Mick as I mentioned on the day about the balance pipe on the back of the convertor it dose 2 things stabilizes the diaphram in that chamber & also relys on the ram air effect which is a signal from the air box/snorkle to the back of the convertor with out it most positive fed systems on the fords will stall when it comes to a stop or slowing down & sometimes they will back fire, I always fit them on the dirty side as on the clean side the signal isn't strong enough for the convertor to react that is for a N/A set up only......

Joe

sly, what you need is a variable lpg mixture like the ones the MED use to sell I think when there fully open the diameter is 65mm I use to always use them on the 5.0ltr conversions almost same power figures compairing petrol to gas..

Joe

Are you still trying to get a batch made Joe? Simon has mentioned these before. If I can find one anywhere, do they work with the OMVL R90/E or similar complex converters? Or would I need to switch to a simple converter?

they will work with any positive feed convertors but be carefull with the convertor that your using as it will not deliver the volume that you will require at WOT most pos-fed convertors will be good up to 200-250hp the ones that I have been using are the Landi, there a custom made set up which will easy supply 300-350hp but the down side is if you are running stright gas there a b**ch to start due to the higher primary seat spring tension but if your set up is due fuel there great... & nah still have it sitting on my bench my problem is to get a few made its going to cost me a s**t load, min is a order of a 100 sets to make it worth while plus I have to modify it for legal reasons...

change that pvc valve to the metal type & how come you havent got the pvc rerouted to under the ISC & then block the vac line of also having the balance line so close the the t/b are you having any problems with it ??

Joe I've had 2 PM's from AFF members who have given me some mods that will increase the R90/E's flow. One has suggested bigger supply lines than the 8mm / 5/16" copper pipes fitted, and bypassing the internal 1/4" tube. This bloke has had a 302 with single R90/E (with a 4-bbl mixer) that went 219rwkw... somewhere around 380-420 flywheel HP.

The other has suggested an internal mod with washers under a spring. This sounds like a way of increasing the primary seat spring pressure? This tip came from a bloke who works for one of the state Sprintgas distributors.

I want to see what can be done with cheap mods to the stock setup before starting to replace components. I know of the Landi-Renzo converter, TurboTaxi has had some very good results with his, this will be on my shopping list if the R90/E can't keep up. BTW a Raptor-fed AU goes approx 260kW, roughly 360HP, though with the mixer ring I'd expect a bit less, maybe 330-340HP.

The pipe from the PCV valve to under the ISC is as stock. The hose from the rear of the rocker cover is re-routed to the (Raptor-supplied) fitting between the pod and blower.

Everything I'd read and heard told me that taking off the balance line from there just wouldn't work... wrong angle and too close to a bend. I'm amazed that it works at all, I was trying to limit revs to about 3500 or so but had an accidental kickdown which spun it to 4200 and it felt to be still making power and not choking. The only real problem has been with sealing up the proverbial 3mm hole. I put in a shorter self-tapper that doesn't seem to work as well as the big-a*** wood screw with a dob of #1 hard-setting gasket sealer.

I have a wideband O2 sensor and meter on order, so I can keep an eye on the AFR. I'm being extra-cautious now on gas, 3000rpm only (which equals 157kW @ an assumed 500Nm).

When I want to really heat up the exhaust system, I just flick the switch to petrol...

It runs good but then there is positive pressure (up to 10psi) in my intake. I wouldn't recommend it for a NA setup!

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with the lines 8 mm I think it will be ok for what your chacing say (250rwkw) what you have to worry about is all the fittings..... at the tank, the lock off & the convertor, there not 8mm & as we had to drill them out when we set up a XB with twin OHG's the engine was built for gas this was a tough car it made 332rwhp plus we wraped the line up to the convertor to keep the liquid as cool as posible before it got the convertor the other thing is that SGI kits only have 8 mm lines & there getting 220rwkw + from GEN III's I know that there SGI kits but the regulator/convertor still need to see that flow of liquid at that point...
can I suggest for you to try something with your balance pipe, if you can fit it in the intake pipe just behind the pod filter with an 90 degree elbow in it & with the elbow facing in the direction of airflow so the back of the elbow will be facing the pod & get a new fitting for the convertor with no holes drilled in it see how that goes the other thing to watch out for is that your convertor may be loosing the signal at WOT which will also caues it to run lean due the the mixer so beefing the convertor up might be just hidding another problem or the convertor is at its limmits & then you modify it........

