Hello everyone,

I recently was able to get my first fd3s and am trying to build it to be semi-daily driven (I also ride a cbr 600) so the first thing I wanted to do was get a full exhaust on the car. Now I am very new to turbos, especially the Seq. twins on this car, but my question is if I buy a full Re-Amemiya exhuast (down/front pipe, mid pipe and cat back) will I need to replace the down pipe in the future if I decide to change the turbos be it single or new non-seq twins ect. (still unsure how I want to build it)

 

if you go single of course, if you go non-sequential no it is not necessary as you are using the same manifold. If you have the oem downpipe you may want to anyway because it is a huge source of heat.

 

I guess a better way to word it is, I am going to replace the downpipe regardless, but I would like to keep the full re-amemiya system even if I go single, is that possible?

 

If you upgrade to a single, a tt downpipe won't fit. It could be cut in half and modified however.

 

Ok, I got think I got it thank you guys.

Now onto my next question if you guys don't mind helping a noob. I guess on the other end, if were to buy say an hks intake, then upgraded to non suq. twins what it still fit, or would that need to be changed?

 

It will certainly have to be changed.

 

Ok, thank you guys and sorry for the probably obvious questions. I am trying to build from the outside and I guess move inward while trying to not waste money on parts just because I changed something later on.

 

From what I understand and have been told...if you upgrade to a full exhaust you may have boost creep issues if you don't have a way to control it. May wanna look into that. Don't wanna blow your motor

 

@Wantanothersven I will certainly keep that in mind, maybe that will give me an excuse to get a pfc.

To those of you reading this with upgraded twins, could you maybe list the parts you have on your car to sort of give me an idea.

 

I just got intakes, a bigger IC and a power FC. Very shortly I will be getting a rebuild with street port, open exhaust and boost controller/gauge.

 

You won't know your getting boost creep without a gauge You can't "control" it without a boost controller

 

are you talking about getting new twins (BNR's) or what?
going non-seq is not an "upgrade"
but to answer this question, yes you can use the HKS intakes with the twin turbos..

and you can use whatever exhaust you want no matter if your single or twin..just the downpipe would need to be different obviously

 

I don't recommend a full exhaust with twins. The wastegate is just too small and it becomes difficult to control boost.

 

Now this may be stupid, but if I were to get larger wastegates for the new twins and a boost controller would that fix the boost creep of a full exhaust.

And if I were the change the turbos, I would not get a new seq. one like the bnr I would be putting something like 2 greddys or something.

 

ok man you have a lot of reading to do before you start modifying your car.

https://www.rx7club.com/3rd-generati...l-links-68640/

But to break it down for you:

Your first modification ever should be a boost gauge. Make sure it is a quality one because with a cheap one you run the risk of it not being accurate (trust me I had that happen to me). The boost gauge will certainly tell you if you have any issues in your turbo system, it will also tell you if you are spiking/creeping due to mods. So get that first.

Second the act of going non sequential in *not an upgrade* of any hardware what so ever. It is basically a change of how the turbos operate. WOT in a stock setup and in sequential form, the first turbo comes online at 2900RPMs (giving an instant throttle response), next at 4400RPM there is a transition dip where the second turbo kicks in, last due to the restrictiveness of the stock setup, the boost drops at 6500RPMS. So in a fully working stock sequential setup the boost response is a follows 10-8-10-8. (if you change the DP then it will be 10-8-10 (all the way till redline).

In a non sequential setup (with full exhast, intake, and SMIC) 10 psi of boost (stock boost) typically comes in at 3800RPMS, is laggy but and holds boost reliably until redline. Now that is very debatable as some people claim they get 10 psi by 2900 RPMS and everywhere in between. All I can tell you is that I have never seen any proof of that. Including my own car (I used to be tried non-sequential for the fun of it), not a another FD, not a video, nothing. Also one begins to wonder why would Mazda design a very complex system when the same could be achieved using the same hardware (yeah right). I even spoke to Brian @ BNR about his BNR turbos in non seq form and he also verified 10 psi @ 3800RPMS. So take that as you will. BTW BNRs turbos are an upgrade whether they are setup sequential or non sequential.

Now the biggest reason people go non seq is not because its an upgrade in power but a reliability of power. With the seq setup there are 72 vacuum hoses (very prone to boost problems) and with a non-seq it goes down to 6 (not very prone to problems). But in my experience, the car was more fun in sequential form (when it didn't have a boost issue). In either sequential or non sequential you are still using the same turbos (unless you purchase BNRs) so whatever hardware bolts on will fit for both versions.


say wha?

The wastegate (not plural) is internal to the stock turbos. If you wanted to run an external wastegate it would be an exercise in the "pain in the *** department' for no good reason since all you have to do is port the stock wastegate to eliminate creep.

BTW a boost controller controls/eliminates boost spikes while porting the wastegate eliminates boost creep.

You have a thing with japanese names...Putting in 2 greddy turbos is not even close to a BNR twin turbo. One is basically a bolton (minus supporting mods) vs the other having to fabricate just about everything...

 

Greddy twin turbo courtesy of curacaosfinest:



Not for the faint of heart.

IMO wait a little while before spending money on upgrades. Learn about the car and make informed decisions on what route to take. These cars can be a handful but are actually pretty reliable in stock form. By not knowing how to properly modify FD's, it is the owners who **** with these cars that gave the rotary a bad rap.

 

@Montego Thank you for the detailed reply. I suppose I shouldve been more clear with my posts, I am not planning on doing something like a turbo swap or anything in the near future. I just like to have a plan, and am trying to gain knowledge based on what is unclear to me. I have read many threads on similar subjects but most as you stated are debated by one side or the other. I am just trying to compile facts and experiences from other fd owners. I know I have a lot of learning to do before I mod anything, and plan on talking to some of the rotary shops in my area like Lucky 7 and Mazdatrix here in california.

And I apologize if I come off as slightly ignorant naming only Japanese brands, I know companies like Petit Racing, Racing Beat and other US companies make fantastic parts, I guess the Japanese companies like HKS, and Greddy just interest me more.

But I do thank you for the information and I will certainly be looking into boost gauges.