goalguy02

iTrader: (3)

Had an old set of turbos that are bad so I pulled the wastegate housing off and ported it. There is still a lip for the flapper to seal against. After puling the turbos and swapping housings, I get no boost and the engine acts like it struggles to reach 3500 rpm and won't go higher. Wondering if I ported too far? There was enough metal left as a lip to seal against. Just banging my head over it right now. All the rods and vacuum lines are connected but obviously something is wrong. Any ideas would be good and happy holidays!

Anthony

JDM-AREX7

even with an open wastegate the engine would run like an NA and rev up (but with no boost :P) you propably hooked something up wrong in the vac lines !!! What mods do u have on the car? what do you mean with struggles? Backfires? misfires? cuts out?

RotaryEvolution

iTrader: (30)

+1

go over everything you moved around while swapping the turbos. even a full open wastegate will allow the engine to still reach redline smoothly and even generate a small amount of boost still. sounds like you disconnected something like the oil metering pump and the car is stuck in limp mode.

goalguy02

iTrader: (3)

Thanks for the feedback and reassurance guys. In all my infinite wisdom I overlooked the obvious and checked vacuum lines, solenoids, etc. Didn't bother to check the crossover coupler that I never tightened. Secured that and all is well. Every time I see someone having a basic, easy fix issue, I swear to myself Ill never be that noob and overlook the obvious....foot in mouth.

Anthony

NeoTuri

iTrader: (2)

It happens.

Once on another car, I had removed and inspected virtually every control component in the engine bay searching for the source of a problem before discovering (by accident) that I had only hand-tightened the intake manifold bolts.

goalguy02

iTrader: (3)

Hahaha

jkstill

iTrader: (11)

Lesson learned: do not install bolts/nuts without tightening.

Exception: when the component to be attached is still off the car.

DaveW

I own, maintain, and drive a racecar. In my experience, the # 1 cause of on-track problems is something that was put in finger tight, and in the rush to make the schedule, was never fully tightened.

So, jkstill is absolutely correct. NEVER install ANYTHING half way unless you somehow put a flag on it so you can't forget to finish the job.

p00shy

iTrader: (3)

Im so newb. does anyone have a diagram of where the wastegate is so i have an idea of what everyone is talking about??

please?

goalguy02

iTrader: (3)

You have to remove the turbos and disassemble them to get to the wastegate.

oyvindjs

iTrader: (4)

First, some info.
You have two types of wastegates, the internal and the external wastegate.
An internal wastegate is integrated in the ehaust turbine housing of a turbo.
An external wastegate is a separate unit you fit to the exhaust manifold.
A wastegates job, is to ventilate exhaust past the turbo when the boostpressure is closing in on a set boostlevel, so the boostpressure stays at that set level and doesnt produce more boost. A turbos job is to force air into an engine by utilizing the exhaust, and for this to be efficient, it has to force more air into the engine than what comes out of it. In order for this to be acheived, the ratios on the exhaust and intake turbine wheels are not identical. Without a wastegate to ventilate excess exhaust when set boostlevel is reached, it will just continue to force more and more air into the engine until it all goes boom.

The FD has a notoriously small wastegatehole, so when upping the boost on a standard internal wastegate, it cant flow as much exhaust as it needs to(cause boost is upped), and this causes the turbo to overboost due to boostcreeps and spikes. So, to prevent this, you must port the wastegatehole when upping the boost over a given level.
The FD is boostrestricted from factory by giving it a restrictive exhaust. SO, just by going from a factory exhaust to a full aftermarket from turbo and back, will remove the backpressure the stick exhaust created, and this will cause the engine to flow air so much better, that the stock unported wastegate cant keep up. This leads to boostcreep, and then the boost is upped on a stock brain, the fuel map cant keep up, and it goes lean, starts to knock bad and goes boom!

here, you can see a VF39(similar design to FD) exhaust housing. you see the exhaust turbine wheel, and you see the flap next to it. this is the wastegate. This door opens when the engine starts to close in on a set boostlevel. Behind this door, you can use a dremel tool or similar to increase the holesize abit, but not so much that you prevent the door from sealing the hole when you arent peak-boosting.


here you see an, well two actually, external wastegates(some use one, some use two) sitting on the manifold. It does the same job as the internal, its just better, easier and you can swap em out if they are too small. Also, most single turboes comes without wastegate.

goalguy02

iTrader: (3)

For clarification, you don't need to port the wastegate when increasing boost. You need to port it when you perform intake and exhaust modifications as the engine is able to flow more air through the turbos but the small wastegate opening is not able to flow enough air to fully and reliably control boost. Other option is to install a boost controller that will allow you to start opening the wastegate sooner than the stock system allows.

p00shy

iTrader: (3)

Wow thanks so much for clearing that all up. preached.

so would it be possible to set the boost really low, sayyy 7psi and then have an open exhaust? so creep would push it up to 10-11?

goalguy02

iTrader: (3)

You could remove the two pills in the vacuum lines to the wastegate and precontrol. And your boost pattern would be around 7-5-7 then creep from there.

dgeesaman

iTrader: (7)

It's a very poor band-aid to a simple problem. If you want band-aids, install restriction in your exhaust.

goalguy02

iTrader: (3)

Agreed do it right the first time.

oyvindjs

iTrader: (4)

this cant be preached and said enough times... Cutting corners will only cost you more in the long run.... and contribute to our engines allready poor reputation created by people doing it wrong and blaming everything else but themselves...