Sluggish and Reaching Boost 'early'

Hey, sry bout the lame subject line but couldnt think of a better way to describe it...
Lately my car has been feeling gutless unless I give it boost and whenever I drive, I'm always getting up to boost when I dont want to be, ie my rpms are below 3000 or I'm cruising on the highway and reach a slight incline.

Could something be malfunctioning, or is this a sympton of any problems down the road? I know the explanation sounds goofy at best, but its the best way I can describe it. Thanks guys... /ubbthreads/images/graemlins/worthy.gif

 

Do this.

 

sounds like your timing is not advancing or is not set correctly at base of +5* with the plug grounded

 

I'm going to have to go with retarded timing as well. That will make it spool faster (more exhaust heat) and have less power at higher RPM.

 

^bingo^

 

Quote:
That will make it spool faster (more exhaust heat)

/ubbthreads/images/graemlins/dunno.gif What does exhaust heat have to do with the turbo spooling? I think you mean more exhaust gases, the temp. doesn't matter unless you start talking about thermal dynamics.

 

sooo, at idle, whats a good timing measurment? in degrees? and what about at other rpms?

is that a stupid question?

 

Quote:
Quote:
That will make it spool faster (more exhaust heat)

/ubbthreads/images/graemlins/dunno.gif What does exhaust heat have to do with the turbo spooling? I think you mean more exhaust gases, the temp. doesn't matter unless you start talking about thermal dynamics.



Actually it IS heat that spools the turbo, not exhaust velocity. but that is Thermodynamics and complicated. look at it this way, its like a studderbox, if the mixture is burning when the exhaust valves are open, it will be burning out through the manifold and turbo, creating expanding gasses (and HEAT)thus spooling the turbo quicker.

As for the timing setting, with the plug grounded, its 5 degrees BTDC, without it grounded at idle it should be at 8* BTDC. check it with a timing light.

 

Flow and heat are related, and both have a large impact on how fast the turbocharger spools.

Put your turbo behind your muffler, and tell us how it spools. The flow will be the same, but the spool? Not so much /ubbthreads/images/graemlins/wink.gif

 

Sry to rehash this, but having kind of similar problems. Doesnt the ecu advance/retard timing anyways, so what does changing the base timing do as far as driveablility is concerned? Also one of my wires on my CAS looks pretty chewed up, like its barely still attached. Will this cause 'sluggish, boost early' problems? Newb question...well I sure am!

 

[jepherz]

PV=nrT, yo. Why else would you retard timing to build more boost? Heat matters.

Our cars have no crank sensor, so when you set up your "base" timing at 5 degrees BTDC, it is syncing it up with the ecu. At idle, the ecu runs at 8 degrees, which is the sync point, plus 3 degrees. If you retard your timing by bumping the CAS back, it will still add on the 3 degrees because it assumes you have the base adjusted to 5 degrees.

 

[jepherz]

Quote:
sooo, at idle, whats a good timing measurment? in degrees? and what about at other rpms?

is that a stupid question?



Search for our timing map and that will tell you everything.

 

true.
Studder box is rpm based, but the anti-lag systems on WRC and the like have as much as -15 degrees between shifting, and/or off the throttle to keep the temps up to get instantaineous transient boost response.