3 mod rule
 

hey i just got my 93 rx-7. i have been hearing about this three mod rule until you need an ecu... and ecu are expensive as hell. i have a cat-back on my car right now and i want to add downpipe and just a simple k&n air filter... will i have to buy ecu chip then? thanks

Definately, yes. Otherwise, you will run too lean. It's not worth the risk.

ECU upgrades aren't that expensive, it's the stand-alone ecu's that are expensive, but you have to think of it as your engine would be a lot more expensive to replace if you blow it due to not having the proper fuel management.

is there a pre-tuned ecu chip i can buy that would be easy to install and not very expensive? could you give me some links... thanks

just look for a used pettit upgraded one or m2 or something like that i see them all the time for about $400-500. check www.thepartstrader.com

upgrade further when you are ready, i have seen these computers running high 11's and i am sure people on this forum can attest to that.

Re: 3 mod rule
 

The restriction of a STOCK CAT and STOCK IC should be enough to still limit you 12psi boost - get a BOOST gauge and an A/F Ratio Guage then do the DP & K&N while keeping an eye on Boost & A/F ratio - if Peak boost is going over 11 (Not Spikes) AND the A/F ratio is not slightly on the rich side at WOT then add a BOOST Controler (manual or Larger pills) I run fine w/ my mods (see sig) and the stock ECU. If it runs Lean at WOT get an adj raising rate Fuel Pressure Regulator to Increase FP (and inj. flow rate) at High Boost

This was discussed about a week ago... sheesh...

https://www.rx7club.com/forum/showth...threadid=44277

Wade

ok. what i hope to do is get a dp and k&n air filter as my only performance mod, beside the cat-back i already have plus reliability mods. is there an ecu chip that i can buy where i can tell the people what mods i have on my car and they send me the ecu all tuned and ready to plug and go? if so what is it called, where can i get it, and how much will it cost? also, will i need a boost controller then or will a boost guage work fine? also, what exactly does the a/f guage tell you. thanks alot for your help.

Are you just gonna stay with the dp and K&N filers as ur only mod ever? IF you are, then just pick up a Pettit or M2 tuned ECU. www.m2performance.com I say go with a standalone unit like the APEXi Power FC if you are gonna add additional mods. You can take the PFC to a local rotary shop and have them tune it to your mods, then once u get the hang of the unit, u can buy the commander and tune it yourself. Plus even if you stay with basic mods such as dp, cat back and intake, I have heard that the base maps are well tuned to accomadate those mods without taking it to a shop. overall the PFC is a better unit. But its also about $300-$400 more than a pettit or M2. Take your pic, but if u go any higher than the intake,cb and dp...get a PFC.

i am not sure if i am going to add anything else after dp, airbox, and reliability mods... just don't know yet. prob not for a couple of years at least if i do

Trust me its not worth blown you engine up! I ran my car without a tuned apex pfc and i pop it. Now my motor is at Rotary Power for a rebuilt.

Sublime5254-
I'd say first find out if/where some rotary shops are in your in area. Im sure some guys on the forum couls name a few in your area. Then if you find a good one that could help ya out, just get the APEXi Power FC. It is well worth it. They can tune it perfectly for you, and porbably teach you how to use it yourself. You can monitor just about anything with it. Boost, air/fuel, injector duty cycle etc... so it saves you a lot of money on gauges and what not. It's a very safe and probably the most "realiable" mod you will ever do to your FD. Just spring for the extra $$ and get one, its better than getting a tuned ECU for around $400 then realizing you want a PFC, because by then u are paying that extra $400. It's still your decision man, but at least get in contact with some rotary shops in your area and talk to them to see if they could help ya out. Good Luck!

- Danny

thanks. i do know a good rotary mechanic that lives close to me that works for a mazda dealership. he is the one that replaced the engine in the previous owners car and the previous owner highly recommended him. do you think that this person could also do a hose job? thanks for the help

hey guys, i have a apex intake, gt exhaust and a rp maindrive pulley, do i have a chance of running lean or am i ok? thanks