Rb25det Making Boost (when Reving)

[tomtomtuning]

Hello Every one,

Some of you might know i am from the USA

I have a S13 coupe (240sx with silvia convertion)

And a S1 RB25DET

Right now I am trying to figure out this boost issue,

Where it creates boost at a stand still.

A lot of ppl say this shouldn't happen.

but some say it can.

In the FSM it say's 0* is the first mark to the left (left - to - right)

and that 15* would be the forth mark

But when set to that mark, it does not idle/rev up normal

So..when I set it starting from the mark on the right (right - to - left)

The car idles, and revs normal, and its very responsive

and doesn't hesitate like when at the other mark

but still creates boost....

Its driving me crazy, but i hope the engine timing isnt off.

And its just the ignition timing.

_________________________________________________

VIDEO !!!!!

Here you can see the boost @ a stand still.

3in downpipe stright into my 5zigen catback (no cat)

With a TurboXS RFL Blow off valve

[/b]

After playing with the timing, it still makes full boost.

Any ideas to what the issue is, or is this normal

Edited April 4, 2007 by tomtomtuning

[tomtomtuning]

Here is a picture of the motor in the car

Car Facts

S1 RB25DET

Greddy Intake manifold

Q45 throttle body

TurboXS Blow Off Valve

Front Mount Intercooler

2 1/2in Hot side (intercooler piping diameter)

3in Cold Side (intercooler piping diameter)

Walbro 255 lph Fuel pump

Z32 Fuel Filter

Stock Turbo

Custom 3in Downpipe (No Catalytic Converter)

5zigen Catback exhauist

Edited April 4, 2007 by tomtomtuning

[mad082]

does the car rev up really slowly now? is it really gutless?

if it is, you have a major timing issue. your timing belt may have jumped a tooth, or your crank angle sensor may be shagged, or worse case scenario (and this happened to a mate of mine a few weeks back) you have a broken cam.

[WogsRus]

what the fcuck. That is near imposible unless your timing is stuffed.

Does the car drive well? aldo how tight is your spring setup in the BOV, maybe the vacume line for that is not connected properly, but techincally these is no way a turbo can make that boost at no load????

[mad082]

also on a side note, i would lose the 3" cooler piping on the cold side. go back to 2.5". the fact is that cold air is denser, so that once it comes out of the cooler it takes up less space than it did when it was hot, so you would be better off with 3" on the hot side and 2.5" on the cold side.

[mad082]

  Quote

but techincally these is no way a turbo can make that boost at no load

unless you have an anti-lag system.

but my guess is 1 of the 3 things i said before. on my mates car he would make 15psi by reving the car on the spot. that was on a ca18. it would accelerate really slow (and just sitting on the spot it would rev up really slow like the timing was really retarded). we just thought the timing belt had jumped a tooth as it was overdue for a new belt, untill we took the rocker cover off and the cam was snapped near where it goes into the crank angle sensor. it still had enough pressure to spin the cas, but not all the time.

[tomtomtuning]

  mad082 said:

does the car rev up really slowly now? is it really gutless?

if it is, you have a major timing issue. your timing belt may have jumped a tooth, or your crank angle sensor may be shagged, or worse case scenario (and this happened to a mate of mine a few weeks back) you have a broken cam.

In the video you can tell (sort of) how fast it rev's up

When i set the timing to the marks on the right, it was real responsive.

but in the factory service manual, it stats that 0* is the first mark on the left.

My car seems 0* is the first mark on the right.

Can any one confirm for me, what TDC is on the crank pulley?

  WogsRus said:

what the fcuck. That is near imposible unless your timing is stuffed.

Does the car drive well? aldo how tight is your spring setup in the BOV, maybe the vacume line for that is not connected properly, but techincally these is no way a turbo can make that boost at no load????

The car is on jack stands, i am doing the brake upgrade right now.

but tomorrow i will try to drive the car some, to see how it is.

All the vacuum lines are fine, i double checked all that

  mad082 said:

also on a side note, i would lose the 3" cooler piping on the cold side. go back to 2.5". the fact is that cold air is denser, so that once it comes out of the cooler it takes up less space than it did when it was hot, so you would be better off with 3" on the hot side and 2.5" on the cold side.

The intercooler piping will be changed sooner or later.

I am going to drive the car the way it is.. for this summer

And i am building another RB25 block/head, and will be installing the built motor in the fall.

