Guess my HP
Dec 5, 2024 | 12:19 PM
#4
TECH Regular
Joined: Sep 2015
Posts: 484
Likes: 76
Good Guess.
If OP gave some more tune parameters, we'd narrow it our guesstimate down:
Injector flow rate, duty cycle, spark advance vs airmass table, and describe the exhaust system in some detail.
Has the factory stock 2-5/8 ID Cat to Head pipe flange been modified or REMOVED ? That restriction alone will cork you hard above 5000 rpm
If OP gave some more tune parameters, we'd narrow it our guesstimate down:
Injector flow rate, duty cycle, spark advance vs airmass table, and describe the exhaust system in some detail.
Has the factory stock 2-5/8 ID Cat to Head pipe flange been modified or REMOVED ? That restriction alone will cork you hard above 5000 rpm
Last edited by Fullpower; Dec 5, 2024 at 12:19 PM. Reason: f
Trending Topics
Dec 6, 2024 | 03:10 PM
#8
TECH Regular
Joined: Sep 2015
Posts: 484
Likes: 76
My magnuson shipped with GM 8.1 L Marine injectors, I think they flow about 42# hr.
I have same cam as you: 212/218 .550" Low Lift on a 4.8LS. 3.2" pulley on TVS1900 makes 11 PSI... My 2 limiting factors are the STOCK airbox and 3" Gibson full exhaust with shorty headers. Pretty sure that 3" pipe and MUFFLER strangles me at or a hair under 500 flywheel HP.
As I said in earlier post, IF you are running stock exhaust, that 2-5/8" INSIDE restriction is going to flatten your power above 4800 rpm.
I have same cam as you: 212/218 .550" Low Lift on a 4.8LS. 3.2" pulley on TVS1900 makes 11 PSI... My 2 limiting factors are the STOCK airbox and 3" Gibson full exhaust with shorty headers. Pretty sure that 3" pipe and MUFFLER strangles me at or a hair under 500 flywheel HP.
As I said in earlier post, IF you are running stock exhaust, that 2-5/8" INSIDE restriction is going to flatten your power above 4800 rpm.
Last edited by Fullpower; Dec 6, 2024 at 03:10 PM. Reason: spel chex
Dec 6, 2024 | 03:34 PM
#9
Thread Starter
Staging Lane
Joined: Jul 2024
Posts: 57
Likes: 10
From: Northern Indiana
My magnuson shipped with GM 8.1 L Marine injectors, I think they flow about 42# hr.
I have same cam as you: 212/218 .550" Low Lift on a 4.8LS. 3.2" pulley on TVS1900 makes 11 PSI... My 2 limiting factors are the STOCK airbox and 3" Gibson full exhaust with shorty headers. Pretty sure that 3" pipe and MUFFLER strangles me at or a hair under 500 flywheel HP.
As I said in earlier post, IF you are running stock exhaust, that 2-5/8" INSIDE restriction is going to flatten your power above 4800 rpm.
I have same cam as you: 212/218 .550" Low Lift on a 4.8LS. 3.2" pulley on TVS1900 makes 11 PSI... My 2 limiting factors are the STOCK airbox and 3" Gibson full exhaust with shorty headers. Pretty sure that 3" pipe and MUFFLER strangles me at or a hair under 500 flywheel HP.
As I said in earlier post, IF you are running stock exhaust, that 2-5/8" INSIDE restriction is going to flatten your power above 4800 rpm.
