RX7^EC

I have a 95 JDM FD..

Im getting a Redom type B ecu, SMIC and boost controllers..

What i want to ask is.. i already have a Racing beat cat back exhaust.. now i want to remove my cat.. is it worth changing the down pipe or is the stock jdm one fine,, i see people say it has a kink to pass the steering coloum.. does this not effect the flow?

thanks

bullet13

iTrader: (5)

The stock down pipe produces a lot of heat in the engine bay, actually replacing that with an aftermarket one is one of the relialibty mods that should be done. Just check to see what mods the ecu is programmed for.

ProjectD

iTrader: (15)

Do JDM FDs have cats in the DP?

Brodie121

iTrader: (8)

No cat in jdm downpipe, straight through 2.5"

fendamonky

iTrader: (6)

If I remember correctly the USDM models were the only FD's to come with a pre-cat. It was an additional requirement the US Gov't threw in there.

RX7^EC - If you are still running your stock ECU than DO NOT get rid of the main cat.

RX7^EC

Still running the stock ecu atm, why do you say i shouldnt?.. will have Hallman RX boost controllers on before I decat! but im getting a RE Amemiya tuned ecu..

The JDM downpipe does not have a pre cat.. hence the question will a aftermarket one really make a diff?

fendamonky

iTrader: (6)

An aftermarket one might make a difference, depending on it's diameter. You cannot, however, us a USDM downpipe on a RHD vehicle, it will not fit as the steering column is in the way.

Do not get rid of the main cat because the increased flow will overpower your wastegate, causing boost creep. Boost creep can/will make your engine go "pop!".

If you want to run a free flowing setup than you will need to port your wastegate and properly modify your vehicle to run the additional boost levels you're likely to see.

Not to be rude, but simply having an "RE Amemiya tune ECU" won't necessarily make it all better. If the ECU is tuned for a car that has different mods than what you've got than you won't be getting a full effect out of the ECU. As soon as you have that ECU tweaked for *your* mods than that "RE Amemiya tuned" catch phrase becomes null and void.

RX7^EC

Thanks for the knowledge and information.. its the B type ecu which is tuned for downpipe, decat and intercooler on stock turbo and fuel pressure setup..

I know with fitting the hallman pro rx boost controllers will solve the boost creep issue... and will only be boosting 0.8 bar just over 11 psi which should still be safe on a stock internals?

korea_senpai

iTrader: (25)

Sounds good any other plans?

RX7^EC

Im getting a Koyo rad which will be put inn the same time as all the other goodies.. oh keeping the stock airbox just replacing with a filter..

Maybe maybe i will put a AEM water meth kit on after all the above has been done and running!

Brodie121

iTrader: (8)

You wont be able to hold 11 psi on a stock wastegate with no cat and downpipe.

Sgtblue

iTrader: (16)

^Agreed.
And understand that a boost controller will only control for boost SPIKE which results from opening up the INTAKE side. It will do nothing for boost CREEP, which can result from opening up the EXHAUST side too much. The only thing you can do to avoid potential CREEP issues is port the wastegate (which requires removing the turbos) or keep enough back-pressure in the system to avoid it, usually by keeping at least a hi-flow cat or possibly a resonated mid-pipe.
If I could make a suggestion, go slowly with the mods until you know more about these cars. I know HKS and possibly Knights Sport make a downpipe suitable for a RHD FD. Whatever you get, have it heat-coated or get some header wrap for it BEFORE installation. That reduces underhood heat that bakes plastic, vacuum hoses and solenoids. Figure a new gaskets...at least for the turbo end and if your feeling really flush, new copper-clad exhaust nuts.
FWIW, I've been really happy over the years with my Bonez hi-flow cat. It doesn't flow quite as well, but another benefit (IMO) for the hi-flow cat over the midpipe/test pipe is that it's quieter and girls eyes don't water from the stench as they walk past your idling car.

RX7^EC

i will be running 2 x hallmans RX boost controllers.. one opperates the boost and the other opperates the waste gate, seeing your controlling the waste gate aswell creep wont be an issue..

Running this setup on my brothers rx7 and havnt had any issues.. but i will do more research into it, thanks for the advice!

Brodie121

iTrader: (8)

That isnt how it works.

the wastegate is the only way to control boost, the other one you are talking about only controls prespool.
adding an aftermarket boost controller will not help if the wastegate cannot flow enough to keep the boost down.

BStallion

iTrader: (3)

You really wanna use that boost controller don't you..

SiH

Boost controllers won't stop boost creep unfortunately - creep is due to a physical restriction of the wastegate not being bale to bleed off enough boost - no boost controller, no matter how good, can resolve that. You need to port the wastegate on teh rubo pack or fit a restrictor in the exhaust if you experience that. Some do, some don't, it' a bit of a gamble.

There's not pre-cat on JDM cars, but a downpipe makes a very perceptible difference to spool.
As said, an LDH downpipe won't clear the column, so you need an RHD one.

