Laust Pedersen

What do you think about my new instruments? Does the installation leave a little to be desired? Don’t worry it is temporary.

In order to properly enhance and control the boost pressure with minimum after market equipment (expense), I have always felt a need to know the pressures in the 1) manifold (boost pressure), 2) intercooler (pressure to wastegate control) and 3) exhaust (before turbine).
I had initially suspected (and now partially confirmed), that the limiting boost factor is the wastegate and not the K26-6 or -8 turbos, so I have modified the wastegate, so it doesn’t open on exhaust pressure.
This modification makes it difficult to control an intended opening due to the intake pressure and furthermore I have “popped” a couple of hoses between the turbo (compressor) and the throttle body. For debugging and tweaking purposes, I have decided to measure the three pressures mentioned above at a number of rpm’s under steady state conditions (no acceleration or deceleration).

I plan to post at least a few of the results in the near future, but first here is the instrumentation at idle. The gauges (underneath the radio) from left to right are pressures 1) to 3). The gauge to the right actually goes to 60 psi.

Laust

BoostGuy951

So, what have you found out? Give us some numbers!

johne

Ditto on that one, give us some numbers Laust. No teasing allowed.

John

Laust Pedersen

Easy, cool down, read the whole thing, especially "I plan to post at least a few of the results in the near future", which probably is in a week or two.

Laust

Ahmet

I'm certainly looking forward to looking at your results.
Ahmet

Laust Pedersen

Here are a few words more on the pressure measurements I am taking on the intake and exhaust. The pickup points, two of which are shown in the photo, are 1) close to the KLR unit for manifold boost, 2) just before the Accuboost boost regulator (cycling valve removed) which is directly connected to the banjo bolt on the inlet pipe to the intercooler, i.e. intercooler pressure and 3) standard test tube on the cross-over exhaust pipe.
As mentioned, the steady state set of pressure data are taken by driving the car with one foot on the brake and the other on the accelerator attempting to keep a constant rpm and going through manifold pressures in approximately 5 psi steps. The rpm’s chosen are 2500, 3000, 4000 and 5000.

The wastegate has been modified so it now is virtually closed all the time. This essentially means, that I can destroy the engine with my right foot, if the (manifold) boost pressure goes much beyond 30 psi which I can achieve at 3500 rpm and about 50% throttle (yes 50% ) and possibly anywhere else from 3000 to 5000 rpm. Danno and I are still in the chip optimization process, so at this point I am not using too high boost above 5000 rpm, since pinging is very difficult to distinguish from mechanical noises. In this version of the chips I am detecting pinging above 25 psi, but the issue is also being provoked by running 89 octane gas. As it is, I have another 2 degrees timing retardation available through the FQS switch.
The data are collected by taking pictures of the gauges, reading them off-line and entering them into an Excel spreadsheet.

The data uncertainties/inaccuracies come from a number of sources, such as boost pressure being very sensitive to throttle position (a few mm of accelerator pedal position easily corresponds to 5 psi) and the camera takes a little time to focus (delay between intended and actual picture). With all this said, I believe that most data are within ± 10%.

Above 15 psi the boost comes in extremely fast, an effect that may be related to the water injection, which occurs at 13 psi. I am struggling with a good explanation for this , while enjoying the effect .

Laust

Laust Pedersen

Here is a snapshot of one of the effects from my overly eager K26-6, namely 28 psi @ 2500 rpm (the gauge needles are only on their first rotation ). Granted, it takes forever to get to that pressure, but I have seen 20 psi @ 2600 rpm through 5th gear.

NZ951

Ummmmmm you are a mad scientist, no other words to describe you.

BoostGuy951

So when will we be able to see pressure numbers in the exhaust manifold? I am intersted in seeing the boost pressure to exhaust manifold pressure ratio. What kind of gas are you running that 30psi on?

I have to ask.... whats with the neon pink intake manifold?

Laust Pedersen

NZ951
“Ummmmmm you are a mad scientist, no other words to describe you.”

For some reason you are not the first one who have said that and true, I like to experiment for worthy goals, in this case unreasonable power with simple means .
To take the drama out: I am systematically pursuing a goal and trying not to blow up my engine in the process.

BoostGuy951
I have half of the numbers and should have the rest for posting this weekend, maybe earlier.
As mentioned I am running 89 octane (gas is getting expensive) and at this point “only” target 25 psi. Higher pressures will likely come later and to combat pinging I can go to better water injection control, more timing retard and higher octane.
“Neon-pink”? No, it is “HiPerCrystal™ Raspberry”, sounds much better, which I found
here .

TurboTommy

Your exhaust back pressure gauge goes to 60 psi, you said? That won't even be enough (it will be pegged). You will have horrific back pressure!

If you're going against basic turbocharging engineering principals, you wouldn't need any gauges for testing because it will be a gauranteed poor showing.

Unless, of course, you are a mad scientist and you just want to see how bad the numbers can get.

Laust Pedersen

TurboTommy:
“Your exhaust back pressure gauge goes to 60 psi, you said? That won't even be enough (it will be pegged). You will have horrific back pressure!”


You wanna bet?
But before you do, remember that I may have a priori knowledge by having peeked at the data already acquired.

Crazy Eddie

Thanks Laust
It looks like I just found my paint for the intacke and cam tower !! Yea ....
regards
Ed

Laust Pedersen

Ed,
You are welcome. I later learned that their prices are not competitive with powder coating (slightly higher temperature and more complicated application technique), but don’t recall the price difference.

Sam Lin

Sam