More grunt from 1FZ-FE

[alanrlow]

So you probably have an all up weight of around 5 tons, maybe a bit more? and you are wondering why it struggles?

That's probably close to the mark, and no I wasn't wondering why it was struggling. It's obvious. I was wondering what I can do to get a bit more grunt out of this venerable big donk.

[alanrlow]

2000rpm is a little low for towing power at 85/90km/h. I'd really recommend changing to a lower ratio diff. It's going to be the simplest, most cost effective and bring the largest improvement you can get for towing short of major engine mods. It's basically what your doing with your gearbox having to downshift all the time.

As for the gas -- a gas ring type setup isn't all that restrictive compared to the snorkel type. They require very little vacuum to get a gas flow. The problem is they are pretty basic at metering fuel. Due to the wide margin of error you can have with a gas tune that still 'seems to run right' this is often overlooked, but I guess it must be setup ok if giving similar power results to fuel. The snorkel type mixers are better, but more of a restriction than a gas ring. The impco 425 is defiantly one of the better designs, but again for the money vs. gains it's not going to cut it. Flow may be restricted at high revs but the majority of the time at 2-3k the throttle plate is going to be the biggest (or at least should be) Even the best gas system isn't going to make it tow better than it would on fuel, and it can't do it on fuel so there's no point looking here.

Headers are going to cost $200-500 and IMO not make enough of a difference, the exhaust upgrade may be a worthwhile prospect if damaged/blocked etc..

Again I would highly stress changing diff ratio's to something more suitable for towing 5 ton loads.

Rather than do anything else though you could invest all your cash in a dedicated LPG turbo conversion and win in all areas!!

Hope this helps!

Thank you for a thoughtful reply. I realize 2000rpm is way below max torque but It seems if I drop back to 3rd revs rise to 2600-2800 and fuel use goes dramatically up but the power on tap doesn't! In fact it's quite happy to cruise in OD at 2000rpm at 90kph on the freeway until a slight rise. Even a slight headwind can drop me back 2 gears.

It's funny, some have suggested the gas ring is at the heart of my problem and restricting everything, even petrol running, while others say it's ok. Any idea how the Impco mounts to the throttle body and would I need to change the converter?

I don't want to scrap a perfectly serviceable exhaust system for no gain so when it's had it I guess headers and bigger diameter system will go on.

As to the diff (times 2) ratio change, as you note, the same is achieved by dropping a gear however this produces no more power only revs. If I hit a hill at 80kph in 2nd gear at 5500rpm it still will be in first and 30kph by the top! It just dies in the arse.

As an experiment I will try another tank of gas in 3rd at 85kph and 2500 and watch consumption. Don't expect it to be very good tho.

I guess a turbo is looking like an option (you listening SWMBO) but I still need petrol as there's no LPG in the bush where I spend a lot of my time. I don't spose you would have any ideas of a drive in drive away cost for a turbo conversion? I probably can't afford it anyway. :-(
Thanks again for a helpful post.

Alan.

[cambelt]

Id say 5.5 ton all up . I have seen a turbo diesel 80 series tow a 15 ton bus up springvale road a couple of years ago and the whole combo was moving along nicely at 60 klm in 32 deg heat .
One of my customers 80,s weighs in at around 3.3 loaded , extra cab ute conversion , started life on duel fuel but not enough power so gas came off , then a full exhaust and headers , uni chip .
You name it this bloke has done it , injector spacers ,hiclones etc etc
Still not enough so 22K later a new 6.5 chev diesel and he is somewhat happy, it tows well but is still slow .
I say the 4.5 did everything better except at 2000 rpm
Dave

[alanrlow]

Id say 5.5 ton all up . I have seen a turbo diesel 80 series tow a 15 ton bus up springvale road a couple of years ago and the whole combo was moving along nicely at 60 klm in 32 deg heat .
One of my customers 80,s weighs in at around 3.3 loaded , extra cab ute conversion , started life on duel fuel but not enough power so gas came off , then a full exhaust and headers , uni chip .
You name it this bloke has done it , injector spacers ,hiclones etc etc
Still not enough so 22K later a new 6.5 chev diesel and he is somewhat happy, it tows well but is still slow .
I say the 4.5 did everything better except at 2000 rpm
Dave

Hiclones.. HaHaHaHaHa lol that's the funniest thing I've heard for a long time..

