I did the search... the only info I found was 07ish old....

Looking for people that have replaced thier LS1 engines with LS3's.

My car is a 98 LS1 car,M6.

Mechanical
As far as the nuts/bolts go, looks like a drop in.

FUEL
What did you do for the fuel lines?
Can you reuse the 98 rails/injectors?
If not, what parts do you need to get this to work?

AIR
Is it cheaper/easier to go one way or the other as far the the TB goes?
(cable vs electric)
What did you do for the air intake hose? (I had a 90mm Fast for a while. It was impossible to get the factory hose on to the TB.

SENSORS
What did you do for the sensors?
What about the reluctor wheel? did you just use the box?

Looks like the knock sensors, map, crank, oil pressure, and god knows what else is different.

OIL
Looks like I need to reuse my LS1 pan right?

COOLANT
Reuse my W/P? (my understanding of the LS3 is the front dress is not interchangeable)

What did you do about that skinny line from the engine to the radiator?


I called S/D, they told me it's a "drop in" I'm not buying that. I'm not an LS guru but, I'm not an idiot either...

Thanks, guys

 

http://www.gmhightechperformance.com...wap/index.html


Not sure how much help that'll be but thats all i could come up w/.

 

I seen that.. It's only part 1 though...

(That article is what got me thinking...)

 

There you go man took me about 2 seconds to find on google lol.
Exactly what you're looking for:
https://ls1tech.com/forums/generatio...02-f-body.html

Another bit of info:
https://ls1tech.com/forums/conversio...onversion.html

 

Seen that one too..

Old info.
And most of what is in there is supposedly incorrect...

 

Just wrapped up installing the LS376/480 into my '99 T/A in September. I used the GMHTP article as an outline to the swap, and it worked out pretty well. It's not my first time around an engine swap, so I may be oversimplifying things. Still have to tune the car and replace the rear axle to handle the power, but that's what winters are for. So, here's some answers:

Mechanical
As far as the nuts/bolts go, looks like a drop in.
pretty much, save for a knock sensor on the driver's side

FUEL
What did you do for the fuel lines? - stock work perfectly fine on a '99
Can you reuse the 98 rails/injectors? I didn't, as the crate motor comes with new parts. The new injectors are much larger as well, so I wouldn't reuse old stuff.
If not, what parts do you need to get this to work? see above <edit> and Qty 8 USCar injector Connector Kit LS3 (L480080000) adaptors

AIR
Is it cheaper/easier to go one way or the other as far the the TB goes?
(cable vs electric) Went with a cable-operated Holley 90mm and reused the old sensors. Some minor trimming was required, but no big deal.
What did you do for the air intake hose? (I had a 90mm Fast for a while. It was impossible to get the factory hose on to the TB. Used new silicone hose adaptors from an online store between the TB and MAF; and the MAF and the Suncoast Creations air box.

<edit> Bought a new MAF and sensor cable: Mass air flow (15904068) & wiring harness (CAS108100)

SENSORS
What did you do for the sensors? Reused as much as possible. The Lingenfelter trigger kit has some nice adaptor pieces that allow use of the LS3 map sensor, crank, and cam sensors.
What about the reluctor wheel? did you just use the box? Yes, Lingenfelter's

Looks like the knock sensors, map, crank, oil pressure, and god knows what else is different. I used LS1 knock sensors on the sides of the block, LS3 map, LS3 crank, LS1 oil pressure behind intake. The newer MAF's require a custom harness as the IAT is integrated with the MAF. <edit> Knock sensor extension harness (Lingenfelter RXC5-KSRH)

OIL
Looks like I need to reuse my LS1 pan right? yes! pan, pickup, baffle

COOLANT
Reuse my W/P? (my understanding of the LS3 is the front dress is not interchangeable) yes, reused my LS1 water pump as the pulley spacing isn't the same from car to car. All accessories must be checked to make sure the serpentine belt will work properly. FYI - crate motor LS3 balancers must be replaced (new bolt, etc...)

