1/16/2024 0 Comments Fuel pressure regulator radiumBefore that things like exhaust mods and RRFPR units were the only tools available and had severe limitations. With this item fitted my experiments suggested the stock motor ran a bit lean mid range and way rich on top end and ST2 proved that was the case when it eventually came to market about 18 or whatever years ago. 20 plus years ago there was little means to adjust the fuel tune of the motor and the adjustable RRFPR was just about the only way to do it. The computers have no idea what the pressure in the inlet manifold is but the injector opening times are calibrated on the basis of a fixed differential pressure gives a known amount of fuel so a rising rate regulator with adjustable pressure maintains a constant differential pressure between the fuel injector manifold and the inlet tract and does so whether naturally aspirated or force fed and does so in the ratio of 1:1. The stock items are also a form of rising rate type regulators but they are not adjustable pressure - basically this means they are referenced to the pressure in the inlet tract that can be close to atmospheric pressure at full throttle and at a deep vaccum of 20 inches Hg or so when the throttle is fuly closed. Most true perfromance gains come from the ignition timing however not the fuelling. Even so the air flow to each cylinder is anything but constant at a given rpm point and this clouds the issue some. Once you have the likes of a WBO2 fitted to the system and better still ST2 like I have those problems quickly dissappear when one can see what is going on in real time. I have nothing against adjustable fuel pressure regulators just that trying to use them blind is the real problem. The link you posted is an alternative approach but that is not for your model year or so I suspect - Roger does a stock looking FPR at a keen price for your model year or so I understand. Of course I would need to prove that by testing and have worked out an easy way to do that with input from one of our friends who has already been down the same path with two Radium dampers fitted. Personally I suspect they will be so effective that they may weil replicate the performance of the stock dampers that is less than perfect when new and it is conceivable that they may do so with just one damper fitted on the inlet side of the rail. GB believes the dampers are not adequate for batch fired systems but that is precisely what their dampers were designed for. To my surprise a search revealed only Radium made after market items - great looking kit the only problem being the hoops one had to jump through to convert for fitment. Can you elaborate? I've seen regulators that say 1:1, but no idea how that's going to effect a Porsche 928?The main problem with the stock regulator/damper combo is the price- now $1800 for a set and a few years ago one of the dampers was not even available. Sounds like you're praising and hating on adjustable regulators. So you've done this before? I don't understand the rest of you comment. You mean this one? It does seem to work the same as the Radium product I've found. This is also why I changed the fuel damper in the back of the engine. I'm thinking the diaphragm being made of some sort of rubber is not moving so easily after 38 years. I have billet adjustable regulator in the my spares box that I used to mess around with the fuel pressure a bit in the days before Sharktuner but frankly whereas it was a good, well made unit, tweaking fuel pressure in a non modulating way creates one better setting and a shed load of wrong ones. I reckon the OEM regulators and dampers have a reliable service life of 15 years tops and after that it is a crap shoot as to how long they last. Roger has an after market regulator option for quite reasonable bucks and both his outfit and GB do after market direct fit modules that take the stock Bosch regulator modules you refer. Fitting a new pressure regulator can make a huge difference to the way a given motor runs but it is not likely to be the new regulator causing the difference it would be the **** poor performance of the old regulator that most likely had holes in a semi solidified & probably cracked diaphragm that consequently could not hold pressure and underfuelled as a consequence, the leakage in the diaphragm playing havoc with the AFR as it spills a shed load of unmonitored fuel into the intake that could also have potential to damage the bore lubrication.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |