Nicely done software. Do you plan to make it available?

 

Thanks. I'll probably release a mostly-complete version within a week or so. I want to fix a few bugs & add a few more features first. At least there's enough there now to get some meaningful comparisons of runs.

 

I was thinking that running the boost too high could cause detonation. Is the fuel cut triggered by too high of a boost level or is it something else? And why is it more likely to happen when it's colder?

 

Colder weather means more dense, so you would likely be hitting fuel cut more often.. But detonation and the timing getting pulled because of it is another thing to take into consideration with high boost.

the lowered restriction lets the turbo spool faster, and also "free-er".. Keep in mind that any boost controller (Not including Closed loop electronic boost control) are calibrated to what is there.. so the max boost level you get is a factor of the restrictions on the system. Eliminate a restriction (in the exhaust), and boost will go a little higher. Its usually not a huge change, but in this specific case, the restrictor pill is calibrated to allow a given amount of "Bleed" of the boost signal so that the wastegate opens at a preset value.. With the turbo spooling faster it will also build boost faster, and the rate of bleed will also change slightly, and with a slightly lower exhaust restriction, the turbine can spin easier and therefore affecting the peak boost along with spikes in boost..

And high boost isnt really a dangerous thing.. Its the ability for the fuel system to compensate and maintain a fuel ratio that doesnt cause allow detonation. The ECU Maps, Fuel Injector (fuel system in general) capacity, air density and fuel quality will all have an effect. The easiest way to prevent problems is to try to limit your boost which in turn would kick in fuel cut (in an attempt to keep the engine from running lean by limiting RPM.. I know, fuel cut to keep the engine from leaning out seems like an oxymoron)

 

Thanks, that was a good explanation.

So is the fuel cut actually triggered by too lean AFR?

 

Has anyone thought of replacing the pill (what diameter is it?) with a slightly larger diameter. Many people did this in the WRX (replaced 1/8 connector with 3/16 connecter). It resulted in a 1psi increase max and it held full boost to redline with no fuel cut on stock ECU. It was defintely more powerful. Many people I know with WRX's still have the larger connnetor in for 15,000 miles with no detrimental effects. Just a thought.

Chad.

 

Gumpy good question

 

Yeah, I was a Wrx guy as well. The best replacement is an adjustable precision brass needle valve, which can be set to bleed pressure through at variable rates. This is not a "bleeder valve" in respect to the old fashioned bleeder valves that would bleed air to atmosphere to control boost, but instead just provides limitless variations of precision flow control.

Here's the link to industrial automations web site:
http://www.valvestore.com/

And here's a link to the Deltrol EN10B precision needle valve:
http://www.valvestore.com/endelbrasnee.html

These are only $20 on sale and are indexed with a locking set screw to ensure setting is preserved. You will have to get some brass barbs from Home depot to thread into each side. The valve store actually sells the proper male barb fittings, I just couldn't find them.......

I have one and it is a very high quality piece of hardware, and the perfect tool if you want to experiment with different restrictor settings.

Btw- I never really saw any major majic in screwing with the restrictor. It really just seems to affect the initial boost response causing more (or less depending on the venturi size) boost spike with various results in held boost depending on the engineering of the factory boost control system(FBC).

If you have the ability to reprogram the FBC duty cycle, the stock restrictor may suddenly become a bottleneck. By opening the flow a bit, you can present more volume of air to the FBC raising the overhead for purging more air allow for a higher level duty cycle allowing higher boost to be maintained. So typically the restrictor is can be particularly important when approaching boost control using new FBC duty cycle programming in the ECU.

Its certainly not a boost control tool, but really more of a tuning enabler for the FBC.

Make sense??


N10S

 

So can you use this Gtech Pro like a dyno?

 

Yeah, the Competition model displays HP & torque graphs & lets you download them to a PC.

 

Would it be safe to use Gtech's downloaded dyno sheets to tweak your air/fuel ratio off of? Meaning how accurate are the dyno graphs?

 

It's hard to say. They seem reasonably consistent, but I'm still trying to perfect my technique. It seems you have to do the runs JUST right in order to get consistent results. I do want to use it as a tuning tool, which is why I wrote software to make up for some of the limitations. If I can get something that does data logging I plan on integrating the data so I get to look at it all at once.

Consider the graph I posted in this thread. It shows a large torque difference peaking at 4500 RPM. I can tell you that this definitely jives with my butt-dyno, the pull in that range is almost ridiculous (I mean that in a good way). So I say it does have potential to be used as a tuning tool.

But then again, what the hell do I know?

 

N10S

Very nice report on how the bleeder valve works. One question though. It seems that the EVO's boost control is more sophisticated than the WRX. Doesn't the pill (in EVO) and the restrictor (in WRX) both bleed to the boost control solenoid. If so, why such different results( the WRX would hold boost till redline and would not spike once the ECU relearned vs. more of a boost spike with EVO). Did you re-set the ECU after each restrictor size change? Thanks for any imput.

Chad.

 

Here's a link to a little information thats worth a read.

http://www.autospeed.com/cms/A_0096/...popularArticle

Don't let the old car in the picture fool you, the concepts really haven't changed. Some interesting configurations, and ideas!

Btw-my earlier comments on using a needle valve are specifically as a simple adjustable alternative to the restrictor pill.The info in the link above shows using a needle valve as a bleeder tool instead.

Hopefully this info doesn't just cause confusion

N10S

 

Bigboogieman .. the gtech can read the rpms off the cigarrette llighter plug ??

Did you wire it up directly to the power supply ???
I'm having problems getting the gtech to register the rpms ..

You making your copy a shareware ??