asianguy02

iTrader: (4)

While the 7 is down for repairs to the tranny I have a couple of questions I was hoping to bounce off of you guys about things I may be able to fix while the tranny is down.

First off, the cabin of the car gets extremely hot on long drives, like to the point of I have to stop and let the car cool off every two hours or so otherwise Ill overheat myself even with all of the windows open. Note, the car itself is fine as far as I know, coolant temps are right where they should be on the stock gauge, and the exhaust overheat light isn't on to indicate running lean.

Second, My main cat looks to be the original one that came with the car 16 years and 97k miles ago, so Im guessing its time to replace it with a new one but since I'm on a budget I am thinking of getting a hi-flow bonez cat from rx7.com and welding it in myself which wont be a problem physically, but the question I have is will this cat with a DP start raising air flow to dangerous levels, or will I be fine as long as I dont get a cat-back to go with it?

Next as I am currently between jobs my upgrade schedule is currently looking like this for the foreseeable future:
Boot and A/F gauge
Boost Controller
PFC
opening up the intake
cat-back
battery relocation/slim battery
SMIC
BNR Stage III's

Current mods include a DP Simplified Seq. vac hoses, currently working on removing emissions equipment from the engine bay, and a JDM ECU.
If anyone has any opinions or other recommendations that differ from this, please feel free to pipe up as I know I'm still new to this and have quite a bit to learn still. Thanks for your time.
Andrew

Mahjik

iTrader: (1)

A downpipe with the Bonez hi-flow cat is fine (as well as adding a catback). Keep in mind that the stock piping is not 3" but the Bonez hi-flo cat will be 3".

asianguy02

iTrader: (4)

what size is the stock exhaust piping, i made an attempt to measure it, but I got some weird size around 2 1/8" or so, also
Not trying to be a jerk, just pointing it out, and besides I still need to get in touch with them as they may not even have the matching size

Another thing I should add, is the heat Im experiencing is coming from the tranny tunnel and doesn't have anything to do with the heater and the fan isn't on.

DaveW

You may be missing some of the OE heat shielding around the exhaust.

asianguy02

iTrader: (4)

about adding a cat-back, I was thinking about opening up the exhaust with the cheap-bastard air box mod for now until I can either put together or buy a M2 clone. I know the general rule seems to be 3 mods before an ecu upgrade, but since the JDM ECU's have a leaner fuel map (at least thats what I've heard from searching) should I stay with the standard rule, or drop it down to two on account of the different fuel maps? One thing I should add is that on idle it smells very rich and even though everything is adjusted within spec it has a tendency to softly backfire while idling.

MSilk

iTrader: (1)

Has your JDM ECU been flashed? after some phone calls I was lead to believe that the JDM market has a lot of flashed ecus. The soft backfire is the same thing mine does.
About the heat, what if your stock cat has failed or is plugging up would it not create more heat in the system. ie the cat and the DP get quite hot.
Maybe wrap the DP next time you have it off, when you go fix the cat.

Thats all I can think of atm

Mike

asianguy02

iTrader: (4)

good question on the flashed ECU, and honestly I have no idea. It came with the car when I bought it and the previous owner was shall we say not particularly knowledgeable about these cars. Ill be giving rx7.net a call on monday about the cat to see if they come as stock replacements that I can weld together, or if I need to fab a reducer for it too.

Mahjik

iTrader: (1)

As long as you keep the boost constant at stock levels (i.e. no spiking or creeping), you can add 3 or more air flow related mods.

asianguy02

iTrader: (4)

but mahjik, wasn't the conclusion that was reached that, even if pressure remained the same, removing back-pressure in the exhaust would cause an increase in the airflow by cubic feet per minute while still maintaining the same pressure in the system. If i remember right, people someone said the stock form of the car flowed 460 CFM and the stock ECU can handle at most 500CFM. Is this wrong?

Mahjik

iTrader: (1)

I don't know that anyone has put numbers to what the car can or cannot handle. However, it's been proven (years ago with dyno testing and A/F logging) that the stock ECU has enough fuel to support all bolt-on mods at 10 PSI. Given you do have a different ECU, but for the most part that should still hold true. The real trick is controlling the boost so it doesn't rise over 10 PSI which is where most people run into problem.

asianguy02

iTrader: (4)

Ok, sounds good. Thanks for the help

asianguy02

iTrader: (4)

say has anyone else noticed the mini-backfiring thing on their FD? Mine idles great for the most part, TPS is within spec along with all of the other idle variables, but the car will idle and have small backfires just like an extra puff of air out of the exhaust. Has anyone else had this, or is it unique to JDM ECU cars?

MSilk

iTrader: (1)

mine does it, but mine is a JDM. When you are accelerating hard and shift gears do you get a backfire?

Mike

asianguy02

iTrader: (4)

nope, its actually pretty quiet for the most part with the stock cat-back, and it only does the backfiring at idle. the most i get under hard acceleration is ignition breakup at high rpms. you might want to look at the dashpot cause when you decelerate its supposed to slow down the throttle butterflies so they dont slam closed.

MSilk

iTrader: (1)

Yeah I have checked the dash pot on mine, It only started when I took out the cat, It was broken and what wasn't broken was a melted mess. I am going to be replacing my ECU with an aftermarket just trying to decide what. I wonder of your car will start with the backfire during hard shifts if there was no cat. Just a thought

Mike

xxicharusxx

iTrader: (1)

what he said ,

all my OE heat shielding is gone and my exhaust tunnel and center console get damn hot as well. I was actually considering buying some sheet metal and making my own heat shielding to keep cabin temps down.