Tricky-Ricky

Although it will alter the airflow characteristics, it should be OK, just make sure you set fuel pressure to std, at best it will throw a CEL, at worst go into limp mode but I doubt that.

Have you done a compression or leak-down test?

Here you go. personally I would be looking to drill and tap the take off plate for just one sensor, but its not a problem to use the two if you can get them to seal properly.

Believe it or not, the air-flow stays virtually the same due to the principle of "conservation of energy" i.e. the flow-rate is conserved while the pressure drops immediately & the fluid velocity increases. In a vacuum system like a NA engine with pressures near atmospheric its a lot trickier to derive any benefit. Probably why there's not been much success with aftermarket air-intakes.That increase in velocity gives that nice "whoosh" people crave at the cost of power. Designing a plenum that could draw in more air via that dp (venturi effect) is a possibility but not easy. They've built mixer-showers for homes using low-pressure hot water (gravity fed) in the same way. Basically, the higher pressure cold water "draws out" the hot water in sufficient quantities (and mixed to correct temperature) to give better performing showers - i.e. not dribblers but not power showers. http://www.shower-gu...uri-showers.htm There's nothing to prevent the same principle being exploited in an intake / plenum. That said, you'd never be able to map it properly on a rolling-road as the car would need to be moving. Anyone got a big fan Jeff can borrow? My thinking was that if you try and increase the velocity by causing turbulence via a vortex effect, it could well upset the airflow metering of the MAF, I have seen this happen on a few engines as a result of moving the MAF position relative to the filter and throttle body.

Wouldn't that just increase velocity rather than total airflow? which is what you need to increase performance.

http://www.ebay.co.u...cEAAOSwl8NVZWHD They don't look too bad at all for the price, and I agree if you don't have a welder yourself it would be a cheaper way to go.

I agree, redesigning the plenum/intake is a good place to start, although the Kinetics is a complete redesign it doesn't seem to help with N/A power from all I have heard, but I think its more aimed at FI. As for the intake, coating it to insulate will only help with idle heat soak, as once any appreciative airflow is present IE on the move, boundary layer effect takes over and the moving air flow inside any pipe work is not affected by heat soak, also that's what the IAT compensation is there for, A simple pipe from MAF to throttle body is basically a pop charger, changing pipe length between MAF and throttle body and MAF and filter will need to be researched very carefully, I have seen some very odd results form moving these positions, be interested to see what they come up with though.

Yes I had a little search, but could only find fuel system upgrades for the R35, and not the std system, but it seemed to indicate that it does run a regulator and return system. As most fuel systems have a voltage to load increase anyway I would have thought they had perfected electronics enough to cover fuel supply increase as boost pressure and fuel demand rises, but apparently not, well at least where boosted applications are concerned.

MAF based WOT with long term fuel trims could give an initial HP increase from breathing mods due to a leaner mixture than stock, assuming stock WOT is safe/rich. Long term fuel trim would then adjust injector pulse duration to due to continual difference in short term fuel trim target/value giving a higher than stock, but lower than when the mods were fitted. MAF is different from speed density/alpha N, the MAF can read increased airflow from breathing mods, and then take a value from a different cell, so slight increases in efficiency will be "tolerated" by the ECU, but large deviations will not, as the cell values are not there to support it. Stock ECU will allow a certain amount of variation due to wear on components, sensor drift, differences between engines, fuel octane rating etc. A proper live map will optimise all the cell values for the cars increased VE etc, giving a larger power gain. This would appear to be supported by people fitting headers and getting a small HP gain, then a remap giving more. That's roughly how I remember mark explaining how the DE ECU managed to null most breathing mods to me quite some time ago, thanks for refresh.

Of topic I totally get your logic with the feul return system I don't get tho how Litchfield got my car fueling properly without one Surely if there was significant drop he would of seen that in the fueling when mapping the car! Ian was more than happy that the car was fueling fine on full chat at the level of boost that the standard pully provides on the stillen kit I am however going to have some safety trips built in to the ecu should and big spike happen either way I'm not saying your wrong But I've coverd a lot of miles of hard driving and had no problems Just interested that's all I am not sure just how the VQ deals with load fuelling, as its a non return system, but I am guessing that the ECU increases fuel pump voltage to increase fuel pressure for higher loads, so I would also guess that if you add a low pressure supercharger the supply pressure at higher load is enough to cover the airflow increase, providing the injectors can flow enough. I would also guess that the HR does the same but with much better control since its a better ECU, I would like to see how the GTR fuel system operates, its certainly possible to have a non return fuel system supply enough fuel to supply the higher airflow that a turbo or two can supply, if the control system is sophisticated enough. But if your going to be adding a turbo to a DE or HR I personally would want to see a return system to increase fuel pressure in line with boost given the airflow increase, however I am a little old school. Be interested to get Mark or someone who has tuned the GTR to give some input on the fuel system?

