Custard

Hi Guys

i have a pretty much stock twin turbo 7, still running the sequential setup with some reliability and bolt on mods. see signature for details.
What i would like to know is, what to do next to get more power and boost while still remaining sequential?im running 12 psi currently on the base mod maps on the PFC and would like to extract more power/boost.
1. to run higher boost, do you need to upgrade the seals
2. can one put a more modern or ball bearing turbo cartridges into the current castings to increase air flow..like a GT28RS?
3. porting waste gates??
4. street porting/bridge porting??
5. what else??

what do you think..im a noob and would appreciate some guidance from those who are getting really good power from the sequential setup. my cars is setup for track use and not drags.

thanks

Greg

4CN A1R

iTrader: (6)

porting seems to be a popular way to get some decent power...the stock twins could prob only be able to handle 14 psi max..people have had different results for more or less than 14 though. i dont think you would need anything more than a street port for the power your trying to puch out. there are alot of things that can be dont though, its up to you

i dont think porting your wastegate would increase hp. just prevents boost creep and spiking

ProjectD

iTrader: (15)

1.no
2.no
3.not unless you are experiencing boost creep
4. not unless your motor is tired and needs a reabuild

I would suggest upgrading your:
intake
fuel injectors (if you plan on staing with the stock twins then 4x 850cc injectors should be enough.)
An ignition amp
you might even look for an efini y-pipe.
You mentioned you have an epgraded exhaust, but you didn't mention if the whole thing was replaced(dp,mp.cb)

And last but not least(actually the most important part) A GOOD TUNE!

Just my 2 pennies, hope this helps

3rd Gen Jeremy

I'm making 331 to the wheels with the twins in sequential form. I'm not sure what upgraded exhaust means. Do you still have the Cats? DownPipe?

I would put an intake on there if you haven't done that yet... it doesn't say anything about it in your sig.

Other than that, I would upgrade my injectors and turn the boost up. I'm running 15 psi all day on the twins and they handle it just fine. Make sure you get a tuner to do this for ya. You're probably pushing the limits of safety using the base map.

You'll be able to get a lot more power / $ by doing that rather than pulling the motor and porting it. You're gonna pay for a rebuild if you do that. Read $$$

Bottom line, either way you go, you're gonna need a tuner to set your ECU up correctly. If you try to do it yourself, you're gonna be getting that rebuild I was just talking about. You'll be surprised how much power a good tune can extract from your car.

A piece of advice though, if you do upgrade the fuel system, go big enough so you can support high horsepower when you want it. I've been running the sequential twins and I like the power but if you're a car guy like I am, eventually you're gonna want some more power once you get used to what you've got. I'm about to go single and luckily I put the big injectors in there so I can support just about any hp level I want.

dgeesaman

iTrader: (7)

No. Some guys running huge power use stock seals. Now if your engine is getting low on compression, going up in power may push you to the point of needing a rebuild, but wear is the issue not the seal type.

M2 used to make ball bearing turbos but no more. BNR will do them in stock housings and get you to 400hp. Any other twin turbo upgrade will be custom.

This is done on stock turbos when run with very high flowing exhaust and intake. It is done to stop boost creep, and usually happens when a person removes the main cat and installs a straight pipe. With a cat-less exhaust and aftermarket intake and cat-back, boost creep is usually going to happen.

Increases flow for more power. Best done when rebuilding an engine. Most folks will not pay to tear down a perfectly good engine just to port it and put it back together again. Porting will prevent passing an emissions test and increases noise, so be watchful of that if your regs are strict.

In the FAQ thread under "advice" is a great roadmap for producing more power. Focus on upgrading the fuel supply and getting tuned for more boost. You should get 14-15psi out of stock turbos with the right fuel supply.

Dave

ProjectD

iTrader: (15)

oh yea, and It would also be a good Idea to upgrade the radiator

phillip.ma

if your going to start pushing more boost its prob best to also look into a bigger intercool. SMIC or FMIC, your going to more cool air to cool down the beast.

for me, the intake didnt do much... i guess youll start seeing more power when the car tries to suck in more air but at this point youll see only a few HP from there. same goes for the exhaust unless your running a DP/HIFLOW/CATBACK setup or a straight pipe setup.

i mean it all depends on your budget... for me the first thing i did was install all bolt-ons and a FMIC with a single turbo. increase fuel injectors and get iridium spark plugs. add a MSD Ignition setup and was happy with that. most people dont understand how much power is gained by losing weight so if you can try to strip some weight off thats not needed if its not your daily driver.

Custard

Thanks guys for the info and advice. just to answer a few questions raised:

1. intake now consists of 2 cone filters
2. exhaust upgraded with MP,DP and is straight through with no CB
3. running the PFC base "mod" map and not the standard base map, so hopefully im safer than previouly thought for now at 12psi.
4. going for BNR's doesnt seem viable for my geographical situation.

i think ill start with a good tune at 12psi and go from there. was told the car was making about 250hp-260hp on the wheels, but have nothing to prove this other than a bench mark kill against an M3 and a C32 AMG recently .

i have 2 ports on my throttle elbow to add injectors. how does this compare to upgrading primaries and secondaries.

thanks for the heads up on the "advice" thread in the FAQ, that paints a good enough picture too.

Greg

Specter328

iTrader: (2)

You should really get a cat-back on there or you are greatly risking boost creep and spike. This means you will need a new motor since it'll blow. A high flow cat is also not a bad idea.

Bonestock

Hose clamps for everything. New radiator and a programmable ecu or a tune.

dgeesaman

iTrader: (7)

Or if you like your exhaust setup as-is, just port the wastegate.

Dave