Petrol to diesel change

[Henry]

Hi there.
I have a 1989 Hilux 4X4 DC with the original 4Y motor in. I have purchased a Toyota 3C Turbo Diesel motor that I want to build in. Could somebody tell me if this is a good idea as everybody speaks well of the 4Y. Ialso would like to know if my current diff ratio will be ok for this engine. The reason why I want to put the 3C in is mainly because of a high fuel consumption. Average on open road @ 110 km/h is 6 km. per litre. My 4Y is fitted with a Weber 36. Please let me know as I have looked today at the new 4Y motor at Autozone complete with everything for R 8000.00. I would like your honest opinion before I start doing all the modifications.

Rgds

Henry

[Family_Dog]

Hi Henry,

I would suggest that you try fitting another carburettor to the 4Y first.

I have just fitted a Weber to my 4Y motor and have yet to full the tank. I can say, however, that before fitting the Weber, on a similar previous trip of 420Kms, I used about 80 litres of petrol. After fitting the Weber, I have done close to 600Km and my gauge is just below the 3/4 mark - I have a LR Tank so have not yet felt the need to fill up, but I am very happy with what appears to be a marked improvement.

Some guys have reported excellent consumption & performance after fitting a VW Golf carb as well.


-F_D

[BenHur]

Obviously being a pertolhead myself I am a bit biased but I have only had bad experiences with diesels.

If you follow the threads on the various forums of Hiluxes that have been giving the owners Shyte it is 99% of the time a diesel, especially TDs.

I Just read on the community forum again about a guy who ended up paying R2800 to fix a diesel's alternator. You get ripped off with parts and service on diesels. R2800 takes a lot of driving to make up if you compare Rand/Km between a diesel and a petrol. A new 4Y with a good carb and right jetting should give you better than 6km/l.

If you consider that you have to possibly look at changing bell housing, radiator possibly the ratios, and all sorts of little odds and ends to get the conversion running properly as well as the higher service costs on diesels it might take you some years to make up the cost in fuel savings, and that is if the engine does not need repairs

Your bakkie will also be worth more with the 4Y engine in it and you might get it sold easier if you ever need to. With the 3C engine in it you might struggle to do so.

Regarding the ratios I saw a guy with a 2L (2.4 TD) complaining about ratios being to short even with his 33s on so you might have the same problem.

[pietpetoors]

Hi Henry, send a PM to Choppie, memberlist.php?mode=viewprofile&u=32
and look at
viewtopic.php?f=8&t=24
He bought a 4y for less than R8k a month or two ago. He is in Krugersdorp.

Could you please update your profile and add your town so we can see where you stay.

[pietpetoors]

And also listen to Harold's wise words at:
viewtopic.php?f=3&t=234

My 2.4 (petrol) fuel consumption averages 13,5lt/100km
(7,4km/lt). With a good tail wind and a light foot you cam get up to 8,5km/lt.

Lets work on 7,4km/lt; at a fuel price of R7.00 /lt. = 94,5 cents/km

Assume your conversion gives you a 20% improvement = 8,88km/lt
= 78,8 cents/lt. (difference = 15,7 cents/lt)

For every R1000 you spend on your conversion you would have to do 6369km to break even. Assume the conversion cost you R30000 you would have to do 191070kmn to break even.
I have ignored the price difference between petrol & diesel.

It hardly seems worth it. Be wary of conversions to save fuel. The cost of the conversion could mean that you actually incur a loss and not a saving.

[Henry]

Ja nee. I have thought about all the modifications that needs to be done and it does not seem wort while. I will now rather stick with my 4Y and refurbish my carburator and maybe fit some branches and a freeflow also.

[BenHur]

A truly wise decision

Good for you Henry.

[SYRON CONVERSIONS]

Henery yes keep the 4Y, there are a few options that you can consider to make the 4Y more fuel user friendly, however whatever you do, it will take many Kilo's to make up the money that you think you have saved.

Fuel Injection

Branches & Free Flow, use the correct size ID Pipe and check that the bends are correct

Air intake, maybe consider a supercharger

Is there a problem with your existing 4Y that is fitted?

What size tyres do you have fitted and what is the bar pressure?

6km per liter at 110 is about correct, I get 7km per liter at 110 on the open road, however due to the various factors I will not get more.

Once heard from another Dude, he just puts in R300. petrol and then gets R300. worth of petrol

If you want to drive a Hilux, no matter what you do, they are heavy on fuel.

I have heard that these 2 and 3 C engines do have front crank pulley problems, the kew way and the pulley, also depending where, what you want to do with your Hilux, these factors will also influence your final decesion on which engine configuaration is Best for your needs.

[Henry]

No problem with the 4 Y as it has done 270000 km and does not use a drop of oil. Tyre sizes are 30 9.5 15 BF Goodrich. I did however found that the fuel pump was overfueling and has replaced it. Yes I will for certainly keep the 4 Y in and has already sold the 3 C engine again. If you could give me the right sizes on the exhaust it will be highly appreciated.

[BenHur]

For a 4Y motor, the exhaust must not be bigger than 50mm. The bends are also imported as Simon alluded to on top. Too sharp bends normally places a restriction on the flow of gas. A Brospeed exhaust system normally works well.

