Re-building an older FI motor
Re-building an older FI motor Application: 97 corvette. 142K miles 97 LS1 w/ Vortech V2 S-trim 6 PSI (the vortech cog-belt kit not the A&A setup) Automatic w/ 3.15 gears
Other modifications:
- Vararam cold air intake
- ported LS1 throttle body
- LS6 intake manifold
- 1.8 yella terra rockers w/ comp 1218 springs
- LG Super Pro long tube headers w/ cats and x pipe
- Borla Stinger exhaust
Loosing a considerable amount of boost to where i'm only getting 4psi max according to my boost gauge. Aside from a lack of boost, everything is running smooth and quiet.
With the engine being the weakest link in my drivetrain, I'm considering re-building the motor to take full advantage of the boost as well as adding an ECS mild blower cam and up to about 7-8psi.
Questions:
1) Assuming I rebuild my existing motor, what components would I be looking to replace? Type, brands etc? Any extra components i should add for strength?
2) Assuming seperate costs for engine removal, parts, machine work, part installation, and re-installation of motor, what cost range would I be looking at?
Goals:
- This car is a street car/daily driver only, but it driven on freequent spirited cruises. I'm not looking to set track records, but i want to be able to back up my boasting.
- 500 rwhp range on conservative tune (currently sitting the 385 range according to dynojet)
- No less than 22 MPG fuel economy with cruise control at highway speed (70-80mph)
Thanks for the help.
Other modifications:
- Vararam cold air intake
- ported LS1 throttle body
- LS6 intake manifold
- 1.8 yella terra rockers w/ comp 1218 springs
- LG Super Pro long tube headers w/ cats and x pipe
- Borla Stinger exhaust
Loosing a considerable amount of boost to where i'm only getting 4psi max according to my boost gauge. Aside from a lack of boost, everything is running smooth and quiet.
With the engine being the weakest link in my drivetrain, I'm considering re-building the motor to take full advantage of the boost as well as adding an ECS mild blower cam and up to about 7-8psi.
Questions:
1) Assuming I rebuild my existing motor, what components would I be looking to replace? Type, brands etc? Any extra components i should add for strength?
2) Assuming seperate costs for engine removal, parts, machine work, part installation, and re-installation of motor, what cost range would I be looking at?
Goals:
- This car is a street car/daily driver only, but it driven on freequent spirited cruises. I'm not looking to set track records, but i want to be able to back up my boasting.
- 500 rwhp range on conservative tune (currently sitting the 385 range according to dynojet)
- No less than 22 MPG fuel economy with cruise control at highway speed (70-80mph)
Thanks for the help.
Not sure how far you can hone out a 97 block, but I say a nice set of 3.903-3.905" Diamond or Wiseco pistons. Something around the 9.5:1 compression range. Add a set of Compstar or Eagle H-beam rods and run with a stock crank. A nice stout forged 346. I would get better set of heads than the older perimeter bolt 97 style. Don't get caught up on LS6 castings though. You dont want too much compression either. Get something decent. Match the cc of the head to the pistons to get the comp ratio you want. Also a decent blower cam would be a nice addition as well.
I would contact Erik at HKE as he is in Texas. He builds some of the best LSx motors.
I dont think you can push the older Vortech brand C5 cog kit past 7-8 psi so that should be ok. I have heard that Steve @ A&A has experience with those older kits, I would ask him.
I would contact Erik at HKE as he is in Texas. He builds some of the best LSx motors.
I dont think you can push the older Vortech brand C5 cog kit past 7-8 psi so that should be ok. I have heard that Steve @ A&A has experience with those older kits, I would ask him.
I made the numbers in my sig all motor with a set of older CNC ported 241 heads with larger valves and a G5X3 camshaft, FAST 90 and all bolt ons. They work when ported, however not many people use them anymore since there's many choices now. I plan on running my same heads (freshened of course) with my new setup. 346 with an A&A kit. My piston choice will yield about a 9.3:1 comp.
A stock 241 head might only be slightly better than your 806. Not really much of an upgrade. All depends on your budget and goals. A 317 head would be a better head and are found cheap. Just match the heads and pistons to get your desired comp ratio.
But......if you plan on making around 500 to the wheels a stock head should get you there easy and cheaply. On a budget, a fresh shortblock with forged pistons, mild blower cam stock heads and your kit 7-8 psi should make that 500 number no problem.
A stock 241 head might only be slightly better than your 806. Not really much of an upgrade. All depends on your budget and goals. A 317 head would be a better head and are found cheap. Just match the heads and pistons to get your desired comp ratio.
