hi guys, i was trying to find posts about midpipe for turbo application. i usually search, but there is no answer toward what i need to know. i have had turbo installed, and it was tuned today, but when we were trying to boost it up to 9psi, the highest boost it went was 7psi. i have RP highflow cat, and we suspected the high flow cat that prevented us from higher boost. does anybody have this kind of experience? i have AEM boost controller. please give me some inputs. thank you
steven

 

Are you running the stock exhaust? If so thats you problem. The bigger the exhaust for a turbo car the better, more air can be forced in from the turbo the faster the exhaust leaves. 3" is a good size to go with.

 

assuming your boost controller is working, then you do have a problem somewhere.

I have 2.5" exhaust and midpipe and I can go over 11 psi and make more than 300 whp with it...

 

i believe my boost controller is working properly, and my mechanic checked the connection, and it was good. mysql, where do you think i have a problem at? do you have any idea? i am using Borla catback and RP highflow. i limited the boost at 7psi, and we tried to change it, but it didn't respond. i will try to change the exhaust, and see how it goes.

 

thats interesting, borla is full 3" until it reaches the muffler. like mysql said I would double check your boost controller. sounds suspect.

 

Have you measured the ID of the borla piping where it connects to the midpipe/cat?

 

I didn't measure the id myself when I removed my borla. I know I shouldn't, but I went by the majority of forum members experiences....

 

halimsteven you can go with a hi-power hks unit that is single and 3". I have one now on my car. it's a bit loud. maybe to loud for some folks w/out a cat.

 

I don't care about the ID of the pipe, just the ID of the connecting flange where the exhaust meets the midpipe. Most exhausts go down to 2.5" to mate up properly with the OEM cat. If this is the case, then your 3" exhaust isn't

 

true, you have a point time to break out the wizzer and welder

question, I remember I while back you mentioned that you modded a silencer for your hks exhaust. what silencer did you use? the apexi n1 maybe?

 

i am thinking about RP midpipe (resonated). i think it will help little bit.

mysql, my RP is 3", and from midpipe to catback is 3", and the catback is 3". when i installed them, they were the same size. i installed both, cat back and RP, at the same time.

i am consufed now....

 

are you using a greddy kit?

 

yeah i am, just the kits, everything else was upgraded (fuel pump, injectors, radiator, int-X, coils) everything that you can think of . any suggestion?

 

apexi active tail silencer.... I don't think I'd recommend it. It did quiet things down, but it's a mechanical spring that moves in the exhaust and I don't know how long that will last in that heat.

If my turboxs system is too loud, I'll buy one or two of the racing beat silencers (they're listed on their website at $88 a pop).



Until you have the GT3071R, you're just pretending you have boost

 

Until you have the GT3071R, you're just pretending you have boost [/QUOTE]
mysql, i know you are trying to make me to get upgrade turbo from mazdamaniac.. don't worry, it already works. i will get it next year, by january. my shop told me it's better to get bigger turbo than modify the internal.
owell, let's help me out about the exhaust.....hahaha....i think this thread is also good for people who want to know what exhaust they can get when they go turbo.

RP supercat (high flow) + Borla = really quite, but it will not last long i was told.
i don't know if it holds the boost at 7psi....i will find out and i will let people know
steven

 

Boost Leak?

 

nope, not at all...

 

I had that problem. I couldn't get my car to make over 6psi with an Apexi Boost controller. It was the stock exhaust causign the problem. I replaced it with a Turbo-XS racepipe and catback and problem solved. I highly recommend that exhaust for a turbo app. It is the only true 3" exhaust available.

By the way. I know this seems scandelous, but I happen to still have myne for sale if you decide to upgrade your exhaust.

 

The stock exhaust isn't that restrictive, just get the Racing Beat midpipe and should be good to go and quiet. running from the cops isn't easy in a car they can hear a mile or two away.

 

that's a good suggestion, so people know what type of exhaust they need to have for turbo application.

it's too loud, i am looking at RP midpipe (with resonator) adn RX7 strore (with resonator). they look the same, but they have different price? does anybody have an experience with these two?
steven

 

A problem I had was a faulty wastegate spring. Wouldn't boost past 6.5 psi no matter what. Even with the upgraded exhaust.

 

Until I see a dyno over 309 whp ill save my money and stick with 300 whp on my greddy.

 

mysql when are you going to the dyno again?

you should be around 350-360whp at 11psi right?

 

I don't know what I will dyno at, and I do not want to guess at it.

There will be a few changes from when I last dynoed:

1. AccessPort instead of int-x
2. Mazsport ignition instead of OEM coils.
3. Full 3" exhaust instead of full 2.5" (both catless)
4. Increased PSI.

I can tell you for a fact there is a dyno of the 3071R over 340 whp on the RX-8. We also know this is a 475 hp turbo, so someone trying to say this turbo cannot do 350 whp is ridiculous.


Having had both turbos, I can tell you the GReddy is not only prone to dying due to the journal bearings, but it also generates a lot higher charge temps.

I have not seen a single greddy turbo car that has dynoed 300 whp, and can make use of 300 whp for daily driving. It's simply beyond what the turbo is capable of due to the high PSI required to make it happen.



What do you think will happen when I hit the dyno again? 308 whp?

Also, I'd like to not only see your 300 whp dyno sheet, but I'd like to hear what kind of fuel and psi you had to use to make it happen. Just a gentle reminder - we know the flow rates for that turbo, so don't embarrass yourself by making up numbers.

 

The 340 hp car is on a dyno dynamics dyno.. OBVIOUSLY thats going to put out huge numbers, they do for everything.

Second of all i dont have a stock greddy turbo its an upgraded mazsport turbo.

When i get my car tuned by scott i will gladly show you my dyno numbers, I just find it funny that everytime you have your car dyno'd its some excuse why it didnt make more power.

If i recall correctly you said you had a clogged fuel pump before.