So a better much more efficient intercooler and piping will be installed then

  mad082 said:

unless you have an anti-lag system.

but my guess is 1 of the 3 things i said before. on my mates car he would make 15psi by reving the car on the spot. that was on a ca18. it would accelerate really slow (and just sitting on the spot it would rev up really slow like the timing was really retarded). we just thought the timing belt had jumped a tooth as it was overdue for a new belt, untill we took the rocker cover off and the cam was snapped near where it goes into the crank angle sensor. it still had enough pressure to spin the cas, but not all the time.

I Plan on checking the ignition timing again (CAS)

And if i can not figure this out, then i will have to pull the belt cover

And try to take a look at the engine timing.

I might also pull the rocker/valve cover to take a look at the cam's too

Edited April 4, 2007 by tomtomtuning

[Cubes]

Not sure.. To me it sounds a little dead just before it starts making boost.

like buuuuuuuuuuuuuuuuuuRUMMM

Maybe I'm used to the 3ltr and how it tends to rev a bit quicker?!?

mine goes.. bruuRUMMM

lol

[mad082]

by the look of the video, i think it may be just a dodgy gauge. it doesn't actually sound like it is spooling, and it jumps up very quick. my mates car you could hear the turbo spool. does one of your mates have a gause you could borrow?

where does they gauge read from?

[tomtomtuning]

  Cubes said:

Not sure.. To me it sounds a little dead just before it starts making boost.

like buuuuuuuuuuuuuuuuuuRUMMM

Maybe I'm used to the 3ltr and how it tends to rev a bit quicker?!?

mine goes.. bruuRUMMM

lol

The video was taken when the timing was off. before i begin adjusting it.

I will make another video tomorrow. showing how it rev's faster and smoother now.

And again, can some one confirm for me which mark on the crank pulley is 0* ?

is it the one all the way to the left, or the right.....

The stock timing should be st at 15* at engine idle of 650RPM

[mad082]

and i think you have to disconnect the TPS too.

[tomtomtuning]

  mad082 said:

by the look of the video, i think it may be just a dodgy gauge. it doesn't actually sound like it is spooling, and it jumps up very quick. my mates car you could hear the turbo spool. does one of your mates have a gause you could borrow?

where does they gauge read from?

Its a brand new AutoMeter Boost gauge....But there is always possiable it could be bad.

I will see if my buddy has another gauge.

It is connected to the Intake manifold, runs though the fire wall and to my dash

I used a crappy digital camera to record the video, so the sound might not be the best.

More videos to come tomorrow.

....

[WogsRus]

the ZERO point is the yellow marer on the pulley. Esentially if the light is on the pulley, the ZERo mark is the first mark form top, so it goes 0 5 10 15 20 25 30

[SECURITY]

my car makes boost with no load.

and its a series 1 r33 gtst. i always thought it was normal.

[tomtomtuning]

  mad082 said:

and i think you have to disconnect the TPS too.

I did disconnect the TPS....

What about the 0* mark... which one is it.. ?

[tomtomtuning]

  WogsRus said:

the ZERO point is the yellow marer on the pulley. Esentially if the light is on the pulley, the ZERo mark is the first mark form top, so it goes 0 5 10 15 20 25 30

Thats what it shows in the FSM....

But when ever i set it to 15 (starting from the first left mark)

The car seems really rough.

I guess the engin timing is that off?????

I might as well just remove the belt cover and take a look at the timing marks on the cam

To see if that is off.

[Cubes]

  SECUR1TY said:

my car makes boost with no load.

and its a series 1 r33 gtst. i always thought it was normal.

I can't say I've ever tried.

Might have to. lol

[mad082]

mine would make small amounts of boost if you just floored it (spike up to maybe 5psi) but wouldn't go to full boost.

[tomtomtuning]

  mad082 said:

mine would make small amounts of boost if you just floored it (spike up to maybe 5psi) but wouldn't go to full boost.

Yes, that i have heard about. i have had 2 SR20's before and that is what they did.. small amount of boost. but not full boost.

Tomorrow the first thing i am going to do is pull the fornt cover and see if i can tell if the timing is off on the cam gears.

And if they are.. then it looks like ill be doing some work to re adjust it....

I will update you tomorrow with what i find, and the out come.

THANKS to every one !!!!!

[mad082]

good luck.