Boost engine on the cheap
09-02-2011, 06:14 PM
#1
Boost engine on the cheap I'm finally building my "Frakenmotor". This is for a daily driven GTO with an APS twin turbo kit.
I ran the stock LS2 for over 2 years with the APS kit at the base boost level of 7-1/2 PSI without a single engine issue, until I drove through a deep puddle and sucked in some water, killing the #7 rod and piston.
I replaced that engine with a forged, low compression LS7 boost motor. This engine however, due to the way the clearances were setup, made a horrible racket. It sounded like a diesel and was embarrassing to drive. I also decided that I really don't need *that* much power. The LS2 was plenty fun as it was.
So I've decided to go back to a 6.0L. Using my original LS2 block, which fortunately escaped any damage to the #7 cylinder. Cost $0
The crank, rods and pistons are from a very low mileage LY6 engine (Iron 6L truck motor). These are dished pistons with valve reliefs for LS3 style heads. The pistons are the same size as the LS2. These pistons won't make noise. Cost $250 + $20 for a 24tooth reluctor.
The heads are from a 2009 Cadillac CTS-V (LSA). These are LS3 style heads with improvements made for boost such as rotacasting for less porosity, and thicker valve heads for heat dissipation, as well as a 'wing' in the intake port for a better air/fuel mixture. These heads flow as much out of the box as a set of ported 243's. Cost $600, I sold my 243's for $500. So net cost is $100. What a Deal!
Head gaskets are LS9, 7-layer MLS. Cost ~$120
New take-off L76 intake to fit the LS3 style heads. Cost $200.
LS9 ZR1 cam 211/230 .558"/.552". The LS2 cam was 204/211 .525"/.525". So a slightly better cam which will idle like stock. If it works in the ZR1, it'll work good enough for me. Cost ~$130 brand new from GM.
In the end, I'll have a 9.5:1 compression 6.0L aluminum GenIV engine, very similar to the Supercharged Cadillac CTS-V, but with a bigger cam and slightly higher compression (9.5 versus 9.1)...minus oil squirters and 200cc. I plan on running between 10 to 12 PSI, using either E85 or 93 pump gas with/methanol injection.
The stock LS2 at 7-1/2 PSI produced 554HP/572TQ at the wheels. I'm hoping this combo, with the added boost, better heads and better cam will produce somewhere in the range of 650HP.
Oh, that noisy LS7 boost motor is being rebuilt back to stock LS7 specs and will replace the anemic 5.3L in my AWD truck.
I ran the stock LS2 for over 2 years with the APS kit at the base boost level of 7-1/2 PSI without a single engine issue, until I drove through a deep puddle and sucked in some water, killing the #7 rod and piston.
I replaced that engine with a forged, low compression LS7 boost motor. This engine however, due to the way the clearances were setup, made a horrible racket. It sounded like a diesel and was embarrassing to drive. I also decided that I really don't need *that* much power. The LS2 was plenty fun as it was.
So I've decided to go back to a 6.0L. Using my original LS2 block, which fortunately escaped any damage to the #7 cylinder. Cost $0
The crank, rods and pistons are from a very low mileage LY6 engine (Iron 6L truck motor). These are dished pistons with valve reliefs for LS3 style heads. The pistons are the same size as the LS2. These pistons won't make noise. Cost $250 + $20 for a 24tooth reluctor.
The heads are from a 2009 Cadillac CTS-V (LSA). These are LS3 style heads with improvements made for boost such as rotacasting for less porosity, and thicker valve heads for heat dissipation, as well as a 'wing' in the intake port for a better air/fuel mixture. These heads flow as much out of the box as a set of ported 243's. Cost $600, I sold my 243's for $500. So net cost is $100. What a Deal!
Head gaskets are LS9, 7-layer MLS. Cost ~$120
New take-off L76 intake to fit the LS3 style heads. Cost $200.
LS9 ZR1 cam 211/230 .558"/.552". The LS2 cam was 204/211 .525"/.525". So a slightly better cam which will idle like stock. If it works in the ZR1, it'll work good enough for me. Cost ~$130 brand new from GM.
In the end, I'll have a 9.5:1 compression 6.0L aluminum GenIV engine, very similar to the Supercharged Cadillac CTS-V, but with a bigger cam and slightly higher compression (9.5 versus 9.1)...minus oil squirters and 200cc. I plan on running between 10 to 12 PSI, using either E85 or 93 pump gas with/methanol injection.
The stock LS2 at 7-1/2 PSI produced 554HP/572TQ at the wheels. I'm hoping this combo, with the added boost, better heads and better cam will produce somewhere in the range of 650HP.
Oh, that noisy LS7 boost motor is being rebuilt back to stock LS7 specs and will replace the anemic 5.3L in my AWD truck.
