Inliners International Forums General Discussion Engines 4200/ no computer

If a person wanted to convert a 4200 to a carb and no computer at all what is required and what kind of power could he expect? Any thoughts anyone?

Carb or EFI, you will make the approx same amount of HP.

EFI will help w/better all around drivability,more useable torque throughout the RPM range,but your total HP out put will be the same if you have your carb tunned correctly & correct size.

Most intakes from the factory,like the one for the Trailblzer/Envoy will have some short comings when it comes to all out HP,so in theory,if you design an intake for a carb correctly,you can make more HP than using the factory EFI manifold,which is usually designed for better low end torque & mid range for the most part,especially for a Heavy SUV like the Trailblazer..

So for HP, I would say if you design an intake for a carb or carbs you will be able to make more Top end HP over the stock set-up.

MBHD

Isn't the real problem the lack of a distributor on the 4200?

I saw one site where they were running an external distributor off a cog belt off the harmonic balancer but it was a racing application.

I asked the same question in the High Performance forum and it doesn't look promising. I also wanted a SIMPLE, no computer setup.

MSD has a distributor for the Ecotec that drives off the back of the cam (intake IIRC). They would have to change the trigger and cap for 6 Cyl pieces, and you would have to have a fairly large engine bay to run it off the front (as the back usually gets crammed up against the firewall). But at least it wouldn't have to be a full custom made one off part.

You could add the distributor drive to whatever you make to lock the exhaust cam fazer (the torque motor that changes it's timing).

inliner member jerry weight(spelling), has allready put a dist on the 4200. get the specifics from him. but from memory, he adds a gear to one of the cams and uses a existing hole and a s10 dist. tom

MSD has a plug and play job for the v8 gen III's igntion, when retrofitting to carb.

If the 4200 uses a simillar cam/crank sensor maybe it should work, might need to adjust the timing selections though. Im guessing.

How about a ignition driver box that would run the stock coil on plug ignition.

Need inputs from the existing engine sensors (crank trigger, coolant, map sensor) - plug it in, and hook up the ignition switch and your done.

thats what the msd does for the genIII v8 carb conversion.

all it requires is crank and cam position input though.

the box only knows when to fire when told, so I wonder just what if anything would be requires to use it on the six banger?

Actually, that would make efi control cake, Id think. Then the only concern would be fuel/injector management.

You could get away without hooking up the coolant sensor - but since its aready there and a pain to delete might as well use it. All the fittings on this engine are straight metric thread with an flange seal/Oring and some are odd ball sizes too.