Heads For Supercharger

[swift700]

HI guys, I just ordered my Magnuson Supercharger for my 2000 5.3 Sierra and was wondering which heads would work best. Should I stick with the stock heads for go to something with bigger valves and chambers. I was considering these ones:

http://www.jegs.com/i/Patriot-Performance/...oductId=1122036

Will these increase power considerably? I have a 210/218 551/551 cam and 1.8 roller rockers.

Appreciate any input.

[bigredmariner]

It couldn't hurt, I'm running stock heads and cam with my Maggie and I can only wonder how much better it will be with a cam and/or different heads. Good luck on your decision and keep us posted.

[swift700]

It couldn't hurt, I'm running stock heads and cam with my Maggie and I can only wonder how much better it will be with a cam and/or different heads. Good luck on your decision and keep us posted.

 

How do you like the Maggie? Any issues with it?

 

I'd like to maximize the blower's potential. I think I might just order those heads. What I like about them is that they are machined from stock LQ9 heads so the accessory bolt holes and valve cover bolt holes should be there. The compression ratio will be reduced considerably (anyone know how to calculate this?) which is favorable for a FI engine. Only potential problem I forsee could be a weakness of the casting base which is fairly thin compared to CNC'd aftermarket heads. I've read this can lead to gasket failure on a blown engine. I'm willing to take that chance, thinking that the lower compression ratio will prevent this altogether.

 

I should mention that the cam swap is really simple on these engines. It should only take you 6 or 7 hours. There are a lot of articles on doing this. I did cam, springs and rockers in a weekend by myself with no problems whatsoever. The balancer is a bit of a pain though, you'll need a good 3-jaw puller for this and preferrably an impact gun.

[bigredmariner]

So far I'm pretty happy with it. It's only got about 2500 miles on it but I'm still happy. Gas mileage actually improved a tad but it's damn hard to stay out of the gas. I just love hearing it whine.

[Jennabear]

You will need to make sure that the new heads are still compatible with the system you purchased.

[swift700]

You will need to make sure that the new heads are still compatible with the system you purchased.

 

Should I call Magnusen for that info?

 

I've calculated that the compression ratio with these heads would be around 8.93:1 which would be a healthy number for the supercharger setup. I could run more boost with little risk of detonation and take advantage of the great flow rate of these heads (70% more intake flow, 60% more exhaust flow @ .550 lift). Anyone care to offer an opinion?

[Wingnut]

I know that that cam doesn't look like much of a blower cam at first glance. What's the LSA?

[swift700]

I know that that cam doesn't look like much of a blower cam at first glance. What's the LSA?

 

It's not a huge cam for a blower, the LSA is 116. It's a high torque cam but with the 1.8 rockers gives nearly .600" valve lift. Also, the rockers make maximum use of the duration because they cause the valve to come off the seat quicker (and close faster) due to the increased ratio. This means they stay wide open for longer.

With the strong low end power of the Magnacharger I think it'll be a nice match in a truck. I still want decent fuel efficiency for when I'm not hammering the gas and this cam fits the bill. Right now it's almost like stock until the pedal goes 1/3 down, then it really sings. I figure if it's not enough cam afterwards, I can always pull it out and swap in a bigger one.

 

The goal with the heads for me is to increase combustion chamber size, reduce compression, and therefore be able to turn up the boost (or even run lower octane fuel if need be). Effectively, it's like adding displacement. The improved flow rate is a bonus at higher RPM's.

 

I hope my theory holds water. I'm pretty sure it does so I'm going to go through with these mods and I'll let you guys know how it all works out in the end.