Homer Posted October 11, 2006 Share Posted October 11, 2006 Most of the kit is now ordered or here, so just need to sort a couple of smaller items. What size fuel lines will be required to supply 800cc injectors on a dual feed stock rail? - Will -6 be okay for the feeds from the FPR? - Is -6 okay for the return? - Does the stock fuel filter assembly allow suffcient flow? - Does the feed from the filter to the fpr need uprating, if so what size? (currently its -6) - Does the feed from the pump to the filter need upgraing (currently stock, whatever that is) Also is PTFE tape okay to use to seal fuel line fittings? Quote Link to comment Share on other sites More sharing options...
Marty Posted October 11, 2006 Share Posted October 11, 2006 these are all my opinion really mate and im sure alot of people will disagree i wouldnt dream of using a stock rail on a single, personally, even a twin feed one, they dont have a big enough internal diameter for 800cc injectors at all, the middle injectors will get starved under high boost, which may damage your engine. you DEFO need to uprate your fuel lines to do this properly, and pump, 2pumps being ideal. Read this thread on fueling... it makes alot of sense, and the americans know alot more than we do about tuning supra's... I was planning on using my standard rail with drop in's etc until i had a good read of this. Phr Fueling Thread a little snippet about modified rails.. the modified stock rail idea was tried and discarded several years back here in the US. The orifice size around each injector is still TINY, and way to small to support the big flow of 800cc injectors. It doesn't matter if you can supply fuel to each end, by the time it gets to the middle, you've got nothing. Proper fluid dynamics requires that there be no restriction to flow in order to support a large injector that can dump fuel at an instant notice. Again, its just a bad idea. Especially when you can get the "proper" fuel rail setup for only 200 GBP and use injectors that cost less than the drop-in Blitz models. It makes no sense. Quote Link to comment Share on other sites More sharing options...
Homer Posted October 11, 2006 Author Share Posted October 11, 2006 Thanks mate, I've read that thread a few times over but just don't trust the info there. Plenty of people both here and Japan run bigger turbos with stock rails without issues (Ian C being a good example), but for some reason the yanks are always saying different. Strange how the retailers of these products are always the ones pushing for the need to change to aftermarket kit... I've not seen any evidence to show the stock rail is insufficient for the setup, until then it will remain stock. The main purpose of the thread was for advice on fuel line size Quote Link to comment Share on other sites More sharing options...
Marty Posted October 11, 2006 Share Posted October 11, 2006 Sorry mate, just thought maybe you'd had missed it Good info i thought I personally trust what hes saying, i know he's a trader etc and its trying to sell a product, but it makes sense if you think about it. Plus they have more supras in america than in japan and the uk combined, so they have had much more experience with them They also have the fastest supra's in the world by far. Looking at the cars on the supraforums if you havent got over 800bhp your a freak guess all you have to do is look down the stock rail to see how restrictive it is compared to ones designed for bigger injectors like you are using. Sorry i could be of no help regarding the fuel lines Quote Link to comment Share on other sites More sharing options...
LeeT Posted October 12, 2006 Share Posted October 12, 2006 Darryl, -6an lines are ample. I run dual UK pumps through -6 lines into dual Toyota filters then out into -6 again to each side of the rail. The return from the rail to the FPR is also in -6an then just feed from the FPR into the stock return hardline. Also i have utilised the stock fuel feed line and just added one other line as the stock hardpipe is near enough -6 size anyhow. TerryS tested the dual feed set up with the stock rail and found it to be fine and he ran this set up on his previous car if i remeber correctly Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted October 12, 2006 Share Posted October 12, 2006 I'm running a single pump, modified twin entry stock rail, 800cc injectors, aeromotive filter and regulator, -6 inputs, and stock line for the return. I'm not quoting any power figures, but lets say it's enough to run 1.8 bar, and has done on several occassions. Quote Link to comment Share on other sites More sharing options...
Alex Posted October 12, 2006 Share Posted October 12, 2006 Thanks mate, I've read that thread a few times over but just don't trust the info there. Plenty of people both here and Japan run bigger turbos with stock rails without issues (Ian C being a good example), but for some reason the yanks are always saying different. Strange how the retailers of these products are always the ones pushing for the need to change to aftermarket kit... I've not seen any evidence to show the stock rail is insufficient for the setup, until then it will remain stock. The main purpose of the thread was for advice on fuel line size Actually Ian's running an HKS rail...but ONLY because he got it cheap, to go with RCEng 720cc Lo Imp injectors. It was not because the stock rail was insufficent. However if you want dual feeds/single return the HKS Rail is Easiest to do as it is built for it. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 12, 2006 Share Posted October 12, 2006 Plenty of people both here and Japan run bigger turbos with stock rails without issues (Ian C being a good example) I'm not a great example of this as I've actually got a HKS rail and top feed 720s I did run two pumps but now I'm only running one, and it maintains fuel delivery just fine at 7200rpm, 1.4bar. I've seen enough singled supras with 650s and the stock rail though. The hole running through the stock rail seems pretty big (how very scientific). Matt's is a very good example of this working in the real world as between him and Terry they aren't afraid to try stuff out! -Ian Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted October 12, 2006 Share Posted October 12, 2006 Darryl I had a stock twin feed rail tested by Asnu with Blitz 850cc's upto 75psi and they reported it was just fine. I ran it in the purple car which had a 74GTS turbo ( 690bhp on a proper engine dyno @ 25psi boost), with no issues at all. I would take a purpose engineered stock rail anyday over a piece of extruded aluminium with holes drilled in it! I understand the need for aftermarket fuel rails for big power cars, but for 99% of applications I would stay stock. I changed the rail on the Purple car to a BL rail, but that is only because I wanted to use Siemens injectors instead of the Blitz. If I had known about PE injectors then I would have stayed with the stock rail. HTH Quote Link to comment Share on other sites More sharing options...
