LPG TB42E Tune up

Post by **Shorty40** » Wed Aug 23, 2006 9:31 pm

So I am about to get the GQ tuned and wanted some advice.

I want to give it the 'works' with this tune.

Specs - GQ TB42E running straight LPG. Stock as a rock.

What things should I do to bring the costs down ? I can do basic stuff like engine oil, plugs, leads etc. As it is straight LPG, the manual doesnt specify what parts to use.

What plugs for LPG ?
What leads for LPG ?
What oil for LPG ?

Anyone suggest a good LPG tuner in Brisbane ? What should I ask for ? I mean do I just ask for a tune up ?

thanks

Post by **skippy's GQ** » Thu Aug 24, 2006 8:50 am

would only use bosh plug leads (about $45) there the best for lpg i ran BP6ES spark plugs in mine was told by lpg gooru that colder plugs are better for lpg, and get a good oil like PENRITE,CASTROL, that 15w/30 and suitable for gass engines, read the lable on the bottle and it will tell you if it ok to use or not..

SKIPPY

Post by **henry** » Thu Aug 24, 2006 5:47 pm

I use Penrite HPR Gas, keeps oil pressure more stable compared to other oils iv'e used. Same plugs as skippy, BP6ES. Low impedence leads, they may affect your radio but you get a better spark. Chuck a new air filter in. Fit a pertronix ignitor points eliminator and you can run a high voltage coil and open your plug gaps up to 1.1mm.

Thu Aug 24, 2006 6:42 pm

If you want a Pertronix Ignitor for a tb42 I have a new combo on ebay at the moment
http://cgi.ebay.com.au/ws/eBayISAPI.dll ... %3AIT&rd=1

Post by **Shorty40** » Thu Aug 24, 2006 9:56 pm

Do I need this pertronix on an EFI TB42 model ?

Thanks for the tips on oil, plugs and leads

Post by **GQ Bear** » Thu Aug 24, 2006 11:10 pm

How did you do the straight gas setup on the TB42e?

All the gas fittets I speak to say it can't be done with efi manifold

Website · Post by **GRINCH** » Fri Aug 25, 2006 10:14 am

try calling these guys it is deffintly possible to do with a gas throttle body http://www.gasresearch.com.au/ or if you want to wait 6 months there a new liquid gas injection coming on the market lots more efficent and can handle big hp, currently they're running a prototype on a 1200hp twin turbo v8. http://www.lpgli.com/features.html

Post by **Shorty40** » Fri Aug 25, 2006 11:10 am

GQ Bear wrote:How did you do the straight gas setup on the TB42e?

All the gas fittets I speak to say it can't be done with efi manifold

It can definately be done. My petrol tank was chucked in the bin in favour of an LPG tank

Maybe see another LPG fitter

I'm not exactly sure of the setup, I just said to the fitter I wanted straight LPG. I had it fitted at The Gas Man in Alexandria (Sydney).

Post by **Jimbo** » Fri Aug 25, 2006 12:01 pm

I dont see why anyone would go straight gas (rather than dual fuel) when they have an EFI GQ???? When you switch to gas the efi is in a closed loop system and runs on gas, when you flick to petrol the gas is shut off and it runs 100% right on petrol....no petrol tuning involved as it is EFI!!

PLus you get 75 litres of petrol (in a LWB) and 100 Lt of gas. If you want to go somewhere without gas u use petrol. If u want to go really far you fill up both and take jerry cans!!!

Can anyone witha TB42E and straight gas tell me why they did the conversion like that? Even if u wanted to up the compresion to rtake full affect of LPG, you would just run premium in the petrol tank.

Cheers

Website · Post by **GRINCH** » Fri Aug 25, 2006 12:27 pm

its very hard/impossible to tune a car to run well and efficently on both systems so a lot of people just tune there cars to run solely on gas. a lot of the gas injection system coming onto the market use the efi system so they will also run closed loop so effectively you should use the same l/100km with the advantage of gas being a third of the price plus they are claiming to get 10-15% more power with the gas due to the higher octane rating.

Post by **Jimbo** » Fri Aug 25, 2006 12:38 pm

Your statement is TRUE if u have a carby but with EFI you tune the gas as usual but the petrol side is NEVER out of tune as it uses the computer as normal to deliver the fuel!!!!!

Whether or not u have dual fuel or straight gas, the tuning of the lpg is the same. The EFI does not effect the lpg tuning

Website · Post by **GRINCH** » Fri Aug 25, 2006 12:46 pm

but the ignition timing is genrally different.

