j4nash Posted May 5, 2005 Report Share Posted May 5, 2005 Should I change out my heads to lower compression so I can run more boost on my LQ9 Or would it be a waste of time and money? Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted May 5, 2005 Report Share Posted May 5, 2005 Should I change out my heads to lower compression so I can run more boost on my LQ9Or would it be a waste of time and money? <{POST_SNAPBACK}> I'd suggest changing the bottom end instead -- then you'd also have forged internals that could take the extra boost. Link to comment Share on other sites More sharing options...
j4nash Posted May 5, 2005 Author Report Share Posted May 5, 2005 i just don't want to pull the motor right now Link to comment Share on other sites More sharing options...
BenKey Posted May 5, 2005 Report Share Posted May 5, 2005 I think it all depends on what you want to do with your setup. If you plan on getting heads anyway and plan to keep your motor boosted, then if the company doing the head can increase the chamber size, then I would say do it. I guess it is symantics. I would not buy heads "specifically" to lower my compression. I would be buying heads to make more power. If in the process I can lower my CR by getting like a 77cc chamber, then that is what I'd do. The problem doing it that way is about the best you'll get is about 9.5-9.6:1. Better than 10:1. Link to comment Share on other sites More sharing options...
zippy Posted May 5, 2005 Report Share Posted May 5, 2005 just curious, how much boost do you plan on running? Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted May 5, 2005 Report Share Posted May 5, 2005 You can run up to 12psi as long as the tune is safe on the stock CR. Anything more than that, and I think you want forged internals anyway. So, having said that, I agree with Ben. If you want better heads anyway, go ahead and get them with larger chambers. If you want heads just for lower compression, I'd say spend that money (well a lot less) at the dyno and get an awesome tune. Link to comment Share on other sites More sharing options...
j4nash Posted May 5, 2005 Author Report Share Posted May 5, 2005 well i am going to start out with the 8 psi but then maybe go to 10 psi Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted May 5, 2005 Report Share Posted May 5, 2005 With that in mind, you don't really need to lower your compression. Make sure you have a good intercooling solution, and a really good tune. Send the extra $$ to me Link to comment Share on other sites More sharing options...
zippy Posted May 5, 2005 Report Share Posted May 5, 2005 With that in mind, you don't really need to lower your compression. Make sure you have a good intercooling solution, and a really good tune. Send the extra $$ to me some have ran as much as 12psi through the stock 10.0:1 compression. you'll be fine. Link to comment Share on other sites More sharing options...
j4nash Posted May 5, 2005 Author Report Share Posted May 5, 2005 even with the smaller pulley most likely i will not see 10psi of boost because of my headers and cam. I am going to start out with the 4" pulley and maybe go as small as the 3.7" Link to comment Share on other sites More sharing options...
BenKey Posted May 5, 2005 Report Share Posted May 5, 2005 even with the smaller pulley most likely i will not see 10psi of boost because of my headers and cam.I am going to start out with the 4" pulley and maybe go as small as the 3.7" <{POST_SNAPBACK}> I saw zero loss of boost levels with the addition of long tube headers. Link to comment Share on other sites More sharing options...
zippy Posted May 5, 2005 Report Share Posted May 5, 2005 did you buy the D1SC? Link to comment Share on other sites More sharing options...
j4nash Posted May 5, 2005 Author Report Share Posted May 5, 2005 P1sc Link to comment Share on other sites More sharing options...
zippy Posted May 5, 2005 Report Share Posted May 5, 2005 with the P-1SC on the L31 and 3.4 pulley i was only seeing 11-12 psi. i'm not sure how much a 4.0 pulley will get you on the LQ9. it was only 8-9 psi with the stock procharger b.o.v.. the stock procharger valve was a constant leaker. switching to the RFL b.o.v. sealed the system off and picked up some boost. Link to comment Share on other sites More sharing options...
Dylan06SS Posted May 5, 2005 Report Share Posted May 5, 2005 mmmmmmmmm.... boost Link to comment Share on other sites More sharing options...
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