I got the Defi BF gauges, and they're metric. I've gotten used to the boost readings, even though they're in bar.

So from the factory, I'm supposed to be running 5.6psi of boost with the greddy TT, yes ? That is about .39 bar, which is right where the needle tops out - around the .4 mark.

Knowing this, I set my "warning" light to .5 bar. HOWEVER, there have been one or two RARE times where I stomped on the throttle in 2nd gear, and saw the warning light go off. When I hit the "Peak" button to see just how high it went on my Defi controller, I watched the needle jump to ALMOST .6 bar! That's almost 8.7psi!

Is this a glitch, you think ? Or did I actually hit that much boost ? This only happened once or twice, but I'm still wondering if it has anything to do with the gauges or if they are reading true...

-slay

 

no boost controller..? you will see boost spikes then, when coming hard on the throttle. i can get mine to spike pretty high with the EBC turned off.

hth,
michael

 

The external wastgates are very solid...highly unlikely you are getting boost creep from those at 5.5psi. However, depending on gear, load, and RPM, you'r boost will vary....probably between 5psi and 5.8psi. I cant image it actually hitting 8psi+ unless there was a leak somewhere.

You might wanna double check all of your vaccum lines and make sure they are safety wired. Zip ties are a no-no.

 

boost creep is when the wastegates cannot bypass enough exhaust gas as the RPMs raise. this is why it "creeps."

boost spiking is when the wastegates do not open fast enough when WOT is applied. this is exactly what slay is describing... a "Spike"

look here for boost creep and spike: http://www.shelbycsx.com/glossary.shtml#B

hth,
m

 

Thanks for the responses, but what is the solution to this ? :0 What should I attempt to do to make sure I don't blow my engine ? Heh.

 

I still have never come close to encountering a spike of that magnitude. That's why I am suggesting checking all vaccuum lines to ensure they are tight and clamped/safety wired.

That would be my first recommendation.

 

Alright GQ, I'll do that, thanks.

 

I have encountered spikes but not as large of a magnitude as you have slay2k. I have seen my peak boost go to .48 which is roughly about 6.9 psi. As Skidazzle mentioned above, a boost controller can help even out the boost.

 

not much really to do with your question.... but...

I have the exact same setup... GReddy TT with Defi BF gauges... I think you saw them at atco right?

Sometimes when i step on the gas hard it will shoot up from a normal .4 bar to possibly .45 bar but not .5... so just check the angle you are looking at it... or record it to make sure....

 

I did record it, it's definitely over .5, something like .53 maybe ?

Anyway, I'll see about the boost controller.

 

I have seen mine spike up to 6 psi before. That's as high as it's spiked as far as I know. That type of thing is going to happen.

I have the Defi gauges as well. My have some strange glitch, sometimes after turning on the car the peaks go waaaay up. One day I randomly checked the peak level, it was above 1 bar. I would know if I hit 1 bar, because my motor would probably have a window in it now. So after messing with it I found that sometimes the peak memory get's wacked out after you power the gauges up. But you said the warning light came on while you were boosting? If so that's probably not your problem.

 

Yeah ETX, the warning light did come on while I was in gear... =\ I'm sure its nothin, we'll figure it out.

 

I wish i had problems with overboost!!!! oh well i be getting the Turbos soon enough!!!

 

Even when my Profec spikes the boost slightly, it is only for a split second. I find it difficult to find a long enough rough to fully program the auto boost control feature of the Profec. So, for example, when I set it to 8.5psi, it still tends to spike to 9psi and then immediately come down. It spikes for less than a second. I have tried messing with the gain and start boost to know avail.

 

gq, didn't ray blow his gasket this way?

 

Has Ray posted on this yet? I spoke to him on the phone, but didnt want to say anything until he formally explained what happened.


A boost spike didnt cause his issue....apparently, his Profec was setup incorrectly, so he was boosting 10psi at all times....without fuel upgrades or changes to the fuel enrichment map.

It sounds like it was accidently setup improperly......

Also, he was using the Defi gauges which read in BAR instead of PSI, so he saw like .8 BAR didnt realize that was about10psi.

Luckily, all he did was blow a head gasket....and minor cylinder wall damage.

If a boost spike occurs, it is a for a split second right when you go WOT,and then it comes back down. It is so brief, and usually at lower RPM, and for such a short duration, it doesnt cause any damage. And again..most of the time, the spike is less than 1psi...maybe a bit more.