1988 Monte Carlo SS LS7 stock short block H/C/I belts out 660 RWHP N/A on 92 Octane!
10-22-2012, 09:48 PM
#1
1988 Monte Carlo SS LS7 stock short block H/C/I belts out 660 RWHP N/A on 92 Octane! Bottom line – 660 RWHP N/A!!!
Not sure why my latest graphs are so wavy at smoothing 5 compared to the baseline for the car (we tried strapping it down to the dyno the same as last time, then differently, made sure we had good tire pressure, re-checked pick-up connections, etc.) but really couldn’t isolate things. Run #16 is the baseline for the car before the heads/cam/intake/TB were installed. On run #4 (compared to run #1) I richened things up a bit at max RPM and you can see that the power jumped up slightly, however I also leaned things up a bit down low and lost 20ft/lbs of TQ so I will need to richen things up there again to get the torque back. It really is nice to see how long and broad the torque curve is!
It’s taken years of research, trial and error and R&D to get here but to say I’m excited is a bit of an understatement……I personally believe that this combo represents the most powerful stock factory short block N/A LS7 running a single DBW TB on 92 octane pump gas with under 12:1 static compression ratio! This is running the motor in 100% street trim (air filter, accessory belt, MAF, full exhaust, 315/35x17 tires on 17x10 wheels).
Some interesting max HP/TQ numbers along the way:
What makes this combo work? Could be anyone’s guess but I believe this boils down to having the “right” combination. I had Greg port the heads for an ultra-high lift cam and the cam I chose takes advantage of the fact that the heads flow to 0.750” lift. I could have chosen a cam with a wider or narrower split but I didn’t….I could have used an intake manifold with a larger plenum for more power up top but made it a dog in the midrange RPM and I elected not to do this. My exhaust system is certainly questionable given the fact that I have the headers starting out with 1-3/4” primaries where most guys making big HP numbers use at least a 2” primary. I personally built these headers 10 years ago when I first swapped an LS1 into my Monte Carlo and built the headers for maximum exhaust scavenging, not maximum tube size although there will be even more power to be had on the LS7 with larger primaries or maybe even a 4:2:1 tri-y since this LS7 motor is pushing in the neighborhood of 800 FWHP (675 RWHP uncorrected!).
I had the car on the chassis dyno for 3 weeks due to multiple commitments I had to keep and rather than continue tweaking this set-up for maybe a only few more HP (and get the torque curve back up) I really would like to crack 700RWHP on pump gas so the car is back home undergoing exhaust surgery for larger headers that I will fabricate and install new mufflers. I also have another intake manifold that I would like to try and likely another larger TB.
You can also debate why on earth do you want max power in the 7400RPM range? Simple answer for me…..in order to run high 9’s (complete street trim as the car sits at ~3560lbs w/driver) you need ~660 RWHP and if the suspension/tire combo was set-up to run high 9’s you would be in the ~142MPH range crossing the lights at ~7400RPM with the 4.11 gears and a 26” diameter tires that I have.
For some additional background, I baselined the complete stock LS7 crate motor with an 85mm LS2 MAF (I couldn’t use the OEM style LS7 cartridge MAF), ported 90mm TB, the Mezziere Electric water pump and BC2 clutch with Moser 12 bolt installed to ensure I had a good reference to compare the bolt-ons with. Before my current mods I tuned this set-up on the dyno for max power and this number is represented by the 492 RWHP / 474 RWTQ. What I found interesting is that when I first installed the motor and broke it in on this dyno (stock TB) its best numbers were 487/470 through a GM 8.5” drum brake 4.10 rear and stock LS7 clutch. I see that most people typically see gains in the 20 RWHP range by just adding the lighter clutch set-up but in my case I believe this was more than offset by going to the Moser 4.11 disc brake 12 bolt rear end.
And before the sharp-shooters with the wet rags come out proclaiming a “happy dyno” or wanting to know what kind of dyno tricks were used, shame on you. There were absolutely zero dyno tricks (using skinny tires out back, artificially controlling temperature at the weather station, cut & pasting numbers on the dyno sheet, etc) and this is not a “happy dyno”. I have dyno’d my car at a local tuner’s shop before and used this dyno the next day (virtually the same weather conditions) and came up ~5 RWHP short so it clearly isn’t on the high side. Just as another frame of reference, two weeks before putting my car back on this dyno a 1970 Olds W-30 455 with ported heads, aftermarket aluminum intake and carb, hi-perf cam, headers and low restriction 3" exhaust managed to knock out a whopping 325 RWHP through a TKO600 4 speed and 3.42 gears!
People who recognize my car or my name know me as a long time Internet contributor and Moderator of several Bulletin Board Forums so I believe my reputation for providing credible information is well beyond reproach. I provide this information freely in the interest of bettering the Internet High Performance Community and educating people who don’t know what is in the art of the possible with these motors.
