Outer Limits 4x4 Board

I have a 4.2 turbo gu and want to know if i put a couple of washers between the vacuum housing and the turbo does the turbo spin up earlier or later?

It takes the same time to spool up, Just ups the boost a touch, don't be a tight ass but a boost controller and gauge

where do you put the boost controller?

In the little vacuum (not really its pressure, i know its diesel) line that comes of the pressure solenoid but its a waste of time unless you wind the injector pump up

I've got a GU turbo diesel and i've been thinking of doing this. Can some one tell me if it will make's them go much better. Say if i put it up to 12 or 14 psi

Thank's

so then a slight increase in boost with 3mm washes, this is more boost at lower revs then.

numbnuts wrote:so then a slight increase in boost with 3mm washes, this is more boost at lower revs then.

NO, it probably won't give you any more boost at lower revs. All you are doing is changing the peak pressure that the wastegate opens at. So your max boost will increase, but the boost pressure at lower revs will be dependent of compressor (turbo) efficiency, which you are not changing.

Rainman - as mentioned above, increasing boost won't make much of a performance difference if you don't increase fuelling as well.

ISUZUROVER wrote:

numbnuts wrote:so then a slight increase in boost with 3mm washes, this is more boost at lower revs then.

NO, it probably won't give you any more boost at lower revs. All you are doing is changing the peak pressure that the wastegate opens at. So your max boost will increase, but the boost pressure at lower revs will be dependent of compressor (turbo) efficiency, which you are not changing.

Rainman - as mentioned above, increasing boost won't make much of a performance difference if you don't increase fuelling as well.

Yea yea he make word better than me

To get the turbo to spool up earlier you need to remove restrictions in the piping. The most effective place is the exhaust and more specifically the dump pipe (this is the small pipe that joins the turbo to the exhaust.) The next area is the intake piping from the turbo to the intake manifold. Let the air expand directly after the turbo for the exhaust and for the intake pipe there are 2 trains of thought. 1. do the same as the exhast and increase the piping size to 3inch asap after the turbo and 2. keep the piping the same size as the turbo outlet as this will maintain the velocity of the airflow. Simple fact is that if you reduce the pressure imidiatly after the turbo, both on the intake and exhaust sides, you will reduce the amount of effort need for the turbo to spool up, hence boost will come on earlier. As for power. I wound my factory turbo up to 14psi, wound up the fuel pump to suit and had an intercooler (not a very effective one) and this increased my power from 98 rear wheel Kw to 116 rear wheel Kw. I also had better fuel economy on the highway.

hey all

All i did was disconect the small bit off pipe that runs
from the turbo to the wastgate. runs 16 psi, bump up the fuel
a bit and its all good plus get a 3" exaust. all the power i need
for now

I didn't think it was wise to run no wastegate at all?

Don't you run the risk of boost spiking without one?

I bought one of these off eBay... TurboTech

Good reviews... some info on here too

Would be better off buying one of these and setting it to 16psi than running no gate

toughnut wrote:Simple fact is that if you reduce the pressure imidiatly after the turbo, both on the intake and exhaust sides, you will reduce the amount of effort need for the turbo to spool up, hence boost will come on earlier.

This works for the exhaust side only, not the inlet side.

quick60 wrote:

toughnut wrote:Simple fact is that if you reduce the pressure imidiatly after the turbo, both on the intake and exhaust sides, you will reduce the amount of effort need for the turbo to spool up, hence boost will come on earlier.

This works for the exhaust side only, not the inlet side.

You miss quoted me. I also stated that there are two schools of thought on this, with the other being to keep the piping the same diameter as the outlet to give you more velocity rather than pure volume

toughnut where u measuring boost now at the turbo still or at the inlet manifold, if your getting 14 at the turbo now and expanding ur pipe to 3" after and running a intercooler, your prolly gettin a few psi pressure drop by the time u get into the inlet manifold.

