Hey guys, I read five7kid's bible stickied to the top of this board, but I am still unsure of the fuel pump issue. I am planning on swapping my 2.8MPI for a SB350 that I built for my Cutlass (which ended up being entirely too much body work), and he says that I should plan on removing the electric in-tank pump to make room for my mechanical pump, but I read in another thread that it is ideal to use both the electric and the mechanical, provided that the mechanical has a return. What do you guys think? If I have to remove the existing pump, what is involved? This is my first engine swap going from fuel injection to a carb, but I am interested to see how this 90 RS Camaro will perform. My Cutlass ran 14.21 with the factory 2.73s in it, and I cant wait to see what the motor will do in a car that is nearly half as heavy.

 

get a block off plate for the mechanical pump and get a fuel pressure regulator that has enough ports for your carb and an extra one for a return to the tank. example, my holley dp has two inputs so i needed a three port regulator (four if you want to run a gauge there)to use the in tank electric pump.

in order to use the mech pump you would have to get a older carb car pickup, drop the tank, and switch them.

 

I thought this was going into a 90 RS??

You'll be losing around 3-400 lbs TOPS, unless you've been doing ALOT of lightening.

Don't expect any kind of "radical" ET difference; maybe somewhere on the order of .3 sec. A nice kick, but not gigantic.

I'd suggest getting the sending unit out of a carb gas tank, and using the mech pum, and no electric. You wont have the ECM in there to properly turn the elec pump on and off, so it's best to just ditch it. You could also in theory use a regulator (Mallory 4309 I believe is the part #) and the elec pump and no mech at all. But IMO the mech pump is the better way to go. All around, less trouble in the long run.

 

The curb weight of the Cutlass is nearly 4600 lbs, and the RS is under 3200. Finding a sending unit from a carbed vehicle...how's the swap-a-bility here? Can I use the one from the Cutlass, or will the parts not line up...stupid OLDS...I was thinking about just rewiring the electric fuel pump like jwfirebird was saying. I'm just trying to avoid the hassles of having to drop the tank. Thanks for your help guys!

 

You can use the in-tank pump as is, with the Mallory 4309 regulator - you just won't have the pump priming when you first turn key, which isn't a problem since you are now carb and you have bowls full of fuel instead of injectors waiting for a supply.

But - sooner or later you'll have to change out that in-tank pump anyway - it's not that hard (just time consuming), but it will have to be done - I have done it on both my 1990 and my 1992 - takes 1 day with no help.

 

No, the Gutless tank is different; so the "sending unit", which includes the pickup tube, is also different. And it wouldn't be possible to swap it without dropping both tanks, regardless.

Your Gutless doesn't weigh that much; and your RS weighs ALOT more than that. You're in fantasy land with those numbers. I'd expect the Gutless to weigh around 4100-4200 lbs, and the RS to weigh closer to 3500-3600 like everybody else's. A definite difference, but nowhere near as radical as you seem to have convinced yourself. Unless of course your Gutless has 400 lbs of stereo stuff, and your RS is gutted and has a glass front cap and a Lexan back glass or something.

 

Gutless...hah. She was alright...could be worse. Could have been a 5.slow...thanks for the insight fellas!

 

fellas......i want to add an electronic pump to push more fuel up to my TBI motor.
will this damage that crappy TBI injector setup?

has anybody done this?....good or bad results?!?!?

 

Please keep posts to the topic of the original thread.

Check the TBI forum for pump recommendations.

 

I like having manual control, thats why i did it this way. as far as replacing the pump everyone on this site says the pumps don't last but ive never had to replace one in this car. ill admit i don't drive it very much but ive had the car for 11 years and i don't think the previous owner did it either.

 

five7 kid was your post intended for me?
just wondering about the boundries.