Forced induction and dual fuel

[chimpboy]

Hi all,

I am just after a bit of general knowledge here because the sad truth is I don't know very much about LPG systems, even though I have one in my dual-fuel Maverick.

When looking at turbo or supercharging an engine, how much more of a hassle is it if the vehicle is already on dual fuel?

I have some ideas about answers to this question but I'll only sound stupid if I write them down, so...

Jason

[-Scott-]

I don't know if there's any complications boosting dual fuel, but I know that when boosting LPG you can turn off the converter heater (only while you have boost) and the expanding LPG nicely cools the intake charge and improves volumetric efficiency (if your boost sensor is downstream of the converter.) If you leave the heater off the converter can freeze when you back off the throttle.

NFI about LPG injection systems...

Scott

[dumbdunce]

is the engine carbureted or EFI when running petrol? stock carburettors present many challenges for forced induction, but most EFI systems can be successfully tweaked for mild boosting. LPG systems are also pretty easy to set up for forced induction. If it's a carbureted engine I'd think seriously about LPG only and turbocharging - throw that nasty carburettor away (well metaphorically speaking - you need a throttle body of some kind).

[chimpboy]

It's a carburetted TB42.

I'd be happy if the turbo/supercharger only operated whilst running on gas, but would still want to be able to run on petrol for increased range and fuel availability when outside the major towns.

Is this plausible? I am just wondering. I'd like to have a little more ooomph from the engine, but not badly enough to spend a huge fortune on it.

[dumbdunce]

It's a carburetted TB42.

I'd be happy if the turbo/supercharger only operated whilst running on gas, but would still want to be able to run on petrol for increased range and fuel availability when outside the major towns.

Is this plausible? I am just wondering. I'd like to have a little more ooomph from the engine, but not badly enough to spend a huge fortune on it.

the plausibility goes way down or the cost goes way up when applying forced induction to any carburetted motor. the easiest way to do it is with a draw-through setup where the carburettor is placed before the compressor. you'll need a carburettor with higher CFM and these setups are always a nightmare to tune plus it is not possible to intercool them. A step up to a throttle body injection system would probably be cheaper and definitely easier - might be able to adapt something off a TBI injected falcon from the late 80's - early 90's? with your lectrik skillz probably the hardest part would be building an adaptor to get the ford thorttle body onto the nissan manifold. Whichever way you go will probably involve paying for a considerable amount of dyno time to get the tuning right.

alternatively consider upgrading to a diesel, a homebrew turbo setup is worlds easier because there's no electronics or carburettor to get right - it's just one screw on the fuel pump and you're done. Diesels also come with extra range, standard. sure you won't have as much power as a turboed petrol engine but a turboed TD42 makes more torque and comparable power to a TB42 - far more driveable with more torque low in the rev range.

(yes I am a diesel elitist)

[460cixy]

plenty of turbo vl commies out there and ther the same donk turbo with gas will give you lots of grunt for not alot of expence. you will need the right you will need a good positive presure type converter and mixer. as much as its old school impco is probly the cheapest and best for forced induction

[Not For Highway Use]

Gas Research Australia (GRA) in Dandenong Vic. I think these guys still produce a dedicated Gas Throttle Body approx $400. These work well. I prefer superchargers but people seem to spend a lot more money on them with mixed results. Bang for bucks I would make the exhaust manifold and use a standard VL turbo. If you do most of the work you may do it for around $1100 plus tuning. Good Luck.

[460cixy]

gra are tops if you dont want economy

[BowTieGQ]

Use the efi inlet manifold and fit Gas Research mixer in place of throttle body. Puts the inlet plumbing right above where your turbo will be hanging of the diesel exhaust manifold. How cheap and easy is that? Use a Garret ball bearing turbo, about T35 same as BA Falcon. Should beging spooling up about 1200-1400rpm and be on full boost at about 1800rpm. You could run a small top mount intercooler and fit the GU scoop right above it. Less plumbing. You could still run efi and not GRA but wont get best results mainly through the distributor timing.

[Draven]

Ive been looking into something similar.

For me its the classic TB42 Turbo vs Holden V8 thing...

Im not sure if this will be of any help to you but heres what ive been learning and a couple of questions i havent been able to answer yet...



Things ive learnt.

1. From face value, it *looks* like the std TB42 produces more torque down low than a 304 V8.

2. a V8 *should* improve fuel economy by upto 25% and should accept LPG pretty easy.

3. The compression ratio of a TB42 almost makes it a perfect turbo / SC candidate.

4. A carb TB42 , would really need to be converted to EFI before a turbo conversion is even thought of.


Questions i havent answered for myself yet.

