Going with 441 LS7 build. Anyone done this, please leave advice or opinions.
12-14-2011, 08:12 AM
#1
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Going with 441 LS7 build. Anyone done this, please leave advice or opinions. I'm using what I already have for now. If you can give advice on how to make what I have work, or what issues I may have, or pitfalls to avoid, I'd appreciate it. 
- LS7 block, stock bore, honed to 4.126
- 4.125 forged crank
- 6.125 connecting rods
- Cam is being checked by Comp Cams for specs; I may know what it is today. Will have to be reground though, or I will buy another based off that cam's specs .. maybe bigger? because of the increase in cubes from 422 to 441? You guys tell me.
- 2.02 aluminum heads. Sorry: just don't have the funds to replace with a LS7 set right now.
- stock intake
- dual pumps with Racetronics (sp) and variable booster
- 55 # Injectors
- D-1SC Procharger with 8 rib pullies and SuperDamper. Crank pinned on both sides (got tired of that problem real quick)
- Plan to upgrade from stock MAF to 100+ mm MAF. Some suggested do a MAF-less tune. But I need more information. Never done that.
- I have EFILive FlashScan v2 for tuning
- I know I need to have a dipstick hole drilled. Any advice or instructions on that?
Helpful responses appreciated. Thanks!
- LS7 block, stock bore, honed to 4.126
- 4.125 forged crank
- 6.125 connecting rods
- Cam is being checked by Comp Cams for specs; I may know what it is today. Will have to be reground though, or I will buy another based off that cam's specs .. maybe bigger? because of the increase in cubes from 422 to 441? You guys tell me.
- 2.02 aluminum heads. Sorry: just don't have the funds to replace with a LS7 set right now.
- stock intake
- dual pumps with Racetronics (sp) and variable booster
- 55 # Injectors
- D-1SC Procharger with 8 rib pullies and SuperDamper. Crank pinned on both sides (got tired of that problem real quick)
- Plan to upgrade from stock MAF to 100+ mm MAF. Some suggested do a MAF-less tune. But I need more information. Never done that.
- I have EFILive FlashScan v2 for tuning
- I know I need to have a dipstick hole drilled. Any advice or instructions on that?
Helpful responses appreciated. Thanks!
12-14-2011, 08:46 AM
#3
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Thread Starter
A 442! Woo hooo!! LOL!
On a serious note, that's interesting, KCS. I will take that advice to my mechanic. Thanks for the input!
12-15-2011, 01:22 PM
#7
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Thanks for the heads-up. I will only run max 12 PSI or so. I have another pulley to bump it down if I want ... maybe about 8 or 9 PSI ... if I am uncomfortable with the KR values.
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12-15-2011, 01:25 PM
#8
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I could use some knowledge about putting an LS7 into a 1998 Trans Am. Will I need some harness extensions or adapters for cam sensor or other connections?
12-15-2011, 02:59 PM
#9
Have Steve at Race Engine Development install Darton sleeves in your block. Then you will be pretty much bullet proove.
Steve can re-sleeve an LS7 block up to a 4.185" bore. With a 4.125" crank that will give you 454" ci., which is the route I am going with.
Steve can re-sleeve an LS7 block up to a 4.185" bore. With a 4.125" crank that will give you 454" ci., which is the route I am going with.
12-15-2011, 08:58 PM
#10
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Just my sought... Anybody that knows, and is honest will tell, what's to come is a build and a rebuild, and it can get on the way of all things we spec. You ask, so... here it is... what i would do? sell the super charger and the 4.125 crank and the heads you got now, & stop compromising, think,.... you already have the money there, get a kick a.. set heads, and a 4" crank, re sleeve the block and make it a 440Ci , have Patrick G spec one out for your combo, and set out to beat the adds, the simple and clean lean and mean way. Wish ever way you go, take your time, and do it rite, and will be more fun that rushing to compromise. After all, you may end up making the same power, and the car will run cool all day, not to talk about the value, of a real kick a.. LS7 in that TA...? ohhhhm, i can see wheelies everywhere.....
