NOS 5177 vs. 5176 what's the difference?

[Camaro_58]

Well, aside from the $200 or so, what makes one emissions legal and the other not. And, where can I get away with the 5177 kit?

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Red 96 Z28, A4, 3.42 gears, K&N CAI, Hypertech air foil, Hypertech PP+ w/scan, GMS MAF, B&M Super Cooler trans cooler, IAT relocate, DRL conversion, MSD 6AL, Flowmaster American Thunder Cat-Back, FLP Headers

[Injuneer]

Wellll....

The 5177 is for LS1 engine. It sprays through the MAF and relies on the PCM to respond correctly and add the extra fuel via the injectors. There is no in-line fuel booster pump supplied. I think the stock fuel system limits it to about 125HP max.

The 5176 is for the LT1 engine. It puts nitrous in front of the TB, after the MAF, and relies on a small pressure regulated stream of nitrous applied to the stock fuel pressure regulator to boost fuel pressure. The higher fuel pressure increases flow through the stock injectors to supply the extra fuel. The PCM is not involved at all. The kit includes an in-line booster pump to allow the system to reach the 85-90psi rail pressure required for 150+HP. There are, in general, more parts required for the 5176 kit. The big price difference, however is accounted for by the in-line fuel pump.

So.... 2 different systems for 2 different applications. The 5176 is not emissions legal. It is available in a "5176-EO" version that is CARB-EO ceertified. The only difference between the 5176 and the 5176-EO kit is the inclusion of an electronic WOT switch on the "EO" version, which prohibits the system from being activated under part throttle conditions where emissions are monitored and regulated. The switch is mechanical on the non-EO version.

The fact that the 5177 is not shown as an emissions legal system means either they didn't bother to submit it for approval, or they know it won't pass, and didn't try.

But the "emissions legal" issue is moot... the 5177 is for LS1's. Unless you'd like to try and spray through the MAF, which a few people have successfully done on the LT1.

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Fred
94 Formula A3: 381/TH400/N2O
Detailed Mod's List
11.513@115.59 on motor; 11.162@127.67, 1.643 60' on a 125-shot. Going with a 275-shot this year