boost control switch 940 B200FT

Hi, Can anyone help? I have increased the boost on my
volvo from 7.5psi to about 12.5psi using a bleed valve
on the wastegate pipe.
On full throtle acceleration in 1st and 2nd I sometimes
get a kick it's like
taking your foot out and then back on the throtle.
I understand that there is a boost control switch/valve
that shuts down the fuel pump if the boost is too high.
The curcuit diagram shows it but the question is WHERE is it?
Some have said that it is near the pedals teed off the boost
guage pipe, mine isn't. Does anyone know where it could be?
This mod makes the 940 a prety quick car!!

Clive.

 

Not vrry quick for long: this probably isn't fuelstarvation but detonation

 

No, the engine will take 20psi. It is definatly fuel cut off.

The switch/valve is documented but I just can't find it's
location.

Clive.

 

Try asking on
www.turbobricks.com
http://forums.turbobricks.com/



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

 

I second that. The B230FT engine will NOT take 20 psi for more than a few
moments, and in any case you need some safety precautions in place before
you go upping boost, like an AF meter and accurate boost gauge. You may be
hitting fuel cut off, but more likely you are experiencing compressor surge.

There is alot to know.

Learn the flow map for your particular turbo, and keep within it's
parameters when you are considering a G Valve or bleed to raise boost. Go to
T-Bricks and begin to learn how to safely raise boost, or you will be
learning all about rebuilding detonated engines shortly.

RS



"Boris Mohar"

 

Sorry your not listening. B200FT. With squirters.

It's probably the stongest engine Volvo built.

Iv'e a lot of experience with tuning engines.
I was runnerup in the national drag racing championships twice.
I built the engine up from 230hp to 600hp relyably.

But that was old technology. no knock sensors or oxygen sensors.

I just wanted to know where the boost control switch was located
on the car.

Regards, Clive.

 

Clive.....what you are lookin' for may be
electronic or "in the chip"......you may need to
up grade or change your chip settings on the
940t....call ipd and chat w/them.....they can give
you a 2nd opinion.....or...try www.turbobricks.com
and look for a thread on boosting the 940...lots of folks
will help over there...good luck !!

 

Rusty - can you describe what compressor surge feels like or what would
bring it on? I have exactly the same symptoms on a '99 V70R AWD that
*is* running at 20psi boost with an IPD exhaust and ECU. It's a strange
feeling.

-K

 

Dig here

http://forums.turbobricks.com/search.php?searchid=467195



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

 

The control switch is behind the drivers knee panel, under the steering
wheel. But, there may not be a switch there at all. Some models didn't
include it, so in that case, it is probably surge. Check Turbo bricks for
specific models. If there IS a switch there, you can carefully dig out the
glue, and re-adjust the screw to cut off later, but...take care.

RS

 

Surge happens when the compressor forces more air into it's turbine side
than the turbine is capable of handling. For instance if you turn up the
boost via a bleed or G Valve, and are asking for 16 hypothetical lbs from a
turbo that can really only handle 12 psi, the compressor will be forcing
more into the turbine side (or surging) than that turbine can handle. The
effect is that the car seems to be stalling, or briefly lurching. It can
repeat a few times in quick succession. If you can get a hold of a
compressor map for your specific turbo, you can see what the safe and
reliable PSI range for your turbo is. You may be able to get 20 lbs right
now, but if you are running out of fuel, or getting compressor surge, it
might be time to turn it down a bit before you melt a piston, or get a
bigger turbo.

It's a rare b230ft that will reliably run 20 psi all day without some fairly
hefty mods, although I know guys who run around 18 without heavy mods. It's
do-able for sure, there are crazy Swedes who get 700 hp, setting it up as a
drag motor. But get ready for some serious $$ if you want to extract that
kind of power from a 4cyl Volvo block.

I have no knowledge of a B200 engine. To be honest, I never heard of that
engine before tonight, and thought is was a typo. I continue to learn.

RS

 

I think you have fuel system LH 2.4, which has the overboost function
built into the ECU program. The ECU compares signals from the air mass
meter and compares it to engine RPM. If it "thinks" there's too much
air going in, it turns the fuel pump relay off. Other fuel systems have
the pressure switch you're seeking.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Thanks - that make sense. I talked to IPD about it a little while ago
and Scott reassured me that 18-20psi is fine on the 99 R motors. Seems
like it's pushing the edge though - especially with the crappy CA gas
that I have to burn.

Same here.

-K

 

I have discovered (for my self and my driving style)
18-22 psi is just too much power for my 1993 940t...
the rear tyres always break loose, and the car is fast
.... so fast, I didn't feel very safe drivin' it like that...
all the time ... I would not let other folks drive the car, as
you had to "know what you are doin'" to keep it under control
and out of "dicy situations".....so, I turned down the boost to
a more confortable setting...I think I hit 8-12 now...It seems
nice, smooth, and strong....my only weak point is/was
the tranny......a buddie of mine who is tweeking his 93 940t
in a "big way" put in a bmw tranny w/some upgraded plates
and clutches...he told me it works like a dream...smooth, and
no blow ups w/all the extra torque and power.....the b230's are
a great platform to build up on...that's for sure......(imho)

 

I've got my head round this now.

I will try a few things and let the group know what happens.


Mant thanks all.

Clive.