Best heads for turbo motor?
07-12-2006, 05:42 PM
#1
Best heads for turbo motor? I bought a set of AFR's a little while ago for a very good price but now I've decided to go with a turbo setup. The heads are 205's unmilled at 66cc's. Can I still use them or should I cash in on them and get a different set? What type of heads should I be looking at for a single turbo GT42/6 setup? I'm new to forced induction so advice is very much appreciated. 
PS Motor is remaining stock till the turbo kit is done, then I'm rebuilding with low compression pistons and cranking up the boost. I'm looking for the best heads for a low compression motor that'll work with stock pistons/rods till I rebuild.
PS Motor is remaining stock till the turbo kit is done, then I'm rebuilding with low compression pistons and cranking up the boost. I'm looking for the best heads for a low compression motor that'll work with stock pistons/rods till I rebuild.
07-12-2006, 05:58 PM
#2
honestly....most people have good results with either stock LQ9's or ported LQ9's,they flow well and drop the compression which will help alot.Besides if you sold the AFR's it'd pay for some LQ9's and still have money left over to go towards the rebuild
07-12-2006, 07:15 PM
#3
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Good. While we're on this subject... 
What are the BASIC advantages/disadvantages of going with the aluminum LQ9 over the 373, iron LQ4 6.0L heads? I am asking since they both offer the same benefit of their combustion chamber volume, which is 71cc I think... Weight, strength, what am I missing?
What are the BASIC advantages/disadvantages of going with the aluminum LQ9 over the 373, iron LQ4 6.0L heads? I am asking since they both offer the same benefit of their combustion chamber volume, which is 71cc I think... Weight, strength, what am I missing?
07-13-2006, 01:27 AM
#4
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If you're planning on running high boost alum. heads would be fine but if you wanting to run high boost Iron heads would be better in the long haul. You wouldnt have to worry about heat warping them. But thats only in extreme cases
07-13-2006, 01:39 AM
#5
I beg to differ... depends on the quality of the casting and type of aluminum used. You don't see top fuel dragsters running cast iron. If you have a good and even clamping load, you should see no problems. Cast iron naturally does not flow as well as aluminum, that is a given, it also allows you to run approximately 1:1 compression more without detonation due to heat dispersion, it doesn't tend to "heat soak" as bad therefor less hot spots. I thought about AFR 205's on mine, but decided to get some #317 6.0L LQ9 heads, port them myself (just a quick cleanup and polishing the chambers to avoid hot spots), and install 2.02/1.575" stainless valves, which are a good addition to any forced induction motor. Just my .02.
07-13-2006, 12:40 PM
#7
Originally Posted by ddnspider
honestly....most people have good results with either stock LQ9's or ported LQ9's,they flow well and drop the compression which will help alot.Besides if you sold the AFR's it'd pay for some LQ9's and still have money left over to go towards the rebuild
I just brought some lq9 heads. il looking for like in the 800 rwhp range so how much porting will have to be done to these heads and how much will it cost ruffly
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07-13-2006, 01:00 PM
#9
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1) Could you use your unmilled 205's? Sure.
2) Should you? Sure. Stock heads are what 68cc? Here is one way to look at it. The harder you push your combo, the less compression you want assuming you only use pump gas. So sure you can make 10-11:1 compression and run 6-8psi (assuming appropriate tuning, intercooling, fuel system).
3) You can look at the power you make at the engine, and basically you can subtract some of the boost that a stock engine'd guy would need to make in order to make the same power as you on boost...
407rwhp + 7psi might be 500rwhp
360rwhp + 9psi might be 500rwhp (something like that)
4) Better flowing heads = less restriction, equals more power at the engine.
5) Now if you had a set of 6.0 heads that were ported and had great flow numbers, you could use those too.
6) 400rwhp + 15psi = 800rwhp (something like that). YOu are hitting double the atmosphere at 1 bar.
2) Should you? Sure. Stock heads are what 68cc? Here is one way to look at it. The harder you push your combo, the less compression you want assuming you only use pump gas. So sure you can make 10-11:1 compression and run 6-8psi (assuming appropriate tuning, intercooling, fuel system).
3) You can look at the power you make at the engine, and basically you can subtract some of the boost that a stock engine'd guy would need to make in order to make the same power as you on boost...
407rwhp + 7psi might be 500rwhp
360rwhp + 9psi might be 500rwhp (something like that)
4) Better flowing heads = less restriction, equals more power at the engine.
5) Now if you had a set of 6.0 heads that were ported and had great flow numbers, you could use those too.
6) 400rwhp + 15psi = 800rwhp (something like that). YOu are hitting double the atmosphere at 1 bar.
07-13-2006, 09:18 PM
#11
Originally Posted by bumpin_records
I just brought some lq9 heads. il looking for like in the 800 rwhp range so how much porting will have to be done to these heads and how much will it cost ruffly
07-13-2006, 10:11 PM
#12
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is putting bigger vavles on the lq9's good for turbo?if so wat are nice sizes and brands?for like a 600 rwhp motor should i port them or just smooth them and polish?wat about a 3or5 angle job positive or negative?
07-14-2006, 10:35 AM
#13
Thanks for all the replies guys. I'm probably gunna sell the AFR's and just run a set of stock LQ9's for now. Getting the kit together is more important right now than a bad *** set of heads.
PS Anyone need a set of AFR 205's? PM me if interested.
PS Anyone need a set of AFR 205's? PM me if interested.
