Turbo thoughts and suggestions
Thread Starter
TECH Regular
Joined: Dec 2022
Posts: 444
Likes: 158
Turbo thoughts and suggestions Current setup
lc9 sbe (i have a rods/piston lc9 ready to go in when I have the time)
799 heads
Truck norris cam
Cast 7875 .96a/r vs turbo on 18ish lbs
E85 on terminator
Tremec magnum
Was considering upgrading/changing up my turbo setup. Looking into g42/73mm turbo from vs. Being a manual in a street car some better tip in turbo response would be nice.
The current hot side is not the greatest as I threw it together real quick with some 2.5in crossover and the merge location isn't the greatest. So if I upgrade I will redo that with a v band instead of the t4.
What a/r size would you recommend for that turbo on this engine. Whp goal around 800. I know the newer turbo tech will help with spool already but should I go with the the larger 1.15 or the 1.01 a/r or even the 1.28?
lc9 sbe (i have a rods/piston lc9 ready to go in when I have the time)
799 heads
Truck norris cam
Cast 7875 .96a/r vs turbo on 18ish lbs
E85 on terminator
Tremec magnum
Was considering upgrading/changing up my turbo setup. Looking into g42/73mm turbo from vs. Being a manual in a street car some better tip in turbo response would be nice.
The current hot side is not the greatest as I threw it together real quick with some 2.5in crossover and the merge location isn't the greatest. So if I upgrade I will redo that with a v band instead of the t4.
What a/r size would you recommend for that turbo on this engine. Whp goal around 800. I know the newer turbo tech will help with spool already but should I go with the the larger 1.15 or the 1.01 a/r or even the 1.28?
Teching In
Joined: May 2024
Posts: 3
Likes: 0
From: NE Oklahoma
Current setup
lc9 sbe (i have a rods/piston lc9 ready to go in when I have the time)
799 heads
Truck norris cam
Cast 7875 .96a/r vs turbo on 18ish lbs
E85 on terminator
Tremec magnum
Was considering upgrading/changing up my turbo setup. Looking into g42/73mm turbo from vs. Being a manual in a street car some better tip in turbo response would be nice.
The current hot side is not the greatest as I threw it together real quick with some 2.5in crossover and the merge location isn't the greatest. So if I upgrade I will redo that with a v band instead of the t4.
What a/r size would you recommend for that turbo on this engine. Whp goal around 800. I know the newer turbo tech will help with spool already but should I go with the the larger 1.15 or the 1.01 a/r or even the 1.28?
lc9 sbe (i have a rods/piston lc9 ready to go in when I have the time)
799 heads
Truck norris cam
Cast 7875 .96a/r vs turbo on 18ish lbs
E85 on terminator
Tremec magnum
Was considering upgrading/changing up my turbo setup. Looking into g42/73mm turbo from vs. Being a manual in a street car some better tip in turbo response would be nice.
The current hot side is not the greatest as I threw it together real quick with some 2.5in crossover and the merge location isn't the greatest. So if I upgrade I will redo that with a v band instead of the t4.
What a/r size would you recommend for that turbo on this engine. Whp goal around 800. I know the newer turbo tech will help with spool already but should I go with the the larger 1.15 or the 1.01 a/r or even the 1.28?
To address your overall question I would go with the 1.01. The newer turbo tech not only helps with spool, but better flowing hot sides also allow you to get away with a smaller A/R without sacrificing much flow up top. Especially if you don't plan to change the cam to get some more RPM, the smaller housing will be fine.
However, if it were me I would change the cam, do a 2¼" hotside, and the 1.28, and move your powerband higher.
Thread Starter
TECH Regular
Joined: Dec 2022
Posts: 444
Likes: 158
I was kicking around the idea of changing the cam up too... a little more top end would be cool
I do like the midrange i have but with a more efficient turbo I probably wouldn't really lose any maybe?
So what like a btr Stage 2 turbo cam?
I do like the midrange i have but with a more efficient turbo I probably wouldn't really lose any maybe?
So what like a btr Stage 2 turbo cam?
You don’t mention power goals at all. So its hard to make more exact suggestions. Ever run it at the track? Know the weight and trap speed? Draggy times etc?
G42 Seems like a lot of money for not much change. It is still a 75mm exh wheel. So you are just dropping 5mm off the compressor side. It will spool quicker. But It’s not going to be a night/day change worth $1000+ IMO.
Biggest bang for your buck would be to go to a twin scroll 1.25 T4 IMO. Then plumb 2" hotside to each side of the scroll. I'd run the S400 based unit in the 75-76mm range with the 87/96 exh wheel squeezed in. VS racing will make these for you for less than that G42. Forced Inductions makes a much more capable version. Or even a 1.10 T6 twin scroll.
If it’s a drag car I’d always say go with more cam. Who cares what it does below 4-5k… you shouldn’t ever have the RPM that low racing. The MS3 cam from Texas speed is pretty hard to beat for a stock headed drag 5.3.
If you want a responsive daily you aren’t revving the snot out of, I think you have an ok cam. Something like an aftermarket wheel S366-72 from forced inductions would pair well with that cam and be a night day spool difference. Capable of similar power as the entry level 78/75s.
Could throw 1.8 rockers on to bump that lift/duration up a tad. Then you don't' need to go through the hassle of tearing the cam out.
G42 Seems like a lot of money for not much change. It is still a 75mm exh wheel. So you are just dropping 5mm off the compressor side. It will spool quicker. But It’s not going to be a night/day change worth $1000+ IMO.
Biggest bang for your buck would be to go to a twin scroll 1.25 T4 IMO. Then plumb 2" hotside to each side of the scroll. I'd run the S400 based unit in the 75-76mm range with the 87/96 exh wheel squeezed in. VS racing will make these for you for less than that G42. Forced Inductions makes a much more capable version. Or even a 1.10 T6 twin scroll.
If it’s a drag car I’d always say go with more cam. Who cares what it does below 4-5k… you shouldn’t ever have the RPM that low racing. The MS3 cam from Texas speed is pretty hard to beat for a stock headed drag 5.3.
If you want a responsive daily you aren’t revving the snot out of, I think you have an ok cam. Something like an aftermarket wheel S366-72 from forced inductions would pair well with that cam and be a night day spool difference. Capable of similar power as the entry level 78/75s.
Could throw 1.8 rockers on to bump that lift/duration up a tad. Then you don't' need to go through the hassle of tearing the cam out.
The 2.25" crossover is good to something like 1600hp flywheel before it becomes a choke point. As others have said you need a turbo with a bigger turbine wheel. 800rwhp will get boring quickly and you will want more power. Trust me hahahah.
Thread Starter
TECH Regular
Joined: Dec 2022
Posts: 444
Likes: 158
Will definitely redo with a smaller pipe when the time comes... and I can see that but I don't wanna give up too much down low since it's street car only... also I'm traction limited. Its in my subaru with a r200 diff/axles and only so much room for tires
