Deer Killer Posted November 29, 2011 Share Posted November 29, 2011 I'll agree, to a point. The car was originally tuned for a 2.5" HKS catback and catted cobb downpipe. My guess is that, flow-wise, this is somewhere in between the stock catback and the open cutout. Theoretically, wouldn't the difference be greatest if the tune been for either the open cutout or the stock catback? Either way, others have posted similar results: http://forums.nasioc.com/forums/showthread.php?t=2273087 Yeah more info there basically confirms what I'm saying, the cutout is getting more than it's fair share of credit. 25 psi @ 11.5 AFR vs 22.5 psi @ 10.7 AFR?? Clearly one of these is going to make power, increased exhaust flow or not. The engine would need to be tuned for identical boost/AFR/correct specific timing with the cutout open and closed to find the true benefit. Sorry personal gripe with internet comparo's on aftermarket parts - they are not controlled for all variables. My science project, other people's muscle car. Link to comment Share on other sites More sharing options...
ChefRacer Posted November 29, 2011 Share Posted November 29, 2011 Isn't the point though that with the exhaust cutout open, the back pressure is non existent therefore allowing the extra boost which wasn't possible on the restricted stock exhaust. I don't think anybody here is trying to hide the fact that increased boost is what causes the increase in power. Link to comment Share on other sites More sharing options...
fahr_side Posted November 29, 2011 Share Posted November 29, 2011 Isn't the point though that with the exhaust cutout open, the back pressure is non existent therefore allowing the extra boost which wasn't possible on the restricted stock exhaust. I don't think anybody here is trying to hide the fact that increased boost is what causes the increase in power. No. The point is that the turbine needs x pressure drop over the turbine to drive the compressor to create y boost. The higher the pressure in the exhaust system behind the turbine the higher the pressure has to be in the exhaust manifold. Higher manifold pressure (EGBP) increases EGT and interferes with exhaust scavenging. You can hit the same boost pressures with a restrictive exhaust. You just won't see the same volumetric efficiency. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
scobaru5 Posted November 30, 2011 Share Posted November 30, 2011 how's the cuttout holding up? Link to comment Share on other sites More sharing options...
charlie_sheen Posted November 30, 2011 Share Posted November 30, 2011 This is sick Link to comment Share on other sites More sharing options...
KoukiS14 Posted November 30, 2011 Share Posted November 30, 2011 You could hook it up to a Hobbs switch and have it boost activated too. Add in a three position switch, and you could do open/closed/boost activated. Link to comment Share on other sites More sharing options...
vman932 Posted November 30, 2011 Share Posted November 30, 2011 You could hook it up to a Hobbs switch and have it boost activated too. Add in a three position switch, and you could do open/closed/boost activated. Electric cutouts do not operate fast enough to have them activated by boost and a hobbs switch. Link to comment Share on other sites More sharing options...
TRSCobra Posted November 30, 2011 Author Share Posted November 30, 2011 how's the cuttout holding up? The motor works great, but the butterfly developed a rattle when it's partially open. RRP sent me a spring kit that puts tension on the valve to eliminate the rattle, but I have yet to find the time to put it on. Link to comment Share on other sites More sharing options...
I Donated thefultonhow Posted November 30, 2011 I Donated Share Posted November 30, 2011 My cutout stopped working the other day. Still need to check if the cable is unplugged or something. It had worked fine earlier that day. Link to comment Share on other sites More sharing options...
TRSCobra Posted November 30, 2011 Author Share Posted November 30, 2011 Electric cutouts do not operate fast enough to have them activated by boost and a hobbs switch. +1 Also, opening/closing the cutout under load or high rpm puts a lot of stress on the cutout motor. Not good for longevity. Link to comment Share on other sites More sharing options...
instantfury Posted March 5, 2012 Share Posted March 5, 2012 sub Link to comment Share on other sites More sharing options...
spec.B Dream Posted March 5, 2012 Share Posted March 5, 2012 Any updates? Looking at doing this as my next power upgrade. Link to comment Share on other sites More sharing options...
