SiH

Hi All,
Ok, I know W/G porting is covered lots - and i've searched and read a lot, but not found the exact answer i need...
I'm awaiting my car to arrive from Japan, and have been collecting bits for it. Power mods already fitted are:

Unknown exhaust
Hardpipe Kit (Although not strictly sure this is power related!)
99 Spec Twins

I have here waiting to fit:
Apexi twin intake kit
HKS 80mm frontpipe
Silenced Midpipe/decat
Power FC
*cough* XS power SMIC *cough* (look, it was very cheap, and is still an improvement over stock - no comments! )

Now, I'm aware that a midpipe may cause boost creep issues, but the fact it's a silenced midpipe may cause sufficient restriction to overcome this.

However, there doesn''t seem to be much info about boost creep from people with the 99 spec twins - does anyone have any experience/know if this is still an issue with them? As the 99 spec car runs more power from the factory due to upped boost, i'm wondering if the wastegate port is an different from the factory on the 99 turbo pack?
Any ideas anyone?
TIA
Si

MrNizzles

iTrader: (5)

Wow, all those mods would definitely add to the effect of boost creep if you were using stock twins for sure. '99 spec, I'm not sure, so I would like to know what this adds up to as well. I wonder, but I really doubt BNR's would need to be ported, least I hope not... would seem a waste otherwise.

4CN A1R

iTrader: (6)

you will most likely have creep. i'm pretty sure the wastegates from the 99 spec are nearly the same as the reg twins. so either porting the wategate or putting the restrictor plates in the exhaust is the only solution...if you are running a strait midpipe.

look inside the midpipe you have. just use common sense, if you can see strait throught then there is no restriction. if i were you i would just watch your boost gauge under boost. i have talked to some guys on the forum that are sporting midpipes and they dont experience creep. no need to port the wg if your not having a problem

SiH

The midpipe is a silenced one, so there is a slight restriction - it's a straight through type, bu tthe baffles still intrude slightly on the pipe diameter
I'd prefer to not add restrictors on top of that, so it looks like i'll add this to the list of things to do before i take the car to get it mapped!
Better buy myself a dremel...!
Cheers all

4CN A1R

iTrader: (6)

the only reason boost creep occurs when a midpipe is installed is bcause the flow is increased so much. if the flow is cut back enough, then you wont have a problem.

and as for porting your wastegate. i would not recommend usuing a dremel unless you have some crazy rough/sharp carbide bit. otherwise you will be at it for hours

cp1

a dremel works great fyi, just use a blue stone bit meant for ferrous material and it works quick too. i use it all the time now instead of my die grinder cause its faster and less noisy. and i dont have to start my compressor!

Prophet7000

I used a dremel with a tungsten carbide bit to port my wastegate. It took me approximately 2 hours to complete, but I was being very finicky.

gracer7-rx7

iTrader: (16)

I get some creep on my 99 twins running an open exhaust. I have not noticed a difference flow wise between a straight mid pipe and a resonated one in actual driving.

Trout2

iTrader: (5)

Since they are not installed, it would be wise to go ahead and port the w/g and not have to take it apart later.

Jack

SiH

Cheers all for the advice - unfortunately they are already installed on the car - but if it's going to creep i need to sort this before it gets mapped
Ah well, in at the deep end i suppose! Time to research removing the turbo pack!

matty

i never understood the logic of opening up the exhaust to simple put restrictor plates in. what a waste of time and poor advice.

gracer7-rx7

iTrader: (16)

me neither. that is why i installed a metal cat in my mid pipe. at least the restriction does something useful like decrease the exhaust stink.

SiH

FWIW, me neither! Hence wanting to port the w/g rather than install restrictors

SiH

lol, is that random abuse aimed at me?! Friendly chap, aren't you?

4CN A1R

iTrader: (6)

thats for that pointless comment, i consider it more as his only options then poor advise.

ptrhahn

iTrader: (9)

The wastegate from the '99's is not the same AFAIK. I've got them, and a ported motor with open exhaust, and they don't creep more than maybe a half pound here or there, which is about the best you could hope for anyway.

matty

how is it pointless? unrestricting the exhaust simple to re-restrict it is just dumb. others agreed....so tell me....how was it pointless?

aoc007

iTrader: (5)

rxcited2 has full boltons with series 8/'99 turbos and he put an unresonated midpipe on, no creep at all with 14psi and even cold nights. It baffled me but I assume the series 8 turbos have a larger wastegate then. If they're already installed on the car try it I think you'll be fine.

matty

some cars get creep and some dont. i dont think anyone has figured out why. so you cant make a conclusion that your buddy's 99's are the reason why he doesnt get creep.

XxMerlinxX

iTrader: (2)

I've also read more than a few threads where people stated the '99s didn't need porting like the US Spec twins did. I've also read where people went in and opened them up a bit more anyway, so since they're on the car already, I'd just wait to see if you need anymore work done to them.

RX7LINK

iTrader: (3)

why a restrictor plate? so people that are lazy to port the wastegate will have lesser chance of boost creep at cold ambient temps and still shoot big-*** fireball out of the exaust when you shift at redline...

not the best solution.. but "IS" an option..

Monkman33

iTrader: (28)

Ok, for those bashing the restrictor plates: Pay Attention, Learn, THEN Speak.
Scenario break's down as follows:
He has the 99 spec twins already installed.
He has a bunch of parts he owns... and wants to put to good use.

What are his options?
Install parts and NOT port wastegate (risk of boost creep)
--If boost creep, what options?
----Option 1: remove turbos and port wastegate
----Option 2: Install inexpensive restrictor plate

or

Install parts AND port wastegate (requires turbo removal)
--If boost creep, what options?
----Option 1: Install inexpensive restrictor plate

The thing about a restrictor plate in an open exhaust is this:
You will still make more power than you did with the stock components.
You are able to TUNE the amount of restriction.
You are now able to use your go-fast parts
You are able to keep it at safe boost levels

I know it does seem counter-intuitive, but it is actually very smart. You are removing weight, you are removing heat (stock cats... bleh!), and you are now giving yourself some control over your exhaust restriction.

Installing a catalytic converter is the same thing with a drawback: You cannot adjust how much restriction there is.

Besides, air flow is more restricted at high volume than low volume, so he will still see gains. Being able to tune the exhaust restriction on a turbocharged vehicle (in an instance where the wastegate cannot support the needed capacity) is an invaluable tool. Ask any knowleddgeable engine tuner.

Adding more fuel or tuning it for higher boost is not the answer. The restrictor plate is a tool that you can use to tune for maximum performance within a given set of parameters in a forced induction setup.

/soapbox

I am just sick of seeing people get ragged on when they are actually bringing up a good point. If you do not understand something, then ask. Don't make an assumption and then be negative for no reason.

And for those that will get pissy at me for telling them to stuff it: Take a look at the options he would have. You tell me a better way to use all of his parts, and NOT require the purchase of possibly Hundred's of dollars of more parts, or even thousands. And saying "tune for more boost to use the flow, instead of restricting it" is not an answer. That is a completely different goal.

My point:
Before making a direct statement, ask yourself whatt he goal/intent of the OP is.

4CN A1R

iTrader: (6)

dude...did you even read the advise i gave the guy?? i will post it below so you can get a double take...

why cant you just leave me alone, and stop being a little bitch

matty

i made no assumptions and i still think its dumb....

matty

laziness....thats a good trait.