Howdy guys, Firstly, I have a single turbo V8 setup going into my HZ van and I want to run straight gas for EPA/engineering reasons, aswell as it will be on low boost for the rare daily . What is the max HP you can expect to get out of a single tank with twin outlets? I am planning on running dual tanks under beside the tail shaft so will this allow me to fetch aroung 550-600hp at the wheels. Now before everyone jumps in and tells me that this insanely stupid power for the street, yes I already know this but as I said it will be extremely low boost on the street and it wont be an everyday ride. 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. Some original photos have not been recovered yet.

you dont need a massive return spring, i had a pretty flexible one on mine running about 17psi and it wouldnt stay open, the pedal felt just like standard too and ive said this a few times but u do realise that running straight lpg has next to no epa benefits, they treat it exactly the same as they would a petrol car so if ur going lpg for that reason u should probably do a bit more research have a search in the lpg forum, most of what ur asking has already been covered i.e. power levels, epa, etc and yer with the return spring like i said theres no need to run a massive spring just find one with enough pressure to snap the throttle shut but not enough to break ur leg off

Quote: Originally Posted by FORZA [View Post] and ive said this a few times but u do realise that running straight lpg has next to no epa benefits, they treat it exactly the same as they would a petrol car so if ur going lpg for that reason u should probably do a bit more research now I wouldnt jump on that too soon. Read the EPA rules, it states that any straight LPG car must be emissioned compliant in order to be LPG complianced. "Owners should ensure they have documentary evidence that the LPG conversion system fitted to the vechile does not affect emissions performance. The manufacturer or distributor of such parts or systems should supply this evidence in writing, based on there own testing efforts and engineering judgement"

Ok, well I was running 25-28psi on my rotor and it needed a bloody big spring to snap it shut. I nearly killed myself the first and last time the throttle stuck open. I guess coz boost should be below 15 might be ok with a mediumish spring, but unsure considering the amount of airflow it will be forcing through. Yeah I understand it still requires to be EPA compliant, but in SA they are lot more leanient towards straight LPG conversions rather than petrol or dual fuel, especially when engineering costs an arm and a leg for emission testing in this state. It just makes it a lot easier to meet the emission levels, plus from what i understand with the new regs it means I shouldn't need to run a cat aswell. I am going in this direction as it works out a fair bit cheaper to setup than a petrol setup considering I have most the parts already, plus the added benefit of higher CR being a V8 and low boost for driveability. Best of all worlds I think. GAS747, what tank setup you running if you don't mind me asking? If you would prefer not to say so over the forum maybe a PM if you don't mind. Cheers guys

I dont know anything technical about the lpg setup to be honest. just the basics

cool thanks anway, I will do some more digging

just send the car to someone that knows LPG and can help rather then wasting money and time trying things?!?!

Its all about the diameter of your butterfly which makes it harder to shut, hence when you have multiple small ones the amount of rotational torque applied to the butterfly is lessened. A way to fix this is oval shaped intakes but very few manufacturers do this, most option to go down the twin 60mm throttle setup or the like.

A local bloke here has a HZ stato with 454 6/71 combo running two 425 setups and a APA tank with twin outlets. Its not designed for massive hp, but it makes as much power at idle as a 202 6 cyl does at MAX rpm lol (watched it on the dyno for sh1ts and giggles). Id be suprised it it made more than 350rwkw.. but its super responsive. From personal experience the 425's are a nice carby and I had no probs with them.

Quote: Originally Posted by GAS747 [View Post] now I wouldnt jump on that too soon. Read the EPA rules, it states that any straight LPG car must be emissioned compliant in order to be LPG complianced. "Owners should ensure they have documentary evidence that the LPG conversion system fitted to the vechile does not affect emissions performance. The manufacturer or distributor of such parts or systems should supply this evidence in writing, based on there own testing efforts and engineering judgement" Paul is spot on. its not a gurantee get out of jail free card but it does help. As i drive mine pretty much every day i get pulled over abit more than the average person (probably once every 2months). Everytime i get pulled over and have to open the bonnet, i just point straight to the "lpg complianced tag". I have never been sent to the epa.

Quote: Originally Posted by GAS747 [View Post] now I wouldnt jump on that too soon. Read the EPA rules, it states that any straight LPG car must be emissioned compliant in order to be LPG complianced. "Owners should ensure they have documentary evidence that the LPG conversion system fitted to the vechile does not affect emissions performance. The manufacturer or distributor of such parts or systems should supply this evidence in writing, based on there own testing efforts and engineering judgement" its basically the same principle as a rwc, at the time of the compliance it may have been emmission compliant but after you change your setup to anything other than stock they rape ya, ive got the epa notice in my room to prove it i think the reason everyone gets away with epa alot more is alot of cops are ignorant when it comes to lpg performance, they just hear the word compliant and automatically assume its all sweet but really ur car still needs to abide by the epa guidelines whether it wheres the tag or not, theres actually a whole section on the epa website dedicated to lpg performance but i cbf finding it Some original photos have not been recovered yet.

Quote: Originally Posted by FORZA [View Post] its basically the same principle as a rwc, at the time of the compliance it may have been emmission compliant but after you change your setup to anything other than stock they rape ya, ive got the epa notice in my room to prove it i think the reason everyone gets away with epa alot more is alot of cops are ignorant when it comes to lpg performance, they just hear the word compliant and automatically assume its all sweet but really ur car still needs to abide by the epa guidelines whether it wheres the tag or not, theres actually a whole section on the epa website dedicated to lpg performance but i cbf finding it Is your car LPG complianced and registered so with vicroads? if its done the right way you should be fine. Id be taking it to an ADR compliance place for a test to see... Some original photos have not been recovered yet.

i always saw a bonus to gas was that it would very easily pass an emissions test, meaning i could quite easily get my car engineered.

It's not that LPG has no emissions, it's that it's lower emissions. But the kit still has to be compliant.

I'd been told either it was it had no emissions from it or that it had no emissions laws both always sounded wrong to me. A lot less emissions put out sounds alot more on the money to me

well from what the engineer said about my injected 5lt in the hilux(another of my toys), if I run it on gas makes it a whole lot easier to engineer in regard to emissions

there is emissions but sweet **** all when u start modifying i.e big turbo etc etc obviously more gas has to be pumped in hence there will be more emissions, there is a fine line in what you can and cant do it comes down to the copper on what they know give the epa a ring they will answer alot of questions they arent as bad as you think

Just do it and get an ADR test done - not cheap though. if it passes an ADR test ur laughing Some original photos have not been recovered yet.

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.

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.