Seagram's 72

iTrader: (2)

I have been dealing with a finicky carb all summer and am ready to kick it for the EFI...

I have a carb'd LQ4 in a chevelle with a 200-4r.

The motor is factory with a cam, headers, 243 heads, and carb intake. Made 380/380 to the tires before it blew the driveshaft.

Fuel system is a 2 year old stock 1970 gas tank with an aftermarket pickup, eletric (low pressure) pump, with -8 twist lock Aeroquip line.

I have two complete truck intakes, dbw pedal, wiring harness, ecm, engine covers... basically atleast one full pull out.

My questions are:

Can I use my factory tank? (not counting the sender) Does it need any baffling or anything else?

I have an aftermarket sender that is made with a -8 return and pickup, can I use that if I use the factory tank?

What is everyone using for fuel line?

Walbro pump?

Filter?

I have a factory harness and am good at wiring, I am assuming reworking this is the way to go? Any good links to pages on modifying this?

How is retrofitting a dbw pedal in a 72' Chevelle, or go to a van throttle cable and tb?

I'm basically doing a feasibility on the FI swap for the winter since the carb has been hurting my wallet, cruising, and time. I had good luck last summer, but not this one.

Thanks

Pop N Wood

iTrader: (1)

You can use an unbaffled tank, but you will need to keep it filled if you plan on any driving that might uncover the fuel pick up. Carbs have fuel in the bowls to help overcome momentary fuel pressure drop out. FI will go lean.

Not sure why you can't use the same fuel lines as the carb. Just add the EFI pump and a new regulator, then run power to the ECM.

Seagram's 72

iTrader: (2)

I'm thinking of getting the parts place tank $450 with pump so I have two issues tackled off the bat.

Next depending on clearance issues I was thinking of running the entire truck setup because I have the engine covers.

I was planning on running 3/8 fi line for pickup and 5/16 for return front to back.

Stock truck fuel pressure regulator.

Anyone use the filter off of a 90's chev truck? I forget the wix part number.

I'm going to try and run the dbw.

I was also planning on running O2's and a MAF, is that ideal?

Where are some good places to look for a harness? I have a "core" or I may DIY it.

I have a stock lq9 computer, I may running a different cam, heads, and headers. Can and should I get this reflashed or do I have to swap to a different ecm.

74novacustom

You can Modify your tank with an in tank setup from Tanks inc.

Most people just use the Corvette filter/regulator combo, its under 50.00 and you dont need to run a return line the length of the car.

Depending on how low you mounted the engine you might be able to get away with the truck setup, You got a cowl hood?

There are many companies doing harness mods.
I used Current performance wiring, they also programmed my computer.
Im having Foxlinders do my E85 Program, but they also do harness mods.

Keeping the Mass and Rear O2s with be the way to go.
Unless you are planning a turbo then you would look to ditch the Mass and go to a Speed Density setup.

Hope this helps

Seagram's 72

iTrader: (2)

Thanks for the advice.

That pump with reservoir from tanks inc seems like the best option yet.

I have a cowl and am test fitting the truck stuff first.

Can I run the vette filter and reg with the truck setup since it has the regulator with return on the rails? It would be ideal to run the vette combo, 33737, but don't know if I can with the truck intake setup.

So you only run rear o2's? Not the front o2's off the truck?

E85 would be nice, but don't want to get too complicated out of the gate.

74novacustom

I installed the Tanks inc settup in my stock gas tank.

I think you might have to change your fuel rails to the non return style, many trucks have the no return system so it should be easy to get one, if you had an LS1/6 intake i could give you one for free.

Now you got me thinking, i know one set is for emissions and the other is for engine operation so they delete one set and and keep one.

LS1MCSS

iTrader: (18)

Delete the rear and keep the front.

Seagram's 72

iTrader: (2)

Do you have an example of a non-return style application? i.e. something I could pick the rails out of?

Any starvation issues with the tanks inc. setup?

I would much rather use the vette filter/ reg vs. the truck reg and a seperate filter. I need to buy a new truck reg, filter, and return line vs. just a vette filter/ reg.