Post by **Jimbo** » Fri Aug 25, 2006 12:49 pm

I have a tb42E and have my base timing at 15 degrees. Does not ping on lpg or standard unleaded. The computer controls the curve, all u can adjust is the base timinng. Mine runs perfect on gas and does not ping on fuel. And if it did ping i would run premium for the times when i needed it.

I just dont se the point when u can have both fuels. I ahve ahd dual fuel cars in the past and its been very convenient when an lpg component (i think it was a solenoid) has stuffed up. Instead of being without a car i just drove it on petrol. Does the motor good anyway.

Anyway i'm still keen to know why ppl have gone that direction

Cheers

Post by **Shorty40** » Fri Aug 25, 2006 1:30 pm

Jimbo wrote:I dont see why anyone would go straight gas when they have an EFI GQ????

I'll tell you why mate. Its the same reason you went LPG/dual fuel in your car. Cost savings

It costs at least double to run on petrol. Why would I want to do that ? Why wouldn't I want to take FULL advantage of the costs savings of LPG ?

BTW - i dont have the need to travel thousands of kilomtres between fill ups. So 100 litres of LPG gets me at least 400km around town and about 500km on the highway. That is plenty for me.

Post by **Jimbo** » Fri Aug 25, 2006 1:56 pm

I never asked why u have LPG in the first place....its obvious i know thats why i have it. I just want to know why u wouldnt leave it dual fuel as everything is there!!!!

Why do u think i'm having a go? i'm just asking why u dont want the use of petrol there as well considering its all set up....The lpg is the add on. The only reason i can see is the added cost of the aftermarket tank.

Post by **Shorty40** » Fri Aug 25, 2006 4:37 pm

Jimbo wrote:I never asked why u have LPG in the first place....its obvious i know thats why i have it. I just want to know why u wouldnt leave it dual fuel as everything is there!!!!

Why do u think i'm having a go? i'm just asking why u dont want the use of petrol there as well considering its all set up....The lpg is the add on. The only reason i can see is the added cost of the aftermarket tank.

Chill pal, Im not having a go at all. And I didn't read your post as you having a go at me

I just told you why I run straight LPG.

If you read my post you wouldn't have asked a second time. But I will answer again. I run straight LPG as it costs significantly less than petrol. That is the reason. Cost. It doesn't get any simpler than that

Cheers

Post by **Jimbo** » Fri Aug 25, 2006 4:40 pm

ok i will ask it in a different way.

Why would you go out of your way to remove the use of petrol? Why not just leave it there? Maybe one day....a slght possibility u might use it. You can still run your 100lt of lpg.

Post by **Shorty40** » Fri Aug 25, 2006 4:44 pm

I didnt exactly 'go out of my way'. The fuel tank made way for the LPG tank. Straight replacement. Everything for pretrol is still under the bonnet. The LPG filler is where the fuel filler was. The fuel guage now operates off the LPG level. Unless I told you it was LPG you wouldnt really know.

My thoughts are not why I would get rid of the petrol, but why would I keep it ?

If I ever wanted to go petrol again (which I wont

), all I would need is a petrol tank.

Post by **Sexy Fingers** » Fri Aug 25, 2006 5:42 pm

Jimbo wrote:ok i will ask it in a different way.

Why would you go out of your way to remove the use of petrol? Why not just leave it there? Maybe one day....a slght possibility u might use it. You can still run your 100lt of lpg.

Ok. this is why. You can tune a car to run well on petrol and lpg, but if you want to performance tune then you'll want to run it on one or the other. Example of this is, with lpg only, you can advance the timing up to around 15 degrees over standard. Do this on a petrol counterpart and you can expect to hear nothing but ping coming from your engine.
Another reason I can think of is that if your car is duel fuel and you don't use the petrol side of it regularly, all the rubber seals in the carby or the injectors may dry up and perish, which may cause air leaks in the system causing bad performance and fuel economy. You may find that when you do switch over to petrol, it'll run like a dog, or may even not run at all.

Fri Aug 25, 2006 5:58 pm

It's easy to setup a TB42E on LPG just use a IMPCO 225 Mixer and plumb it in front of your standard Throttle Body, use a Impco L or E convertor and wire/plumb it up.

Impco 225 flows 329cfm

TB42 is 4169cc = 254cubic inches

Max cfm required at 4500 @100%VE is

254 cubic inches X 4500 rpm / 3456 X 100%VE = 330cfm

There fore the Impco 225 is perfect for the Job

Hope this helps i have on on my truck and running straight LPG and has more power then it did on petrol.

http://cgi.ebay.com.au/impco-225-gas-mi ... dZViewItem

This will also work on a carby if you know what you doing the seller does not. ;-)

Cheers Cameron

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