Converting LS1 EFI to N/A
 

I have an 01 SS and I'm currently in the middle of my build. I'm putting in a LQ4 and boring it out to a 408 with a P.C. I've been entertaining the idea of putting a blow thru carb on and N/A it rather then the injection. The reasion I'm thinking of doing this is because my cost of tuning and parts could be cut by 4000k (minus a different hood) where I'm from. (non U.S). Carbs can be tuned real nice these days, and all the major engine builders when doing dyno shoot outs are still using carbs.

What are everyone's thoughts on this?

Thank you.

Not exactly sure what you're asking - I'm presuming "P.C." is a ProCharger, though I'm not certain - which would mean that a "blow-through carb" makes sense. On the other hand, a N/A carb I'd think would be more finicky than a properly tuned EFI (even with speed-density) setup, but then again "your mileage may vary".

If it's a street-oriented machine, well I don't know what the environmental regs are for Canada, so I'd say it's technically doable. I just can't believe that a carb setup would be really $4k cheaper than tuning the existing EFI setup - especially if you swap your existing LS1 stuff onto the shortblock you got.

Hi,

Sorry yes P.C means ProCharger. Well, I think the savings would come in the tuning department (so I'm told). I already have the L92 heads so I was going to put on a FAST 102 with matching t-bod, bigger injectors, a MAP sensor depending on how much boost I decided on, FAST Fuel rails etc. Most of that I wouldn't need along with less tuning correct?
Perhaps I should look elsewhere for tunning? I'm just trying to gather some info, I'd like to stay injected though, I just hear from all the old school car guys their point of views and I respect that. But that doesn't mean it's what's best fir these LS motors. Quite frankly, the whole reason I wanted and bought an SS is for the new technology.

Thanks for replying.

To be honest, I think sticking with what the motor was engineered to use would be the best idea - seems like downgrading it to a carburetor would do little more than reduce your power and increase your fuel use.

Though arguably, the evaporative cooling a carb provides does give a bit more HP.

But as for cost, you're still going to have to get a carb-specific intake manifold vs. the FAST, as well as a new harness to wire in a new ignition controller, as the OEM box will miss having the injectors to control.

OTOH, you could start with 60# injectors, a 2-BAR MAP, and a L92 intake to go with the heads, tune for speed-density, and be 85-90% to where the carb setup would be for MUCH less hassle. Add a ProCharger to that, and you'd still be ahead of the game, IMHO.

The caveat to all this is that the machine is to be a mixed-use machine, rather than a track-only toy, where the carb setup would have fewer downsides.

But that's my simple opinion.

I honestly would stick with the injection. Supercharging a carb setup is tricky and finicky at best. Carbs work on a vacuum principal and the best way to SC a carb is via wet compressor such as the old 671 blowers you see sticking out of a hood with a pair of Holley carbs sitting on. Wet compressors can have intake detonation issues if not set up properly and that can be catestrophic to the engine and blower. Pushing air into the top of the carb will not offer the same result since the air pressure will be greater in the venturi than the float bowl. The LS series engines use a dry manifold design and the injectors spray a fine mist directly onto the intake valves. Evaporative cooling is minimal but atomization with the stock and better yet with aftermarket injectors is excelent. Supercharging an LSX engine IMO should be done with a dry manifold.

Massey

like everyone has been saying here, it would be best to go with the F/I that came with the car. Swapping to carbed with a procharger is not making this engine N/A.

You might save some money in the bank, but the trouble and time you will put yourself through might not be worth it.

Yes you are right, my mistake on the wording. I was meaning a carb set up vs a injected one. Thank you for your comment.

Great feedback everyone, thank you very much, it's greatly appreciated!