Joe, I'm giving your last post a lot of thought... I'll be tied up a lot with work until next Friday so I probably won't get back to it until then.

Meantime, I've been working on a few things:

• Sealing the intake leaks, there is still a small leak around the LPG pipe but overall much improved.
• Blocking the 3mm hole. Now sealed with an 8g, 12mm self-tapper cut down to 5mm and a liberal dose of #1 hard-setting gasket cement. Both hot & cold idle are now much smoother, hot idle especially is beautiful, as good as it was when the LPG system was brand spanking new..
• Getting a wideband O2 sensor and meter to keep an eye on the LPG AFR and help me set up cold-idle enrichment properly.
• Trying to source a s/h Airod variable mixer
• Booking in a dyno run next Friday to check the petrol AFR's now the leaks are under control, and hopefully get a number!

I'll post more as things develop.

Since my last post, I've sourced a less-restrictive LPG mixer (Airod variable venturi). I fitted it on Sunday, along with a replacement throttle body (the old TB having the restrictive 42mm mixer jammed and sealed inside it). I also had to make some changes to the intake as the "new" mixer moves the last bend a few cm. I'd previously booked a dyno run for Monday and thought the less restrictive mixer would help things along a bit. What could go wrong...?

Plenty, as it turned out. How about 153rwkw (others are getting 190-200 from their Raptors), a bit under 7psi of boost (should be 9-odd) and AFR's in the low 10's? Not to mention some pipe separation (my workmanship BTW, not Raptor's) and some very professional repair work by the guys at Blacktrack. Petrol runs BTW. We ran out of time to do any troubleshooting on the day as I had to get to bed for dogwatch, so that had to wait until today.

A bit of arithmetic shows that boost and AFR are both 20-25% low. The belt's not slipping and there's no indication of any problem with the head unit, so I decided to go looking for air leaks first.

Starting at the head unit I worked towards the TB checking each clamp, eventually finding the last one on the TB was loose and the rubber joiner was folded back on itself at the bottom of the TB... not conducive to a good seal. Here's the general area:


So after remounting the joiner and tightening it down, along with a slight realignment of the other joints, it was time to go for a spin. Oh, I also reflashed the tune and reset the ECU as idle speeds have been 200-300rpm higher since installing the mixer. The intake now looks like this:


The improvement was obvious straight away. It's felt a bit doughy since I rushed the mixer install... now I know why. Now it's responsive right from idle. Anyway I did some gentle warming-up then set up to give it a quick 0-100 (or thereabouts ) full-throttle run. Away she went, chirping the treads in 1st as 4000rpm arrived (and traction is pretty good with the LSD) then PHSSSSHHHHHT! Yet another pipe separation, my fault again for having mistaken where a barb was and putting a hose clamp in the wrong place

So we limped home at dusk for a repair, ready for another go another day. Positives are:

• It went harder than it did before I changed the LPG mixer (that chirp at 4000 was a real surprise)
• Idle is now back to stock, smooth and unfussed on either petrol or LPG
• Having had the tranny serviced this morning along with increasing the line pressures and having a cooler fitted, shifts are now as good as stock without flaring or hesitation. The 3-4 change had got really dodgy at around 3000rpm in 3rd. As the converter unlocked in 3rd before changing up, revs would flare to 3600 or more for a second or two. All that is gone now, replaced by decisive shifts that surprisingly don't feel any harder than before... no banging or jerking. I'm pleasantly surprised.

So for now I'll just drive it for a week or so to be sure it stays all good, then I'll tee up another run at the dyno. I think the figures are going to be a lot better next time...

Where do you go for your Dyno Run's Sly? Would be good to find somebody local so I can get this thing tuned right.
Had enough of the backfires!
Good work in sorting yours BTW
Mick

I had this dyno run done at Blacktrack at Thornton, mainly because they are a Ford Flash Tune dealer and can custom tune. Not much help with tuning an NC unfortunately, and they don't like LPG at all... I only had a petrol run done. To Dyno tune LPG, Gaspower at Cardiff, Gossies at Morisset or Tag Performance at Kurri are the only locals I know of. Sorry, one more, John Collins at Broadmeadow can tune old-school systems with a power valve, but apparently doesn't do computerised systems.

Thanks for that Sly! Gaspower at Cardiff is pretty close to me. I'll drop in and have a chat I think.
Mick

Hope you catch Tony on a good day, he 's legendary for not being warm & fuzzy