I Donated thefultonhow Posted March 6, 2012 I Donated Share Posted March 6, 2012 Funny that you bumped this thread today. I checked over the weekend why my cutout wasn't working, and turns out I probably killed it by hitting the exhaust against a steep driveway at my relatives' house on Thanksgiving, which then hit the cutout motor against the floorpan and killed the cutout. It's unclear right now, because they haven't responded back to my latest email, but DMH is either going to warranty it (despite the fact that I bought it from someone else, and had no proof of purchase, and it was damaged due to events beyond their control) or are only going to charge me the $40 for a new motor and gearbox, rather than the $180 for a whole new cutout. I'm liking their customer service! Either way, looks like I will be back in business soon. I'm going to change the orientation of the cutout to prevent against this in the future, though. When I get Infamous1 to do my retune for my Process West TMIC, I'm going to see whether he can tune for the cutout both closed and open. I have a free dyno baseline that I won at a raffle at a local shop's open house, so I'm going to dyno twice with it closed and once with it open. Link to comment Share on other sites More sharing options...
spec.B Dream Posted March 6, 2012 Share Posted March 6, 2012 Cool stuff. I'd love to see those results. Link to comment Share on other sites More sharing options...
TRSCobra Posted March 6, 2012 Author Share Posted March 6, 2012 Still haven't had time to install the spring kit to cure the rattle that occurs when the valve is partially open, but otherwise all is well with the cutout. Selling the car soon for an econobox that gets good mileage on my 100+ mile daily commute... Link to comment Share on other sites More sharing options...
spec.B Dream Posted March 6, 2012 Share Posted March 6, 2012 Let me know if you want to part with the downpipe and cutout kit when you sell the car. I've even got a choice of OEM, HFC, or catless downpipes I'd offer in trade if required. Link to comment Share on other sites More sharing options...
charlie_sheen Posted March 7, 2012 Share Posted March 7, 2012 If he passes, pm me trs and id be happy to take it off your hands. I have a stock dp or a cobb you can choose from. So far your setup has been my fav so far, and im barely a fan of e-cutouts Link to comment Share on other sites More sharing options...
TRSCobra Posted March 7, 2012 Author Share Posted March 7, 2012 I'll keep you guys in mind. The car's going in for service this weekend. If surgeline decides to retune it (surging issue), I'll have them do it with the cutout closed, so I can switch out the DP and not have any ill effects. Link to comment Share on other sites More sharing options...
mmmmspecb Posted March 7, 2012 Share Posted March 7, 2012 Awesome setup, I would love to run something like this... Link to comment Share on other sites More sharing options...
ChefRacer Posted March 8, 2012 Share Posted March 8, 2012 Btw, did you ever have any issues w the heat on the axle boots or anything? Link to comment Share on other sites More sharing options...
TRSCobra Posted March 8, 2012 Author Share Posted March 8, 2012 My right inner boot has been seeping out small amounts of grease from a loosening clamp for some time now, but it hasn't changed since adding the cutout. Link to comment Share on other sites More sharing options...
GrasshopperLGT Posted April 5, 2015 Share Posted April 5, 2015 Been thinking of this mod. Not for the power but for the LOUD NOISE!!!! Anyone else have experience with this? Link to comment Share on other sites More sharing options...
charlie_sheen Posted April 6, 2015 Share Posted April 6, 2015 Dont do it if you slam your car, or even really lower it much. On my LGT I knocked three motors off of the undercarriage. Other than that, the car sounded pretty wild. With an EWG even wilder. Never saw any negatives to it other than the laggy-ness down low in the rpm range. That, and the older folks asking me how much power my v8 was making. That always made for interesting conversation. Go with RaceReady over QTP if youre looking at brands. After i got tired of replacing motors i decided to just manually block off and unblock the Y-pipe with a plate. Link to comment Share on other sites More sharing options...
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