bromy Posted October 14, 2006 Share Posted October 14, 2006 Just had the extrusion delivered from the US so I can now make a start on the plenum chamber for my n/a, I cut a small test piece and had a practice to see how it will come out complete with velocity stacks, every thing will be bolt on no welding.. I want to do it this way as I will be using the standard throttle body to start with then a q45 thereafter so all I will need to do is machine a new end plate and bolt it up This is what I am trying to achieve Quote Link to comment Share on other sites More sharing options...
JamieP Posted October 14, 2006 Share Posted October 14, 2006 Looks great...How much do you think it will owe you?... good luck with it:) Quote Link to comment Share on other sites More sharing options...
bromy Posted October 14, 2006 Author Share Posted October 14, 2006 Looks great...How much do you think it will owe you?... good luck with it:) The expesive part is the D extrusion that has cost £90 delivered from the US other bits few quid, machining is what I do for a living so nothing to do it all. Quote Link to comment Share on other sites More sharing options...
SatSport Posted October 14, 2006 Share Posted October 14, 2006 will you still be able to keep the battery in situ? Quote Link to comment Share on other sites More sharing options...
Kranz Posted October 14, 2006 Share Posted October 14, 2006 You won't have to cut the plenum back by the #6 intake runner as you're not LHD like the one in the pic???? Doing this like in the pic will hurt distribution to that cylinder. Really you want it to be sloped the other way so there's more volume for the #6 runner to draw on. Quote Link to comment Share on other sites More sharing options...
bromy Posted October 14, 2006 Author Share Posted October 14, 2006 Battery will go into the boot and will need to relocate the PS resevoir, I weighed that up about cutting the back at 45deg and realised I dont need to do it, I was thinking of splitting the chamber in two for better distribution to the back cylinders but dont think I will gain anything for the extra work, we'll see how it goes I might monitor both 1 & 6 for egt's after Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted October 14, 2006 Share Posted October 14, 2006 Nick do you not think the plenum should taper a little? Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted October 14, 2006 Share Posted October 14, 2006 Sorry my bad just saw the last picture Quote Link to comment Share on other sites More sharing options...
Daston Posted October 14, 2006 Share Posted October 14, 2006 that looks sweet, any chance of you knocking these up in your spare time Quote Link to comment Share on other sites More sharing options...
bromy Posted October 28, 2006 Author Share Posted October 28, 2006 More pics of my progress, just the stacks to machine now and vacuum holes Quote Link to comment Share on other sites More sharing options...
uk-rich Posted October 28, 2006 Share Posted October 28, 2006 nice one, very well done Quote Link to comment Share on other sites More sharing options...
terribleturner Posted October 28, 2006 Share Posted October 28, 2006 Brilliant work mate Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted October 28, 2006 Share Posted October 28, 2006 The expesive part is the D extrusion that has cost £90 delivered from the US other bits few quid, machining is what I do for a living so nothing to do it all. Fancy knocking a few more out after you have finished for a tidy profit trader membership Quote Link to comment Share on other sites More sharing options...
JohnA Posted October 29, 2006 Share Posted October 29, 2006 It looks very nice, but you also have to take into account airflow inside, when it is under pressure. If it was flowing water, it would probably be OK, but air has some nasty habits of creating high-and low pressure regions so that under stress some cylinders will see fewer air molecules than others. And it's not always the 'obvious' ones either. Ideally you need to do some R&D, fitting bleeding nipples on the runners (that you can later cap off) and verifying that under vacuum or boost there is no pressure difference among any two cylinders. If there is (most likely case) then you have to start tapering the inside until they are all equalised. It's not trivial either - 10% more air in cylinder 6 compared to cyl 1 means that cyl6 will be running leaner than 13:1 when cyl1 is at 12:1 (assuming the ECU is allowing the same amount of fuel in all cylinders) Performance-wise, it is very important for all cylinders to be making the same power at the crank, so they are not working against each other. Safety-wise, remember that your wideband will be showing an *average* of the 6 AFRs of all cylinders, so you can potentially get a holed piston without the WB showing anything nasty. Quote Link to comment Share on other sites More sharing options...
Guru Posted October 29, 2006 Share Posted October 29, 2006 Why can't anything be simple Quote Link to comment Share on other sites More sharing options...
bromy Posted October 29, 2006 Author Share Posted October 29, 2006 It looks very nice, but you also have to take into account airflow inside, when it is under pressure. If it was flowing water, it would probably be OK, but air has some nasty habits of creating high-and low pressure regions so that under stress some cylinders will see fewer air molecules than others. And it's not always the 'obvious' ones either. Ideally you need to do some R&D, fitting bleeding nipples on the runners (that you can later cap off) and verifying that under vacuum or boost there is no pressure difference among any two cylinders. If there is (most likely case) then you have to start tapering the inside until they are all equalised. It's not trivial either - 10% more air in cylinder 6 compared to cyl 1 means that cyl6 will be running leaner than 13:1 when cyl1 is at 12:1 (assuming the ECU is allowing the same amount of fuel in all cylinders) Performance-wise, it is very important for all cylinders to be making the same power at the crank, so they are not working against each other. Safety-wise, remember that your wideband will be showing an *average* of the 6 AFRs of all cylinders, so you can potentially get a holed piston without the WB showing anything nasty. Totally understand what you are saying and it would be easy to tap each runner and attach pressure gauges to measure presure in each of them and applying a airline with a gauge through a sealed end, not sure about vacuum though but would that matter too much as it is lean anyway when it is sucking air and not under positive pressure?, here is a pic of a plenums inside that jamiep has just got (post *48) http://www.mkivsupra.net/vbb/showthread.php?t=86368&page=4 Quote Link to comment Share on other sites More sharing options...
JohnA Posted October 29, 2006 Share Posted October 29, 2006 ...it would be easy to tap each runner and attach pressure gauges to measure presure in each of them and applying a airline with a gauge through a sealed end, ... No pressure line, that is a static condition and everything will look honky-dory. You need to check the readings while there is realistic airflow through the intake, and the engine is consuming air. Therefore you need to look for pressure differences with the engine running and boosting If you can't get your hands on differential gauges, then 6 cheap identical boost/vaccum gauges are the next best thing. They could be fixed next to each other on a piece of plywood, and the passenger could have them in his (or her!) lap while you're boosting. It would immediately be clear if one is lagging behind. Quote Link to comment Share on other sites More sharing options...
JohnA Posted October 29, 2006 Share Posted October 29, 2006 duplicate Quote Link to comment Share on other sites More sharing options...
johnd-mkiv Posted October 29, 2006 Share Posted October 29, 2006 Looks a nice bit of kit mate well done Quote Link to comment Share on other sites More sharing options...
TLicense Posted October 29, 2006 Share Posted October 29, 2006 Looks like some tidy machining! Best of luck! Quote Link to comment Share on other sites More sharing options...
paul mac Posted December 17, 2006 Share Posted December 17, 2006 got onto this one a bit late, how is it going ? is it on the car yet ? Quote Link to comment Share on other sites More sharing options...
Jake Posted April 30, 2007 Share Posted April 30, 2007 That's a work of art that is! I'm very jealous of your skills. How did it work out in the end? Quote Link to comment Share on other sites More sharing options...
Lebsteif Posted February 23, 2008 Share Posted February 23, 2008 Hi Bromy, did you finished it yet? Quote Link to comment Share on other sites More sharing options...
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