12-17-2011, 04:18 PM
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Can the D1 provide 12 lbs on a 442 without spinning it to the ragged edge? F series blower would seem be a better fit.
Camster has some good advice. Dry sleeved LS7 block would be a far stronger foundation to start from. You could also sell the LS7 block outright and sleeve an LS2 or 3 and maybe save a few bucks.
Camster has some good advice. Dry sleeved LS7 block would be a far stronger foundation to start from. You could also sell the LS7 block outright and sleeve an LS2 or 3 and maybe save a few bucks.
12-18-2011, 07:56 AM
#16
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Interesting what these guys are doing:
GM Performance Supercharged LS7
One vendor did tell me the compression is a key factor in whether their high-displacement LS7's were designed to handle boost or not.
I did feel the 12 to 13 PSI my 422 peaked at would drop with 441 cid. But, I also have a larger pulley to reduce the boost some more, if the cubes delivered the bulk of the power I wanted.
Some say why boost an engine only 5 PSI (I read that in another post). When I first put the D-1SC on my stock engine at 5 PSI, that amount of boost may not seem like much. But, 5 PSI of boost took my dyno performance from a 296.3 RWHP and 358.2 RWTQ, SAE corrected (this is an automatic) to 486.3 RWHP and 487.0 Max RWTQ, SAE corrected.
5 PSI of boost on the Procharger resulted in nearly 40% increase in power!
If the LS7 441 NA only made, say 500 to 600 RWHP, for comparision sake, 40% increase in power would yield 700 to nearly 750 RWHP.
... on a modest 5 to 7 PSI of boost.
Maybe ...
I'm just speculating ...
GM Performance Supercharged LS7
The LS7's cast aluminum pistons were replaced to enhance strength under high cylinder pressure and reduce compression. Forged-aluminum coated pistons from Diamond are used. They are dished to lower the compression ratio to a detonation-avoiding 9.0:1. The blower-specific pistons also have a thick crown and reinforced pin bosses.
Stock 2.16-inch titanium intake valves and aftermarket (but stock-size) 1.59-inch Inconel exhaust valves are used. The thermal properties of the Inconel valves better suit the higher combustion temperatures of a force-inducted engine.
On the 6.2L LS9, the blower generates about 10.5 pounds of boost, but only about half that with the 7.0L displacement, so Thomson machined a new, smaller-diameter pulley to spin the blower faster and bring the boost up to about 14 psi.
Some say why boost an engine only 5 PSI (I read that in another post). When I first put the D-1SC on my stock engine at 5 PSI, that amount of boost may not seem like much. But, 5 PSI of boost took my dyno performance from a 296.3 RWHP and 358.2 RWTQ, SAE corrected (this is an automatic) to 486.3 RWHP and 487.0 Max RWTQ, SAE corrected.
5 PSI of boost on the Procharger resulted in nearly 40% increase in power!
If the LS7 441 NA only made, say 500 to 600 RWHP, for comparision sake, 40% increase in power would yield 700 to nearly 750 RWHP.
... on a modest 5 to 7 PSI of boost.
Maybe ...
I'm just speculating ...
12-18-2011, 08:16 AM
#17
From what I have read and been told the ls7 is not the block to boost. If you are serious about running boost then maybe you should consider either resleeving or selling that block and going with an ls3.
I would try and talk with some of the vendors to hear what they have to say. I know AES had a boost specific 390 short block that was designed to take the abuse.
I would try and talk with some of the vendors to hear what they have to say. I know AES had a boost specific 390 short block that was designed to take the abuse.
12-20-2011, 05:04 AM
#18
5 PSI of boost on the Procharger resulted in nearly 40% increase in power!
If the LS7 441 NA only made, say 500 to 600 RWHP, for comparision sake, 40% increase in power would yield 700 to nearly 750 RWHP.
... on a modest 5 to 7 PSI of boost.
Maybe ...
I'm just speculating ...