The big problem with using a SC intended for another car is the amount of fabrication to make it fit/work, one of the guys on the supra forum used a Jag SC and it turned into an epic build. While you could use the std fuel injectors with FI it would limit your power, you will also need to fit a fuel return system in order to use a rising rate fuel pressure regulator, which is necessary to increase fuel pressure in line with boost pressure, so you might as well fit a bigger pump and injectors anyway.

I completely agree with someone delving into the manifold/plenum side of things, as its already been proved that its a major restriction to achieving more power from the VQ, I remember Jezes chips well, bit of a breakthrough in the s13 tuning world back in the day, however I'm not sure of the analogy, as the old Nissan ECUs where well known for there overfueling at full load, and a little adjustment to the std map is all it took, but on the enterprising side it was a massive step forward and put him in good stead for where he is today. On a side note whatever happened to Jezes mate Dan, dint he start a brake company, is he still going?

Not quite sure what you expected fella....you must have read countless threads on this subject, do you really think a small tuning shop are going to come up with a radical new design by trial an error, when the major manufactures have CAD and flow testing, and large sums of money for development at their disposal, yet they still haven't come up with a better design to make millions from.

Your obviously that way inclined so that's good Yes that was my point, if you can DIY it then fine if you cant or cant be bothered then the kits are for you...you pay you money you take your choice as they say.

Your not going to see any real world gains, all they will be doing is losing the intake resonator, there have been countless intake designs on the market and all of them don't really see anything worth paying the money for apart from looks.

Same here, which is one of the reasons for putting up the link, I find a lot of the kits sold for various tuning/modification of cars....and a lot of other things for that matter are vastly over priced for what they actually contain, granted it saves you having to source the individual parts, but if I'm going to save a decent amount of money I am quite happy to do the ground work. But then there is the other side of the coin where some people don't have the time or patience or knowledge to hunt around, and are happy to pay to avoid that, But I am afraid my mind set is that the vast amount of tuning parts available are over priced, and since I have a background in engineering I can usually identify what will work or last and what wont, without paying silly money for it.

A compression test will only reflect the condition of the bores and ring seal, it wont give you any incite into bearing oil supply problems, as a result of low oil level/pressure.

Just for those who are quite happy to go the DIY route, I came across this http://liljerk.morph...l_pump_install/ which is quite comprehensive, and as I thought should not be much of a problem, apart from perhaps welding, or getting a return spigot welded to the existing fuel rail, the rest seems quite straightforward, and also coverer's the modifying the carrier to take the bigger wallbro pump. http://zchickz.com/fuel16.jpg

Most of the fuel return kits I have seen don't even include a pump, and all look pretty basic as far as fittings go, nothing special from what I can see, in fact I would guess you could pick up the fittings somewhat cheaper if you know where to look.

Not sure if the HR is much different, but the DE should see 14 psi at idle, and 43psi at 2,000 rpm, cold pressure will depend on what the pressure relief valve is set to, I wouldn't expect the HR to be much different, most modern engines run similar oil pressures these days.

Std figures for hot oil pressure are idle 14psi or more and 43psi at 2,000rpm or more, cold figures will depend on the pressure relief valve and whether its spring is weak,

Does the HR still use the nasty pressed steel fuel rails Mark? as for return line I was just thinking braided line and compression fittings, does the pump also need to be changed then? should be easy to drill and tap the nylon fuel pump carrier to take the return line.

Ahh I missed the ECU Tec in your sig, so I presume its got an analog input trigger for fail safes, so you can calibrate the input for a pressure sensor?

Can you not just T into the std oil pressure take off point, or at the switch?

Should be fairly easy to knock one up, providing you can either drill and tap the existing fuel rail, or buy a new one with two fittings, add a decent FPR and some hose and a fitting for the return, shouldn't cost anything like they charge for the kits.