How does it work?

[Blacklemming]

Hi everyone,
As I'm looking at a new engine and tranny,
I came by a Chevy ls3 with a carb on top.
It would be a 480 hp
It's fuel injection so.
How does this work,hp losses,extra cost?
I do like the look.

[Detroit Bill]

Originally Posted by Blacklemming

Hi everyone,
As I'm looking at a new engine and tranny,
I came by a Chevy ls3 with a carb on top.
It would be a 480 hp
It's fuel injection so.
How does this work,hp losses,extra cost?
I do like the look.

You will get lots of opinions. Is this to put in an existing car? What is in the car now?

You may need engine mounts.

You may need to get headers made (that could be pricey).

Fuel injection is great, getting it to work correctly might take some time and money. Does it come with the ECU (electronic control unit) for the injection? If so what make is it. What make in the injection? Installing fuel injection is a lot more involved.

You may need to do some trans mount work.

Overall it will be more money initially than putting an engine with a carburetor. It will be more money that putting in a Ford engine where there are likely engine mounts and headers available.

Putting a non Ford engine in it make make it a little harder to sell if you choose to sell it in the future.

Good Luck!

[Blacklemming]

I just want to fit in with the"dark side owners"

[mikeinatlanta]

A bit confused by your post. You wanting to install a carbed or injected LS?

[Tommy]

blacklemming,
There are a few ls3 Cobra owners here on the American side of the forum, but I think there are a lot more on the Australian Cobra Club part of the forum. You may get better help there.

[john chesnut]

I have an LS6 with a Tremec T56 transmission in my Cobra. It's a stock engine with the factory fuel injection. I'm not sure what your are looking for from your post. If you provide some details I may be able to help out. I'm in upstate NY.

[Tommy]

For those wanting to help, I think I understand the question now. BTW, blacklemming is in Europe. I think the question is this. He can get a stock LS3 (fuel injected) to use in his car. He wants to run it on a carburetor instead. He wants to know what he will lose in performance, and what changes he'll need to make to the stock engine to use the carburetor.

[joyridin']

You won't lose much hp if the carb is set up correctly. Maybe 10 hp at the most? If I were going that route, I would probably not buy a 480hp version assuming you were going to buy a crate engine. Buy the 430hp version for a lot less money, throw in a $400 cam and the carb set-up, and you can have 515-525 hp without a problem. You would void the warranty by removing the EFI, so it would not matter.

I would never think about removing the EFI though. LS3 engines have a pretty killer set-up right from the factor and can support close to 600hp on the stock system.

[john chesnut]

There are a few options. An ls3 is easily converted to a carburetor. You can keep the individual coils and use a controller and wiring harness from MSD that is made for this conversion. Or, you can convert to a distributor for the "vintage" look. A carburetor will probably make more peak HP.

Personally I love the EFI. I'm making a new engine cover that will hide the stock intake and coil packs and look like individual velocity stacks for my LS6.

[john chesnut]

Sorry. Double post.

[Tommy]

I hope the OP will forgive this slight off topic. .... I'm planning a Chevy powered project and I like everything about the LS engines except the appearance. John, I'd love to see what you are building for an engine cover. Please post pictures when you can.

[john chesnut]

Tommy, here is the cover that I built for the Cobra a number of years ago. I'm going to be modifying it with a center section with the velocity stacks running down the center. I haven't decided exactly the final configuration yet. I will be rerouting the inlet and filter into the stock intake. The new cover will disguise it.
(Since this picture was taken I've replaced the throttle cable with a longer black one for better routing)

My Cobra is on jack stands. I recently started tackling a number of things that I wanted to change or improve. It's been slow go. My health is poor and I'm limited on what I can do. I'm selling all of my projects and misc parts.

[Tommy]

Thanks, John.

[Blacklemming]

Originally Posted by Tommy

For those wanting to help, I think I understand the question now. BTW, blacklemming is in Europe. I think the question is this. He can get a stock LS3 (fuel injected) to use in his car. He wants to run it on a carburetor instead. He wants to know what he will lose in performance, and what changes he'll need to make to the stock engine to use the carburetor.

Tommy, you're right .
I live in Belgium.
I've been reading a lot on the web about ls 3 engines.
What I don't understand is that there are,
1 efi set ups
2 carb set ups
3 efi set ups with carb
????
I would like the efi set up with carb for the old Skool look,if it's possible?


