SFI fuel injection setup for 4.1L

[CTX-SLPR]

Why? If the short block is the same (which I do believe it is) and the thermostat is on the back in the FWD orientation but you turn it around it goes in the front? I know it would be goofey with the way its mounted but I'm not seeing why it absolutely won't work. The man with the Geo (I'm bad with names) has an LC2 intake backwards on his 109 engine due to hood clearance, he doesn't seam to have a problem. The heads are symetric so there is a coolant passage at both ends.

 

[joedirtmcd3]

so if I blocked off the coolant passage in the front of the heads it would flow to the rear of them, instead? This all seems very iffy to me and without the manifold and heads in front of me I can't be sure...

 

[CTX-SLPR]

Why would you block it off? The intake probably has dead pads where the other water passages are. I'm actually tapping the dead pads on the back the LC2 intake to add flow to the back of the intake to help cool the chambers down.

 

[joedirtmcd3]

i just meant theoretically. I wouldn't actually block it off. What i meant by it is this: If I flipped my carbd manifold the other direction, would the coolant flow to the back of the heads instead so that it could come up through the thermostat and recirculate?

Basically I dont understand the coolant flow through the heads. It seems as though since the rear coolant passages are blocked off that it serves as a dead end for coolant flow

 

[CTX-SLPR]

The coolant gets pumped into the block by the waterpump where it cools the cylinder barrels first before rising around them through the deck into the heads where it circulates forwards to the crossover in the front of the intake and the thermostat. If its hot enough it goes back into the radiator for cooling. If you turn the manifold around you instead are pulling the hot coolant off of the back of the heads away from where the pump put it in. I think its actually a better system which would lead to less cylinder to cylinder variation since the shortest path through the coolant system is now across the bank of the engine rather than into the block and up the front waterpassages into the cross over.

I'm not a professional engine builder so I could be wrong in going from therory to reality. In all honestly you could use a Hot Air intake and build an adapter elbow to move the throttlebody to a more usable place if you wanted though they aren't very good as far as flow, especially in an NA application. I'm working on using the computer system off of a L67 supercharged (or L36 NA) Series II motor to run my intially NA 4.1 but I'm short quite a bit of pieces and I doubt I'll have it running before April so thats little help for the now for you.

 

[joedirtmcd3]

That makes more sense now. So basically If I wanted to achieve better cooling characteristics through my heads I could block the passages in the intake up front and have the heated coolant exit to the radiator from the rear coolant passages, furthest from the water pump. This would basically be the same as reversing my current manifold or installing the SFI manifold facing the rear of the engine.

 

[CTX-SLPR]

If you wanted to use that intake, you'd have to figure out how to get the Throttlebody to clear the cam sensor which shouldn't be hard. You'd also need to make your own upper radiator hose out of probably molded elbows and straight pipe to get it pointed in the right direction. EFI wise you would need the following reproduced items
Harness, Cam Sensor, Coil Pack, Ignition module, injector harness, ignition harness (Caspers)
Coolant Temp sensor, Idle Air Control motor, crank sensor, knock sensor (Parts store)
Mass Air Flow Sensor (I suggest a translator from Full Throttle and late model MAF off of a Camaro), EFI balancer with reluctor rings, injectors (used or something like that)
For a fuel system you will need either an inline external high pressure pump and not run the tank below like 1/4 tank, a sumped stock tank for an external pump and a bit more leeway on how far down you can go, or a custom built tank with an internal pump and baffling. As far as I know, again no expert on chevettes, there is no EFI application to rob from. It is possible you could find a factory tank with roughly the same size and filler location and use it though like some A-body (64-72 Skylark and siblings) use the 89-96 B/D-body (Caprice, Impala SS, Roadmaster, Fleetwood) tank since its rear fill and symetric.

 

[CTX-SLPR]

That makes more sense now. So basically If I wanted to achieve better cooling characteristics through my heads I could block the passages in the intake up front and have the heated coolant exit to the radiator from the rear coolant passages, furthest from the water pump. This would basically be the same as reversing my current manifold or installing the SFI manifold facing the rear of the engine.

I wouldn't go as far as better cooling in fact, I'm a physicist and I deal lots with theory and don't have a lab rat motor yet, but I don't see why that manifold you have wouldn't work. Your big problem will be fuel system and wiring, I don't see why what you have now won't work mechanically and this coolant thing isn't a big deal as I see it. Worst case is that since its designed for a water pump on the backside of the intake is that you have to route the bypass hose to the backside of the block to hook it up and get creative with the heater stuff. If worse came to worse with the bypass you could plug the port on the back of the intake and the waterpump and then drill small holes in the thermostat to allow slow bypass so your pump doesn't cavitate.

 

[joedirtmcd3]

I have a 15gall summit fuel cell. I'll have to look at the stuff again next time i go home...

 

[texasturbo]

The way the water flows thru the engine determines how effective the cooling will be. looking at the top of the deck on a short block v6 buick. The front of the engine has no provisions for the water to come up into the head. The back of the block does. On an intake like the one for the LC2 engine. water flows thru the water pump, thru the cylinder block to the back, up thru the heads and thru the heads to the front. Then thru the passage in the intake to the thermostat and out to the radiator. There is consistent directional water flow thru the engine. On the intake for a front wheel drive application. The flow is the same, but the intake is designed to flow the water back to what would be the back of the engine. They did this so you wouldn't have a radiator hose coming from the very front of the engine. Your pics illustrate this very well. Turning a front drive intake around for a rear drive application will create hot spots at the front of the heads since the water will not flow thru the head. Instead it will go thru the block, up into the head, but then directly to the intake/thermostat and out to the radiator. Why the intake works for the guy with the GEO is it only runs for a quarter of a mile at a time and not on the street...

 

[joedirtmcd3]

If what you are saying is true, wouldn't that imply that my carb'd intake manifold would create these same hot spots since the coolant flows right out the front of it rather than to the back?

**Edit- I think I see what you are saying. Because there are no provisions in the carb'd manifold for coolant flow in the rear, the coolant must pass from the back of the heads to the front in order to recirculate through the radiator. However, since the FI manifold has the coolant ports in the front, reversing it would cause the coolant to bypass the front of the heads and instead flow right up and out of the intake manifold. So in order to counter this, the coolant passages would have to be blocked off in the FI manifold and some sort of cutom setup would have to be made. This would probably be pretty risky and not every efficient either.

CONCLUSION: Run these SFI manifold facing the rear of the engine or don't run them at all. Now where can I find a grand national intake manifold...?

 

[texasturbo]

No...... Take your carb intake and turn it around...........now where is the water coming out????? The back....does this mean the front of the head has no water flowing thru it??........ Yes....

Find the water ports on the FWD intake.. Place it on a motor like you would for a RWD application.... Where are the ports in relation to the head?? Where will the water flow....????? not thru the head... Study it closely and you will see. use your current carb set up to visually see how the water flows thru the engine. Start with the water pump, block, head then intake.. Follow the flow for the FWD setup, then turn it around and put that intake on a RWD set up. it will not flow the same... hence you will have little to no flow at the front of the head on each side.. it will heat soak, possibly blow a head gasket or worse....

This will not work well if at all for the street car....

 

[texasturbo]

Exactly.. Sorry didn't see your edit...

 

[CTX-SLPR]

I wish to appologize for leading you wrong, I didn't see that the water passage was in the back of the intake like I though and the witness marks on the block in my pictures, aweful cold to go look at it now, made me think thier were the large water riser passages in the front of the block. I now agree that this one won't work without some creativity on the water passages to make sure you cool #1 and 2 sufficiently.