Pete Posted October 12, 2006 Share Posted October 12, 2006 Also is PTFE tape okay to use to seal fuel line fittings? Isn't there some proper stuff for this? Don't skimp on fuel connector bits. A small leak can cause the death of your car! Particularly in fuel pump department - there's special electrical stuff for fuel resistance durability. Quote Link to comment Share on other sites More sharing options...
Alex Posted October 12, 2006 Share Posted October 12, 2006 I used PTFE tape...does the job - even the aeroquip hose fittings etc *need* it to ensure a good seal. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 12, 2006 Share Posted October 12, 2006 I used PTFE as well - just make sure it's on the threads and not poking out into the fuel flow Fuel leaks aren't that bad It takes a lot more to make fuel go up than most people realise, thanks to movies. Petrol puts out cigarettes As for the in-tank stuff, I used a choccie block connector and plastic tie tags, and they have survived for a couple or years just fine. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 12, 2006 Share Posted October 12, 2006 Stock lines, regulator and rail is just fine, I have people crying when they bring an HKS fuel rail for a Skyline and I show them one cut in two next to the stock Nissan rail, and they see the stock one is nearly twice as big, inside... Aeroquip connectors should never have any other sealing used, PTFE tape is terrible stuff, it gets into all sorts of places it shouldn't. I'd just uprate the pump and injectors, then leave everything else stock, myself. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 12, 2006 Share Posted October 12, 2006 I'll just add that I only used PTFE tape on the adaptors that screw into the FPR - the aeroquip fittings otherwise seal perfectly as designed without any need for gack to gum them up. -Ian Quote Link to comment Share on other sites More sharing options...
Wez Posted October 12, 2006 Share Posted October 12, 2006 I am running single walbro, stock fpr, stock rail, stock fuel dampner and stock lines with PE injectors and not seen any issues. I do not like twin pump setups and if my pump becomes an issue I will upgrade to something like a single bosch 044 or bigger. Quote Link to comment Share on other sites More sharing options...
TLicense Posted October 12, 2006 Share Posted October 12, 2006 Stock lines, regulator and rail is just fine, I have people crying when they bring an HKS fuel rail for a Skyline and I show them one cut in two next to the stock Nissan rail, and they see the stock one is nearly twice as big, inside... Aeroquip connectors should never have any other sealing used, PTFE tape is terrible stuff, it gets into all sorts of places it shouldn't. I'd just uprate the pump and injectors, then leave everything else stock, myself. Chris, you've said that the stock regulator will be fine many times. It's not true. The stock regulator is not adjustable, and for the injectors to flow the amounts that they're flow tested at you need to adjust the pressure to the same pressure as they were tested at. There isn't a standard pressure for flow testing, so somone could be fitting what they think will be 800cc injectors that have been tested at 4 bar for example, only to find that they're not flowing enough fuel. It's because the stock system, with the stock regulator, would be keeping the pressure at the 40psi (can't remember the exact figure) that it's set to. Also if you take a look in my twin turbo conversion thread, you'll spot that the stock Supra rail, when compared to something like the phr rail, is tiny. Maybe it's different for the Skylines.... I would definitely also swap the lines. I have -8 running to a high flow filter, splitting to two -6 lines going to the rail, -6 going to the regulator, and then a -6 return to the tank. When you compare a -8 or even a -6 line to a stock line you'll understand why! As with ALL fuel lines, you MUST pressure test them before use. This is best done off the car, but if need be can be done by pressurising the fuel system on the car. I would take it to 1.5 times the max operating pressure as a minimum and 2 times would be better. If you test the lines off the car, you should also test the system as a whole using the above method for example. Whilst I agree with Ian about how fuel isn't as bad as people would have you believe, I've seen a couple of cars go up due to fuel fires, and have heard lots of stories on here to make me very paranoid about it. Lastly, you should not need any PTFE on any of the fuel joints. The tapered conectors form a seal without need of any sealing device whilst ORB connectors require an O ring. That's all. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 12, 2006 Share Posted October 12, 2006 I would still leave the stock (high quality, no "issues") if possible, and map to suit the fuel pressure it offers, otherwise buy something like a Bosch Motorsport adjustable reg, or the one I do, that was made for Toyota Team Europe, and is just as good as the Bosch one at less cost. Some the cheap regs are rubbish and unreliable. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 12, 2006 Share Posted October 12, 2006 I may be fitting O-rings to my pressure regulator at some point to provide a better seal. Apart from that the Aeromotive reg has been rock solid for the couple of years it's been on and I've heard of no-one else having issues with it. It holds pressure accurately and ramps it up and down in line with boost/vacuum nicely. Is the Skyline rail appreciably bigger than the Supra one? I've not noticed the Supra one is bigger than the HKS one I've got -Ian Quote Link to comment Share on other sites More sharing options...
