Is this for real????
 

I read somewhere that having a after market intake and exhaust system alone can allow your motor to blow! Can this be true??? Apparently the RX-7 doesn't have a sensor to detect more air flow or not so the map sensor just ignores this so the fuel goes lean. Resault? Boom! Unless there is an adjustment in the fuel through the ECU this could be a problem. Has anyone else heard of this?

Yes- it happens, if you have a downpipe, midpipe and catback (in most cases) Its from boost spike, you run to lean and you lose apex seals.
How long have you been a member of the forum?
-Ben

Yes it's true. The intake allows more air than the stock computer can handle and will possibly begin to run lean. Remember it's running with a fuel map, not MAF. I'm sure you can get away with an exhaust and downpipe. A fuel computer, boost controller and injectors should be preemptive to any other mods.

It is definiately true, do a search and you'll see that many people have popped a moter with just these mods.

I just put in a new engine from Malloy's along with a Koyo Rad, Turbo Timer, Apexi Duel Intakes, and an exhaust (from previous owner). What else should I do to it to prevent this nightmare? I don't want to buy another engine after couple months!

you will need an ecu upgrade. depending on what you want to do with the car, you might want to go ahead and get a power FC or other stand alone ECU. Until then, try not to push the car too hard.

Would an Apexi Super AFC Fuel control system do the job as well?

From what I understand, it would be better than nothing but no, it wont do the job as well.

How about the Greddy E-Manage? Since I have actually used a Power FC I'm a little worried about using it. So basically if I just get a Power FC I will be pretty much set for other mods as well without buying an expensive ECU, correct? So do I need to get the Commander or the Power FC? or Both? I'm kind of broke at the moment from all these recent repairs :(

Just get a power FC, you wont be dissapointed.

yea do you have to have a commander or is it just helpful?

What do you mean by "exhaust"? A cat-back? Do you also have a downpipe and/or midpipe?

Do you have a boost gauge so you can monitor your boost? As long as you keep boost levels at or below 10psi, then you should be relatively safe with the stock computer.

If you have just the Apex'i intake and an aftermarket cat-back, then you should be fine with the stock computer. Again, you must be at or below 10psi of boost.

If you have Apex'i intake, cat-back, and downpipe, you are pushing it, but again, if you are at or below 10psi then the stock ECU should still work just fine.

If you have a full exhaust, then your wastegate (assuming it's stock) will not be able to redirect enough exhaust to keep boost levels below 10psi.


A Power FC with commander and datalogit will set you back about $1400. You'll probably also want to dyno tune it and that will cost extra as well. I wouldn't get one unless I wanted to run more than 10psi of boost.

the commander is very useful, but you dont need it. you will need to have the power fc tuned though! KDR is really good and well known for tuning power FCs.

as JONSKI stated, as long as boost is at or below 10psi, you should be safe.

You can monitor a lot of things with the commander, like water temp, boost, intake temp, knock etc. etc. I think its pretty nice to have.

This is true, but it is also an exceptionally stupid statement. Unless you take care of the problem, you can't drive the car without one eye on the boost gauge, and babying the throttle. So if you drive your RX-7 like a little old lady, then you can keep it under 10 PSI.

The Power FC allows you to push the car, without worrying about the boost. Get it. Without the commander you can still drive your car without worries, although in an untuned state. A tuner will need either a Commander, or a Datalogit to tune with a laptop.

What you should do, which you obviously didn't do, is read the threads that are stickied at the top of the 3rd gen sections, which mention why you don't go out and just start modding an FD willy-nilly.

If you just need to "get by" for now get a Pettit upgraded ecu with the unlimited chip. You should be able to find one for $450ish used. Then down the road when you out grow it its no loss cause you can sell it for $450 and get all your money out of it. You wont have to worry about setting it up or tuning it or anything, you can just plug it in and go. Is a Power FC better? Well yea sure it is, but its also a lot more money, complication, and maint, at this point in time for your mods its not needed.

STEPHEN

search for the "3 mod rule" theres PLENTY to read about on this. And every car is different. Some will blow with intake, dp and exhaust, some can run intake and full exhaust like my car just fine on the stock ECU