Boost questions for a rookie. I'm trying to school myself:
08-14-2001, 08:34 PM
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Boost questions for a rookie. I'm trying to school myself:
What is the spec'd boost on the stock system? Is this average or peak?
When aftermarket tuners offer a 1.0 bar chip, is this average boost? What is peak if that's average? Are there spikes?
Besides amount of boost, what other parameters are adjusted, and what are the adverse affects of changing these parameters?
When aftermarket tuners offer a 1.0 bar chip, is this average boost? What is peak if that's average? Are there spikes?
Besides amount of boost, what other parameters are adjusted, and what are the adverse affects of changing these parameters?
08-14-2001, 09:13 PM
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Some answers..
What is the spec'd boost on the stock system? .5 bar or 7.25 psi.
Is this average or peak? This is peak (not to be confused with spikes)
When aftermarket tuners offer a 1.0 bar chip, is this average boost? No, peak. 1.0 bar is 14.5 psi.
Are there spikes? Yes. What they can go up to, I think 1.3bar or 18.85 psi.
Besides amount of boost, what other parameters are adjusted, and what are the
adverse affects of changing these parameters? Fuel to air mixture. Advancing the timing. Affects- needing higher octane. More $$ for gas from digging into the boost. HTH
Is this average or peak? This is peak (not to be confused with spikes)
When aftermarket tuners offer a 1.0 bar chip, is this average boost? No, peak. 1.0 bar is 14.5 psi.
Are there spikes? Yes. What they can go up to, I think 1.3bar or 18.85 psi.
Besides amount of boost, what other parameters are adjusted, and what are the
adverse affects of changing these parameters? Fuel to air mixture. Advancing the timing. Affects- needing higher octane. More $$ for gas from digging into the boost. HTH
08-14-2001, 09:13 PM
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some answers:
boost values are quoted as average boost pressures under WOT. The stock system runs between .8 and .7 bar (which is ~11.6 to 10.2 psi). There will be peaks in the boost due to taking your foot off the throttle quickly.. the engine slows down but the turbo is still makes lots of boost for a few moments.
The other things tuners change are primarily the advance (or retard) of timing and the fuel map (which directly correlated to injector duty cycle). Fuel maps can cause the most damage if done wrong. Running too rich is OK and many ECUs will put the injectors always on during WOT. Running too lean can cause problems. For one, you can burn things up that way since the combustion chamber doesn't get much of a chance to be cooled by the incoming fuel/air mixture. The fine line here is that you want to burn the perfect amount of fuel for the incoming air (O2 sensors help the ECU gauge how well it's getting the mixture right).
The other things tuners change are primarily the advance (or retard) of timing and the fuel map (which directly correlated to injector duty cycle). Fuel maps can cause the most damage if done wrong. Running too rich is OK and many ECUs will put the injectors always on during WOT. Running too lean can cause problems. For one, you can burn things up that way since the combustion chamber doesn't get much of a chance to be cooled by the incoming fuel/air mixture. The fine line here is that you want to burn the perfect amount of fuel for the incoming air (O2 sensors help the ECU gauge how well it's getting the mixture right).
08-14-2001, 09:20 PM
#4
Re: Boost questions for a rookie. I'm trying to school myself:
8-9psi or so (assuming you are talking bi-turbo 2.7)
spikes - hopefully not if all is working well
1 bar - differs from chip to chip need to look at vendor mapping. Includes greater possibility of spikes. 1 bar would be the preferred max but most have spikes and variations at different rpms.
In general more fuel and air. What can happen - more power/heat. More heat more power things can break. This is assuming the chip is properly programmed to boost fuel as it creates greater boost etc.
GIAC chip does a great job of handling all the parameters. All you have to do is drive.
spikes - hopefully not if all is working well
1 bar - differs from chip to chip need to look at vendor mapping. Includes greater possibility of spikes. 1 bar would be the preferred max but most have spikes and variations at different rpms.
In general more fuel and air. What can happen - more power/heat. More heat more power things can break. This is assuming the chip is properly programmed to boost fuel as it creates greater boost etc.
GIAC chip does a great job of handling all the parameters. All you have to do is drive.
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