keep it at a stock 10 psi, and get some sort of upgraded ecu (no idea which one because i dont know what i really need for the mods i already have). Near future i wanted to get some injectors(once again, no idea what size),Supra TT or walb. fuel pump. I just want to do whats right and will make some nice safe power for me without cranking the boost up. Money isnt really much of a problem since this is a weekend car and ill be saving for it anyway, but let me know what you think. Thanks again

FDNewbie

iTrader: (10)

There isn't (too) much power you can gain while remaining at stock boost. You already have a freeflow system (from intake to exhaust) so you've freed up a great deal of restriction. Running an upgraded pump or injectors would be a waste of your $$ if you keep the car stock, because they stock fuel system is more than adequate up to about 14 psi. Also, no need to get an aftermarket ECU if you're going to be holding stock boost.

Now if you mean you just don't want to run too much boost, you're right, and that's the key. You can do just fine at 14 or 15 psi on the stock engine and turbos, but w/ upgraded pump and injectors. That'll also allow you to take advantage of the freeflow exhaust you have. I prob. wouldn't waste money on a fuel computer, since the ECUs can handle that. I think your best investment for now and later would be a boost controller. Use the boost controller now to limit your boost to 10psi, since you basically have a midpipe, and when you get an ECU down the line (say, a Power FC, which is the most popular right now), you can still use and may even need the boost controller.

BTW...where in VA are you?

LemonR1

Thanks a lot for the info, and btw im in Hampton. For right now i just want to stay at stock boost and im not looking for power really (the car is already hard to get used to from a civic), just anything to make me feel like if i put my foot on the gas its not gonna cost me more money. Im going to try to find the most creep/spike free boost control system i can find, because i was spikin to 14-15psi (on the first turbo at only half throttle,didnt understand that) when i first got my car back, i opened up both boost controllers all the way and it boosts to 7 then drops to 4 at around 5k and i let off when i notice the boost dropping. Will that have any negative effects on the motor or turbos?

FDNewbie

iTrader: (10)

NP. There are a couple of good guys down your way...I think they have a thread going in the NE section. Check it out.

Just in case you don't know, even at stock boost, do NOT boost in turns/corners. You will find yourself flying into the wall/opposing traffic, or even facing the opposite way. Indeed, the FD is a beast, and RWD is very diff than FWD. You can push your way through a turn the whole time w/ a FWD car like a civic, but if you get on the gas too early in a turn in a RWD car, esp. one w/ as much power - and sudden power at that - as the FD, it's a disaster waiting to happen. In short, trail brake coming INTO the turn, and slowly begin to give it gas as you're coming out of it. A boost gauge is a must, so you can make sure you're not boosting (any positive boost) as you're exiting the turn (in fact, for any part of the turn). The wheels have to be 100% straight before you get back heavy on the throttle, or you'll find yourself going sideways. Also, be aware that boosting can break the tires free quite easily if it's wet outside. So when it's raining out, drive like it's on ice. When it's snowing out, leave the car at home Hope that helps.

Not sure what you meant about opening up both boost controllers... but yes, spiking to 14 - 15 psi....man, lets just say you're lucky you still have your motor. Chances are, you may not be so lucky the next time that happens. At that moment, the ECU is only delivering enough fuel for the stock 10psi, yet you're producing much more than that. In effect, you're running very lean for that condition, which will eventually lead to a blown engine. Plain and simple. In fact, that's one of the most common ways FD owners lose their engines. So stay WAYYY off the gas for now until you get a good boost controller. If you want a good, simple, and cheap one that'll work w/ a single and the twins, I'd recommend the Greddy Profec B.

LemonR1

I have a MBC on both the precontrol and wastegate line that was installed before i bought the car and I now know that they are crap. Anyways, I opened them both all the way so i could just have maybe little to no boost until i get my boost prob fixed.
Thanks again and I was actually planning on the profec B.

alberto_mg

FDNewbie - This is not true. You don't want to run higher than 12 psi on a stock ECU.

LemonR1 - I suggest you spend some time reading the stickies especially the FAQs. I'm pretty sure the answer to all your questions are there. Don't take advice blindly. This question comes up about once a month and most of the people who know what they are talking about it ignore it under the assumption that if you are too stupid/lazy to get the info yourself, you aren't worth answering.

Boosting to 14-15 psi will blow your motor. Yes it will happen with the slightest bit of throttle. You don't need to be full throttle for it to spike and blow an apex seal.

If you are looking for the safest setup, I recommend the following:

You NEED to either get a cat (high flow or stock is up to you) to add restriction to the exhaust and keep boost levels in check and/or a boost controller (especially if you keep the gutted cat). You also need to get a boost gauge if you don't already have one.

the car is plenty fast at 10psi of boost and from what I remember reading it should be OK up to 11-12 psi of boost on the stock ECU. I suggest you research that on your own. There are a few good threads in the Advanced Tech section.

Forget all about bigger injectors and a more powerful pump. Do some research on the fuel system and you'll find that the stock system is good to 300++ HP at the wheels.

Do maintenance: fuel filter, change all fluids (coolant, tranny, diff, motor), bleed brakes, get a bigger radiator if you want your car to last.

Oh, I'd get a compression check on the motor to check its overall state b4 you blow your wad modding a weak motor. Rotaries aren't forgiving of poor mods. Run just a little lean by running too much boost and you're history.

FDNewbie

iTrader: (10)

Alberto, I never said on a stock ECU. You must have misunderstood. I said he should be fine running 14 - 15psi on a stock motor, twins, and fuel system, since the stock fuel system can handle right up to about 14psi, aka the 300+ hp you mentioned, with an aftermarket ECU. In fact, I specifically recommended the PFC. My point was that upgraded pump and injectors weren't a necessity for him to get a bit more power and still remain reliable. The ECU and boost controller are priorities, however.

I also disagree with you telling him to take off the gutted car. Someone shelled out the money for that job, and it increases his power potential greatly. Why not keep it on and get the Profec B, and see if it does the job?

alberto_mg

I guess I did indeed misunderstand.

As for gutting a cat, its easy. Grab a long fricking screw driver and do a little of the old in/out with it. I've done it a few times on various cars. I recommended getting some kind of cat to add enough back pressue to decrease boost spikes *and/or* a boost controller. He said he is looking for reliability after all. Plus an open exhaust makes my clothes smell like crap and the girls definitely don't like a guy who smells like he's been working on a car all day.

FDNewbie

iTrader: (10)

Well looking back on my statement, I guess I didn't write it too clearly either

I didn't know gutting a cat was that simple lol. Oops. You're def. right about the reliability part tho. MP is def. a negative in reliability, but a large positive in power. Hi flow cat is prob the way to go (find one w/ low miles on the forum...don;t waste your money buying it new. The forum is your friend )

I've read people complain about open exhausts making their FDs stink and what not...I don't think mine does, but if you stand close to the exhaust, or I'm at a light and a light wind blows the exhaust fumes forward, I can easily lose a passenger LOL. Maybe I do have the smell, but I just don't notice it anymore??

LemonR1

Well just to let you guys know, my girlfriend was behind me coming home from buying the car in Carolina, and she said the exhaust smelled very sexy. Thanks for all the input btw, its a lot of help. I have 33k miles on my motor and about 30k on the turbos. If i buy the Greddy profec B, then i will be able to keep the gutted cat safely? If not then ill buy a high flow one. I'll be staying at stock 10 psi....hopefully, I just replaced the radiator with a new metal one from Mazda when the turbos were replaced and im doing all the fluids/filters this weekend, so hopefully ill be able to drive this money-mobile sometime soon.