TB42 & TB45 Fuel Economy

[dom14]

Hey Guys,

Can you please post the fuel economy(not guesses though) of your EFI TB42/TB45 units,
both petrol and LPG?
I am avoiding carby TB42's under the assumption they are guzzlers on either fuel, but please let me know your economy if I am wrong about that.

Very much appreciated.

The way I clock the economy is by filling either fuel full tank and run it for 100km or so then refilling it back to full tank and divide the 100km by the amount of fuel liters that take it to be fulltank.

Thanx.

Cheers

[Bob]

http://www.nissanpatrol.com.au/forums/showthread.php?1757-Fuel-consumption-economy-report&highlight=fuel+consumption

Try this Link

[billyj]

their all guzzlers, my old tb42e used to average 20l per 100 around town, best ever fwy run was 13l per 100, once i turboed it it still averaged 20l per 100 but went a shit load faster.

[dom14]

their all guzzlers, my old tb42e used to average 20l per 100 around town, best ever fwy run was 13l per 100, once i turboed it it still averaged 20l per 100 but went a shit load faster.

Yeah, but my RB30 is not any better now, and worse by the looks of it. It burns more LPG and more petrol than ever.
I just can't justify it unless I sort it out, otherwise TB42e is a better choice or TD42, if I can afford it.
The thing I'm really pizzed off about right now is the LPG economy, which I haven't been able to improve, even after installing an AFR gauge kit and tuning it for LPG. I don't care much about petrol economy, 'cos petrol is only useful on extreme outback treks where I can't locate any LPG servos. I have a mutli tank LPG setup, so I dunno whether some LPG get stuck in one of the tanks behind the hydro T valve. I just need to find out, but in the meantime, I'm dying to have a unit with more power. :D

I used to get minimum of 6km/L on both fuels on highways. Now it's doesn't clock anywhere near that.

[billyj]

cruiser is doing 13l per hundred while towing 2t...not quite as quick as the turbo patrol was for now.

to truely get the tune right for lpg you really want the dissy regraphed as lpg has quite different timing requierments to petrol, any dual fuel setup will always be a compromise, yes you can get both to run ok but not perrfectly well short of lpg injection and dual mapped ecus etc.

have you done any other mods eg lift bigger tyres roof rack etc that may be costing you economy?

[dom14]

cruiser is doing 13l per hundred while towing 2t...not quite as quick as the turbo patrol was for now.

to truely get the tune right for lpg you really want the dissy regraphed as lpg has quite different timing requierments to petrol, any dual fuel setup will always be a compromise, yes you can get both to run ok but not perrfectly well short of lpg injection and dual mapped ecus etc.

have you done any other mods eg lift bigger tyres roof rack etc that may be costing you economy?

There is a lift(2 inch I think). I don't use the roof rack & tyres are standard 31 inch (235/85 R16), so the tyres are hardly causing any excess traction.

I suspect something else is going on. Engine itself may be on it's way, but the compression tests came out ok so far.

[dom14]

their all guzzlers, my old tb42e used to average 20l per 100 around town, best ever fwy run was 13l per 100, once i turboed it it still averaged 20l per 100 but went a shit load faster.

20l per 100 around town is pretty good. The best RB30 can clock is 6km/L as oppose 5km/L of TB42, but your figures above says 100km/13L, which translates to pretty much 6km/L. I see no difference comparing to RB30.
To me, it looks like 3L RB30 engine isn't producing any economical advantage over a TB42 when the TB42 is fine tuned and well maintained.

[Throbbinhood]

Might be time to give that carby another rebuild?

FWIW, my rb30 with 3" lift, 33's, winch bar, draws +200kg tools, other junk, carrying 5 adults and an unloaded 7x5 trailer used 19L/100km from Pakenham to Warnambool.

Fully loaded on the way back, still 5 adults, a heap more stuff in the back of the car, and the 7x5 was now fully loaded plus a kayak amongst other things (probably an extra tonne of stuff, helping sister move), used 16L/100km on the way back.

Go figure it used less with the heavier load. Was a better wind on the way back though.

[dom14]

Rather than buying another rebuild kit, I reckon I'm better of spending that money on a new carby, and then again that money's better off spending on an EFI setup. I'm ok with the EFI conversion, but just not too keen with spending the time on it.
It's bit hectic atm.
I'll see if I can patch it up for the time being.
LPG system need some looking into it. I've never replaced the converter & mixer with new ones.
Perhaps it's about time I do or consider an EFI conversion.

[mudnut]

I took my carby and kit to the local dyno guy. and it really ran a lot sweeter on the dyno, even before he tuned it. You haven't got any brake pads dragging?

