xtremerevolution Posted February 13, 2010 Report Share Posted February 13, 2010 I seem to be the only guy here who works on this engine, but I figure someone else might come along as crazy as me. ZZP makes a $200 upper intake plastic insert for the L36, in which they essentially reduce the length of the runners by 3". I've been told that this really wakes up cars with an aftermarket cam. I don't have a cam, but I do have an intake, exhaust, 1.8 ratio roller rockers, and a ported LIM, all of which contribute to a better breathing engine. I'll take pictures today as I do everything, but I'm being told by a member on the Bonneville Forum that a reduction of 1" in the runner length should give me quite a boost of power given my modifications and the overall engine design. The L27 has nearly just as much torque as the L36, but 35hp less, which is partially due to the cylinder heads, and partially due to the intake design. The intake runners on the L36 are significantly shorter than the ones on the L27. Observe: L36 LIM: L27 LIM: As you can see, the L27 LIM runners are at least half a foot longer than those on the L36. Unlike with the L36 upper intake plentum, the L27's upper intake works in conjunction with the LIM to create the runners instead of just serving as an extension. the problem with this is that there is a sharp angle at the point where the UIM meets the LIM. What I'm going to do is shorten the runners by 1" down to that point. Lets see if we can make an L27 come alive. Pictures with further detail to come. Quote Link to comment Share on other sites More sharing options...
douellette Posted February 13, 2010 Report Share Posted February 13, 2010 id be interested in seeing that Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 14, 2010 Author Report Share Posted February 14, 2010 Hahaha, damn this really opened up my top end Quote Link to comment Share on other sites More sharing options...
Night Fury Posted February 14, 2010 Report Share Posted February 14, 2010 Did it already?! Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 14, 2010 Author Report Share Posted February 14, 2010 yeah. Pulling the uim is a cakewalk. I've done it at least 5 times now. The plastic insert was a quick dremel job. Ill post pictures in a bit. While I was in there, I also tapped two threads for plugs for the throttle body coolant passages. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 14, 2010 Author Report Share Posted February 14, 2010 Alright, so here's what I did I cut off the inner walls of the runners a little over an inch down, thereby shortening the length of the runners. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 14, 2010 Report Share Posted February 14, 2010 have any before pics? Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 14, 2010 Author Report Share Posted February 14, 2010 have any before pics? Damn, didn't get those. Just imagine the runners in an oval. I'll try to find a picture somewhere. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 14, 2010 Report Share Posted February 14, 2010 such an odd way to change the design of the intake... should help build a little more top end power though. and from what i can tell, it bypasses that little channel before the port? essentially making a shorter runner and a larger plenum... Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 14, 2010 Author Report Share Posted February 14, 2010 such an odd way to change the design of the intake... should help build a little more top end power though. and from what i can tell, it bypasses that little channel before the port? essentially making a shorter runner and a larger plenum... That's correct! Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 14, 2010 Report Share Posted February 14, 2010 http://www.grapeaperacing.com/tech/inductionsystems.pdf good reference should you decide to dive a bit deeper into the induction system... Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 14, 2010 Author Report Share Posted February 14, 2010 http://www.grapeaperacing.com/tech/inductionsystems.pdf good reference should you decide to dive a bit deeper into the induction system... Good information. Fortunately for me, tuned ports only help over a narrow RPM range as described by the article. It did build up a bit more top end power, from 4500 to 5400 rpm. Definitely a welcome addition to an engine that has an otherwise very poor top end. Quote Link to comment Share on other sites More sharing options...
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