If the LS7 441 NA only made, say 500 to 600 RWHP, for comparision sake, 40% increase in power would yield 700 to nearly 750 RWHP.
... on a modest 5 to 7 PSI of boost.
Maybe ...
I'm just speculating ...
ex. 5psi may have given you almost 200 more hp but 10psi wont give you 400.. catch my drift? That increase in power % is going to shrink as you add more boost and try for more ponies.
BTW- some interesting suggestions in here. OP- it does sound like you are compromising some here, everyone knows a true gear head will get bored with what they have (power wise at least) sooner or later (usually sooner) so why start off with something that is already going to be maxed out? A non-friendly FI engine and a blower that is spinning for all its worth. Id really think about this before hitting the green light.
12-20-2011, 09:49 AM
#19
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Thanks again for all the advice.
As a counterpoint, all the vendors I talk to say if I get dished pistons designed for boost, make the compression ratio fit a boosted configuration and my internals are forged (as they are), it's all in the tune.
Some others who claim success at boosting even a stock LS7:
As a counterpoint, all the vendors I talk to say if I get dished pistons designed for boost, make the compression ratio fit a boosted configuration and my internals are forged (as they are), it's all in the tune.
Some others who claim success at boosting even a stock LS7:
There is always going to be a limit to any engine with how much boost it can withstand to hold. Increasing the durability of the rotating assembly allows to increase that limit but the engine itself can only withstand so much cylinder pressure before things exit stage left.
The key ingredient to keeping an LS7 happy with higher boost levels is in the tune. You can rattle an LS7 apart at 10psi if you didn't know what you were doing. With that being said we've pushed a stock sleeved stock LS7 block to 23psi without any damage so asking for it to handle 15psi in your set up is just fine.
The key ingredient to keeping an LS7 happy with higher boost levels is in the tune. You can rattle an LS7 apart at 10psi if you didn't know what you were doing. With that being said we've pushed a stock sleeved stock LS7 block to 23psi without any damage so asking for it to handle 15psi in your set up is just fine.
At 7.0 liters and 7.5 lbs of boost on our stage 2 engine package utilizing our MTI Racing proprietary cylinder heads and valvetrain, we have acheived over 800 horsepower on a STOCK LS7 in our engine dyno test cell.
The final product is quite amazing. Huge power and tons of torque down low in the rev range where you drive the car. (600 rear wheel torque at 3000rpm and above)
The final product is quite amazing. Huge power and tons of torque down low in the rev range where you drive the car. (600 rear wheel torque at 3000rpm and above)
We have run 25 psi of turbocharged boost (1500+ hp and 1500+ lb-ft of torque) with the LS7 block in our customer's standing mile Z06. We also have lots of customers running 10 to 15 psi of boost on turbocharged and supercharged LS7 blocks without any block related problems.
12-20-2011, 10:03 AM
#20
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Speculating indeed. As you add more power and search for more ponies outta the engine, you will find its much harder to produce higher numbers. The higher the hp number, the more boost it would take to get there.
ex. 5psi may have given you almost 200 more hp but 10psi wont give you 400.. catch my drift? That increase in power % is going to shrink as you add more boost and try for more ponies.
ex. 5psi may have given you almost 200 more hp but 10psi wont give you 400.. catch my drift? That increase in power % is going to shrink as you add more boost and try for more ponies.
The Z06 arrived as a 2006 model in the third quarter of 2005. It had a new 7.0 L (7,008 cc/427.6 cu in) version of the Small-Block engine codenamed LS7, which produced 505 hp.
The complete HO Intercooled ProCharger System will transform your new C6 Corvette Z06 into a 714+ flywheel horsepower monster, capable of destroying many exotic supercars of two to four times the cost. After installing a ProCharger on your LS7, your Corvette will have a .22 power to weight ratio- that means your C6 Z06 will be faster than the following: 2009 Corvette ZR1, 2008 Mercedes SLR McLaren, 2008 Porsche Carrera GT, and 2008 Ferrari F430!