Building a factory five gtm but want to use the 5.3 out of a silverado other than the engine managements what else does the stock computer control? If we are using a 2008 LS3 but 1999 gas tanks will the pumps mate with a computer for the LS3? What are the challenges that I will need to overcome if I do not use the LS1. Are there other components that are needed to run that will interfere/fit with the stock computer, throttle control, power window regulators, a/c controls ect....

As I said I am planning on using a hi-po engine out of a Silverado (not iron block) and the computer, harness and wiring are included. I know what I need to do mechanically just not electronically.......

What did you need to do to get the LS 2,3,7 to work? Is it at all possible to use the computer out of silverado on the gtm? what challenges do i have to face using the 5.3 instead of an ls1? Myself and a few other people are trying to get this to work and are doing as much research as we can and i thought that you guys would have the most info out of anyone thanks in advance.

 

Do a little searching; using a 5.3 and a truck ecm is definitely possible (it isn't for emissions since you can't use a truck powertrain in a car, but that is another story).

 

Have you tried calling Factory Five tech support with your question?

Or make a post over the ffcobra forums.

I wouldn't see why it wouldn't work.

Tails

 

Im actually doing the research kind of for the people at ffcobra forums haha. We have been trying to research the 5.3/6.0 and their interchangeability with the ls1 on the gtm. What we are really trying to do is find cheaper alternatives to the lsx engines and the porsche trans to spread the user base and make the kit a bit cheaper and try to reach the 30k mark that factory five would like the kit to be able to be done for. Sorry if its been talked about before i didnt think i would see alot of topics on the gtm ill try and do some searching and see what i can find.

 

5.3 should be awsome you can still use hp tunners plus there has been many turbocharger in the 600hp, the engines are dirt cheap too...good luck

 

Im planning on it being a semi daily driver so dont want hp to be too high but i do know the potential of the 5.3 and really like it. I think it would be great for the gtm especially considering ive found a 5.3 with 28k miles for around 700 when ls1s are going for wayyy more. thanks appreciate the help.

 

Ahh ok cool then. Man if you can find a cheaper alternative to what they have available for transaxles that would be awesome. That along with the paint / prep work I read about all the time drive the cost of the kit up there pretty high. Plus there seems to be a lot of "how the hell do ya make this fit" type scenarios in putting that car together. I know if you pick Dave Borden's brain over there he could help you out a ton. He was one of the first ones to put a gtm on the road..

Tails

 

if its just the engine harness doe the silverado's have the vats??
i know the 5.3 can go into f bodys, i know of a guy thats done quite a few of those not sure which harness he is using (f bod or 5.3) but these are older 5.3's.

i would think the fuel pump wouldnt matter as you can swap the pump in our cars and tie it into the factory harness.

i have acually been looking into a gtm lately
hope i answered a few questions at least

for the record though when i swapped my 414 into a v6 car i went with a harness from street and performance

 

Here are a couple of things to think about

DBW – The Silverado has DBW correct? You could do cable but it’s more work,, also what about cruise? If using DBW did you get the Silverado TAC and gas pedal and the cables between everything?

Cruise Control – Are you planning to interface the Silverado PCM to the Corvette multi-function stalk so the cruise control will work? It's a nice thing to have. How does the brake and clutch signals interface to the Silverado PCM to disengage the curise control?

Fuse Box – Are you planning to use the Corvette fuse box? I didn't.

Fans – Is there a signal out of the Silverado PCM for fan1 and fan2 control? Are you using Corvette fans? I'm using a Spal fan controlled by the fan1 ground signal.

AC Signal – Are you going to run the AC via the PCM? Are you using a GM AC? Fan on with AC? Off at WOT (I think). I didn't use the GM AC and it's not wired via the PCM although it will turn on the fan. The problem was my PCM had dual climate control.

Fuel Pumps – Is there a relay control of the fuel pumps out of the Silverado PCM? Are you using the Corvette tanks? I didn't.

Are you keeping any of the emission systems? EVAP control? Can you interface the vette tanks with the Silverado PCM for EVAP control? Does the Silverado have AIR pumps? I ditched all emission systems.


Some other things...

Exhaust - Will the FFR supplied exhaust bolt up to the 5.3 manifolds or do you need different manifolds? I built headers for mine.

Brackets - will the FFR supplied relocation brackets work on a 5.3?

Intake Manifold - Does the 5.3 have that really tall manifold? If so,,, it may not fit under the rear hatch.


I think what you trying to do will work,, but you’ll really need GM wiring diagram (shop manuals) for the Silverado as well as the Corvette parts you are using. IT’s the only way to know how these systems wire up.

Good Luck…