Quote: Originally Posted by LTD351T [View Post] The tank in my car has more than 2 outlets. Its not a regular tank at all, far from it. But it is all std parts, no mods, etc. Flows enough for 900+fwhp just off empty. Same with lockoffs, no mods. VFF30 will do 500+rwhp, but couple it with elec lock, VFF30's can shut if you hover around 0" vac. Simple conservative rule of thumb, a stock APA outlet is good for 220rwkw in average weather with average automix. Heaps of people do the '3mm' mod on the tank lockoff and remove the EFV, in 'theory' good for about 260rwkw going by same above conservative rule. About 31% more flow. Newer tank locks and tanks are different to the older stuff, might flow more? If you want to legally do twin outlets you need the older 4 hole APA or manchester tank, NOT the newer 3 hole units. Ditch the thread in PRV, replace with thread in AFL/filler, ditch regular filler, replace with outlet assembly, done. Have to juggle around to fit, but will fit. All fully legal if done by gas dude. Cheap too. Some people have throttle return issues with GRA, some don't. It could come down to velocity through the mixer? Not really 100% sure, an old setup using twin 440's stuck open with 10psi, only 260rwkw but it was scary as hell. Thats why I use a primary throttle-setup so that it will always shut, once shut, it supplies vac to bypass valve, then the GRA shuts-in theory. Haven't had throttle stick issues with up to 18psi now. Mine are older mixers, say 10+ years, back when they had 'gas research' logo, not the 'awesome' logo they have now. Another thing to think about is the pressure on the metering rod system, vapour pressure on top of boost, it could restrict the closing, as its pushing the rod in. Their have been many iterations of the GRA mixers, maybe some are more prone to sticking open? I think it comes down to not having the butterfly setup properly. Some from a few years ago leaked a lot of vapour from the metering rod slider. GRA or Impco......some good and some bad about each. GRA 'can' have throttle sticking issues for some. Can be a bit harder to tune but fine if you know a good dyno shop. They are more expensive, but by the time you hook up Impco with t/b and hat its about the same. GRA more compact, stronger, easier to plumb. Impco, specifically 425, flow well, simple to tune and get to run well, can be better all round for daily drivers...........EXCEPT if you have backfire, they are weaker, they can be made strong, but its harder to do, time consuming. Regarding emissions, engineers, etc, could be different in other states but in ACT, the bottom line is that you will need to pass basic testing, but it can be done on a regular dyno, you have to meet certain criteria but when running LPG very easy to meet that. Hence easier to engineer, last time I looked it sorta said that you were void from having to meet the strict regs, and only need simple testing for LPG. Hey mate, good info here. Do you have a view on how much a newer style APA tank with the 3mm mod and twin lines (off the one outlet) to twin convertors will support? Also, when we say it will flow a certain amount of rwkw - I'm assuming engine combo will influence this? Ie a high strung 4cyl may require less fuel to produce the same power as an 8 for example?

Quote: Originally Posted by tufflux [View Post] Thanks for that LTD, saved me registering on the ford forums to ask your opinions. Just outa curiousity, if I run twin 4 valve apa tanks with the above mods(with balance/fill line between the two tanks), run twin outlets from each and then quad converters like yours effectively I could reach 700hp plus from the setup. Also, what do you mean by a primary throttle-setup? does that mean you run the twin throttle bodies off your active manifold, and then another primary throttlebody inline in front of this? if so would it be easier to run twin 425's instead with a large single throttle? Also guys, how do the lockoff need to be setup? Is it a matter of 1 VFF30 per convertor + standard electric lockoffs on tank? this is where I get confused and there is no performance specialist in adelaide for LPG. You cant use balance lines between tanks, if you have two tanks they cannot be linked in any way, unless you use a hydrostatic valve-you dont want to they dont flow very well. Even the same sized tanks at same height will drain into each other, even slight temp variations will make them feed unevenly. You don't want that as one could end up 100% full of liquid? maybe...Due to it filling from lockoff not AFL, nothing to limit level. A decent sized tank with two outlets, twin B2's and good lockoff setup should do 700hp, fwhp or rwhp? it should do that at rw, many variables also to consider, some setups dont work same as others, some use more fuel. Primary throttle, big throttle before mixers, two cables, if GRA stays open big one still shuts, then bypass opens, then GRA closes. Bit of effort to get working, etc, and bulky but 100% safest. Could have used twin 425's but they are bulky and weak. Not active manifold, funnelweb with fabricated stuff on top, 5" pipe bend, 5" throttle then pipe and sheet creation. VFF30 and elec lock, both in engine bay, elec lock supplies for start and running, VFF30 supplies bulk flow. I run my VFF30's just on boost press, no vac at all. But with single elec lock might want to hook vac also, depends on combo. Many people making decent power with just elec locks but gotta be modded, seen one die at 150rwkw on dyno, they just suck IMO. I think century elec locks, one model is good, but not found in Oz much, US has them, bigger, identified by 1/4" bspt/npt fittings, not 1/8th. If you wanted two tanks for range/capacity, its awkward to setup for big flow. Have had setup with two tanks, 2 outlets per tank, and ran one line from each outlet to each converter, messy....worked fine, but one tank generally empties before the other, runs fine after that just doesnt have same peak flow potential. ---------- Post added 22-11-10 at 21:05 ---------- Quote: Originally Posted by Cuz [View Post] Hey mate, good info here. Do you have a view on how much a newer style APA tank with the 3mm mod and twin lines (off the one outlet) to twin convertors will support? Also, when we say it will flow a certain amount of rwkw - I'm assuming engine combo will influence this? Ie a high strung 4cyl may require less fuel to produce the same power as an 8 for example? My data is based on older locks, have seen newer ones, they look better internally, from memory, years ago now, but same EFV, some say EFV trips, stops flow, have seen one vent to atmo, didn't stop flow-just poured out.....quality control issue maybe...? At a guess 500rwkw give or take. Once your flow is up you run into tank boil off territory. IE a no restrictions 60lt tank will still drop power after 25 seconds of flowing 700 odd FWHP, depends on fuel composition in tank and tank temp. Pressure can vary heaps based on vapour press of various fuel mixtures we can receive at the pump. Range is huge, haven't tested myself. Yeah engine combo changes requirement for sure, bsfc, some engine make more power on less fuel. A stock 351C with 8psi might max a setup with 220rwkw, but same gas setup might do 260rwkw on another engine. Boost comes into play also, if tank press low, boost adds additional need for tank press to get same flow. One reason why vapour injection can struggle or need massive hardware to support boosted apps, when your tank press is low with chit automix and -10*C weather, say for example, and your running 25psi boost, your pressure differential soon drops to fuel injected levels. A bbq bottle of automix in the fridge overnight is a real eye opener to pressure and behaviour- didn't do it myself.

