Hello, After having some hot starting problems, I decided to change both fuel pressure regulators. So I had a look to the threads about it of some good skilled f-chatters (especially thanks to "No doubt" for his helpfull write up). There are 2 types of FPR: - 137960 (Ferrari ref.) / 0280160731 (Bosch ref.) Valid for the early model. 3.0 bar. Inlet M14x1.5 / outlet straight barb to hose with clamp. - 147281 (Ferrari ref.) / 0280160738 (Bosch ref.). Valid for the later model. 3.8 bar. Inlet M14x1.5 / outlet M16x1.5. The FPR for the early model is easy to buy for a reasonable price from many makers, but the later is more expesive because now its not available from Bosch neither any other maker except Ferrari dealers. An spanish Ferrari dealer asked me 600 for a pair of FPR's, while you can buy earlys for 100 a pair. At this point I had to do something, and I moved to the risk of installing adjustable FPR's as used on racing/modified cars. So I bought 2 FPR's from Sard Racing (japanisse aftermarket brand), and 2 gauges. Here they are: http://flickr.com/gp/90532357@N05/BL3F2b I know that a FPR can be replaced taking apart almost nothing of the car, but I like to have the more free space as possible for working confortable. So I disassembled the air filter box, intake tubes, idler valves and the oem FPR's to figure out it's thread pattern. Some pics: http://flickr.com/gp/90532357@N05/31551M http://flickr.com/gp/90532357@N05/1ME289 http://flickr.com/gp/90532357@N05/obc281 The difficult part was that the aftermarket FPR's come with 1/8 npt to straight barb adapters, so I needed a machining Workshop to make the adapters: 1/8npt to M14x1.5 and 1/8 npt to M16x1.5. And don't forget that some custom bracket will be needed too. But it was really easy; I used the lower part of the oem bracket for attaching to the original place (the engine) and bolted the new FPR's to it as you can see on the pictures: http://flickr.com/gp/90532357@N05/8F3sa4 http://flickr.com/gp/90532357@N05/dA8Jc5 http://flickr.com/gp/90532357@N05/c23fc8 I used some teflon tape to avoid fuel leaks and bolted the FPR's to the car: http://flickr.com/gp/90532357@N05/226Vjt http://flickr.com/gp/90532357@N05/DAHYLH http://flickr.com/gp/90532357@N05/tXHSPh http://flickr.com/gp/90532357@N05/62j04G When everything is reinstalled in its proper place, and check again thats all right, its time to start the engine, checking for fuel leaks and adjusting the fuel pressure. In the 348 workshop manual can be read that the early model (3.0 bar) needs to be adjusted with engine idling and the depresión intake connected to 3.4 bar. So I decided to set my later 348 (3.8 bar) to 4.3 bar (maths basic level). Pictures here: http://flickr.com/gp/90532357@N05/z55G7S http://flickr.com/gp/90532357@N05/Bh826g http://flickr.com/gp/90532357@N05/B05yB4 http://flickr.com/gp/90532357@N05/y83662 And it seems to work right nope, more than that my 348 now pulls like never before, and I am soooo happy.
I have been told absolutely not. I would verify the tape you used is fuel and alcohol safe, or remove it immediately.
Thanks for your kind words guys. I'll be proud to add a link to this thread in the sticky, thanks Ernie. A nice way to put together useful information for all of us. About the use of teflon, I must say that it's something that I really didn't like to do, but npt threads must use a sealant to assure a leak free joint. I've driven the car a couple of days and everything seems to be OK for the moment... I like the risk, I'm living on the edge, I'm a Ferrari owner
From: How to Properly seal Fuel Fittings and Fuel Lines "To choose the appropriate thread sealant, look for it's chemical resistance to fuel (diesel or gasoline) or oil running through the line. Backyard mechanics will tell you they've used regular old gas resistant teflon tape (yellow stuff) with success. This is not recommended because it risks breaking free. Liquid or paste type thread sealants are kinder to sensitive components down stream. Mechanics repairing injectors, fuel pumps and carburetors can tell you first hand it is not uncommon to trace fault in the fuel component to clogging from a piece of teflon tape that washed off the ends of the threads, clogging in the first tiny micron orifice it encounters, if not the fuel pump then an injector or carburetor gallery. Either way it's a costly repair. Liquid or paste type sealant won't clog. For gasoline, regular old gasoline resistant Aviation Form-a-gasket Number 3 is the best option. Another product also offered by Permatex is the High Temperature Thread Sealant. Tech data on this sealant says it has medium solvent resistance and is recommended for fuel sender type applications. With the advent of ethanol present in modern gasoline, I favor Form-a-gasket No. 3 which specifically states solvent resistance to gasoline, especially on modern engines that use injectors rather than carburetors such as the E-TEC and HPDI (high pressure direct injection) and any diesel engine." Good Luck, I hope I am wrong on this!!!!!
