Willy, A little confused. Trying to be helpful. Are you saying: 1. the stock FPRs keep the pressure in the fuel rail at 90psi when the car is switched off AND this persists on restart at idle unless you somehow bleed the system? Or, 2. The FP as measured on the rail AFTER the aftermarket RRFPR indicates the above symptoms? Or, 3. one of the above but FP is returning to normal on restart at idle (but not before this)? If 1, sounds like the stock FPR have stuck. If 2, are you regulating the fuel pressure with a signal line from the intake? If not, I think you should be. If 3, is this a problem? If I am not being helpful, tell me, Philip
Thanks for your help Philip. I will only use pressure when referring to the FRP and I will only use regulator when referring to the FPR. The 2 stock regulators are set at 52psi and are in the tank and do not reference to manifold pressure. I initially thought that each fuel pump fed a fuel rail and were independent however I quickly found that adjustments to one regulator instantly altered the visible fuel being returned by the other regulator. Bleeding the shrader valve on one rail instantly dropped the pressure on a gage on the other rail. I now have the 2 rails joined with a T fitting and a gage in the middle. The system is non-return having the regulators and their return lines within the tank. I can now adjust quite accurately the pressure at idle and can get both regulators set approximately the same by physically watching the fuel returns overflowing the pump buckets and getting them the same. Also if one regulator is set at a higher pressure than the other you can hear the lower set one dumping more fuel. The pressure therefore is determined by the lowest set regulator. That is to say I can increase one with no effect on the pressure unless I increase the other as well. With less than a third full tank you can run the motor with the access covers removed. The regulators with associated plumbing are hosed on the backside of these covers. So I set and equalize the regulators at 65psi and go for an easy drive. I stop and with the motor running I get out and check the pressure which is still at 65psi. I then drive to my secret safe test road and do my 3rd gear only run from 60 - 95 mph which interval is set on my Prologic Performance Box and check the time. This is my dyno. The car feels flat from 60mph to around 75mph then feels very strong. The 3.9 sec time is a full 0.5 sec slower than the best so far. I get back home and without shutting off check the pressure which is now up to over 90psi. I turn off the motor and bleed the pressure off by just unscrewing the pressure gage slightly and catching the small amount of fuel into a towel and then re-tighten. I immediately start the motor again and the pressure rises to 65psi as set. If I had only one regulator I could easily surmise that it sticks and lets the pressure build to 90psi and then frees up when I release that pressure. The fact is there are 2 regulators and logically both would have to stick closed as the pressure is always that controlled by the regulator with lowest set spring pressure. I took a break from writing and have just returned everything to stock configuration and confirmed that I had 52psi. I went for a quick hard run and the pressure had again increased to 90psi plus. This latter pressure before shutting off varies from 80-95psi whether with tweaked regulators or stock. I can find no other restriction in Ricambi's drawings for the fuel delivery lines. What is interesting is they show a fuel pressure sensor (item 35) with a separate pipe from the right hand pump cover yet this isn't shown on the drawing for pump itself or the drawing for the delivery piping. More importantly there is no such device on my car. The regulators are purely mechanical with only a ground wire so wonder what the missing sensor is supposed to do. The regulators are a simple spring on diaphragm device and the pressure they limit to is what comes out of the pump covers so I am baffled as to what is effectively stiffening both springs to allow these higher than set pressures. I would be grateful if someone at Ricambi or? could shed some light on the factory fuel delivery system for my car especially since the Ricambi drawings do not accurately represent what is on my car as in there being no fuel pressure sensor at the location shown on the drawings. More specifically what does this missing sensor get read by and what then happens if it reads abnormal fuel pressure? John does your WSM shed any light? Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I have finally installed a quality external FPR with a return line. I have fixed the in-tank FPRs closed and inoperable (reversable). I am now able to adjust the FRP with some consistency. Initial road testing shows 60psi FRP (stock is 52psi) gives a repeatable 4.4 sec 60 - 100mph time on an 80deg F day compared with a stock car's 5.4 sec. No flat feeling or bog. I now am ready to get it on a dyno and get some accurate AFRs and see if the tune can be improved. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Willy- After all the work Ferrari did to make the 575M a returnless system, you have reverted to a 550-like set-up. Any problems with return fuel temperature? That required a fuel cooling system on the 550.
