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maggied LS2 adding Headers what pulleys?

1K views 9 replies 7 participants last post by  Remo 
#1 ·
LS2 maggied V, im getting 5.5 psi with the 2.8 top and stock crank pulley. It has a zoomers cat back system. I am going to install 1 7/8 headers with no cats this week. I was told the boost would drop with the headers and no cats. I have a 8in crank pulley and a 2.7in blower pulley on hand. Im looking for 8.5 to 9 psi, can anyone tell me what pulley setups to get me in the ball park? Or tell me what psi they are getting?

Also do i need to run a diffrent spark plug? I am running stock plugs with 35,000 miles now.


Thanks
Remo
 
#3 ·
I don't know much about your other question, but you should be running some NGK TR6 plugs. I would run the Iridium Plug...NGKTR6IX
Yup, that's exactly what I would recommend, as I made that exact change. With the "stock" boost, you can probably be fine with the stock spark plug. If you overboost the maggie, however, I'd recommend going to this exact colder plug.

LS2 maggied V, im getting 5.5 psi with the 2.8 top and stock crank pulley. It has a zoomers cat back system. I am going to install 1 7/8 headers with no cats this week. I was told the boost would drop with the headers and no cats. I have a 8in crank pulley and a 2.7in blower pulley on hand. Im looking for 8.5 to 9 psi, can anyone tell me what pulley setups to get me in the ball park? Or tell me what psi they are getting?
With just the 8" crankpulley, I got ~9psi. I live in So Cal. At times, and for reasons I can't explain, I would see ~10psi. Go figure.

The entire rwtq will shift up with this change. It is significant and it is noticable. I'd say that 30+ rwtq after the change is what you should see (note--this is WITHOUT considering the headers--I never ran headers, so you might/should see even more).

A 2.6" pulley will get you approx the same boost as a 8" (it is a little less, but it's fairly close), but I got belt-slip, so keep that in mind.

I never ran a 2.7" pulley. I wouldn't waste your time with it though if you have the 8" crankpulley. It's all the boost you really want to push out of the 112. Any more and I'd start thinking about the 122.
 
#4 ·
Keep in ming, boost is relative. Your psi will drop with the headers, but your still pushing more air, making more power.
With that said, if you drop to 5 psi, it'll be hard getting another 4lbs out of the Maggie. But at 7.5 - 8, you should be making good power.
Good luck and post up how that 2.7" pulley fits on the Maggie.
 
#5 ·
I'm assuming you do not have headers now. Getting 5.5 psi with stock pulley setup makes me wonder about the ability to compare boost readings from one boost gage to another.

I get 5.5 psi until I reach 6k RPM at which point the boost goes up to 5.8 max, and I've got headers. If you put headers on and if your boost indeed does drop, it would be lower than mine ... maybe > 0.5 psi lower? The only explanation I can think of is that either the gages can't be compared or I suppose your larger motor is consuming the excess air provided by the MP112 better than mine thereby reducing the boost slightly but that still doesn't explain the entire difference.

In any case, too bad we all don't use the same gage with much better resolution to give us highly accurate and hence comparable readings.


EDIT: Oh, btw, thanks guyz for reminding me about the sparkplugs if I do the OD pulley.
 
#6 ·
I have the LS6 with kooks 1 7/8, 8" crank pulley and a 2.7" blower pulley and I set right on 10lbs. Sometimes it's about 11 but most of the time 10. I do have a cam and -8cc dished pistons so there may be a slight differance but that's where I'm at.
 
#7 ·
For the guys with the 8" OD pulleys and 8 RIB setup (inc. myself) can any of you post a pic of how you're routing your serpentine belt please?

Also, what belt sizes are you using? When I switched I found that I could no longer route it with the longer 1025 belt, instead had to go down to a 952 as the belt would touch when going from crank up to tensioner.

It still doesn't look right as the belt doesn't fully wrap the s/c pulley so I'm a little concerned.

Much appreciated.
 
#9 ·
Thats no cats through the factory resonator and flowmaster mufflers. I tried it without the resonator but the car was way to loud and sounded horrible over 3k. The factory resonator is like an x pipe that is wrapped in glass and it really toned the car down and made it very deep with the flows, no cats, and headers. I can park it outside the house and leave it running and it shakes pictures on the wall.
 
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