[Dieseltrain]

Is the tuning mapped to be towing 5.5 tonnes of stuff ? Maybe the thing is running way too much ignition timing and losing so much power when adding the extra 3 tonnes of weight ?

[alanrlow]

Is the tuning mapped to be towing 5.5 tonnes of stuff ? Maybe the thing is running way too much ignition timing and losing so much power when adding the extra 3 tonnes of weight ?

That's a very interesting question. It was tuned on Armadale 4WD's dyno when the Unichip was installed and I told him I was getting the Unichip to improve towing capability so I would presume that's what he did. Mind you if you load a vehicle up on a dyno and tune the timing for max power I can't see how plonking a few tonne on the back would make any difference to the timing.
Are you thinking that the knock sensor is detecting pinging and retarding the timing? I certainly have never heard any pinning and I know what it sounds like.

[Dieseltrain]

That's a very interesting question. It was tuned on Armadale 4WD's dyno when the Unichip was installed and I told him I was getting the Unichip to improve towing capability so I would presume that's what he did. Mind you if you load a vehicle up on a dyno and tune the timing for max power I can't see how plonking a few tonne on the back would make any difference to the timing.
Are you thinking that the knock sensor is detecting pinging and retarding the timing? I certainly have never heard any pinning and I know what it sounds like.

Are you serious when you said " Mind you if you load a vehicle up on a dyno and tune the timing for max power I can't see how plonking a few tonne on the back would make any difference to the timing. " ?????

Adding 500kg will make a world of difference as there is more load on the engine, therefore detonation is more prone to happen due to the higher load . Especially if its been put on a dyno to tune for max power, it will already be tuned on the limit. ALso quite alot of tuners are prone to using a very high ramp rate when tuning to give better power figures, which replicates NOTHIGN like the real world Km/h per second the car will actually accelerate at, so the timing maps are generally good for lower gears but can be on the edge in the higher gears.

Adding 2500kg's or more will cause the tune to be in a world of hurt ! Im betting Once you load it up, the knock sensors are retarding the timing so far its lucky to make anything close to 50% of the stock power. Most Factory Ecu's will pull as much as 20 degrees timing if knock is excessive . Im guessing this could be the issue ?

[alanrlow]

Are you serious when you said " Mind you if you load a vehicle up on a dyno and tune the timing for max power I can't see how plonking a few tonne on the back would make any difference to the timing. " ?????

Adding 500kg will make a world of difference as there is more load on the engine, therefore detonation is more prone to happen due to the higher load . Especially if its been put on a dyno to tune for max power, it will already be tuned on the limit. ALso quite alot of tuners are prone to using a very high ramp rate when tuning to give better power figures, which replicates NOTHIGN like the real world Km/h per second the car will actually accelerate at, so the timing maps are generally good for lower gears but can be on the edge in the higher gears.

Adding 2500kg's or more will cause the tune to be in a world of hurt ! Im betting Once you load it up, the knock sensors are retarding the timing so far its lucky to make anything close to 50% of the stock power. Most Factory Ecu's will pull as much as 20 degrees timing if knock is excessive . Im guessing this could be the issue ?

Hmm, I thought I was, have to give it a rethink.
In that vein then, do you know how long the ECU waits before advancing the timing again. IE, it detects knocking, retards the timing to stop the knock, I presume it must at some stage advance the timing again. It can't stay retarded until the ignition is turned off can it? Do you know if I can simply retard the distributor slightly to reduce overall advance? I have a vague memory the Unichip chap said it didn't matter as the chip would adjust it to what he had set it to but obviously it can't advance further that the dizzy is currently at. If you know what I mean.

[Dieseltrain]

It would all be in the Unichip im guessing as it runs electronic advance for the dizzy timing ?

It wont stay retarded forever, it will return to normal timing once knock has gone, however towing 5 tonnes, even on the flat is still pulling 5 tonnes. Could explain why its such a pig when loaded up, as others have said they have same motor and have no dramas towing.

Some piggybacks and Ecu's will allow the user to set the amount of timing to be pulled out once a certain ammount of knock is detected.

Probably the best thing ( not the most cost effective ) would be getting it Datalogged when towing and see whats happening with knock.

Would explain why Empty it runs fine, but with a shiteload of weight it dies in the ass maybe? Just some suggestion Call your tuner and ask their advice on the matter.