What did you do about that skinny line from the engine to the radiator? all lines from the radiator were reused (coolant and tranny). No problems there.


I called S/D, they told me it's a "drop in" I'm not buying that. I'm not an LS guru but, I'm not an idiot either... It's really close to a drop-in. Save for a few modifications and change overs on parts. Wasn't all that hard, just a bunch of Saturday's dedicated to getting it done.

 

Very interesting thread, I'd love to do this swap in my car.

Overall, it looks pretty straight forward. However, my car is a '98 T/A M6, and I've read that this swap is not possible in a '98 due to the fuel system design that the '98 cars use. Can anyone clarify on that??

 

SMKNLS1, This is what I was after!
(hope you don't mind a few million questions...)

What did you do about the emissions stuff? use the LS3 stuff?

By your pics, the skinny coolant line comes off of the X-over line now?

More amazingly stupid questions to follow....

 

A.S.Q #1

What did you use for the ECM?

 

No problem with the questions, love to help, if I can.

For emissions, I reused the evap canister from the LS1 and laid it on top of the driver's side fuel rail. I don't really like the position and may move it eventually. The rest of the emissions (cats, etc..) were also reused.
Fairly certain I used Lingenfelter's MAP sensor harness LS1 to LS3 (CE-109103) adaptor. Hopefully, tuning the LS3 MAP won't be too crazy.

Forgot to mention, that on the fuel system, I upgraded the in-tank fuel pump to a Racetronix unit to handle the higher flow requirements.

Also, for the throttle body, I had to purchase (GM #12556454) TB to valve cover tube, but you can also reuse the stock one.

On the oil pan, the LS1 dipstick and tube are also required...

Reused the existing PCM, just haven't tuned it yet.


The skinny coolant hose connects in the same general area as it did on my previous LS6 intake & valley cover setup. I didn't have to do anything special for it to fit >>> see picture of old setup>>>

 

Wesmanw02 - I don't pretend to be an expert since my car is a '99. But, with all the work that this swap entails, you're pretty much removing and reassembling the entire drivetrain and fuel system of the car. While I didn't remove the fuel lines, if I had a '98 and that was the limiting factor, I'd buy lines and a plastic tank from a '99 and just make it part of the swap. It's not that much more work.

 

Perhaps someone knows what it actually different between the two fuel systems that requires modification??

 

what did you do for the tranny? did you get it rebuilt or get a brand new one?

 

The only difference in the 98'-99' f-bodies fuel system is that the 98's fuel pressure regulator is mounted on the rails, where as the 99+ have the fuel pressure regulator built into the intank unit, thats the difference.

 

awesome thread, in for this one! ill be watching and might throw in a few stupid questions of my own lol

 

The car has a FLT level 4 tranny with a SY 3500 converter. It only had 2K miles on it when I started this swap and is holding up pretty well so far. I'm still breaking in the new rearend (S60) and the engine, so I haven't beaten on it yet.

 

I would just install a corvette fuel filter and use the LS3 rail. Then all you need is a vette filter and a few fittings. No need to swap the fuel tank and lines.

 

how long did this conversion take?
i'm looking at taking on this same exact project here in a few years.

 

Hard to tell, but I only spent Saturdays working on the car. I remember starting in late June dissasembling the LS1, buying parts in July, and installing in August and September. If you had a full week off work, I'm sure it could be done pretty quickly.

My swap also included a full brake system upgrade and rear end install that stretched the whole thing out. Then winter got in the way. The car was tuned in May and is just being broken in now.

Good luck with your project. After doing all this work, I'd have to say the car is a level or two above the old setup. The only regret I have is not throwing on a Maggie as part of the upgrade, but I'll get to that eventually!

 

where did you get your ls3? crate/complete or out of another car? i've been looking online and the ones i've seen range at about $7k