But......if you plan on making around 500 to the wheels a stock head should get you there easy and cheaply. On a budget, a fresh shortblock with forged pistons, mild blower cam stock heads and your kit 7-8 psi should make that 500 number no problem.
I'm not familier with the 317 head. Is that from a truck?
Yes, they are from a 6.0 truck (LQ9/LQ4). They are basically like an LS6 head with a larger combustion chamber to lower compression (72cc). Many people use them on a 5.7 to drop the compression for forced induction and have the flow like an LS6 243. We just installed a ported set of these on my buddy's car with a procharger. Dropped the compression from 10.0:1 down to about 9.5:1.
853/241 head 66cc
243/LS6 head 64cc
317 72cc.
853/241 head 66cc
243/LS6 head 64cc
317 72cc.
OP, first, your motor is not the weakest link right now. Your boost leak is. Figure out where your boost is leaking. It may be a blower problem which can add significant overhead to your current budget.
Second is that the 97-98 LS1 blocks and heads are the least desirable. This is a great time to hunt down a 6.0 iron block with 317 heads. Bore it out .030, stuff a decent rod and piston in there and call it a day unless you're intending on really digging in.
Second is that the 97-98 LS1 blocks and heads are the least desirable. This is a great time to hunt down a 6.0 iron block with 317 heads. Bore it out .030, stuff a decent rod and piston in there and call it a day unless you're intending on really digging in.
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This afternoon while clearning off grime from a road trip, I decided to check the tooth-count on my SC pulley. it's a 34 tooth cog belt. The Owners manual says the kit is supposed to come with a 30-tooth belt. This is a pre-owned kit with the previous installation being on an 02 Zo6. My only conclusion is that the ZO6 owner had the pulley changed to go easier on the motor if he were running decked heads, a stroker kit or something else.
A new 30 tooth pulley will be on the way here on monday. Going back to this size should get me between 3-3.5 more psi and according to my calculations put me in the ~440 rwhp range (see math below)
Current HP: 386 rwhp = ~471 Crank assuming 18% drivetrain loss for Auto Transmission
Vortech blower average ~18 rwhp per psi on LS1 stock motors based roughly on the LS1 tech article here:
https://ls1tech.com/forums/forced...l-results.html
18 x 3.0 = 54rwhp gain
+386 original rwhp + gain = 440 rwhp = ~537 crank hp
Extremely satisfactory numbers for my street machine.
A new 30 tooth pulley will be on the way here on monday. Going back to this size should get me between 3-3.5 more psi and according to my calculations put me in the ~440 rwhp range (see math below)
Current HP: 386 rwhp = ~471 Crank assuming 18% drivetrain loss for Auto Transmission
Vortech blower average ~18 rwhp per psi on LS1 stock motors based roughly on the LS1 tech article here:
https://ls1tech.com/forums/forced...l-results.html
18 x 3.0 = 54rwhp gain
+386 original rwhp + gain = 440 rwhp = ~537 crank hp
Extremely satisfactory numbers for my street machine.
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Verdad Gallardo This afternoon while clearning off grime from a road trip, I decided to check the tooth-count on my SC pulley. it's a 34 tooth cog belt. The Owners manual says the kit is supposed to come with a 30-tooth belt. This is a pre-owned kit with the previous installation being on an 02 Zo6. My only conclusion is that the ZO6 owner had the pulley changed to go easier on the motor if he were running decked heads, a stroker kit or something else.
A new 30 tooth pulley will be on the way here on monday. Going back to this size should get me between 3-3.5 more psi and according to my calculations put me in the ~440 rwhp range (see math below)
Current HP: 386 rwhp = ~471 Crank assuming 18% drivetrain loss for Auto Transmission
Vortech blower average ~18 rwhp per psi on LS1 stock motors based roughly on the LS1 tech article here:
https://ls1tech.com/forums/forced...l-results.html
18 x 3.0 = 54rwhp gain
+386 original rwhp + gain = 440 rwhp = ~537 crank hp
Extremely satisfactory numbers for my street machine.
A new 30 tooth pulley will be on the way here on monday. Going back to this size should get me between 3-3.5 more psi and according to my calculations put me in the ~440 rwhp range (see math below)
Current HP: 386 rwhp = ~471 Crank assuming 18% drivetrain loss for Auto Transmission
Vortech blower average ~18 rwhp per psi on LS1 stock motors based roughly on the LS1 tech article here:
https://ls1tech.com/forums/forced...l-results.html
18 x 3.0 = 54rwhp gain
+386 original rwhp + gain = 440 rwhp = ~537 crank hp
Extremely satisfactory numbers for my street machine.