TLicense Posted October 12, 2006 Share Posted October 12, 2006 I would still leave the stock (high quality, no "issues") if possible, and map to suit the fuel pressure it offers, otherwise buy something like a Bosch Motorsport adjustable reg, or the one I do, that was made for Toyota Team Europe, and is just as good as the Bosch one at less cost. Some the cheap regs are rubbish and unreliable. If you've got spare enough cc's to be able to map out a significant pressure change then you've got the wrong injectors. If it's the injector is too big, it will make mapping for the subtleties of idle difficult. Plus once you've hit around 80% duty, then that's it, you either risk going static or raise the base pressure. You need to run the right size injectors at the right base pressure. No two ways about it. I totally agree on the regulator side though, although I wouldn't start thinking that you need to start spending silly money, as Ian says the Aeromotive's have a good rep on here, but there are also several other's that produce reasonable kit (weldon for example) But definitely stay clear of the FSE range etc, as my personaly experience has found them to be lacking. Quote Link to comment Share on other sites More sharing options...
Homer Posted October 12, 2006 Author Share Posted October 12, 2006 Thanks very much for all the input guys, good to see everyone agrees Unfortunately it didn't confirm too much, so I think I'll go ahead with the original setup I had in mind and see if it works (Ian, it'll be in your hands then) Single walbro Stock fuel line to filter Stock filter Stock line to fpr Aeromotive fpr (Already installed so no sense in changing) -6 lines to stock rail (Maybe change to -8 as it's not much bother) 800cc injectors (which are unlikely to see 80% duty cycle) Just a final thought - Is it really worth converting the rail to dual feed? Chris seems to think not, but then most people seem to think its required with larger injectors. Quote Link to comment Share on other sites More sharing options...
LeeT Posted October 12, 2006 Share Posted October 12, 2006 Thanks very much for all the input guys, good to see everyone agrees Unfortunately it didn't confirm too much, so I think I'll go ahead with the original setup I had in mind and see if it works (Ian, it'll be in your hands then) Single walbro Stock fuel line to filter Stock filter Stock line to fpr Aeromotive fpr (Already installed so no sense in changing) -6 lines to stock rail (Maybe change to -8 as it's not much bother) 800cc injectors (which are unlikely to see 80% duty cycle) Just a final thought - Is it really worth converting the rail to dual feed? Chris seems to think not, but then most people seem to think its required with larger injectors. Darryl, There's no point in putting a -8an line from the stock filter to the rail as it is bigger than the main feed pipe. Just stick with the -6, it will be fine. Quote Link to comment Share on other sites More sharing options...
Homer Posted October 12, 2006 Author Share Posted October 12, 2006 Okay, mate, that makes things much easier as I already have all the -6 fittings and pipework. What are your thoughts about the dual feed? I know you did yours, but is it *really* necessary? Quote Link to comment Share on other sites More sharing options...
LeeT Posted October 12, 2006 Share Posted October 12, 2006 Okay, mate, that makes things much easier as I already have all the -6 fittings and pipework. What are your thoughts about the dual feed? I know you did yours, but is it *really* necessary? Well Imo it is pointless having a twin feed rail if you only have the stock feed line. If you want a dual feed i would suggest either replacing the stock feed with a -8an line and Y'ing into -6's or adding a 2nd pump and putting in an extra -6an feed line, filter etc. As IanC has already pointed out, he only has the one pump and is running fine so i wouldn't say it was necessary, just nice to have Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted October 12, 2006 Share Posted October 12, 2006 Okay, mate, that makes things much easier as I already have all the -6 fittings and pipework. What are your thoughts about the dual feed? I know you did yours, but is it *really* necessary? Do what Terry did. Find an Asnu tester, (injector testing machine), and get them to flow test the stock rail and injectors. I did mine that way, as Terry's tests had proved OK. Just for reference, I get 76% duty at 1.8bar with AFR's around mid to low 11's, and my fuel pressure is lower than most. Quote Link to comment Share on other sites More sharing options...
Ian C Posted October 13, 2006 Share Posted October 13, 2006 Single walbro Stock fuel line to filter Stock filter Stock line to fpr Aeromotive fpr (Already installed so no sense in changing) -6 lines to stock rail (Maybe change to -8 as it's not much bother) 800cc injectors (which are unlikely to see 80% duty cycle) You might want to put the FPR *after* the fuel rail -Ian Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.