Pondering the fuel delivery problem

[GretchenGotGrowl]

Obviously more air requires more fuel, and stock fuel systems have a limit. So last night I thought I'd see if the gusy boosting their SS Camaros w were having the same problem. It turns out the L99 are. They can't seem to get the ECU to make much of awith the fuel control module. At most they can get about 1 volt increase and no change in the pulse width. If that holds true with our cars, I think we have to bet a voltage regulator or an secondary pump. What do you guys think? Should I go ahead an buy one? Which would you buy and why? I personally don't like the potentiometer route because that's more wiring, adjustments, etc.., but I don't know if there are good options for an aux. pump for this car. MSD does make a nice kit to boost the voltage but it won't work on returnless systems. I can't find out if our fuel system is returnless or not.

Just thought I'd get a discussion going since it looks like several of us are running into this problem.

[GreenWithEnvy]

Had a turbocharged Scion tc before I bought my Camaro. I put three different turbo kits on it so I know a decent amount about turbocharging a car. Only thing I'm not extremely familiar with is the direct injection. My question is has anyone tried using a piggyback system such as the AEM FIC or a Greddy Emanage Ultimate or even a complete replacement for the ECM like an AEM EMS or a Haltech unit? I know companies are worried about tuning the factory ECM, but from my experience these units are a simple way around this. I know when tuning these units it's based off of rpms and boost pressure. You just plug in the amount of fuel you need into the different cells in the table. Would this not work on our cars? Also as far as the compression goes. The Scion tc is 10.4:1 with an aluminum block and is able to run 8-10psi safely... so I would have to imagine this engine would be around the same.

[GretchenGotGrowl]

Originally Posted by GreenWithEnvy

Had a turbocharged Scion tc before I bought my Camaro. I put three different turbo kits on it so I know a decent amount about turbocharging a car. Only thing I'm not extremely familiar with is the direct injection. My question is has anyone tried using a piggyback system such as the AEM FIC or a Greddy Emanage Ultimate or even a complete replacement for the ECM like an AEM EMS or a Haltech unit? I know companies are worried about tuning the factory ECM, but from my experience these units are a simple way around this. I know when tuning these units it's based off of rpms and boost pressure. You just plug in the amount of fuel you need into the different cells in the table. Would this not work on our cars? Also as far as the compression goes. The Scion tc is 10.4:1 with an aluminum block and is able to run 8-10psi safely... so I would have to imagine this engine would be around the same.

I think I saw a post about someone trying the piggyback route. However, Vince is quickly learning how to tune these things. The problem is, once he solves one thing we find something new. The fuel problem probably won't be any easier to solve with a piggyback as compared to programming the ECU. It looks like our low-pressure pump is just too smalll. We've got to figure out how to bump the voltage or find some aftermarket replacement. That's my opinion anyway. I'd love to see someone try the piggyback...if it works then I'll seriously consider it myself.

[GreenWithEnvy]

Just a little off topic, but any idea where I can get a turbo manifold for the V6? That is really all that is holding me up from giving this a shot.

[rhd]

Originally Posted by GreenWithEnvy

Just a little off topic, but any idea where I can get a turbo manifold for the V6? That is really all that is holding me up from giving this a shot.

have one made, call rmstexas.com they are the ones doing mine

[GreenWithEnvy]

Originally Posted by rhd

have one made, call rmstexas.com they are the ones doing mine

Thanks... if you don't mind me asking how or where is your turbo going to mount?

[rhd]

Originally Posted by GreenWithEnvy

Thanks... if you don't mind me asking how or where is your turbo going to mount?

im doing a twin kit the turbos are going to sit up alittle and near the front.

[xx_ED_xx]

Well On the Direct injection engines I am not sure how they are doing the fuel system. I was going to log into gm global connect and look but my buddy at GM ignores me most of the time so i cant go look for myself and get the info. Anyhow I am sure they are pumping it to another pump near the motor and then boosting that pressure. Similar to a diesel.

I honestly dont think it is as simple as ramping the voltage up to the pump or pumps.

After googleing it here is what the pdf file from GM has to say..

High-pressure engine-driven fuel pump for multiple injection events
To overcome the higher pressures inside the combustion chamber, as well as supply the
multiple injection points of the direct injection nozzles, an engine-driven high-pressure
pump supplies fuel to the injectors. This high-pressure pump feeds a high-strength fuel
rail that feeds a continuously variable pressure fuel rail attached to the injectors. The
high-pressure pump is supplied by a conventional fuel pump mounted in the fuel tank.
The high-pressure pump can supply up to 1,740 psi (120 bar) of pressure, although it is
dependent upon fuel demand by the engine. For example, at idle, the fuel system is
regulated to about 508 psi (35 bar) and increases with demand. The high-pressure pump
is mounted on the end of the cylinder head and is driven by the exhaust cam.

[GretchenGotGrowl]

Originally Posted by xx_ED_xx

Well On the Direct injection engines I am not sure how they are doing the fuel system. I was going to log into gm global connect and look but my buddy at GM ignores me most of the time so i cant go look for myself and get the info. Anyhow I am sure they are pumping it to another pump near the motor and then boosting that pressure. Similar to a diesel.

I honestly dont think it is as simple as ramping the voltage up to the pump or pumps.

After googleing it here is what the pdf file from GM has to say..

High-pressure engine-driven fuel pump for multiple injection events
To overcome the higher pressures inside the combustion chamber, as well as supply the
multiple injection points of the direct injection nozzles, an engine-driven high-pressure
pump supplies fuel to the injectors. This high-pressure pump feeds a high-strength fuel
rail that feeds a continuously variable pressure fuel rail attached to the injectors. The
high-pressure pump is supplied by a conventional fuel pump mounted in the fuel tank.
The high-pressure pump can supply up to 1,740 psi (120 bar) of pressure, although it is
dependent upon fuel demand by the engine. For example, at idle, the fuel system is
regulated to about 508 psi (35 bar) and increases with demand. The high-pressure pump
is mounted on the end of the cylinder head and is driven by the exhaust cam.

Yeah, and I think Vince has got the high pressure pump pushing closer to 1,900 (don't quote me no that, but it is higher than 1,700), but the low-pressure (in-tank) pump is now the problem. ROD1 seems to be having a similar issue with his nitrous setup. On the L99 engine they are having limited success with using a BAP, so I'm concerned that if Vince does figure out how to increase the voltage to that pump we may not get much more out of it. I'm seriously thinking of an in-line pump.