Taz, unfortunately as you have read, the in tank FPRs did not like being fiddled so had to go with an external FPR with return line. I was loath to cut the factory in tank fuel lines to attempt an in-tank FPR. The fuel rails themselves get plenty hot and I have made sure the return line is away from the exhaust manifold. The returned fuel would cool on its way back somewhat. I have never heard of a fuel cooler needed in high power blown V8s. Easily fixed if needed. Ideally Bosch would have had an injector size giving 10-15% more fuel flow but they didn't. The next and only size up in that injector style was a full 40% higher in fuel flow. I have a set and will try them at some point but they would need only 35psi FRP which I feel might be too low for proper atomization.
Willy- Sounds like a worthwhile thing to try as long as you got them for a reasonable price. Will be interesting to see what she shows on a dyno if you have access to one. We have all kinds of runs that Bradan has done for comparison.
I have already purchased the bigger injectors. $133 each from Bosch compared to $324 from Ricambi!! I am loath to do any comparisons between different dynos. What counts is how it performs as in the trap speed in the 1/4. I will be using the dyno time to collect AFRs. The dyno my friend has reads notoriously low amongst the LS engine tuners in Perth however he is one of the busiest because his customers cars do most of the winning. As an example my cammed LS7 Ute read 440 rwhp on his dyno yet it it did 120mph through the traps on an 11.8. Using the formula, that speed and the car's 3,870 lb with driver (me), showed 522 rwhp needed to achieve 120mph. If I come back to this forum with a measly 450 rwhp dyno reading most would say what's he so excited about? I have always questioned that formula as giving a too high rwhp but knowing that the stock car does 117mph and at 13 fwhp /mph gain I will be upset if I don't see 122mph at some future time. By the way my Ute does 4.5 sec 60-100mph. My 575 does 4.4 sec so far in a 90 lb heavier car and driver. I have recorded a 60-117mph time of 7.1 sec which added to a 4.2 sec stock 0-60, has it reaching 0-117mph in 11.3 sec or 0.9 sec quicker than stock and that is with a manual 3-4 shift. Yes, I like playing the numbers game to compare with other cars. These numbers would approximate a stock Z06 Vette's rather than the regular Vette's which compare with a stock 575. The Vette had to go up a litre in displacement and 75hp for that improvement while the 575 only needs a bigger exhaust and more fuel.
Willy it's good to see all the updates - I somehow missed everything from early December. I see a single regulator in your pics - did you tie the fuel rails together both at the inlet and the outlet as a common system and do a single return? Taz makes a good point, as fuel overheating was a real bugaboo for all return type fuel systems until the OEM's found different ways to reduce fuel pump output at idle. Initially both Detroit & Japan put big honking resistors in the circuit as voltage droppers when the engine was idling, but many pumps had problems with this as their motors lost too much torque. Next was the PWM solution from the Japanese, which was more elegant, worked well, and restored the lost torque. You can test to see if you've got a fuel heating problem by letting the car idle for a fair amount of time, then open your gas cap and see if you get a huge whoosh of escaping pressure. The evap system should keep the fuel tank from overpressuring, but it would be interesting if you notice more escaping pressure than when you ran the returnless system. Too much vaporisation is only half the problem with hot fuel. The other half is that hot fuel is lighter and less dense than cold fuel, so its calorific value is lower. This means the engine will make less power on hot fuel than cold, and this was demonstrated graphically to me around 25 years ago when we were doing 12 hour dyno runs on remanufactured industrial engines and they would begin losing power as a result of the fuel heating up. Once we installed a fuel cooling system on the dyno, that sorted it.
Cribbj, thanks for that info, I will watch that carefully, I can directly measure the return fuel by opening the pump access with fuel below 1/3 and putting a thermometer in the return flow with the engine running. What temp is too hot? The FRPs are common, if you look in the Ricambi drawing you can see a line connecting the two fuel lines which goes over the top of the tank. I had a gage on the opposite FR just to make sure.
