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Discussion Starter #1
Hi! I've heard that TBI can be "tuned" to a certain extent by installing an adjustable fuel pressure regulator. My question is this, how different of a change can the regulator "make up" for? Only CIA/ exhaust mods? Or as crazy as a mild cam or heads?
I know that TBI can be properly tuned by flashing a new chip, but if the regulator works for some changes, I'd like to pursue that route first. Thanks.
 

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As power levels rise injectors are open longer ,and longer.
Turning up the pressure shortens duty-cycle back down ,basically..
 
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At smaller throttle angles, it can also improve atomization (depends on the injector(s)), which could improve MpGs.

It does work better if the tune is 'made aware' of the changes, however, especially at extremely low injector pulsewidths (4th gear cruising, decelerations, etc).
 

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Discussion Starter #4
How would one know what to set the pressure to? I'm assuming just checking the plugs?
 

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Turning up the pressure shortens duty-cycle back down ,basically..
The PCM will adjust to the pressure you set. It is not going to change the amount of fuel delivered for a given engine load.So you put out money and time and the PCM will just adjust the Lbs/Hr right back to the same point as before you started.

This only helps if your injectors are "maxed out" and your modified engine needs more fuel..

How would one know what to set the pressure to? I'm assuming just checking the plugs?
If you go too far the PCM will have trouble at idle and start up.
 

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Basically only practical place would be at the dragstip. You disconnect the O2 sensor, clear your memory and you pretty much are changing the 'jet size' as if it were a carburetor. And find what gets you the best times.

Any normal driving, like Z said, puts you into closed loop. PCM adjust via integrator and block learn functions. And negates any changes. It even extrapolates those 'adjustments' and uses them for open loop fueling.
 

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Discussion Starter #7
Ok, I think I understand now. I Forgot about the closed loop operation! I guess chip tuning is the only real way.
 
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Yeah, anything you throw at it to change air breathing, changes the volumetric efficiencies across the map. The first table to be address after the changes. They you go for optimizing fuel and spark.
 

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Instead of flashing your chip you may consider this. DynamicEFI There is a member that had one for sale and may still have it. WTB would be the place to go, maybe.

Mark: Snowman-33
 
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Instead of flashing your chip you may consider this.
DynamicEFI
There is a member that had one for sale and may still have it. WTB would be the place to go, maybe.
For pre-LT1 stuff, tough to think of a better deal than
Dynamic EFI
even if you have to buy it brand new.
 

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Discussion Starter #11
Instead of flashing your chip you may consider this. DynamicEFI There is a member that had one for sale and may still have it. WTB would be the place to go, maybe.

Mark: Snowman-33
How have I never seen this? That would be perfect.

Though I couldn't tell if it's an entirely new ECM, or a mod to the existing one.
 

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How have I never seen this? That would be perfect.

Though I couldn't tell if it's an entirely new ECM, or a mod to the existing one.
You can do it either way. Send yours in or buy it outright. I bought it after considering shipping. It was so minor that it just made sense to me to get one, being in Oklahoma put me about midway. I paid $450. On a side note. Depending on what I find out about using a Holley Sniper and the EBL. I may be selling my EBL.

Mark: Snowman-33
 
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