2fast4u_rx7

I got my Downpipe on yesterday and wow what a difference. I can finally hear my turbos spooling. Its been two days and my Stereo hasnt been on. Not only the sound is nice but the the boost picks up quicker. I swear I gain 10-15hp. The guy at the muffler shop was bitchin about the install because it took them from 1pm-5pm to finish. Costed $150 cad in labour alone but I think it was well worth it since I dont have the proper tools and I would break something. Now I also have a midpipe and I was told from my previous post not to put it on becuase it will caus boost creep. I was wondering if I kept on the oem cat will that have enough restriction for the midpipe? or what if I got a retriction plate? No other mods on the car besides the engine is a JDM in a USDM RX7 and I have Apexi intake and a after market muffler unsure of the brand.

Black1993rx7

i have a custom intake and a downpipe with no spiking. It did up the boost to 10.5 psi or so but no problems yet.

GoodfellaFD3S

iTrader: (213)

Leave the main cat on the car.

2fast4u_rx7

So I can put on the mid pipe on as long as I keep the main cat on, Is that what you are saying? Thanks for the reply

MADDSLOW

iTrader: (11)

You can't put both a midpipe and a main cat on, its one or the other.

2fast4u_rx7

Do you have a midpipe as well or just the Downpipe?

2fast4u_rx7

Oh I understand now. I thought the midpipe bolted behind the main cat. What if I got a High flow cat will this make any difference or affect anything?

MADDSLOW

iTrader: (11)

A HFC would be a LOT safer than a m/p, but I'm not too experienced about using them with the stock ECU.

spandy

iTrader: (1)

If you go to a midpipe, make sure you upgrade your ecu first, not the other way around.

Read the faqs, then read them again, then anything you don't totally understand, search it out, then read the faq again, and again, search some more, read some more, etc.

Enthu

iTrader: (1)

I'd get an ECU before any other mods. I spiked too high on just a DP and intake. Next mods should be upgraded radiator and an ECU.

pinkrx7

iTrader: (2)

forget just a radiator. get in on ramys v mount

jkstill

iTrader: (11)

Find another shop.

I did it myself in 2 hours. The tools required are minimal.
This was the second mod I did to the FD, the first being the vacuum hoses.

It all seems so long ago...

CareBear

I have the HKS 3" downpipe, but I'm unable to screw the upper back bolt on because it goes into the pipe itself. What's up with that? I have to custom-make a bolt that I can screw on...not good (JDM)

dgeesaman

iTrader: (7)

If you leave the main cat in your boost is much less likely spike or rise.

So don't do a high flow until you have an aftermarket boost controller, IMO.

Dave

jkinluv

Same here.

dgeesaman

iTrader: (7)

Using tuning to cover for boost spikes is stupid.

Use a proper boost controller.

Dave

donz

iTrader: (2)

^if not I live close to you and will buy your roller when you blow it up!

Joe Geiman

a stock catback with a down and midpipe will give enough restriction to prevent overboost. It's been safe for 3 years for me.

JamesVaughn3rd

iTrader: (3)

Mine went on, rough, but it went on. Now when I took my pipe off after a three years, the pipe had heated up and deformed and covered that bolt. I had to sawzaw the pipe off, it wasn't pretty.

MAXX65

iTrader: (2)

Well I wish I saw this forum a week ago . I have only been into the turbo scene for about 5 months, so I have a lot to learn. On sat. I just installed a down pipe, mid-pipe and an apexi N1 exhaust. As you more experienced Rx-7ners will expect, its not driving as good as expected (its back firing when switching grears at higher RPMs). Now that I have read this forum I have learned that I may have done this prematurely.

First of all, with having a mortgage in San Diego, I can’t afford to go out and get a new ecu and tune it for a few months, so should I take off the mid-pipe? And if so, what should I replace it with? A normal cat? Will this prevent me from spiking and saving my motor?

Second thing, so I have always used HKS exhausts on my Hondas. This is the first Apexi exhaust I have every used and I have found that I chose one of the loudest exhaust that Apexi makes, the N1. I have already purchased the silencer for it, but what do you guys think about resonators?

Thanks for any feed back.

OneRotor

iTrader: (3)

and port your waste gate.

2fast4u_rx7

What if I run the down pipe with the mid pipe with the restriction plates in there, Will that be enough to prevent boost creep?

BuffDaddy915

Maxx65...put tha stock cat back on n u'll be fine until u can get a ecu n tune it.

2fast...sure restriction plates (when installed right) will help. But I would just put tha cat back on

RX7LINK

iTrader: (3)

^^ +1 Yes. Put ur stock cat back on until u get a new ECU and proper tune. it will save your motor

tuning" .. u meant "buying a ecu w/out getting properly tuned" ... right?

good tuning > boost controller only

dgeesaman

iTrader: (7)

No, I mean that if your boost is not solidly controlled, then using a more extensive fuel map is a backwards approach and subject to future problems. No matter what your tuning, you still need your boost to be controlled to match it. Including getting the boost to match the levels of the stock ECU.

If you're getting boost spikes, then put a proper boost controller on and you'll eliminate the spikes. It's cheaper, easier, safer, more extendable, not stupid.

Dave