: LS3 Swap CTS-V



Minytrker
07-30-13, 02:15 PM
I finally put the V on the dyno the other day, not too bad for a daily driver with a stock LS3. It gets 24-26mpg as a bonus.
It made 425/436 sae
Mods are:

2012 Crate LS3 (stock)
K&N CAI
OBX Headers w/cats
LS7 Clutch
X Pipe
Gutted Stock Mufflers
G Force Axles

131033

03cobrarocks
07-30-13, 04:41 PM
That seems pretty good for the mods listed! But I am coming from the mustang world hehe


About how much power is that over a ls2 with the same mods?

Manofmetal01
07-30-13, 07:37 PM
That seems pretty good for the mods listed! But I am coming from the mustang world hehe

About how much power is that over a ls2 with the same mods?

Could be wrong but I'm thinking in the 360s or maybe that was stock. I havent dynoed but i like to tell myself im around 480 at the flywheel hehe. Quite a bit of loss through drivetrain.

FoD
07-30-13, 08:10 PM
How are you getting that much torque without a stroker or FI? Doesn't seem right.

Minytrker
07-30-13, 11:06 PM
How are you getting that much torque without a stroker or FI? Doesn't seem right.

Have you been around alot of ls3's? I seen several of them make around the same torque or higher with with a cam and other mods. Also seen plenty make way less torque with a big donkey dick cam in them, theyll make a ton of hp but no torque. I'm guessing the cai and headers I have just work well with the stock motor, its definitely stong for a stock motor. I had it on another dyno (mustang dyno) and it made 423/420sae but since then the tune has been changed alot. The car definitely liked the richer a/f ratio...it made the best numbers at 12.2-12.4 a/f compared to the lower numbers on the mustang. It pulls like a train and blows the tires off easily so I have no reason to doubt 2 different dyno's. Its WAY faster than my G8 that runs 12.9's.

odthetruth
07-31-13, 06:41 AM
That seems pretty good for the mods listed! But I am coming from the mustang world hehe


About how much power is that over a ls2 with the same mods?

LS2 with same mods would make 370, 380. So around 50whp more...

Skidmarcx
07-31-13, 08:55 PM
Sweet numbers man.....

carlson_mn
08-01-13, 12:46 AM
you're telling us you average 24-26mpg and make 425hp? I believe one of the two statements, unless all you do is drive 60mph in 6th gear. Great numbers regardless of what dyno it was on.

03cobrarocks
08-01-13, 12:03 PM
LS2 with same mods would make 370, 380. So around 50whp more...

Dang that is a pretty big difference.. Isnt the only difference between ls2 and ls3 the heads? Or am I way off...

My brothers ls2 vette makes 382 rwhp with kooks, mufflers and bbk intake and it's an automatic... I know comparing dyno numbers isnt the end all be all but weird that his automatic car would make as much as manual ctsv with same motor.

PISNUOFF
08-01-13, 12:42 PM
you're telling us you average 24-26mpg and make 425hp? I believe one of the two statements, unless all you do is drive 60mph in 6th gear. Great numbers regardless of what dyno it was on.

My heads and cam LS2 made 400/400 and got 26 mpg.

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Dang that is a pretty big difference.. Isnt the only difference between ls2 and ls3 the heads? Or am I way off...

My brothers ls2 vette makes 382 rwhp with kooks, mufflers and bbk intake and it's an automatic... I know comparing dyno numbers isnt the end all be all but weird that his automatic car would make as much as manual ctsv with same motor.

Heads, cam, intake and bore size.

CTS-V_07
08-01-13, 07:15 PM
I had a ls2 put down 426/418 through a m6 with ts cam long tubes kooks muffler... It put down 408/400 on a Mustang dyno so those numbers sound right for a ls3...

carlson_mn
08-02-13, 12:27 AM
I can get 26 on the highway but I average about 17 in 75% city driving. I guess I'm okay with that.

lollygagger8
08-02-13, 11:21 AM
I can get 26mpg with my heads/cam combo on hwy.

In town it avg's 14mpg....damn skinny pedal

mackey
08-02-13, 04:23 PM
what's involved with the swap? planning ahead (hopefully many years) when my motor goes.

Minytrker
08-02-13, 06:37 PM
you're telling us you average 24-26mpg and make 425hp? I believe one of the two statements, unless all you do is drive 60mph in 6th gear. Great numbers regardless of what dyno it was on.