Thanx for helping out

[joyridin']

Originally Posted by Blacklemming

Tommy, you're right .
I live in Belgium.
I've been reading a lot on the web about ls 3 engines.
What I don't understand is that there are,
1 efi set ups
2 carb set ups
3 efi set ups with carb
????
I would like the efi set up with carb for the old Skool look,if it's possible?


Thanx for helping out

That would be an LS engine with a throttle body style injection instead of a port fuel. You can buy a LS 3 and use something like a FAST system on the engine. This looks similar to a carb, but is actually a throttle body and the injectors are under where the float bowls were located. I have also seen a port fuel style injection that uses a carb style throttle body just for the air intake. The injectors are still in the intake manifold mounted near where the intake bolts tot he head. This seems like it would be a lot of work just for looks, but if you are planning on using a Holley HP or Dominator style ECU, it is relatively easy to hook up. A lot of older style GM engines where EFI wasn't originally available use this style.

Lots of options. All will work reasonably well if set-up correctly. You may want to visit this site for more information.

LS Engine News & Discussion - LS1Tech.com

[Blacklemming]

Originally Posted by john chesnut

There are a few options. An ls3 is easily converted to a carburetor. You can keep the individual coils and use a controller and wiring harness from MSD that is made for this conversion. Or, you can convert to a distributor for the "vintage" look. A carburetor will probably make more peak HP.

Personally I love the EFI. I'm making a new engine cover that will hide the stock intake and coil packs and look like individual velocity stacks for my LS6.

If I do it like this wouldn't it be the best of both worlds?
Carb for the looks and stil the computer to control everything.
If I understand it correctly

[Blacklemming]

Originally Posted by joyridin'

That would be an LS engine with a throttle body style injection instead of a port fuel. You can buy a LS 3 and use something like a FAST system on the engine. This looks similar to a carb, but is actually a throttle body and the injectors are under where the float bowls were located. I have also seen a port fuel style injection that uses a carb style throttle body just for the air intake. The injectors are still in the intake manifold mounted near where the intake bolts tot he head. This seems like it would be a lot of work just for looks, but if you are planning on using a Holley HP or Dominator style ECU, it is relatively easy to hook up. A lot of older style GM engines where EFI wasn't originally available use this style.

Lots of options. All will work reasonably well if set-up correctly. You may want to visit this site for more information.

LS Engine News & Discussion - LS1Tech.com

That's wat I was hoping for ,those 2 options you mention.
Fast system or carb just for air intake.
They both look verry nice.
I will take a look at the site
Thanx

[Tommy]

Blacklemming,
I'm no expert, but here's what I think you need to know. ... On a computer controlled engine with electronic fuel injection (like most modern engines), the computer controls both the ignition functions (e.g., timing advance) and the fuel functions (how much fuel to add to the air coming into the engine). If you replace the fuel injection with a carburetor, the computer no longer controls the fuel function. So it is not the same.

In general carburetors can be tuned to produce slightly more power than fuel injection at wide open throttle. But electronic fuel injection performs better across a wider range of RPM and throttle settings. That is why they typically get better fuel economy.

[Gaz64]

A carburettor can make more power because the fuel IS vaporised by the time it gets in the cylinder. The whole tract is full of vaporised fuel.
Have a look at individual runner outboard mounted injectors like V8 Supercar, F1, etc. The big horsepower cars run their injectors outside the trumpet.
Fuel ecomony is obviously worse with a carburettor because of wasted fuel going out the exhaust at valve overlap.

The difference may only be 10hp which would not be worth the loss of driveability, cold start performance, fuel ecomony etc compared to OEM port EFI.

[Blacklemming]

I'm been reading a lot this weekend due to the heavy raining over here .

I am a torque guy,hp is nothing whiteout torque.( my opinion)
The car is strictly for street driving so those high rpm hp's aren't useful .
And verry expensive!!!!!( raced with bikes so I know)

As I understand it correctly,
I can mount an other intake manifold just for the air intake( intake has a hole for the maf sensor),and mount an wicked k&n filter on top.
The one I found was a edelbrock victor jr,I don't know about the rpm range.
It was from 2500-6200 I guess.

I know i have to buy an other gas pedal.
Do I then work with the stock gm wire harness and computer?

Or do I have to go to an other compagnie who make there own,and there own
Computer ?

I don't seem to find any pictures of the exhaust sensor mounting on the sidepipes?
The best thing would be to make a 4-1-4 on each side with a mounting hole in the middle I think?(correct me if I'm wrong).

I think some more reading is nessacery