And lastly but certainly not least I’d like to thank Steve Barker (632C2 on the Corvette Forum) for the countless days and weeks of having my car on his dyno for all of the trials, tuning and R&D work, THANKS Steve!
- Engine/Drivetrain Spec’s
- Stock 2006 LS7 crate motor short block
- Stock GM LS7 heads hand ported by Greg Good
-400+ CFM intakes
-250+ CFM exhausts
-66cc combustion chambers
-277cc intake runners
- PAC 1.55” Springs 640/240lbs
-250+ CFM exhausts
-66cc combustion chambers
-277cc intake runners
- PAC 1.55” Springs 640/240lbs
- 0.040” Cometic MLS head gaskets (11.79 SCR, 8.84 DCR)
- Solid Roller Cam by Bullet
-258*/273*; 112* + 4* LSA installed 108.5*
-0.781” intake
-0.747” exhaust
-Isky EZ-roll SR lifters
-Smith Bros 3/8” pushrods
-Jesel 1.8RR
-C5R Timing chain
-Crower adjustable Cam gear
-0.781” intake
-0.747” exhaust
-Isky EZ-roll SR lifters
-Smith Bros 3/8” pushrods
-Jesel 1.8RR
-C5R Timing chain
-Crower adjustable Cam gear
- Beck Sheetmetal intake
- Injector Dynamics ID1000 injectors
- NKG TR6iX spark plugs gapped at 0.040”
- GM Stock ignition coils and plug wires
- NW 102 TB
- LPE 100mm MAF
- True equal length 1-3/4” primary (round port, not D-port!) stepped to 1-7/8” headers; 30” overall length with 3-1/2” dia. merge collector, 3-1/2” dia head pipe to the X-pipe and full 3” exhaust w/Walker DynoMax reverse-flow mufflers and 3” tailpipes
- Meziere electric water pump
- ATI 10% underdrive crank pulley
- 4” dia inlet tubing with K&N conical filter
- Elite Engineering catch can
- RPS BC2 Clutch and Alum Flywheel
- T-56 2.66 1st gear transmission
- Moser 35 spline Tru-trac12 bolt 4.11 rear w/12” disc brakes
- 2.5 BAR E38 PCM tuning
Not sure why my latest graphs are so wavy at smoothing 5 compared to the baseline for the car (we tried strapping it down to the dyno the same as last time, then differently, made sure we had good tire pressure, re-checked pick-up connections, etc.) but really couldn’t isolate things. Run #16 is the baseline for the car before the heads/cam/intake/TB were installed. On run #4 (compared to run #1) I richened things up a bit at max RPM and you can see that the power jumped up slightly, however I also leaned things up a bit down low and lost 20ft/lbs of TQ so I will need to richen things up there again to get the torque back. It really is nice to see how long and broad the torque curve is!
It’s taken years of research, trial and error and R&D to get here but to say I’m excited is a bit of an understatement……I personally believe that this combo represents the most powerful stock factory short block N/A LS7 running a single DBW TB on 92 octane pump gas with under 12:1 static compression ratio! This is running the motor in 100% street trim (air filter, accessory belt, MAF, full exhaust, 315/35x17 tires on 17x10 wheels).
Some interesting max HP/TQ numbers along the way:
-stock LS7 intake w/90mm ported TB: 618/518 RWHP/RWTQ (stock injectors)
-ported LS7 intake w/90mm ported TB: 631/518 RWHP/RWTQ (stock injectors!)
-Beck Sheetmetal w/90mm ported TB: 639/522 RWHP/RWTQ (ID1000 injectors)
-Beck Sheetmetal w/102mm NW TB: 660/522 RWHP/RWTQ (ID1000 injectors)
One attribute that I found very interesting while tuning this combo that is certainly indicative of an N/A motor putting out mega-HP is the simple fact that I maxed out the 2006 ZO6 E38 PCM MAF table (Mass Air Flow g/sec at 511.99 @ 9815 Hz) using the LPE 100mm MAF starting at only 5673RPM. I had to switch this over to a 2.5 BAR operating system to expand the MAF table frequency in order to properly manipulate the A/F tables.-ported LS7 intake w/90mm ported TB: 631/518 RWHP/RWTQ (stock injectors!)
-Beck Sheetmetal w/90mm ported TB: 639/522 RWHP/RWTQ (ID1000 injectors)
-Beck Sheetmetal w/102mm NW TB: 660/522 RWHP/RWTQ (ID1000 injectors)
What makes this combo work? Could be anyone’s guess but I believe this boils down to having the “right” combination. I had Greg port the heads for an ultra-high lift cam and the cam I chose takes advantage of the fact that the heads flow to 0.750” lift. I could have chosen a cam with a wider or narrower split but I didn’t….I could have used an intake manifold with a larger plenum for more power up top but made it a dog in the midrange RPM and I elected not to do this. My exhaust system is certainly questionable given the fact that I have the headers starting out with 1-3/4” primaries where most guys making big HP numbers use at least a 2” primary. I personally built these headers 10 years ago when I first swapped an LS1 into my Monte Carlo and built the headers for maximum exhaust scavenging, not maximum tube size although there will be even more power to be had on the LS7 with larger primaries or maybe even a 4:2:1 tri-y since this LS7 motor is pushing in the neighborhood of 800 FWHP (675 RWHP uncorrected!).