I always measure at the manifold. You don't get any of the variables that you have mentioned. Having said what I have in my previous posts I have maintained the same size pipe the whole way through but I do have a 3inch outlet for my turbo

I already have the three inch exhaust and dump pipe. so are you saying to increase the other pipe going across the motor to 3 inch and if so can i use mild steel tube for this?

It depends on what you have and what you want to achieve. For you're application I'd suggest that you maintain a similar size tube, maybe increase it slightly but the best thing to do is to make the pipe as straight as possible and take out as many bends as possible as well. Just think of any little thing that will slow down or disrupt the air flow. The main reason I suggest to increase the size of the pipe slightly is that you can't take out all the bends and if you don't increase the size of the pipe then the bends will slow down the airflow and therefore effect when boost comes on and for how long it comes on. The actual length of your exhaust has a little bit to do with where the peak power is delivered in your rev range ie a shorter pipe will bring peak power down slightly lower. A good exhaust tech can get some good gains just playing with this.

I have the exhaust from beudafest in qld. and what about the mild steel?
also my mate has a gq and his pipe over the motor is quite larger than my factory one.

Mild steel is OK but you need to use mandrel bends just like your exhaust. Press bends will restrict the flow.

thanks for your help ill give it ago while on holidays next week.

The best thing to do is put your truck on a dyno. It'll be the best couple of hundred dollars you spend if they know what they are doing.

toughnut wrote: You miss quoted me. I also stated that there are two schools of thought on this, with the other being to keep the piping the same diameter as the outlet to give you more velocity rather than pure volume

No I didn't. The other side of the inlet that you are talking about is under pressure, and a bigger pipe will not reduce this, just give a greater volume to compress. It is entirely different to the exhaust side, which is the side that drives the inlet side. You can not acheive what you are talking about, as in the exhaust side, the hot exhaust gas is under pressure, and expands quickly as it cools, giving the drop in pressure, however on the inlet side, the low pressure side is on the air filter side, and you will not be able to drop the pressure btween the turbo and manifold with a bigger pipe, maybe a poofteinth at first point of throttle, but only because there is less boost pressure in there, nothing any dyno or seat of the pants will ever pickup.

apparently mild steel flakes from where the steel is heated when welded and you can get flakes from surface rust. i reckon it's crap so i used mild steel.

Could someone in the know comment on the above about running no wastegate at all (I just know it is a silly idea and they have a particular purpose as for specifics ). When I was talking to a really old school diesel mechanic mate of my old mans who specialised in mack truck mechanical work. He was like "a waste what ?! narr narr spit on it and piss it off" Basically was saying that you don't need it. Why would he be saying this ??

JemmyBubbles wrote:Could someone in the know comment on the above about running no wastegate at all (I just know it is a silly idea and they have a particular purpose as for specifics ). When I was talking to a really old school diesel mechanic mate of my old mans who specialised in mack truck mechanical work. He was like "a waste what ?! narr narr spit on it and piss it off" Basically was saying that you don't need it. Why would he be saying this ??

There are plenty of turbo diesels without wastegates. In these systems the boost pressure is limited by fuelling and the governor (rev limiter). I wouldn't advocate removing/disabling the wastegate from an engine/turbo designed with one though.

if you are going to dissable the wastegate..... you will actually lose performance..... unless, as stated, you get it dyno tuned to match the boost you are running. THEN, you need to get a pyro to keep an eye on the EGT.

quick60 wrote:...The other side of the inlet that you are talking about is under pressure, and a bigger pipe will not reduce this, just give a greater volume to compress.

Due to friction losses, the pressure will reduce from whatever value it has at the compressor outlet to a lesser value at the inlet manifold. Increasing the dia, will reduce the pressure drop, particularly as toughnut explained if there are many bends. Some intercoolers are better than others for the same reason.

quick60 wrote:...the hot exhaust gas is under pressure, and expands quickly as it cools...

No! Where do you get your gas theories from? Ever seen a hot air balloon inflated by cooling the air?