Guest Martin F Posted April 15, 2003 Share Posted April 15, 2003 Is there a formula or recommendation somewhere for a certain size WI nozzle ? I've looked through the Aquamist site and although they have a flow diagram for a few different sizes, they don't quote what type of flow (i.e. sizes of nozzle) is recommended for what applications. This is purely with reference to the Aquamist system, as i have had this on the car since i bought it and a few different jets in the centre console. Just wondering if i am using the right one, now that my pump seems to be working better than in the past....LOL Quote Link to comment Share on other sites More sharing options...
Alex Posted April 15, 2003 Share Posted April 15, 2003 I use the .7mm one. This was down to a complex mathamatical computation which would just confuse you mere mortals.....ha ha ha haaaa..... Or was it really because that's the nozzle CW fitted to my car?? Yep it was one of those two scenarios I have a feeling we need the larger one purely cause of the displacement of our motors...and bigger is better! Quote Link to comment Share on other sites More sharing options...
Nathan Posted April 15, 2003 Share Posted April 15, 2003 Hi Martin, It's advised to go for 8~15% of the total max theoretical fuel flow, starting at the lower end and only going up if EGT's and/or det demand it. The ERL jet sizes give the following flow based on their race pump as has been supplied with their ‘regular’ kits for a while now. These are APPROXIMATE flow rates only: 0.5mm = 190cc per min 0.6mm = 230cc per min 0.7mm = 260cc per min 0.8mm = 290cc per min 0.9mm = 320cc per min 1.0mm = 340cc per min So, for a Jap spec it would be: 6x 440cc = 2640cc theoretical max fuel flow per min. 8% of that = 211.20cc. That is the jet flow you would start with given the choice, but you can’t get the size so I would go for the 0.6mm. A 0.7mm would be a good starting point for a car using 6x 550cc injectors ie stock UK or uprated Jap spec. Taking the other end of the scale, my old car at 8x 550cc would suggest a 1mm jet at least but after testing I found that a .7mm was all I needed. Theory often falls apart in the real world so testing is essential. The last thing you want to do is run a bigger jet than necessary as it will kill power. As I’ve said before, using WI on cars that aren’t detting or having EGT problems is pointless anyway IMO. Regards, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted April 15, 2003 Share Posted April 15, 2003 Originally posted by Nathan The last thing you want to do is run a bigger jet than necessary as it will kill power. That's exactly my concern. Thanks for your reply it all makes sense, will have to make sure i have the jets with me next time i visit a RR. Quote Link to comment Share on other sites More sharing options...
Nathan Posted April 15, 2003 Share Posted April 15, 2003 The problem is that no RR I know of measures EGT, and that is the main area you need to be monitoring in the case of the MK4, as the ECU can kill det in all but the most extreme cases but the EGT's can still go through the roof (usually as a result of pulling the ignition back which increases EGT yada yada....) I've seen them hitting 1150 deg C with no det whatsoever. As you've probably guessed, I very much like EGT gauges Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted April 15, 2003 Share Posted April 15, 2003 Originally posted by Nathan As you've probably guessed, I very much like EGT gauges Cheers, Nathan TDI PLC I have one For protection purposes only. Quote Link to comment Share on other sites More sharing options...
Nathan Posted April 15, 2003 Share Posted April 15, 2003 Originally posted by Martin F I have one Ahh......! I Didn't know that........ What temps are you hitting flat out at the moment then? The only real way to check it is under full load at high rpm. Most rolling roads top out at 120mph-ish and that isn't really enough. The engine won't be working hard enough for a long enough time period. You've really got to cane them to get a true figure. Go to your own private test track, get her in 6th (or 4th) at around 160mph or 6K rpm and see what you get. Or even a top speed challenge day thingy. Flash readings on dynos are useless. Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted April 15, 2003 Share Posted April 15, 2003 Originally posted by Nathan Go to your own private test track, get her in 6th (or 4th) at around 160mph or 6K rpm and see what you get. You think i'm going to be looking at my EGT gauge at those kind of speeds ?? LOL Well the highest i have seen is about 950deg C if i remember rightly. I tend to find the highest boost and temps come doing about 60 - 70 mph up a slight incline in 6th and whilst flooring it. I have the warning set at about 1050deg C and it's this i rely on as i can see the red LED out of the corner of my eye if it comes on. What i really want to do is to see if i can see a drop in EGT at 1bar when the WI pump activates, but it would be better to do this with somebody else driving. Then likewise on a RR see if at 1bar power drops off or stays the same or increases, hence indicating problems with jet size. But for that i will have to put all the bits back. Quote Link to comment Share on other sites More sharing options...
Nathan Posted April 15, 2003 Share Posted April 15, 2003 Originally posted by Martin F You think i'm going to be looking at my EGT gauge at those kind of speeds ?? LOL Thats what the Alex Holdroyds of this world are for.... I tend to find the highest boost and temps come doing about 60 - 70 mph up a slight incline in 6th and whilst flooring it. Your injectors won't even be really working at that kind of load. The incline bit is good but at 70mph in 6th I'd wager that your duty cycles are pretty low (or they should be). An EGT is only valid when the injectors are at their max cycle, because it's usually lack of fuel that sends the EGT's up. In short, if you're hitting 950 on the test in question theres no way your EGT's would be less at 160mph/6K. Not unless your midrange is as lean as hell anyway. What i really want to do is to see if i can see a drop in EGT at 1bar when the WI pump activates Sounds too complicated and difficult to measure properly to me. All you need is two (careful) flat-out runs. On with the WI activated and one without. I very much doubt if your EGT's are a problem at 1 bar so seeing what it does at that boost level is immaterial IMO. Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
Guest Martin F Posted April 15, 2003 Share Posted April 15, 2003 Originally posted by Nathan I very much doubt if your EGT's are a problem at 1 bar so seeing what it does at that boost level is immaterial IMO. Good point, but i thought that because that is the point at which the WI pump activates that i should see a momentary drop in EGT''s or do you think that the ECU will advance timing once the WI is online so quickly that i'd never see anything on the EGT gauge ? Looking for the momentary drop in EGT's at 1 bar was more as a means to see how effective the system was at reducing EGT rather than any of it's other properties. Quote Link to comment Share on other sites More sharing options...
Nathan Posted April 15, 2003 Share Posted April 15, 2003 You probably WILL see a drop in EGT at 1 bar with water activated but the fact remains that it won't really serve any useful data. It might be interesting to see how much power it loses if anything but the bottom line is that you won't really be doing anything other than satisfying your own curiosity and knowing that it does indeed operate. The exercise is to see what EGT's the car hits under full load without water and only use it IF you need to bring them down. Any other instance doesn't seem necessary to me. As for the ECU advancing timing when the WI injection starts I very much doubt if that will happen as you are unlikely to be detting at 1 bar anyway so the ignition shouldn't be pulling back any more than the stock map. If it is then I'd say you have a fuelling problem. I fully understand that you want to see how effective the WI is at reducing EGT but what it does at 1 bar could bear zero relation to what it does at 1.2+ bar when the injectors are maxed and shes starting to take rapid deep breaths.... Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
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