Could someone explain the failure of a pressure regulator, would they remain fully open, closed or partial. To check if they are working would you just put a pressure gauge inline?
The 358 race engine has one of these and we installed a gauge along with the hardware. We run it at 60-65 psi with some different injectors. The cool thing is that the 3.8 bar stock regulator equates to fuel pressure of 55 psi. The tests on-line for injector flow use a benchmark 45 psi to calculate power ratings. Our stock 19 lb. (18.x really) injectors are capable of serving an engine making up to about 360 HP with an 80% duty cycle, which the industry considers safe. Heh. You can push this to 400 HP. Imagine the potential. Greater pressure means more fuel with each squirt. More air, more fuel means more power. All part of the equation to find more power on these engines. However, you just cannot add fuel pressure and expect more power at the wheels. Too bad.
Vince I recently put a capristo stage 3 on my f1 and it seemed to run very good with the stock air boxes. Then I went to a groupe m air intake and the car has a big hesitation on moderate acceleration in first, it's no problem if you just trump on it. Is it possible i am not getting enough fuel from 1 to 3 thousand. To me it would seem that the new air box is giving too much air of idle. What do you think?
After many kms of driving I can tell that the teflon tape is working well, with no problems, fortunately for me. I am not saying that I recommend everybody to use taflon tape for preventing fuel leaks through npt threads, I'm just sharing my own experience. So you can choose the kind of sealant you prefer. However I don't trust systematically in what a seller says about his own product, because sometimes he exagerates about the benefits of using what he's selling and the risks of using anything else.
A FPR usually fails when it can not keep the fuel pressure required constantly due to a cracked membrane that leaks fuel to the return pipe or to the depression intake pipe. It use to be a minimal leak that drains fuel when the engine is turned off, so the fuel pressure is too low for the next start up causing a hard start. Yes, you can check it with a pressure gauge inline.
I'm not trying to get more power, I'm trying to set the fuel pressure to the standards, but paying less with these regulable units. However I've noticed a better throtle response, not saying more hp's, but the car is slightly diffrent now. And I like it.
We used teflon tape on the race car pressure regulator. Just make sure that the one you use is rated for gasoline. I think it's in a red roll instead of a blue one. Even Home Depot has it! @taz355 I am not sure of the cause of your stumble. Generally I'd think that means too much fuel, not less, being squirted into the cylinders. How old are your spark plugs? Do you have enough spark? Of course, a small vacuum leak may manifest itself this way too. I cannot believe the intake is the cause.
Hey guys looking for your expert advise please. I’m just about to replace a faulty Fuel Pressure Regulator and want to know the safest way to achieve a fuel tight seal when I tighten the fittings. Seems there is a variation in views on whether using Teflon tape is safe or not so I would rather use a paste or sealant to avoid any issues. Could someone recommend one they have successfully used to do this job and that resulted in no leaks? What did they use as the factory? Thanks Jon
Generally, those fitting seal, no additional sealant, is needed. There is aviation fuel safe thread sealant that can be used for fuel lines specifically, I have it I can check when I get home. Permatex makes is. Sent from my SM-G990U using FerrariChat.com mobile app
Hey guys After searching for over two months I’m no nearer to sourcing an FPR for my ‘94 348 ts. The FPR is the later 3.8 bar version fitted with the dual screw threads. No one, but no one, has them. Although there are a lot of scammers claiming to. I’m wondering if I can retro fit the older FPR with the Barb ( 3 bar) as I have seen the odd one of these for sale. It would involve replacing the fuel line too as the connector would then be wrong. Has anyone done this successfully with the engine in the car, and would a reduction in pressure affect things too much? Any comments/ suggestions welcome. The car has been off road since April and I’m missing out on all the (rare) UK sunshine!
The picture at the link shows a 3.0 Bar FPR (137960) so the description might be wrong. The 3.8 Bar FPR, 147281, should look like this (Standard PR298 shown, available at Summit Racing etc.): Image Unavailable, Please Login
I few days ago I received an email from autoepoca.it offering two (allegedly) OEM 3.8 bar fuel pressure regulators for 398 Euros. I seem to be on their mailing list even though I have never done business with them. May be worth looking into if you are interested.
Thanks but this is the early version with the Barb. Mine is the later version with just the M16 and M14 threads
Thanks I’ll follow it up - but some of these items are the early type with the Barb that are the wrong ones. I’ll see if the others are ‘real’ as I’ve discovered a lot of people claim to have them but don’t
I just got off the phone with Summit and they have none in stock. They have a shipment coming in but all of those parts are spoken for. I'm thinking of going the adjustable route, but from what I recall, getting the right fittings (i.e. threads) can be a pain.