I had the car on the chassis dyno for 3 weeks due to multiple commitments I had to keep and rather than continue tweaking this set-up for maybe a only few more HP (and get the torque curve back up) I really would like to crack 700RWHP on pump gas so the car is back home undergoing exhaust surgery for larger headers that I will fabricate and install new mufflers. I also have another intake manifold that I would like to try and likely another larger TB.
You can also debate why on earth do you want max power in the 7400RPM range? Simple answer for me…..in order to run high 9’s (complete street trim as the car sits at ~3560lbs w/driver) you need ~660 RWHP and if the suspension/tire combo was set-up to run high 9’s you would be in the ~142MPH range crossing the lights at ~7400RPM with the 4.11 gears and a 26” diameter tires that I have.
For some additional background, I baselined the complete stock LS7 crate motor with an 85mm LS2 MAF (I couldn’t use the OEM style LS7 cartridge MAF), ported 90mm TB, the Mezziere Electric water pump and BC2 clutch with Moser 12 bolt installed to ensure I had a good reference to compare the bolt-ons with. Before my current mods I tuned this set-up on the dyno for max power and this number is represented by the 492 RWHP / 474 RWTQ. What I found interesting is that when I first installed the motor and broke it in on this dyno (stock TB) its best numbers were 487/470 through a GM 8.5” drum brake 4.10 rear and stock LS7 clutch. I see that most people typically see gains in the 20 RWHP range by just adding the lighter clutch set-up but in my case I believe this was more than offset by going to the Moser 4.11 disc brake 12 bolt rear end.
And before the sharp-shooters with the wet rags come out proclaiming a “happy dyno” or wanting to know what kind of dyno tricks were used, shame on you. There were absolutely zero dyno tricks (using skinny tires out back, artificially controlling temperature at the weather station, cut & pasting numbers on the dyno sheet, etc) and this is not a “happy dyno”. I have dyno’d my car at a local tuner’s shop before and used this dyno the next day (virtually the same weather conditions) and came up ~5 RWHP short so it clearly isn’t on the high side. Just as another frame of reference, two weeks before putting my car back on this dyno a 1970 Olds W-30 455 with ported heads, aftermarket aluminum intake and carb, hi-perf cam, headers and low restriction 3" exhaust managed to knock out a whopping 325 RWHP through a TKO600 4 speed and 3.42 gears!
People who recognize my car or my name know me as a long time Internet contributor and Moderator of several Bulletin Board Forums so I believe my reputation for providing credible information is well beyond reproach. I provide this information freely in the interest of bettering the Internet High Performance Community and educating people who don’t know what is in the art of the possible with these motors.
And lastly but certainly not least I’d like to thank Steve Barker (632C2 on the Corvette Forum) for the countless days and weeks of having my car on his dyno for all of the trials, tuning and R&D work, THANKS Steve!
Last edited by John B; 10-22-2012 at 10:18 PM.
Trending Topics
10-23-2012, 10:46 AM
#9
TECH Enthusiast
iTrader: (6)
Join Date: Apr 2011
Location: South Chicago
Posts: 658
Likes: 0
Received 0 Likes
on
0 Posts
A Lsx engine in a SS is the engine that car should have always had, mean looking sob.
10-23-2012, 11:17 AM
#11
10-23-2012, 11:22 AM
#12
10-23-2012, 08:14 PM
#15
Thanks for all of the props guys!
You wouldn't make this comment if the nearest E85 gas station was 101 miles away one way from your house!
Not when you are an accomplished head porter like Greg Good!
Oh yes, I'll be right in line with all of the guys that brought their cars out on trailers 
Not really other than these were the best heads that he had done to date!
There's a pic of it at the bottom of my first post.
I only spin it up to ~7600RPM but I should video it on the dyno (I will at the track too)...it sounds absolutely incredible 
Angle mill the heads and run it on e85. Lack of compression on a motor like this is a waste!
Any issues with a 1.55 spring on factory castings?
So based on some of your comments I assume you will be taking it to the track?
Oh and just out of curiosity did Greg Good have much to say in the cathedral port versus rectangular port debate as far as making horsepower.
Any pix of the intake manifold?
It must sound awesome at 8k rpm.
10-24-2012, 06:13 AM
#19
TECH Enthusiast
iTrader: (13)
Join Date: Sep 2007
Location: SC
Posts: 666
Likes: 0
Received 0 Likes
on
0 Posts
I've always loved this car. I your car was part of the reason I did my swap in the first place. If those aren't some damn amazing numbers, I don't know what is. You definitely got your moneys worth!!