Yes it gets 24-26mpg at 70-75mph if its all highway driving. I average 21-22mpg with mix of highway and city driving. It actually gets better mpg at 70+ than at 65mph. At 70-75mph the engine is in its sweet spot vs 65mph its lugging it alittle more with the prms being slightly lower. I get better mileage than my friends stock ls2 ctsv with my ls3 ctsv. This is with alot of tuning being done on my car. My G8 has almost a hundred less horsepower and my ctsv gets better fuel mileagethan it does. High hp doesnt always mean crappy milege, friends blown z06 makes 600+hp at the wheels and it gets 26mpg on the highway. With the ctsv or any vehicle with decent hp you can get great mpg's with the cruise on BUT of course you get on it alot then the mpg's drop really fast!

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what's involved with the swap? planning ahead (hopefully many years) when my motor goes.

Going off memory the only thing that I remember I had to change was I changed my MAP sensor pigtail to a LS3 plug so I could run the stock ls3 map sensor.

mdleal
08-02-13, 11:35 PM
Pics?

PISNUOFF
08-03-13, 12:23 AM
what's involved with the swap? planning ahead (hopefully many years) when my motor goes.

Map sensor, cam sensor, the crank has the incorrect reluctor wheel to match your LS6 and your strut tower brace may not fit over the LS3 intake.

JFensty
08-03-13, 09:13 AM
Map sensor, cam sensor, the crank has the incorrect reluctor wheel to match your LS6 and your strut tower brace may not fit over the LS3 intake.

Is that really it? I mean I know the crank could be the deal breaker for some, but is it a bitch to tune?

PISNUOFF
08-03-13, 09:43 AM
Forgot about the knock sensors for you LS6 guys also. Really, you just take the parts off your LS6/2 that you need and it's plug and play. The tuning isn't harder than tuning for heads and cam.

liqidvenom
08-03-13, 06:55 PM
Forgot about the knock sensors for you LS6 guys also. Really, you just take the parts off your LS6/2 that you need and it's plug and play. The tuning isn't harder than tuning for heads and cam. you are an evil man making this seem easy

Minytrker
08-04-13, 03:16 AM
Pics?

132409

Minytrker
08-04-13, 03:22 AM
Is that really it? I mean I know the crank could be the deal breaker for some, but is it a bitch to tune?

Sorry about that. I didnt look what year you had. Since I had a LS2 with 58x already it was a simple swap. Its still not hard either way to swap it in your car. I have had several LS2 swapped camaro's and trucks. I just used the box from lingenfelter to convert the cam and crank signals so the ls1 pcm could read it. The tuning is the easy part, not a big deal. IMO opinion there isnt a hard ls swap when your starting with a ls based vehicle unless your maybe going to a dry sump ls7 or ls7 then that makes it a little harder, lol.

fastech27
12-13-15, 10:03 PM
Wonder if there if it ran without tuning? Would like to do this swap myself...Jim 2007 cts v

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Way to go, saw a ls3 new from chevy for $5900 with plugs wires and intake pretty complete

jclayc
12-14-15, 08:28 PM
I'm about to swap a 416ci LS3 in to my LS6 so I'm learning as I go.
The reluctor wheel is the biggest deal if you have a 24x like I do. You can either go with a $500 Lingenfelter module to "translate" or, like me, get a 24x reluctor wheel put in the LS3.
The cam timing gear is also an issue - you have to go from the LS3 one bolt cam to a 3 bolt cam and timing gear. Get a Gen IV front cover as well, if you don't have it already.
For the LS6, as mentioned, you have to drill/tap the LS3 knock sensor location to fit the LS6 knocks (and get an extension harness for them and the cam sensor)
If you're going with a LS3 intake, you'll either have to swap to a LS3 MAPs and add an extension harness or use your old MAP and use a "translation" dongle and extension harness.
If you're going with the LS3 intake & fuel rails you'll also need new injectors or at least injector harness adapters, I think.
I don't have an answer about the tune. Will it run? Maybe... do you really want to run it like that? I'll add a basic tune before taking it to have it dyno and street I tuned.

Unless I'm forgetting to list something, I think that's about it. I'm going to run Mamo/AFR 235 heads that are cathedral port... so I can keep my LS6's FAST 102... which I believe means I can keep my MAP, FAST fuel rails & injectors.