[MS-75]

Hi mate.

Reading throught your descriptions indicates to me your best bet to extract more grunt is to upgrade the mixer ring. Those rings can be horribly restictive.

One suggestion I'd make is to do a 0-100km/hr pull on petrol with the mixer ring in place, and then one with it bypassed. That'll give you an idea of the effect the restriction is having.

Unfortunately, as you have an N/A motor, apart from freeing up the inlet tract there isn't much you can do without pulling the head off and improving the flow and upping the compression. The other issue is that due to the head casting that increasing cam lift requires some clearancing with a die grinder. It's not hard to do, but it does mean that the head has to come off completely to do the job.

I'd consider changing to a gas research throttlebody perhaps as a cheaper option to help somewhat.

As for cams, there are a few places that can do it. I can source 1FZ cam blanks, but by the time you have them ground up it's not cheap.

After you optimise the inlet tract the next thing I'd do (from a bang for buck perspective) is have some head work done - bowls, seats and increase compression. (only 9:1 stock, and the valves are pretty badly shrouded)

Hope this helps.
Sean

[Draven]

on top of what's been recommended, I'd suggest some real world ECU tuning. chuck the boat/caravan on the back, get the tuner in the passenger seat with laptop, and drive up some hills. if there's anything funky going on, that'll show it up (and even if not, the data logging should give you an idea of what's going wrong).

That 4.5L should be able to handle 5 tons up a slight incline, which from what you're saying is needing 2 gear changes

[alanrlow]

Hi mate.

Reading throught your descriptions indicates to me your best bet to extract more grunt is to upgrade the mixer ring. Those rings can be horribly restictive.

One suggestion I'd make is to do a 0-100km/hr pull on petrol with the mixer ring in place, and then one with it bypassed. That'll give you an idea of the effect the restriction is having.

Unfortunately, as you have an N/A motor, apart from freeing up the inlet tract there isn't much you can do without pulling the head off and improving the flow and upping the compression. The other issue is that due to the head casting that increasing cam lift requires some clearancing with a die grinder. It's not hard to do, but it does mean that the head has to come off completely to do the job.

I'd consider changing to a gas research throttlebody perhaps as a cheaper option to help somewhat.

As for cams, there are a few places that can do it. I can source 1FZ cam blanks, but by the time you have them ground up it's not cheap.

After you optimise the inlet tract the next thing I'd do (from a bang for buck perspective) is have some head work done - bowls, seats and increase compression. (only 9:1 stock, and the valves are pretty badly shrouded)

Hope this helps.
Sean

Unfortunately it's not a simple matter to remove the mixer, it's locktighted onto the TB and the inlet hose to the air cleaner has been shortened to fit so it won't reach the throttle body now.
The rest sounds like spiraling out of my budget range.
I'll keep thinking on it, thanks for your input.

[alanrlow]

on top of what's been recommended, I'd suggest some real world ECU tuning. chuck the boat/caravan on the back, get the tuner in the passenger seat with laptop, and drive up some hills. if there's anything funky going on, that'll show it up (and even if not, the data logging should give you an idea of what's going wrong).

That 4.5L should be able to handle 5 tons up a slight incline, which from what you're saying is needing 2 gear changes

When I get back to WA I might just do that.
Yeh I would have thought that too. Big lump of a motor like that should be better than it is.
Thanks for your reply.

[andrew_mx83]

Unfortunately it's not a simple matter to remove the mixer, it's locktighted onto the TB and the inlet hose to the air cleaner has been shortened to fit so it won't reach the throttle body now.
The rest sounds like spiraling out of my budget range.
I'll keep thinking on it, thanks for your input.

some (im guessing 2 inch) pipe and hose joiners + hose clamps

if u get desparate u could measure up what u need and go for a wander thru a wrecker, there will be something that will fit.

instead of locktighting the mixer ring back on use a hose joiner and maybe a bitvof pipe if needed

[cambelt]

This motor makes 165 kw and 400 od nm on petrol , if your not prepared to even try an remove the gas ring then why keep asking what to do . Its a known fact that gas ring mixers have trouble keeping the correct mixture over the engines operating range, and its also well known in the trade these days not to fit this type of system to larger engines. Try the most easy thing and run it on straight petrol for a few hundered klm without the ring on.
Dave