Switching from 3.4 SFI to 3.4 supercharged/carb

[cardana24]

I am thinking about doing this switch. I started out with a 2.8 carbed 1985 jeep cherokee. From there I have added a 3.4l from a 94 camaro, and I am running that SFI. I still would like some more power from this 3.4l, it has more power than the 2.8 but it still leaves plenty to be desired. So I have picked up a Fageol carbed set up. This was previously running on an S10, so I am wondering what would be required to switch back to running a carb and supercharger? I have one supercharged vehicle currently but it is fuel injected and uses a centrifugal blower.

I know I will need to take the current manifold set up off and add the new LIM, blower, and carb. I know I will need to add a distributor back into the equation. Should I get one from an old 2.8? Or should I see if MSD has one to fit.

How about fuel? I am currently running an intake fuel pump from a 88 jeep cherokee, which is a fuel pump that is made to feed a multi point set up as the one found on the inline 4.0. I know carbs require lower fuel pressure, what would be a good pump for my set up? I would like to find another intake model that I can just replace my current one with so I can just wire in a fuel pump relay and be good to go. Then from there I am guessing I would need to go to an adjustable regulator, and since I would not have electronics controlling the fuel pressure I am guessing I would need an FMU. Which ones do you guys recommend? I am currently running an AEM adjustable regulator on my other supercharged car and I am happy with it's performance. I have run a Vortech FMU in the past and I never felt like I got a very accurate tune using different ratio discs in the unit.

How about belt length? Anyone have a good way to get that close, before I go to the parts store and by 10 belts?

What else am I missing? I already have a hole in my hood so height is not a concern.

Feel free to add and advice or recommendations on products to use.

[bszopi]

Since you already have it running as SFI, I would almost be temped to try to keep it fuel injected. You could drill the manifold for fuel injectors and make a custom fuel rail. Then you would be able to keep the DIS as well. Just use a TB in place of the carb.

Or, you could have the injectors under the TB and have them spray that way...

[cardana24]

Since you already have it running as SFI, I would almost be temped to try to keep it fuel injected. You could drill the manifold for fuel injectors and make a custom fuel rail. Then you would be able to keep the DIS as well. Just use a TB in place of the carb.

Or, you could have the injectors under the TB and have them spray that way...

hmmmmmm....maybe

We do not have any speed shops where I live so I would need to find someone that can drill the manifold and make me custom rails. I am fine re doing the wiring but making custom rails and drilling holes precise enough for the fuel injectors is not something I can do. If you know someone that can do that then I am all ears.

[geoffinbc]

Lets say you go carb. Thats no problem use the current pump it does not matter just get an adjustable bypass regulator for a carb. Aeromotive has tons.

You can go EFI by drilling the lower blower manifold if space allows. Or you could make a plate for the top of the blower with 3 injectors on each side and then a throttle body on top. This is a common solution for blowers. Fuel in the blower also helps keep it cool. You could also convert to TBI and run that in place of a carb. Then you get the tuneability and reliability of fuel injection and the off camber performance if you hit the trails.

There are no MSD distributors. There is a mechanical one found on Carb'd S-10's and Camaros with remote mount coil or the electronic distributor common to TBI S-10's and MPFI Camaros.

[cardana24]

Lets say you go carb. Thats no problem use the current pump it does not matter just get an adjustable bypass regulator for a carb. Aeromotive has tons.

You can go EFI by drilling the lower blower manifold if space allows. Or you could make a plate for the top of the blower with 3 injectors on each side and then a throttle body on top. This is a common solution for blowers. Fuel in the blower also helps keep it cool. You could also convert to TBI and run that in place of a carb. Then you get the tuneability and reliability of fuel injection and the off camber performance if you hit the trails.

There are no MSD distributors. There is a mechanical one found on Carb'd S-10's and Camaros with remote mount coil or the electronic distributor common to TBI S-10's and MPFI Camaros.

If I stuck with the current SFI set up would I be able to run with the super charger? Can my current ECM 94' camaro 5 speed ecm run the engine with boost? Would I need a different MAP sensor? Other than figuring out a way to mount the injectors what other problems would I be looking at? It sounds like leaving it SFI may be more cost effective if I can get it to run properly with the current fuel and ECM.

[geoffinbc]

Well the stock program obviously wont run it. But a modified one will work quite well. Buicks and GMC Syclone/Typhoons did it all on a OBDI ECM with SFI

[cardana24]

Well the stock program obviously wont run it. But a modified one will work quite well. Buicks and GMC Syclone/Typhoons did it all on a OBDI ECM with SFI

well I currently have the stock OBD1.5 ecm, the one that cannot be programed. Is there not a way to alter the fuel pressure via a FMU, or else use a different MAP sensor to make the OBD1.5 run the set up?

[geoffinbc]

Oh I thought that crazy ECM did not show up until 95. Well maybe go back to 93. Or switch to MPFI like the 3.1L FWD Cars I know those ECM's are easy to chip.

[cardana24]

Oh I thought that crazy ECM did not show up until 95. Well maybe go back to 93. Or switch to MPFI like the 3.1L FWD Cars I know those ECM's are easy to chip.

I have a MPFI ecm from a 3.1, 92 Cavy. I have not tried hacking into it yet though. If I did switch to that ecm could I just have a program burnt to accept the boost?

[geoffinbc]

Yup.

[cardana24]

Yup.

do you know if anyone has done a write up on doing that switch? Or do I just need the Pin Outs of ecm then match the wires up? Is it any harder than takin the MAP sensor wire and hooking it to the map sensor PIN on the new ECM (I know there is more than the MAP sensor I was just using that as an example)? Are all of the 3.4 sensors compatable with the 3.1 ecm?

Also who burns the chips? I don't have the stuff to do this.

[ghrarhg]

http://www.cruzers.com/~ludis/quadplugecm.html

Has a list for all the pinouts.

[cardana24]

Thanks for that link.

So assuming I switch over to the Cavy ECM, then what else would I need? Just an FMU? Or will the map sensor compensate for the boost. Or will I be able to get a burned chip that controls the fuel for the boost? I assume the stock injectors and fuel pump can keep up with just 5 PSI.

[geoffinbc]

Make sure the injectors are big enough and get the chip made to do the job. I am not a big supporter of add on devices to band aid the ECM or trick sensors. I always believe the ECM should handle the task. It also makes for easier trouble shooting and proper data logs as well.

[cardana24]

Make sure the injectors are big enough and get the chip made to do the job. I am not a big supporter of add on devices to band aid the ECM or trick sensors. I always believe the ECM should handle the task. It also makes for easier trouble shooting and proper data logs as well.

In your opinion are stock 3.4 injectors big enough? Where can I get a chip made for my set up?

I don't like FMU's either, but I also do not want to run lean.