The ECU will have been mapped in Japan for 100RON fuel (Japanese measurement of RON is different from you guys in the US, but AFAIK it's still a higher octane rating than even your highest octance fuel) - I wouldn't really want to risk it, but if you do, then I'd spend a good while with your car on the rollers checking AFR's and EGT's.

RX7^EC

Ok soo ive been thinking.. thanks for the concern with the boost creep im not to worried about it as ill leave room for sum creep not going to be boosting hi..If it becomes a problem i will sort it out then.

im going to leave the stock JDM downpipe on to help with some restriction.. Will be running a tuned ecu and my wastegate and boost controller setup thingy and a SMIC.

Put the car on the lift to check how easy the main cat is to remove.. now my new questions are..

I dont really wanna delete the airpump as i will have to import the whole belt kit to remove it etc...

Soo can i just leave it be and connect the air pipe onto the new mid section?

Also on the other side of the cat what is this thing connected there? pic below..

fendamonky

iTrader: (6)

Sup mate, branching out from FDUK I see

As for the ron/octane rating difference. UK 98 RON = US 94 Octane. Each step down follows a similar trend in America (93/91/89 typically).

You're def right though, the OP needs to be careful before just diving into mods he's not familiar with, and trusting in the tuning on an ECU that was meant for a vehicle other than the one he owns.

fendamonky

iTrader: (6)

Just what exactly do you think is going to happen? How much are you talking when you say "sum creep" (spelling "some" wrong just hurt me a little..) because you're not going to be boosting high?

Do you plan on cutting the boost down to 8psi or something so that when you get creep you only have time to creep to 11psi or so? I really don't think you understand what you're talking about here. Your stock fuel system WILL be maxing out at about 13psi. If you go into this expecting, even anticipating, to creep starting just below that point than you're an idiot. I'm sorry.

Simple solutions to your potential problem: 1) Upgrade fuel system. 2) Port wastegate so it can handle flow. 3) Retain exhaust restriction.

You don't seem to get it. The "tuned ecu" doesn't mean a damn thing unless it's tuned for your exact vehicle. The fact that RE-A tuned a PFC for their Touge car, and you happened to be the lucky recipient of said PFC does NOT instantly transform your car into the RE-A Touge monster.


I think you really need to put down the car magazines, and back away from the mid-pipe before you break something. Spend more time reading the FAQs and Archives here and less times thinking of ways to cut corners so you can be mad tyte like FnTF5 with a chameleon FC/FD/240/370/ferrari drift car.

If getting a belt is too much of a hassle than you really need to consider leaving your car the way you found it. You're just going to break something otherwise.

And fwiw, you can disconnect the clip on your air pump and unplug the piping without any problems. I did that in England when I put my midpipe in. I purposely left the airpump there for inspections

shawnm565

iTrader: (3)

ok so I have the SMIC, 3 inch downpipe, and hks intakes, I am getting boost creep and the boost will spike to 15lbs and the ECU will cut to fuel, causing a loss of power and obvously a bad thing. so my question for you is if I get bigger injetors and fuel pump and a after market ECU will I be safe to run at 15 lbs boost? oh and once I have all that get it tuned.

fendamonky

iTrader: (6)

In all honesty your best bet is going to be getting your wastegate ported. Once that is done you shouldn't really need to worry about boost creep.

What all do you have with regards to your exhaust setup? If you get a tunable ECU (like the PFC for example) and you do the fuel mods than you should be fine for 15psi. The big thing you want to be careful about at that point is going to be intake temperature. Also, for anything in that range you'd be wise to start considering some form of Auxillary Injection. Even so, if you don't address the cause of boost creep (an overwhelmed wastegate) than upping the boost intentionally will only lead to higher boost creep. I don't think you can overwrite boost creep by simply tuning to a higher level.

I never really experienced much boost creep, but I kept decent restrictions on my exhaust until I was ready to make all the necessary upgrades. When I went with a straight through system I also put in a larger fuel pump, bigger primaries, upped the fuel pressure, added BNR Stage 3 twins (with ported wastegate), installed a good boost controller and added several other ancillary mods.

I also had my car on my dyno getting tuned for the new setup before it left the shop (I didn't want to mess with the turbos myself, so I went to one of the better known shops in England to have the work done).

I attribute my lack of problems to the fact that I didn't go throwing things on my car hap-hazardly with no real idea of cause and effect.

shawnm565

iTrader: (3)

I bought the car like this so lol im just figuring out what the guy did wrong and what the best route for me to fix the issues on top of that im a newbie to cars in general heh but I love to learn ha

BStallion

iTrader: (3)

heyy guys, how do you know when boost creep is happening?

shawnm565

iTrader: (3)

If I had to guess its probly when the second turbo kicks in

shawnm565

iTrader: (3)

3inch from turbos back