Thats what I thought about the O2's, fronts are for operation, rears are for emissions (monitor cats and what not), essentially useless to us. Someone correct me if I am wrong.

Seagram's 72

iTrader: (2)

I have two complete truck intakes (minus regulators) If I can combine the non-regulator side of both regulators

chuckd71

iTrader: (23)

A truck intake will fit under a cowl hood. If you check the classifieds you can get returnless rails for $40 or so shipped. I might even have some in the garage. There are different styles though, some older rounded ones and some newer squared ones.

Seagram's 72

iTrader: (2)

Thanks, will any rails work off a truck say 05-07 and do I need the injectors too? I have 2 complete 03' lqx manifolds. Just want to know if my injectors will work.

I have seen some A Body guys use a 07 Monte pedal. Anyone know if this works with an 03 truck harness?

chuckd71

iTrader: (23)

The ones that fit an L92 type intake are a bit wider across I think. At least the E85 rails I have are wider than my 2002 rails.
Injectors might need to be sized up a bit from stock but I'm not an expert on that. I'm sure someone will chime in.

Seagram's 72

iTrader: (2)

Thanks, I usually go to the parts store and compare the two. If I can get a rail w/ injectors that fit my manifold that may be the route. I'll also look at the plug type.

I thought about going to a car intake,but the injector plug is different and foremost I would have to modify/ change my water pump and some of the front drive.

Even thought about a FAST or Edelbrock, but $$$

Still seeing which dbw pedal will work.

Goal at this point is to convert less harness using the parts I have and spending less than $500

74novacustom

Included in the price of the harness mod from Current performance wiring they swapped the injector plugs to new car plugs.

Floxlinders sells the swap waterpump kit to allow the use of truck accy and the LS1/6 intake. Thats what im running.

Seagram's 72

iTrader: (2)

I'll have to price that out...

74novacustom

If i remember correct to mod the harness with them programming it for my cam, intake, and gears and whatever else was 750.00

the water pump was around 200 with the idle relocate kit and belt.

Seagram's 72

iTrader: (2)

Something too look into, I couldn't get their site to work on the phone, but will try again later.

Seagram's 72

iTrader: (2)

Looking at basic fuel delivery the options are:

1) current setup with external pump, loud, possible starvation at low fuel levels, have to mount the pump and maybe get a pusher. $100

2) parts place tank/ spectra tank ( same p/n's) everything in one shot, pump similar to walbro, sending unit included, heard of starvation at low levels ( maybe un baffled?), $375

3) tanks inc pump, need to use factory sender, requires tank mod, heard sits high and may require clearancing, $225

4) b body tank with aftermarket pump, heavy mod to floor and maybe frame (I installed a new trunk pan last year and don't want to cut), modifications to straps, about $175

Someone let me know if I am missing anything, but I figure these are the options for under $400

chuckd71

iTrader: (23)

I think someone posted dyno numbers showing a truck intake was at least as good as an ls1 intake, and for FAST stuff to make a difference you have to be winding the crap out of your motor and racing and whatnot. Might as well stick with what you have for now. Some guy in the classifieds is selling some rails with injectors for $60. My harness and pcm with a basic tune from chevythunder.com was right at $500 (that includes the pcm, as I didn't have one). In hindsight that too seems like a lot, considering how many people use diagrams and do it themselves. Probably should have done mine myself as well.
For tanks, getting a stock tank, cutting it open to baffle it then doing the tanksinc thing might be a good route. Replacing the pump in a spectre would be the easiest though.
This is how I'm going to handle fuel lines in my next swap (probably an old truck of some sort next year). https://ls1tech.com/forums/15254895-post14.html

Seagram's 72

iTrader: (2)

Thanks chuck, I read that post and was going to price out the kit tonight from work. I like the nylon and easy to make/ fix/ add onto.

Still deciding on the tank, but there is no clear answer, bottom line is I hate my loud external pump right now.

I will check out that fuel rail post.

I am going to check out Chevy thunder as well