What camshaft are you using in your boosted application?
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
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What camshaft are you using in your boosted application? Can you guys share your setups and what cam you are using? The more info the better but engine size, intake manifold and turbo specs would be appreciated. If you can describe how it spools up, horsepower, how far you rev to and if you are satisfied with the results that would be awesome.
My cam is a LJMS stage 1, 222/227 and 113lsa +3. My set up is a .030" over 5.3, cnc'd ls6 heads, flat top pistons, huronspeed, ls6 intake, 4l80e no transbrake, 3.25 rear end gears, 3000rpm stall converter, 25" tires, the basic cast $400 VS 7875 turbo with .96ar turbine housing.
It revved to 6200rpm and made 550whp on 13psi. Bottom end is lacking imho, can barely get it to spin tires, probably could use some more tuning before I would even think about swapping cams. (I have been thinking high lift truck type cam)
Since all that, I swapped over to a VS G42 clone - 80mm journal bearing turbo with a 1.25ar housing and a 4" bumper exit exhaust. Getting bigger injectors/more fuel. I can update after the new set up is done. I want 700whp and good torque, enough to be a little scary. Sounds like I can get there pretty easy with correct parts and tune.
My cam is a LJMS stage 1, 222/227 and 113lsa +3. My set up is a .030" over 5.3, cnc'd ls6 heads, flat top pistons, huronspeed, ls6 intake, 4l80e no transbrake, 3.25 rear end gears, 3000rpm stall converter, 25" tires, the basic cast $400 VS 7875 turbo with .96ar turbine housing.
It revved to 6200rpm and made 550whp on 13psi. Bottom end is lacking imho, can barely get it to spin tires, probably could use some more tuning before I would even think about swapping cams. (I have been thinking high lift truck type cam)
Since all that, I swapped over to a VS G42 clone - 80mm journal bearing turbo with a 1.25ar housing and a 4" bumper exit exhaust. Getting bigger injectors/more fuel. I can update after the new set up is done. I want 700whp and good torque, enough to be a little scary. Sounds like I can get there pretty easy with correct parts and tune.
Has nothing to do with your cam or motor. (assuming its tuned correctly). Its the converter. What does the "3000" rpm converter actually rev to when you press the brake and mat the gas?
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From: Alaska
OP: "describe how it spools up,"
.
stock gen III 5.3L, TSP 208/214 .551" Low-Lift VSR78/75 billet .96 A/R 2600 stall, 3.73 gear 6000 pound 4WD.
Estimated 600 crank horse, maybe 500 wheel. idle spark 23 degrees, my SPOOL strategy is to run it lean at 14.7 until 110 kPa, maximum possible timing on 90 octane until the LAST row on airmass = 1.20 g/sec where I have 9 degrees spark, except at the torque peak 4000 -4400 rpm had to go down 6 degrees advance.
PE starts out at 10%, but I pour on 28% in the 4000 -4400 rpm cells, again, Knock mitigation for 90 octane.
My BE starts gentle at 9% 125 kPa and rolls up to 25% over 165kPa
.
Was supplementing fuel with Toluene, Acetone and Isopropyl on initial tune up, and construction of spark table, estimated 92 octane for the first couple hundred miles, was regularly pushing 193kPa over 12 # wastegate springs.
Have since backed off to 10.5# spring pack, and running 90 octane straight pump gas at 180 kPa.
spools up damn quick. No dragy times to report, but 45 mph to 110 is a RUSH !
.
stock gen III 5.3L, TSP 208/214 .551" Low-Lift VSR78/75 billet .96 A/R 2600 stall, 3.73 gear 6000 pound 4WD.
Estimated 600 crank horse, maybe 500 wheel. idle spark 23 degrees, my SPOOL strategy is to run it lean at 14.7 until 110 kPa, maximum possible timing on 90 octane until the LAST row on airmass = 1.20 g/sec where I have 9 degrees spark, except at the torque peak 4000 -4400 rpm had to go down 6 degrees advance.
PE starts out at 10%, but I pour on 28% in the 4000 -4400 rpm cells, again, Knock mitigation for 90 octane.
My BE starts gentle at 9% 125 kPa and rolls up to 25% over 165kPa
.
Was supplementing fuel with Toluene, Acetone and Isopropyl on initial tune up, and construction of spark table, estimated 92 octane for the first couple hundred miles, was regularly pushing 193kPa over 12 # wastegate springs.
Have since backed off to 10.5# spring pack, and running 90 octane straight pump gas at 180 kPa.
spools up damn quick. No dragy times to report, but 45 mph to 110 is a RUSH !
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
Likes: 33
Unfortunately I can't drive the car to tell you until I get the exhaust done. Huronspeed hasnt gotten back to me about when they can take the car.