1. Is there *any* way of improving a TB42's fuel econ? In theory a decently tuned turbo conversion should improve things as the compression ratios should rise (boost) , giving a more efficient engine. But then again, the engine is not really going to be 'on boost' all the time on the highway.

2. I havent manged to find a ECU yet that would run 2 fuel / ignition maps for a turbo, dual fuel environment. In my thinking a good ECU would almost solve any duel fuel issues.

3. Is there really any point to the conversions ? a V8 gives less torque when std, and a turbo TB42 isnt really going to be any different in the bush (sub 1600 rpm)

4. confirmed costs for either conversion. Ive been told to expect anywhere from $7500 to $9000 for a V8 conversion. But im really not sure about a turbo... But im thinking something like..

EFI Conversion (Minus ECU) - $1500
Decent aftermarket ECU (capable of switching fuel / ign maps) - $1500
Decent Turbo - $1500 ??
Exhaust manifold and moding current exhaust - $700
Intercooler and inlet plumping - $1500
Misc (misc bits & Dyno) $ 1000

Total = $7700

I hope im wrong, but i havent even included wiring up all the loom etc...




hope this helps...

Glen

[BowTieGQ]

Draven, you're on the ball. I couldn't justify the $$ at a Chev conversion or the 1UZFE on the floor in shed. The turbo is cheaper and, from all my homework, should have more torque and be earlier than a stockish V8. Compression is fine as is. And oddly so is cam everyone tells me. I think the economy is crap due to power to weight. It cant be that inefficient. A turbo fixes that. On the highway it should be in the boost range of revs but only need the throttle to open a little to bring it to the boil. Unsure if there are ECU's with two maps for dual fuel. I can recall something like that. I'll look into it for you. There is a "black box" from ICE in Cheltenham that can run two curves for dual fuel applications. Even they said that the curve is crucial off boost to keep the car drivable. There should be no difference off boost to a turbo or na engine. Especialy a mild setup at about 5pound only.

[GRINCH]

Ive been looking into something similar.

For me its the classic TB42 Turbo vs Holden V8 thing...

Im not sure if this will be of any help to you but heres what ive been learning and a couple of questions i havent been able to answer yet...



Things ive learnt.

1. From face value, it *looks* like the std TB42 produces more torque down low than a 304 V8.

2. a V8 *should* improve fuel economy by upto 25% and should accept LPG pretty easy.

3. The compression ratio of a TB42 almost makes it a perfect turbo / SC candidate.

4. A carb TB42 , would really need to be converted to EFI before a turbo conversion is even thought of.


Questions i havent answered for myself yet.

1. Is there *any* way of improving a TB42's fuel econ? In theory a decently tuned turbo conversion should improve things as the compression ratios should rise (boost) , giving a more efficient engine. But then again, the engine is not really going to be 'on boost' all the time on the highway.

2. I havent manged to find a ECU yet that would run 2 fuel / ignition maps for a turbo, dual fuel environment. In my thinking a good ECU would almost solve any duel fuel issues.

3. Is there really any point to the conversions ? a V8 gives less torque when std, and a turbo TB42 isnt really going to be any different in the bush (sub 1600 rpm)

4. confirmed costs for either conversion. Ive been told to expect anywhere from $7500 to $9000 for a V8 conversion. But im really not sure about a turbo... But im thinking something like..

EFI Conversion (Minus ECU) - $1500
Decent aftermarket ECU (capable of switching fuel / ign maps) - $1500
Decent Turbo - $1500 ??
Exhaust manifold and moding current exhaust - $700
Intercooler and inlet plumping - $1500
Misc (misc bits & Dyno) $ 1000

Total = $7700

I hope im wrong, but i havent even included wiring up all the loom etc...




hope this helps...

Glen

aparently you can get memory cards for the wolf 3d ecu that allow you to switch maps via the hand controler. give KP performance in brissy a call, extremly helpful & knoledable.

[Draven]

Hi GRINCH, Im really chasing something that will store both maps and change them at a flick of a swich .. that way it can be wired straight upto the LPG / Petrol switch. I might give KP a call early in the new year...Im still trying to get as many facts together myself at the moment

[Draven]

BowTieGQ,

I hope that the inefficencies of the engine are just because its designed to be a long lasting industrial brick. Introducing a turbo and maybe a port & polish / balance im hoping , would help things lots.

