[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Increasing boost
JOE wrote this and I'm wondering about this!!!!!!!!!
The turbo mods that I made to my 1987 5KTQ (1.9 bar) involve the following:
1) Strap the intercooler across it's width with a WIDE pipe strap, or two
if needed (depends on the length that you get) - This strap is essentially a
really big hose-clamp (you know, the metal kind)..
2) replace the intercooler - throttlebody hose with Napa Fleet-Truck hose
- VERY HEAVY HOSE - you will need two different diameters - one is about 2",
and the other is about 3" (both Inside Diameter measurements) The hoses slip
into each-other, with the smaller diameter working as an adapter to fit the
larger hose onto the intercooler end of things.
DO NOT PROCEED UNTIL YOU HAVE DONE THE ABOVE TWO STEPS!!!!!!!!!!!!
This is very important, as you can exceed the boost limitations of both
the hose and the intercooler very easily and quickly with the following
3) disconnect the frequency valve from the top of the wastegate - plug
it's line so that the frequency valve line is closed.
4) insert a T-fitting into the boost line which is plumbed into the bottom
of the wastegate. Run a hose from the T to a pressure regulator (mechanical
type, 0-15 psi provides a nice, tunable range - if your range is too wide,
such as 0-200psi, it will be hard/impossible to make find adjustments at the
lower end of the range)
5) disconnect the pressure hose from the computer (located in the
passenger footwell). Pull the hose up to your glove box, and connect a second
regulator on the hose. Route the output of this regulator to a T-connector.
Connect a pressure gauge to the T-fitting, and run the end of the T-fitting to
You now have control over:
1) Boost pressure - by regulating the downforce on the top of the
2) The computer's reading of boost pressure
By regulating the downforce exerted on the top of the wastegate, you can
effectively control when the wastegate opens (ie. more boost before
By regulating the computer's reading of boost pressure, you can bypass the
computer's safety limits.
THIS LAST POINT IS VERY, VERY, VERY, VERY, VERY IMPORTANT TO UNDERSTAND!!!
ONCE YOU HAVE ADDED THE SECOND REGULATOR, YOU WILL HAVE THE ABILITY TO
DETONATE YOU MOTOR ON COMMAND - The computer will only see as much boost as
you allow it.. if you set the wastegate regulator to maximum boost, and the
computer regulator to minimum pressure, the computer will have no idea that
the boost is excessive - HEREIN LIES THE TRICK!!!!
Once installed, you can set the wastegate regulator to 0 psi, and the
computer to 15psi, and the car will boost only as high as the spring in the
wastegate will allow it - if your spring is very strong, it may be able to
provide an overboost condition. If not, it will simply stop making power at a
certain point (probably 1.2bar).. By slowly increasing the wastegate
regulator setting, you can increase the boost pressure... Then, once you
reach the computer's cutoff (you will know you have hit this when the computer
decides to kill the ignition - usually around 1.5 bar), you can set the
computer's regulator to this pressure.... Now, you can increase your
wastegate boost, while making fine-tune adjustments of the computer's measured
boost from the cockpit (you shouldn't have to change this one very
Don't be afraid of this procedure - My friend and I have both been running
this mod on our cars for 6 months now, and there are NO ill effects - I have
adjusted mine to max-out at 13psi (1.9 bar), and am VERY pleased with the
results. There are MANY people on the Q-List who have been driving at this
level for years with no ill-effect.. Boosting beyond this level without
internal motor mods can cause a leaning-out of the mixture, and subsequent
I would DEFINATELY recommend trying this mod - the car is SO MUCH MORE
FUN TO DRIVE, with truely minimal additional stress placed on the motor..
Any comment about this one? I'm Skepitcal about this because I love my
"pilmary" car to death and don't want it to DIE on me.
Audi 200t 10v