09-03-2011, 08:32 AM
#5
LS7 motors weren't meant for boost and just really aren't that good a candidate for boost being they have such thin cylinders walls to get that 427 c.i. 427 c.i. is great for boost as long as it's in a block like a LSX, Superdeck ERL, or RHS block with some meat around the bores.
Sounds like you put some good thought into using GM parts that will more than work for what you intend to do.
Sounds like you put some good thought into using GM parts that will more than work for what you intend to do.
09-03-2011, 09:53 AM
#6
http://sdparts.com/details/gm-factor...parts/12638427
You can find it a little cheaper but they get you on shipping! Dont forget this bad boy only works with front cam sensor, doesnt have the lobe for the rear cam sensor.
09-03-2011, 09:57 AM
#7
Ballin outta control playa
http://sdparts.com/details/gm-factor...parts/12638427
You can find it a little cheaper but they get you on shipping! Dont forget this bad boy only works with front cam sensor, doesnt have the lobe for the rear cam sensor.
http://sdparts.com/details/gm-factor...parts/12638427
You can find it a little cheaper but they get you on shipping! Dont forget this bad boy only works with front cam sensor, doesnt have the lobe for the rear cam sensor.
I was just seeing again that parish gained 100rwhp by switching to the z06 cam so Im thinking that will be the way to go.
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09-06-2011, 06:04 PM
#8
Lingenfelter has the ZR1 cam for $130.
WasSlow has it for $113.
Pace Performance has it for $120.
The LS7/Z06 cam is almost identical to the ZR1 cam, but it's also a 3-bolt front cam sensor cam. These can be found used for $50-$100.
The older LS6/Z06 cams are the LS1 rear cam sensor style. The 2002+ LS6 cams have a much different profile though, but are still great for boost. 204/218 int/exh @ 50 duration 0.551" / 0.547"
To use the ZR1 cam in a 4.8L, you could upgrade to the Gen4 timing cover, LS2 timing set, and extend the cam sensor wires. This adds to the cost, but gives the benefit of being able to run any type of cam from then on.
Here's the Gen4 cover kit for $140. http://sdparts.com/details/gm-factor...arts/x12600325
You could probably find the timing set in the classifieds here for cheap. I believe all you need is the (2x) cam gear and bolts. I would get the whole set new though. http://sdparts.com/details/n-motion/sd7240
I'm going to have to extend my cam sensor wires in my 5.3L equipped truck when I install the LS7. http://sdparts.com/details/scoggin-d...nter/cas109081 $70
09-06-2011, 06:11 PM
#9
I've also seen pics of broken LS7 cylinders, including ones that were naturally aspirated.
11-17-2011, 12:40 PM
#15
https://ls1tech.com/forums/parts-cla...s-pistons.html
The only thing I had to change was the reluctor wheel (removed 58x, install 24x). I had the machine shop do this for me since they have the alignment tool.
12-01-2011, 03:41 PM
#17
I drove the car to work today. I like it!
It may be because I haven't driven anything fast in a year, but it feels like it pulls a lot harder than it did with the LS2, at the same boost (7.5 PSI). I do realize that 7.5 PSI on a high flowing engine is much more air flow than 7.5 PSI on a less flowing engine. I'm sure with the ZR1 cam and LSA heads, this engine flows a bit more.
I'm also very happy with the selection of the cam and 9.5 compression.
With this cam, I can't tell a difference in idle quality from the stock LS2 cam at a 550 RPM idle.
As for the compression choice...with the LS2's 11:1 compression, I had to run methanol along with 93 octane to achieve 14 degrees advance at peak torque (around 4400 RPM) IIRC. Without methanol, I could only run 9 degrees before it would knock, and at 9 deg, it ran like crap. So methanol was mandatory (or E85 or race gas).
With the 9.5:1 compression, I'm now running 20 degrees advance on 93 octane, no methanol! And like I said above, it pulls hard. Hard enough to break the tires loose from a 50 roll and make it go sideways.
It may be because I haven't driven anything fast in a year, but it feels like it pulls a lot harder than it did with the LS2, at the same boost (7.5 PSI). I do realize that 7.5 PSI on a high flowing engine is much more air flow than 7.5 PSI on a less flowing engine. I'm sure with the ZR1 cam and LSA heads, this engine flows a bit more.
I'm also very happy with the selection of the cam and 9.5 compression.
With this cam, I can't tell a difference in idle quality from the stock LS2 cam at a 550 RPM idle.
As for the compression choice...with the LS2's 11:1 compression, I had to run methanol along with 93 octane to achieve 14 degrees advance at peak torque (around 4400 RPM) IIRC. Without methanol, I could only run 9 degrees before it would knock, and at 9 deg, it ran like crap. So methanol was mandatory (or E85 or race gas).
With the 9.5:1 compression, I'm now running 20 degrees advance on 93 octane, no methanol! And like I said above, it pulls hard. Hard enough to break the tires loose from a 50 roll and make it go sideways.