Sorry Willy, I'm not following you, but it's early here and the brain may not be firing on all cylinders yet. I had missed the crossover "common" line on the top of the tank, but I'm still confused on your new regulator arrangement. From the photo in your previous post, it "looks" like you only have a single new regulator and you're returning from the left hand fuel rail only? A pic is worth a thousand words - so have you done your system like any of the three below? It would appear from your photo that you've done it like the left hand diagram? If so, I would suggest that if you want to use a single reg, that you consider redoing it according to the middle diagram. The right hand diagram would allow you to adjust the fuel pressure for the right rail independently of the left, and although I've shown two return lines after the regs, you could tie those together and have a single return coming back to the tank. p.s. About the fuel heating, there's really not a temperature where it's "too" hot, IMO. It's just that the cooler you can make it, the less vaporisation you'll have, and the more BTU's it'll carry per unit volume. Obviously unless you have a refrigeration system (like the 550 fuel system) you'll be doing very well to get it down to within 10-15 degrees of ambient during the summer. Image Unavailable, Please Login
Cribbj, I have done it as in the left. All along I have used a temporary primary gage on the right hand rail which responds to adjustments on the left hand rail. I accept that it would be more instantaneous if I also tied them together as in the second diagram, this I will do. There was a slight delay and bouncing of the needle in the primary gage which quickly settled down after making an adjustment. I don't feel there would be any advantage to a second FPR as the both FRPs will always be governed by the lowest set FPR. I have looked at Ricambi's diagram for the 550 and see that the freon/fuel heat exchanger is only for North American cars for 1999 and 2000. What did the earlier and all Euro cars use if anything? You have got me thinking however and I wonder if an intercooler as used in a blown engine or an oil cooler mounted just behind the egg crate would handle cooling the fuel before it made its way back to the tank. My driving to date has been short duration runs but I can see that after an hour on the road the fuel in the tank would definately go up in temp and thus cost me some power at a minimum.
Further to this, the images etc are of a temporary set-up. I plan to plumb it all in nicely when the final solution is achieved. In that regard I have just had another look and there is room for the FPR along side of the fuel tank so that placement will eliminate the need for any fuel cooling as the return line will be very short and not subject to engine compartment heat. The balance hose is just attached to the fuel delivery hoses with push-on T-fittings (probably need a heat gun) so I could just fit the hose to the FPR from there with a 4-way fitting.
Hi, I have done a search for this to no avail. I hope I can get the Bosch part numbers for these ECUs without having to pull them out. My Chev guru is going to try and see if he can find one of his expert contacts who might be able to into these ECUs to get a proper live tune. Are they used on another vehicle? Cheers.
I am still searching for the elusive fix. I have mounted the FPR back with the tank so there are no fuel return heating problems. I am pretty sure now that the stock pumps cannot supply enough fuel. There are some neat kits available using a 2 litre surge tank and either one or two Bosch 044 fuel pumps. These are individually rated at 600 - 700 hp however it is advised to use two in series for over 600hp. The surge tank kit for two pumps however shows them mounted in parallel. I am keen to explore this mod but wonder if any of you have experience with these very popular fuel pumps. I would use the factory pumps to feed the tank. After many months of only filling the tank part way so that I could access the tank internally, I filled up. This may be coincidence but with the tank full the flatness I was feeling seemed to go away. Encouraged I went to my 'dyno road', set the V Box and immediately equaled the 4.4sec 60-100mph best ever time I had recorded. I also thought I had detected some slight pinging, so on the roadside I upped the FRP to 65psi from the 62psi previously set and it did a new best of 4.2sec with no audible pinging (I have poor hearing). I was elated, remember a 599 takes 3.9sec and a stock 575 is 5.4sec. Now after 2 weeks of temperatures way to hot in Oz to go out and do performance checks, I went out early this morning. The tank is down to half and the flatness has returned with no other changes and I could only manage 4.6sec. I am convinced the stock pumps feeding so much more pressure are just marginally able to supply when fed by the head of a full tank so I want to try the new pump(s) and surge tank set up. I would like to stay with Bosch pumps. Any comment or advise before I spend more $ would be appreciated. Cheers.
Willy, I used a Bosch 044 with my Noble, V6, rated about 370 bhp. When I upgraded to run closer to 450 - 500 we used an uprated Bosch pump. As I recall, people used the uprated pump to put down up to 650 bhp. I am afraid I don't recall the specs but the bottom line is a single pump did the trick in a V6, Philp
Willy, it might be useful to monitor the fuel pressure at the rails to see if your pumps are keeping up. The quickest indication that you don't have enough flow will be a drop in fuel pressure. Our in tank pumps are supposed to be rated for 110 liter/hr @ 60 psi. This is about 350 HP worth of fuel per pump, which ought to be plenty for you, but that's not to say that the output hasn't dropped with age, plus since you're asking more from the injectors by running higher fuel pressures, the pumps' output will drop off quickly at the higher pressures. I used to be a big fan of the 044 Bosch pumps, but there are better alternatives now, so in my book, the 044's have slipped down to the 2nd tier due to their older roller cell technology. If you go through the Bosch Motorsport catalog, there are several new turbine pumps, which are the same style as our OEM pumps, and which put the 044 to shame, plus Aeromotive have come out with a new one they call the "Stealth" which is the same style turbine pump, and it flows well over 250 l/hr at 65 psi. If I needed more fuel delivery, I think I'd consider one of these new turbine pumps over the older style 044's. They're quieter, produce less pulsation, and they're MUCH smaller, so they should be easier to adapt to the OEM fuel basket setup. The early 456's used a smaller version of the 044 pumps, but all the newer cars have switched to the turbine style. I did a few side by side photo comparisons of these pumps and posted it on the "other" Ferrari forum last year. One thing is certain, you don't want to be running out of pump or injector at WOT. That's the quickest, surest way to grenade your motor, short of running it without oil.
