LT1 Fuel Regulation, LT1 knowledgables please

[sled_dog]

I just bought a set of fuel rails for my LT1 intake, comes with a stock regulator. Now should I upgrade to an aftermarket regulator? Is the stock one vacuum referenced? If not does anyone make one that is? This is going on my 383, with as of right now unknown injectors(likely SVO 24lbs, stock 24s, or LS1 28s).

 

[89fullsiz]

Is this an LT1 with an LT1 PCM? Or is it a gen I with a modified LT1 intake? Assuming it is a LT1 with LT1 computer, then the computer will handle it, it is not vacumm modulated. You can get adjustable regulators but unless its a 93 speed density the computer will adjust the injectors to negate whatever changes you made as it relearns. Only LT1edit or tunercat can adjust your fuel trim tables which your going to need to do anyways.

The LS1 injectors are also rated at a different fuel pressure than the SVO's or even LT1's, you can't go wrong with some 24 lb SVO's assuming this is a low end mild build up, 30's usually aren't too much for a 383 but that is in a F-body or vette that gets spun up alot more than I imagine the K5 will.

Hope that helps, my LT1 is a little rusty and my SBC knowledge is forgotten so if its a Gen I I don't really know. I'm pretty sure I'm going to be going with an LS1 when the TBI motor gives up on me.

 

[sled_dog]

This is a modded LT1 intake with TPI. Whenever I build a buggy or my next project, it will be Gen III.

 

[Lonnie P]

All LT1 engines have a vacuum referenced regulator. I have many of these & they all have one.

The LS1 after '98 did not have a vacuum reference as the regulator was relocated to the fuel tank.

Chances are you do not need an adjustable unit unless you have many mods. As stated above they are often compensated for by the computer negating any change. You can richen the mixture with an adjustable regulator, but the PCM will remove excess fuel at part throttle. The LT1 PCM can add fuel at full throttle based on lean part throttle mixtures, but it never subtracts at full throttle. Most LT1's are too rich at full throttle anyway, so you likely do not need one if stock. In your case there is no substitute for computer tuning.