[Throbbinhood]

mudnut what'd it cost to get your carby rebuilt and the dyno tuning time?

[dom14]

mudnut what'd it cost to get your carby rebuilt and the dyno tuning time?

Yeah, mudnut, how much did it cost mate? The rebuild kit is around 80 bucks, but rebuild usually cost as much as a new carby, hence the reason I'm not too keen on getting professionally rebuilt. Spending that money on a brand new carby is a better option I reckon.

As for the dyno, closest I've got so far to that is by investing on an AFR gauge kit which cost me around 200 bucks and I fitted it myself. The best money I've spent so far. I just need to work on the carby & the LPG gear to get the best out of my AFR gauge.

[dom14]

I took my carby and kit to the local dyno guy. and it really ran a lot sweeter on the dyno, even before he tuned it. You haven't got any brake pads dragging?

Not sure. I'm gonna have to check it. I wonder whether the rear bearings might be dragging as well. Need to check that as well.

[mudnut]

Not a lot, to be honest, as it is a case of not what you know but who you know. He didn't use the whole kit, either. Just parts the parts he knew were toast. It probably only took him half an hour to have the carby on and running.

[dom14]

Not a lot, to be honest, as it is a case of not what you know but who you know. He didn't use the whole kit, either. Just parts the parts he knew were toast. It probably only took him half an hour to have the carby on and running.

I can do it now in half hour 'cos I've been tearing apart this Nikki carby for like million times.
But, still it amazes me that I pretty much know nothing about it's internals and how everything work together to produce a good AFR.
All in all, it's been a great fun exercise for me.
It's that I don't always enjoy having to tune the carbies all the time, 'cos older worn out carbies need attention all the time, and
there are times you get sick of it, while the other times you enjoy it.
I know, mine needs a needle seat and needle again, but it pizzes me off, 'cos the current kit is only four years old.
The issue is that some of these aftermarket rebuild kits are crap, particularly the needle and seat(the most important and delicate part of the kit). There are no jets in the kit. The accelerator pumping plunger and the rubber boot is also important, but all the gaskets I learned to cut myself. It's not an arm and a leg cost for me to buy another kit for $78 trade price from Burson. It's that I can't justify it. It's either a new carby or 'new' EFI engine for me. And if I put an EFI engine in it, then it will be a matter of time before I put turbo in it. :). I just wanna fiddle around with carby bit longer I rekcon. :D

Another thing that amazes me about carbies is that a perfectly working carby starts crapping itself when it is faced with a totally different weather conditions. :)

[dom14]

Not a lot, to be honest, as it is a case of not what you know but who you know. He didn't use the whole kit, either. Just parts the parts he knew were toast. It probably only took him half an hour to have the carby on and running.

If you do know a bloke who fully rebuild carbies under $200, do let me know.

[mudnut]

This bloke is very much into racing and his knowledge is extensive. He has even built a vaccuum test bench, so he can achieve maximum gas flow for the heads he builds.

[billyj]

before you go buying a new carbie, go get a dyno shop to do a couple of power runs then they can actually see what the afrs are doing in real time under load.

an afr gauge is only half the battle to getting a tune right while 14.7:1 may be stoich and ideal at cruise you will be loosing power under load as best power is made at about 11-13:1 so if everything is working right you should be running rich under wot then lean off when at cruise. if your only at 14.7:1 under load then your at a much higher risk of pinging and proobly running less timing than ideal to compensate. the point being that if your down on power your going to be using full throttle or more throttle more often trying to pick up and maintain speed

72405 this is the 355 holden stroker i hand built for my old vs ute made about 240kw with a cam suited to low end torque

[dom14]

before you go buying a new carbie, go get a dyno shop to do a couple of power runs then they can actually see what the afrs are doing in real time under load.

an afr gauge is only half the battle to getting a tune right while 14.7:1 may be stoich and ideal at cruise you will be loosing power under load as best power is made at about 11-13:1 so if everything is working right you should be running rich under wot then lean off when at cruise. if your only at 14.7:1 under load then your at a much higher risk of pinging and proobly running less timing than ideal to compensate. the point being that if your down on power your going to be using full throttle or more throttle more often trying to pick up and maintain speed



Thanx for the tip mate. I'll richen up the AFR a bit and see what it does.
I leaned the LPG mixture under cruising 'cos I was told to do so.
The intermittent nature of the issue baffles me a bit.
Carbies(two of them) have issues.
I need to spend some time on dismantling them and playing with the jets, etc.

Yeah, a dyno run is way overdue. I wanted to be confident with the carby & ignition system and LPG gear(mixer, converter, etc) before I take it to a dyno. I'm not sure that's the best approach.