A lot depends on which catback, there are some that are very restrictive that do not require the WG to be ported.

Thanks Banzai,

I am actually considering the HKS hi-power 3" cat-back, magnaflow mid-pipe and HKS downpipe from you guys. Funny enough I emailed you guys about it and your tech guys said to be cautious about the boost creep and suggested porting the WG.

So maybe you can chime in on the HKS model :nod:

Cheers

Why are you pushing your luck? You could just leave the main cat in place until you get the ecu/fuel/wastegate sorted out.

That was me you were talking to. The system you are talking about will most likely result in boost creep without a ported wastegate

Thanks for the input. Would require some modifications that I would want to avoid since the main cat isn't 3". I am still exploring options, so running a Power FC is on the table and porting the WG plus removing the restrictor pills. It would be easier for me when I'm ready to upgrade to single turbo.

Cheers , appreciate all the input gents. :icon_tup:

LOL @banzai-racing yup that was me lol!! ...definitely exploring all options out there. WG porting, fuel management etc... New to the rotary world so really appreciate all the comments.

Cheers

Sure. Just for the record. Almost no downpipes neck down to work with the stock main cat, but people run them like that anyways. Banzai ran it like that and still got +30hp
https://www.rx7club.com/3rd-generati...added-1104322/

No harm in running 3"->2.5"->3" in the exhaust while you get it all straightened out.

One of the big problems with creep is you you will hit fuel cut on the stock ECU.

If you are new to the car then you need to read my thread about hp gains for each part added, with dyno sheets for each part. https://www.rx7club.com/3rd-generati...added-1104322/

Narfle beat me to it

HKS downpipe bolts up just fine.

https://cimg4.ibsrv.net/gimg/www.rx7...3d882350e3.jpg

Thanks Narfle, that could be a possible action to take as well. Will consider all options and decide on a route to take.

Thanks Banzai will take a look at the thread suggested.

Appreciate the help so far

Cheers

Leave the main cat. Even with a ported wastegate you may not be able to control boost to a safe level. The biggest advantages from removing the cat are flow and power gains on a modified car with proper tuning. There will be little benefit on a stock ecu and mostly stock car. Removing the cat on a stock ecu car also results in annoying popping and backfiring from the exhaust as well as smell. Wait until you can get a proper computer like a power fc and professional tune. Remember, a motor is a lot more expensive than a power fc.

Port the wastegate. Boost controllers and pills will only operate w/i the limits of the wastegate. Once you've exceeded the amount the wastegate can expel, the excess is going to increase your boost pressure no matter what controllers you have

Thanks guys, appreciate the input.

A little history about the car. I got the car with some rust damage I'm currently sorting out so the car is pretty much pulled down and now would be a good time to make such exhaust upgrades. I can purchase a PFC right now if necessary, that's not the issue, I just wanted to feel the car for what it is with a completely stock ECU so I could gauge the gains from the car once I convert to a single. NOTE: I have never driven the car more than 50 feet and that was it, immediately started tearing her down. Car is not registered etc... so couldn't drive it on the streets, well legally at least.

Considering to do 3" - 2.5" - 3" for now and feel what the car is like and continue to learn more about it. I'm sure there will be other issues that come up along the build process.

@Banzai thanks for the pic of the DP and MP....assume that's the stock MP which is what? 2.5" there about?

Cheers

Also, quick question. If i keep the stock MP would i still need to port the WG?

Thanks

No, go to the thread I linked to earlier.

Thanks much Banzai and everyone else. Seems like the stock MP is the safest bet until ready for the single turbo conversion.

Cheers :icon_tup:

my car for example . Greddy trust SMIC. stock airbox. 3inch downpipe. stock cat . stock exhaust. stock ECU

99 spec twins. efini Y pipe , ported wastegate. sequentials working. primary turbo is 11psi Max and secondary is 11 psi aswell but slowly drops down to 8 or 9 psi as the rpm rises at WOT. all this was done in ambient temperature around 60F

I haven't experience any major spike or creep. atleast that's what the boost gauge read after my initial completion of porting and the downpipe smic mod. I since then removed the gauge and just enjoying the stock twins and mopping the floor with stock sti evo and 370z in my town. fun stuff

Removing the pills will help with boost spike and maybe creep, but what will it do with boost response?

Will it affect it?

Just as another point of reference, my series 8 has a 3.5" straight through exhaust from the turbo back, ported wastegate, non-sequential conversion and a manual boost controller set to 10psi. Doesn't creep and has been running fine on the stock ECU for two years.