Here is a bit of advice but it is only my opinion - If you are merely after saving money due to decreased consumption, go for the exhaust only, not the branches as well. I believe they do not make that much difference (if any) in consumption that they are worth their price. A branch is better suited if you need to change the engines power delivery characteristics like having more low down power when towing or more high end power for racing.

For fuel economy, your engine needs to breathe well i.e. a non-restrictive exhaust system with just the right amount of backpressure and a proper clean and non-restrictive air intake system. The normal Donaldson OE air cleaners on these bakkies are good enough. As long as the filters inside are clean and in good nick the will provide enough clean air into the engine. Some people drill extra holes into the side as they believe the intake is too restrictive. All this does is it makes the engine noisier and the filter more susceptible to damage like water entering. In addition, you now suck more hot air into the engine from the engine bay instead of from behind the light (cooler air via front). The same goes for pancake and cone filters.

[Scooter]

Henry, I have a wildcat branch for sale if you are interested. Take a look

viewtopic.php?f=7&t=363

It came off my 4Y and that is only because the garage didnt listen to me when I explained what I wanted and they replaced the entire system not just the exhaust.

[GTO]

I agree with Benhur I fitted a Brospeed Branch and Powerflo exhaust just over 3 years ago.
3 weeks ago I found the branch had fine cracks on some of the welds and was blowing.
The branch was 1 month older than the 3 year warranty so Powerflo tried rewelding it but it still leaked.
I decided the refit the original manifold.
Fuel consumption and power in my opinion havent changed at all :!: :!: :!:

[BenHur]

To get the full benefit of a branch you need to use it in conjunction with a cam that is also cut for your specific application.

When we swopped my 22R engine for the 7M-GE the vehicle was send to De Graaf's in Gezina to build a custom piece that connected the old exhaust (50mm Brospeed) with the new manifold which was now on the wrong side of the vehicle. The 7MGE std Manifold is very short and consits of two 3 into 1 pieces running dual exhaust from there. What the guys from De Graaf's did was to weld two pieces of 50mm pipe onto a connection plate that fitted onto the manifold and then they welded the collector (the 2 into 1 piece) directly beneath that (about) 100 mm further. I did not know any better so I did not complain.

I then took the vehicle to my neighbours' workshop and we put it onto the dyno since the Mr Turbo was still running a bit rough on the default map. But on the very first run on the dyno ( 45 seconds the first bend in the exhaust was glowing hot (like a turbo after a 1/4 mile run. We stopped the dyno immediately and on advice of my neighbour took the vehicle back to De Graaf's who gladly fixed their bad design. What they had to do was to move the 2 into 1 collector 1 meter further from the manifold thus running 2 pipes for about a meter before going into the 1 pipe.

Immediately I could feel the engine running better and back on the dyno we saw a 10HP at 3500 RPM improvement IIRC compared to the first run.

Got to run - I will continue my story later.

[BenHur]

When we dyno'd the vehicle after the exhaust was fixed it still ran hotter than we wanted but it is much better. The reason for that is still the restriction on the flow of the gas that causes the pipes to become very hot. When the gas enters the exhaust pipe and it picks up a restriction to flow due to the diameter of the pipe and the bends therein it slows and the heat is build up there. As the heat build up the gas expands and the more it expands the more restricted it gets. So you get a thermal run away effect which makes the first portion of the exhaust to become glowing hot.

So I spoke to a few exhaust "pros" and the advice I got is as follows. The first portion of pipe from the manifold through the first bend must either made "straighter" ( which is impossible in my case) or it should be replaced with higher diameter pipe allowing the gas to expand. Now the problem with that is again that most of the exhaust guys' machines cant bend 63mm pipe sharp enough to make the bends here properly. So now I am still sitting with this problem.


The point that I am coming to is that if your design on the first part of the exhaust system is critical. The main aim on a branch is to ensure that all the pipes are of equal length before coming together in the collector. But by doing so they sometimes bend these pipe at funny angles which again will cause the thermal runaway problem and that is why I suspect many branches crack after a while.

So in my instance a proper build branch may be a way around the problem. I can then have 6 thinner (more manageable for the exhaust manufacturers' bending machines) pipes that run to a collector at the correct distance from the engine to provide the torque I need.

BTW on one of the Supra forums I read that the guys there also struggle with manifolds running glowing hot. But instead of using branches on their supra engines (7M-GE and 7M-GTE) they keep the original manifolds but they have it together with the 1st portion of the exhaust pipe treated with a ceramic coating to keep the heat inside the pipes to prevent the thermal runaway.

[BenHur]

The problem that I have with may of these branches we use on our 4x4s is that they were designed by guys who normally build these them for racing cars. So their main aim is top end performance.

On a 4x4 you rather need low down torque since you want power when crawling on a track or when towing. So if I were to install a branch I would have it done at a shop that also have dyno capabilities so that they can build a system that delivers the power where I need it and test it on the dyno to see the end result, rather then buying an off the shelf system that was deigned according to someone else's requirements/specifications.