Yeah I want the two tanks for the range if I do want to take it for a long run. Is it possible to run two tanks, twin outlets each tank (a & b) leading into a common manifold for each line from each tank (ie Outlet 1 on Tank 1 joins Outlet 1 on Tank 2) and then single line from the y piece up to each of the convertors(saving on amount of lines running into engine bay. This way it would run like dual fuel with a switch to change between tanks. Wouldn't This allow me to run solely on one tank then swap over to the other? Or is it just best to stick to the single tank

From memory the regs state you have to use hydrostatic valve for any lines that feed together from dual tanks, even if they are switched independently. You can thank twin tank AU wagons for that, people drove them around only using one tank, and every fill the theory is they filled the tank that wasn't being used a little bit each time. A few of them peeled open......so they changed the rules, at least thats what I heard. Best you check the rules I could be way off, few years ago now I last looked at that stuff. Or think PPI tank, made to measure etc. Single tank is always simpler.

do you mind me asking what your PPI tank set you back when you bought it? Can you actually buy them here in aus or only overseas and import it in?

i can get PPI tanks if LTD351 cant

Well i'm looking at 1 metre width between the rails, about 850mm depth between the diff and the rear of the car, and the current tank sits 350-400 deep so I guess 350 and less in depth. Any rough Idea of price and tank dimensions I would be looking at?

APA are now the Australian distributor for PPI.

Really? That makes it easy for blokes now!

Yeah, thats what Guy said last time I spoke to him.

Quote: Originally Posted by tufflux [View Post] Now to my questions, I know that one of the guys from XFORD has his ltd351 turbo putting out 750+hp off a single tank that was supposedly legally modified(ie twin outlets twin lines with lockoffs/afl's on the tank itself). He uses two GRA throttles and quad convertors. I know all to well of the inherent problem of the throttle sticking on GRA due to my old GAS TURBO RX7, and the fix being heavy arse return springs. I suspect this is why he has the twin throttles to lessen the load on each throttle plate but i will be getting in contact with him if I can for more detail on his setup. My question is, am I better off running twin 425's in front of a couple large throttle bodies instead of GRA so that I don't have throttle sticking issues? or is there a new way of modding the GRA carbs so they will definately close without a huge arse return spring that makes your right leg ache from driving. Can fix the throttle problem - if you want more info PM me and I will fill you in No spring required and throttle will feel standard... Some original photos have not been recovered yet.

Got onto the chick who is the rep. for these tanks in Aus. She is finding out what price/availability is on the tanks. The qoute form specifically states that the 305 series isn't available till next year but that works ok for me becuase it means I have more time to save, plus the car is unlikely to see the road till the end of next year at the rate I am going (tooo many toys in the build). Going for a 305 series, 4/6 cell(cant remember), 1000mm wide and I think from memory it works out to be 120ish litres usable gas.

what outlet configuration? get them to make it with what you want.

Quote: Originally Posted by LTD351T [View Post] what outlet configuration? get them to make it with what you want. Any chance you can let me know what configuration yours is? I was thinking twin outlets, filler and gauge

I'd say to go for dual valveboxes, then you have options to add more outlets later on. Or just go for three outlets straight up. Cramming two outlets, filler and gauge into one PPI valvebox is tight. The configuration of my tank is overkill and then some.