Thanks for the input guys. The stock injectors at the factory FRP of 52.2psi (3.6bar) support 534bhp according to RC Fuel Injection by inputing the FRP and adjusting hp until the equivalent injector at 43.5psi standard test pressure gives the rated flow of 267 ml/min. This shows they are marginal At the 65psi I have been using for my best runs the injectors are supporting 596bhp. I have another set of same style Bosch injectors which flow 373 ml/min at 43.5psi. These injectors would need only 36psi to support the same 596hp. My concern is that the spray pattern will be affected at that low pressure as the design operating pressure is 55.1psi (3.8bar) which supports 766hp!! I will try these first however. pma1010, I don't have info on the duty cycle duration. John, thanks for the tip on the Aeromotive Stealth pump.
I hooked up another cheap FRP gauge to the FR balance hose I had installed and taped it to the windscreen. I have also installed the bigger injectors. The performance at 36psi FRP with the new injectors is the same as with the stock injectors at 65psi FRP which conforms with the injector worksheet. The FRP under full throttle drops up to 5psi the instant I hit the throttle and then wobbles around there all the way up. A few on/off throttle applications in second results in the motor bogging on about the 3rd one. So now I give it more pump. Assuming the new pump(s) will handle either set of injectors which would you go for, the big injectors and 35-40psi FRP or the stock injectors and 60-70psi FRP?
Willy, I would opt for the stock ones at the higher pressure first, because don't forget that your ECU's are still "hard" coded to go open loop at WOT, and this open loop map is based on the stock injector output. If/when you hit WOT with new injectors that are probably 1.5x bigger than stock, the ECU's are going to tell them to go to the same duty cycle as the originals, and that's a LOT more fuel to be dumping into the motor. At least with the stock ECU's you can "tune" their output a bit by adjusting the fuel pressure - with the new injectors, you could reduce their output some by cutting back on fuel pressure, but like you, I'd be concerned about the quality of the spray. What you really need is a dual channel wide band AFR monitor that would work on both banks, and equipped with some data logging. That'll enable you to see how "happy" the engine really is under some of these conditions.
This link is to a fuel pump test including the Bosch 044 and the Aeroflow Stealth. Pretty big flow numbers for all. Fuel Pump Comparison Test : Real Street Performance Engine Parts, Pistons Rods Cams Valvetrain and More
Willy, Seems like any of the pumps will do what you need. I have not been reading your thread as closely as I should but I thought you have deduced 2 conclusions before: - running the stock injectors with an auxilliary FPR (AFPR) working at 60-65 psi produced your desired results (accel, lack of stumbling or delay etc) in live (on the road) testing; - your stock fuel pumps maybe inadequate to support the flow requirements you need and hence you are upgrading the pump. You also concluded, I think, that a dead head (returnless) fuel delivery solution was incompatible with running higher fuel pressure and therefore built a fuel return system. If correct, this obviates the higher fuel pressure concern. Fourth, you've found higher flow injectors that can support your fueling needs but you have no way to regulate their performance once the system goes open loop (WOT, high rpm) when fuel is just dumped into the motor by the ECU w/o reference to the A/F ratio. In sum, the conclusions tell me that there are two ways to proceed: (1) stock injectors, fuel return system as modified, In (return) line AFPR and modified pump. You have I think what you need to do this. (2) new injectors specifically rated to support fueling requirement at WOT/high rpm operation, fuel system as modified or stock, modified pump. As I read your text, I don't think you have this equipment today. So, why not proceed with option 1? Doesn"t this satisfy Occum's Razor? By the way, when I was playing around with a supercharged car a few years ago, we ran an AFPR at 72.5 psi with no issues. HTH, Philip