This is the converter. It probably doesn't flash high enough but I know if I make more torque it will flash higher. The tuner made it go dead rich as soon as it hits 0psi of boost. I posted my dyno before but its pretty weak imho, especially on the low end. If I were a betting man I bet a better tune could get it where I want it. If not I would look at a cam with a bit more low end grunt as a next resort before buying a different torque converter. But dyno time is expensive and I hope to do it as few times as necessary, so I want what is hopefully my "final boss" combo for this car before I dyno again. Hope all that makes sense. Lol
https://www.jegs.com/i/JEGS/555/60414/10002/-1
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
Likes: 33
OP: "describe how it spools up,"
.
stock gen III 5.3L, TSP 208/214 .551" Low-Lift VSR78/75 billet .96 A/R 2600 stall, 3.73 gear 6000 pound 4WD.
Estimated 600 crank horse, maybe 500 wheel. idle spark 23 degrees, my SPOOL strategy is to run it lean at 14.7 until 110 kPa, maximum possible timing on 90 octane until the LAST row on airmass = 1.20 g/sec where I have 9 degrees spark, except at the torque peak 4000 -4400 rpm had to go down 6 degrees advance.
PE starts out at 10%, but I pour on 28% in the 4000 -4400 rpm cells, again, Knock mitigation for 90 octane.
My BE starts gentle at 9% 125 kPa and rolls up to 25% over 165kPa
.
Was supplementing fuel with Toluene, Acetone and Isopropyl on initial tune up, and construction of spark table, estimated 92 octane for the first couple hundred miles, was regularly pushing 193kPa over 12 # wastegate springs.
Have since backed off to 10.5# spring pack, and running 90 octane straight pump gas at 180 kPa.
spools up damn quick. No dragy times to report, but 45 mph to 110 is a RUSH !
.
stock gen III 5.3L, TSP 208/214 .551" Low-Lift VSR78/75 billet .96 A/R 2600 stall, 3.73 gear 6000 pound 4WD.
Estimated 600 crank horse, maybe 500 wheel. idle spark 23 degrees, my SPOOL strategy is to run it lean at 14.7 until 110 kPa, maximum possible timing on 90 octane until the LAST row on airmass = 1.20 g/sec where I have 9 degrees spark, except at the torque peak 4000 -4400 rpm had to go down 6 degrees advance.
PE starts out at 10%, but I pour on 28% in the 4000 -4400 rpm cells, again, Knock mitigation for 90 octane.
My BE starts gentle at 9% 125 kPa and rolls up to 25% over 165kPa
.
Was supplementing fuel with Toluene, Acetone and Isopropyl on initial tune up, and construction of spark table, estimated 92 octane for the first couple hundred miles, was regularly pushing 193kPa over 12 # wastegate springs.
Have since backed off to 10.5# spring pack, and running 90 octane straight pump gas at 180 kPa.
spools up damn quick. No dragy times to report, but 45 mph to 110 is a RUSH !
This is good info, thank you!
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On The Tree
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Im assuming this is an electronic boost controller? If it is you can ramp it in way harder down low. Sometimes the ebc is a pain and you can always disconnect it and run a manual controller to see if thats whats causing the slow spool. You could also have incorrect timing which would make it run rough and have no low end.
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
Likes: 33
Im assuming this is an electronic boost controller? If it is you can ramp it in way harder down low. Sometimes the ebc is a pain and you can always disconnect it and run a manual controller to see if thats whats causing the slow spool. You could also have incorrect timing which would make it run rough and have no low end.
Yes it is.
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
Likes: 33
For reference this very very similar combo was making 562ftlbs at 4000rpms. Its a t56 so its not a converter causing the high torque reading. I didn't intend for this thread to be all about my diagnosing car but I think I better check some basic things...
https://ls1tech.com/forums/forced-in...questions.html
https://ls1tech.com/forums/forced-in...questions.html
Without seeing a datalog of what is actually going on, there is no way to know if the problem is the tune or not. Slow spool and power falling off too quick on the top end could be a result of any number of mechanical or tune related issues. A log would at least give people a better idea of what direction to look in.
Unfortunately I can't drive the car to tell you until I get the exhaust done. Huronspeed hasnt gotten back to me about when they can take the car.
This is the converter. It probably doesn't flash high enough but I know if I make more torque it will flash higher. The tuner made it go dead rich as soon as it hits 0psi of boost. I posted my dyno before but its pretty weak imho, especially on the low end. If I were a betting man I bet a better tune could get it where I want it. If not I would look at a cam with a bit more low end grunt as a next resort before buying a different torque converter. But dyno time is expensive and I hope to do it as few times as necessary, so I want what is hopefully my "final boss" combo for this car before I dyno again. Hope all that makes sense. Lol
https://www.jegs.com/i/JEGS/555/60414/10002/-1
This is the converter. It probably doesn't flash high enough but I know if I make more torque it will flash higher. The tuner made it go dead rich as soon as it hits 0psi of boost. I posted my dyno before but its pretty weak imho, especially on the low end. If I were a betting man I bet a better tune could get it where I want it. If not I would look at a cam with a bit more low end grunt as a next resort before buying a different torque converter. But dyno time is expensive and I hope to do it as few times as necessary, so I want what is hopefully my "final boss" combo for this car before I dyno again. Hope all that makes sense. Lol
https://www.jegs.com/i/JEGS/555/60414/10002/-1
Those converters stall rating is a guess at best. As they assume X amount of NA hp and X weight vehicle with Y gearing/tire load. So it may stall to 3200 behind a built 6.0 in a 4500lb truck with 3.10 gears and a 30" tire. But behind a mild 5.3 at much lighter weights and shorter gear/tire, it may stall to 2400. So if you can’t foot brake over 3k with “na power”. Then its going to be difficult to light the turbo off efficiently no matter what cam or tune U have in it.
For reference this very very similar combo was making 562ftlbs at 4000rpms. Its a t56 so its not a converter causing the high torque reading. I didn't intend for this thread to be all about my diagnosing car but I think I better check some basic things...
https://ls1tech.com/forums/forced-in...questions.html
https://ls1tech.com/forums/forced-in...questions.html
make sure there are zero leaks as well. You should get the mpvi from hp tuners so you can log whats going on. Thats gonna be the easiest solution instead of just chasing your tail
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
Likes: 33
This converter ain't cheap. Lol. Its the equivalent to the XHD series Sloppy Mechanics ran back in the day with good results. It does have a anti balloon plate built in. If it was total crap it would flash really high with any amount of power. Honestly it feels pretty good to me. I'm going to play with tune and check for leaks etc before making any more big changes.
XHD th400 version:
https://www.jegs.com/i/JEGS/555/60429/10002/-1
Thread Starter
On The Tree
Joined: Oct 2012
Posts: 198
Likes: 33
Most would say my rear end gear is too low as well, 3.25. But I like the cruise rpm. Overall I am happy with the manners of the car so I'd rather not change the stall or change gears. I consider those last resort since this car is really just a nice day daily driver. I think I can get where I want with a better tune and making sure everything is done correctly.
I will post my tune this weekend if I have time. I was told before the timing looked ok but was way too rich.
I will post my tune this weekend if I have time. I was told before the timing looked ok but was way too rich.
Most would say my rear end gear is too low as well, 3.25. But I like the cruise rpm. Overall I am happy with the manners of the car so I'd rather not change the stall or change gears. I consider those last resort since this car is really just a nice day daily driver. I think I can get where I want with a better tune and making sure everything is done correctly.
I will post my tune this weekend if I have time. I was told before the timing looked ok but was way too rich.
I will post my tune this weekend if I have time. I was told before the timing looked ok but was way too rich.
This converter ain't cheap. Lol. Its the equivalent to the XHD series Sloppy Mechanics ran back in the day with good results. It does have a anti balloon plate built in. If it was total crap it would flash really high with any amount of power. Honestly it feels pretty good to me. I'm going to play with tune and check for leaks etc before making any more big changes.
XHD th400 version:
https://www.jegs.com/i/JEGS/555/60429/10002/-1
XHD th400 version:
https://www.jegs.com/i/JEGS/555/60429/10002/-1
It drove terrible on the street, wouldn't hardly flash, it would hit a wall at 3,000rpm which was way outside its happy zone but with the bottle turned on, it was a completely different animal.
There's a reason people use PTC, FTI or Circle D regularly and not Jegs.
You may very well need to throw more power it as well.
My current converter wasn't locking up very well shifting at 6,500rpm, very little rpm drop, I moved my shift points out to 7,000rpm and it got much tighter which was visible in the rpm drop on the logs.
I don't think the dyno is that far off either, a stock LS 5.3 makes 270-290chp.
Factor in cam and heads and say you're at 350chp, -20% for drivetrain losses through the 4L80 and you end up at 280whp.
13 psi is nearly double atmosphere so you're right on at 550whp.
You've got a little engine that needs rpm to spool up and the converter enables or inhibits that.
If you aren't using an EBC, start there, those bring the boost in down low way faster than gate alone.
2.48 first x 3.25 out back is 8.06 starting line ratio (SLR). For a street car that's plenty of gear.
When it comes to converters, the general rule of thumb is, shift drop of +1200 is okay for a street car and <1200 is what you'd want for a drag car. So once you start hitting it with your planned boost, and let's say the shift drop is 1400, it's okay for a street oriented combo. To go into more detail, it's all about what you want. Folks will generally want the shift drop to keep you in the best part of your power band, and to also dropping you say down around peak torque where you have timing pulled.
When it comes to converters, the general rule of thumb is, shift drop of +1200 is okay for a street car and <1200 is what you'd want for a drag car. So once you start hitting it with your planned boost, and let's say the shift drop is 1400, it's okay for a street oriented combo. To go into more detail, it's all about what you want. Folks will generally want the shift drop to keep you in the best part of your power band, and to also dropping you say down around peak torque where you have timing pulled.