Im very surpised i havent been able to find a aftermarket ECU that can do the dual fuel thing. I play with my 92' 300zx's factory ECU a little and its got 3 sets of fuel / Ign maps!! One normal map, one for failsafe, and one for highway (5th gear) I would have thought that aftermarket stuff would have more functions than a 15 year old OEM ECU.... Im sure Motec would prolly have this....but.....i just dont feel like spending the million dollars

I would really appreciate any info you could get for me.

[chimpboy]

If I were to fool around with fitting EFI to the TB42, perhaps using the Falcon type of setup that (I think) Bru21 did, would that necessitate a new LPG mixer, or would the existing Impco gear be able to utilise the EFI throttle body instead?

Jason

[Draven]

Im pretty sure that all you need to do is find another adapter for the impco system to fit the Falcon throttle body. It 'may' even be the same. Im assuming you are talking about a SPFI setup.

[BowTieGQ]

Draven, here are my guesstimated costs for straight LPGTurbo:

EFI inlet manifold only(should be here this week) $400
GRA mixer and converter $600
Turbo anywhere from $1000 - $2000 but more like you said $1500
Exhaust manifold $400 plus section to first join as mine is new from there
Intercooler ? A second hand top mount cant be worth more than $150
New Bosch HEI distributor to suit turbo $800
Plumbing, scoop, dyno tuning etc $500
Thats about $4500ish due to no wiring and ecu etc.

[BowTieGQ]

Draven, here are my guesstimated costs for straight LPGTurbo:

EFI inlet manifold only(should be here this week) $400
GRA mixer and converter $600
Turbo anywhere from $1000 - $2000 but more like you said $1500
Exhaust manifold $400 plus section to first join as mine is new from there
Intercooler ? A second hand top mount cant be worth more than $150
New Bosch HEI distributor to suit turbo $800
Plumbing, scoop, dyno tuning etc $500
Thats about $4500ish due to no wiring and ecu etc.

[GRINCH]

ems used to make a dual sport whitch allowed you to switch between maps, but they no longer make them.

[RaginRover]

if you were up for an adventure you could try a megasquirt - although it might be a fair bit of trial and error.

I am looking to setup a dual mapping and put coil packs in my rangie with a megasquirt down the track (probably waaaay down the track !)

http://www.msefi.com/


Tom

[Wotto]

the Unichip can be done the way you want, (operated by the fuel switch on the dash) with a map saved for each fuel. theres a bit of a write up about it on their site. it was in a 4500 GU

[jessie928]

look at a LINK ECU

it has the capability of dual maps

try maybe ems aswell

with wolf, i think you need 2 dongles.

Jes

[BowTieGQ]

I just realised something after all these posts. Why do you need two maps. ECU runs engine on petrol and shuts off when on LPG like most dual fuel systems. But yes, that still means EFI and throw carb. You then only need to run distributor, which I think you can get those sort of boxes everywhere, such as ICE.

[Chucky]

Why not just run a dedicated laptop instead of the normal range of ecu's. A good laptop can be had for around $1000 and it would be able to do anything you needed it to.
I know a guy who runs a skyline with this sort of set up and he reckons it the ducks nuts.
He also runs it though his stereo and stores all his music on it can play dvd's, even access the net whilst in the car but that is all just a bonus.

[hottiemonster]

Why not just run a dedicated laptop instead of the normal range of ecu's. A good laptop can be had for around $1000 and it would be able to do anything you needed it to.
I know a guy who runs a skyline with this sort of set up and he reckons it the ducks nuts.
He also runs it though his stereo and stores all his music on it can play dvd's, even access the net whilst in the car but that is all just a bonus.

what about all the bashing around all the time whilst four wheel driving, that is the reason i dont run a GPS from a laptop or music. To many vibrations and shock, have known of a few people to kill laptops in four wheel drives.

A car would be fine coz you might go over a speed hump occasionally, but as you mentioned its a rice burner so i am guessing he avoids the speed humps, gutters and general bumps.

anyone else have an opnion on laptops in 4wds?

[blkmav]

anyone else have an opnion on laptops in 4wds?

This is why I bought a good old tape video camera (MiniDV) for shooting wheeling videos. I didn't trust HDD or DVD cameras for reliability.

[RaginRover]

what about all the bashing around all the time whilst four wheel driving, that is the reason i dont run a GPS from a laptop or music. To many vibrations and shock, have known of a few people to kill laptops in four wheel drives.

anyone else have an opnion on laptops in 4wds?

if you buy the right one there is no way you could exert more force on it that it was capable of handling - mine works well and I have my work one that basically lives in the car.

Tom