Is This Symptoms Of A Boost Leak?

[InterCooL]

hey guys

i just chucked a fmic on my r33 (stock otherwise but zorst and coilpacks)

i'm running stock boost, it boosts perfect, holds it well, etc

it idles well and generally is great

but when i floor it, it looses heaps of power outside of first gear

its not sudden, it just doesnt go fast in 2nd, 3rd or 4th. i thought it might be rich and retard but its not a sudden cut. its just behaving crap

i've checked my cooler clamps quickly and they seem perfecct

is what i describe symptoms of a boost leak or am i totally wrong?

any other tips? i dont have a compressor so its hard to do a pressure test...

cheers

[cheez]

are u running an aftermarket ecu? when did u put the coils in and if at the same time as front mount has it been tuned?

also might be worth grounding the boost solenoid, give u bit better boost? also does the car feel laggy in the other gears?if so might be an issue with the crank angle sensor. did u knock it at all when installing frnt mount or move it by chance?

got a pic of ur engine bay so we can see the set up?

[Race_Bred]

If you have a boost leak you would hear it on boost, it would be a louder then normal shhhhhhh and u may not reach max boost,

if all clamps are sweet and you dont have a leak then you might just have to get a boost controller and turn up the boost, installing the cooler does add a bit of lag and change how the car accelerates

[siddr20]

I sorta had the same problem today..

went for a drive.. gave it some, then car behaved weirdly after a while.. wasnt going anywhere, and 1st, 2nd, 3rd felt like what you described.

So anyways pop the bonnet, and i could hear a hissin noise..

im like yup a leak somewhere..

Check your hoses going to the bleed valve..

I re did mine.. car is fine!! goes harder

[InterCooL]

thanks for the input guys

i found a post by KeyMaker describing how to do a test for leaks, and turns out i actually do have one. so i'm getting a new silicon hose (kit one wasnt long enough...) and gonna do it again. i just went ot the servo with my tools at midnight and they didn't ask anything

here's the test;

1. take your pod and AFM off.

2. use a baked bean can (full) and put it into your rubber intake pipe (assuming its still the stock one).

3. tighten up the hose clamp onto the tin creating a seal.

4. Open the throttle body with a brick on the accelerator pedal, so you can read pressure on the boost gauge.

5. take a hose that is plumbed into your intake between the turbo and the plenum or off the plenum itself (you could probably use that nipple you installed).

6. Get an air compressor and pressurize the system through the hose and get someone to read the psi on the boost gauge. you only need about 5psi. you can use the compressors at the servos.

7. Listen for a leak. and use the soapy water in the spray bottle to find exactly where it is.

[WogsRus]

yeah except don't go over 50 psi, as teh can explodes, i tried it with a plastic high pressure cap for plumbing, still exploded at 50 psi, but the manifold leak is a lot harder as the engine needs to be in such a position so that the vales are closed and not allowing air to go through the engine and out the exhaust. Anyway have fun.

[InterCooL]

yeah except don't go over 50 psi, as teh can explodes, i tried it with a plastic high pressure cap for plumbing, still exploded at 50 psi, but the manifold leak is a lot harder as the engine needs to be in such a position so that the vales are closed and not allowing air to go through the engine and out the exhaust. Anyway have fun.

yeah when i tested it, the air was passing out the exhaust but i had enough volume of air to pressure it up a few pounds (very briefly) and i found the leaking hose. i think its fixed...

what angle would you need to get the crank in in order to keep all the intake valves closed?

here's a piccy rb 25's apparently like sausage and vegetables

[Birnie]

That's gotta be one of the most helpfull things I've ever heard!

You should make a little DIY "boost leak identification" thread...seriously

The can is a crack up too

Are you pressurizing thru the wastegate feed?

Edited June 21, 2007 by Birnie

[InterCooL]

i was pressurising through a vacuum line in the intake plenum (with the throttle open)

however this was leading to most of the air being pumped through the engine and out the exhaust

perhaps if i had the throttle closed, and pressurised it through the wastegate pressure line, it may work better. however with my fmic, there is no wastegate vacuum line adapter, so i might have to go and get on made up, and hopefully this will show my boost leak... as i have found out i still have one..

[moonus]

srsly, i thought my car had a boost leak as well cos it didnt go anywhere through 2, 3 ,4 and 5. the boost guage was still hitting boost but the car was just revving like it was in nuetral with no speed. i think a lot of people, like myself think its a boost leak when its really a slipping clutch

Edited June 25, 2007 by moonus

[Craved]

Drill a hole in your can and pressurise it through that --- and use an empty can