I'm getting expensive ideas, thinking of dropping a 3.8 in the magna. Just wondering, whats the economy of one of these in a FWD manual magna? Just curious thats all.

I imagine pretty much the same as a 3.5, unless you are hammering it, when it will be worse. Might be slightly better if you drive sedately. Difference certainly not going to justify doing an engine transplant for that reason alone.

Exact same as 3.5 really...

Bullshit!

It's better than 3.5 as you don't have to rev it as much, driving around with a 50/50 mix highway and street (and the occasional limiter bash) I was getting 10l/100k's. I don't exactly drive that sedately either...

Bullshit!

It's better than 3.5 as you don't have to rev it as much, driving around with a 50/50 mix highway and street (and the occasional limiter bash) I was getting 10l/100k's. I don't exactly drive that sedately either...

Yeah and i have a 3.5 and i can get better then that. If your theory worked... V12s would be the most efficient engines on the planet

Every conversion to datevowners have commented on improvements, given the amount I have done I think I should know lol

Every conversion to datevowners have commented on improvements, given the amount I have done I think I should know lol

Had i have kept the magna i would have paid you or ben a visit a long time ago to have one dropped in.

I think that is pretty conclusive. 3.8L is better on fuel. Comes down to more sophisticated ECU electronics controlling fuel/spark better than in the 3.5L (if the 3.8L is still in a 380), at a guess. And presumably design work on the pistons etc to reduce friction, but you would have to compare piston design, bearing sizes and materials etc to be sure of that.

Only time I drove a 380 it was firmly stuck on 15L/100 km. Not too impressive.

Yet another 21 posts of unrelated "answers" mostly spam deleted from a Tech subject, either answer the question asked or STFU

If you want to discuss Toyota Sprinters, go to a Toyota forum, if you want to discuss 4.2l builds, open up a new thread.....this thread last I looked was about economy on a conversion?????

Ok well i will re-add that i believe the differences between 3.5 and 3.8 on fuel is near neglectable in a fwd magna .

Reckon the 380 motor would give better economy as it is a torquey engine which would require you to rev it less to get it up and going. Common sense really. I Own a manual 3.0L manual Magna wagon and a VRX AWD sedan with 3.5L engine. Sedan gets better economy when cruising compared to wagon and the wagon is a lighter car. More torque from idle should equal better economy.

Reckon the 380 motor would give better economy as it is a torquey engine which would require you to rev it less to get it up and going. Common sense really. I Own a manual 3.0L manual Magna wagon and a VRX AWD sedan with 3.5L engine. Sedan gets better economy when cruising compared to wagon and the wagon is a lighter car. More torque from idle should equal better economy.

LOL you get better economy in your AWD compared to FWD? First i have heard of that...

3.0L aren't the most efficient engine, if the wagon is a 4sp auto i'd say fuel economy would be pretty similar but fwd would be a little better around town at a guess?

I think the main point is, you should drop a 3.8 into Blackie. ;)

I think the main point is, you should drop a 3.8 into Blackie. ;)

Its looking that way.. Got to get rid of a few things to start funding it, but might as well considering all the other stuff I've done to it...

Fascinating subject! I didn't know that the 380's donk could slot into a TJ. Same engine block bolts/mounts, etc??? Any changes needed to a stock TJ's 4 speed auto? Finally...the big question...

How much of the folding does it cost...engine and labour?

Fascinating subject! I didn't know that the 380's donk could slot into a TJ. Same engine block bolts/mounts, etc??? Any changes needed to a stock TJ's 4 speed auto? Finally...the big question...

How much of the folding does it cost...engine and labour?

Check eBay, I have several there. Also call in and you will see them in the flesh lol

No mods needed to your trans at all

Price depends on a few things and how you want to about the conversion. If you want it done properly or back yard style

Best fuel econemy magna ive ever driven is a 2000 model TH 3.0l manual. That had the most insane fuel econemy and beat all the magnas ive had on fuel and they were all 3.5l auto and manual.

I drive a 1996 KH Verada with a 3.5l auto... I gotta say, the whole torquey thing with regards to less revving to get it to go... Around town I barely rev it at all, it sits at about 1.5k or 2k at most whenever I drive, it's only when i flog it that it gets a little revvey :D (about 6000 kinda revvey haha)

At the end of the day your driving style will determine your economy the most.

for a 3.5 to 3.8 conversion the difference is very little, if you are driving it easy maybe a bit better but if you are driving it hard then a bit worse.


Overall though, this is such a great conversion it's hard to believe!

Maybe I'm missing something, but how much petrol would you save compared to the money you would spend for the conversion, engineering, getting it all legal etc?

How many years before you are ahead? ;)

Maybe I'm missing something, but how much petrol would you save compared to the money you would spend for the conversion, engineering, getting it all legal etc?

How many years before you are ahead? ;)

it's not something you do to save on fuel, as I said any difference is very little.

You do it to gain a heap of power for a reasonable outlay of money! Especially if your old 3lt or 3.5lt is nearing the end.


I think the OP just wanted to be aware if he would be up for a larger fuel bill.

That's a good point - what are the legalities of the 6G72/4 to 6G75 engine swap in NSW? Does it need an engineers certificate?
For economy calculations, you'd want to factor in these extra costs.

No need for engineers certs, I checked with the RTA and the NRMA and they said it's fine.

All stock engine mounts are used and all original emission gear can be hooked up if desired.

Never been asked to pop the bonnet and check when I've been caught being naughty on the road either....

I'd imagine it would need engineering absolutely. The general rule of thumb from the RMS is that if it wasnt available for that specific car in that model, it needs to be engineered.

Engineers certificate isn't required in NSW for a 6g75 conversion, it is covered under
"‘Owner certified’ minor modifications which can be accepted for registration purposes without formal certification".

Example of "minor (owner certified) modifications"...


Engine changes where the capacity increase is less than 15% above the maximum size engine available for the
vehicle (providing no major structural modifications are necessary and where noise and/or exhaust emission
ADRs apply, all standard equipment such as carburettors, exhaust systems, exhaust gas recirculating valves,
oxygen sensors and catalytic convertors relating to noise and emission control are retained and operate
correctly).

And in terms of notifications...

Does the RTA require notification of the modifications?
All major modifications must be reported to the RTA. Minor modifications made to the motor vehicle or its
equipment which affect registration details must be reported to the RTA to ensure that accurate records are
maintained. These details include engine number, engine capacity/motive power/number of cylinders, body shape,
fittings, number of seating positions, unladen (tare) weight, gross vehicle mass, axle code, wheelbase & overall axle
space. If the unladen weight has changed, the owner must provide a weighbridge ticket for the vehicle in its new
configuration.
Modifications are reported to the RTA by obtaining an Adjustment of Records and a ‘blue slip’ from an
Authorised Unregistered Vehicle Inspection Station (AUVIS). For details of your nearest AUVIS contact the RTA’s
Customer Service Centre on 13 22 13.

Yea Dave that's bs lol

Reading about 3.8s fairly frequently. Not many give details though. Where should I be looking if I'd like an idea of cost, and how many kms a 6g75 has (can you even get them new)?

Reading about 3.8s fairly frequently. Not many give details though. Where should I be looking if I'd like an idea of cost, and how many kms a 6g75 has (can you even get them new)?

The engine itself will cost 600-2000 from a wrecker depending on the kms and where you buy it. They can range any amount of kms. You will need to look at wreckers. you can get them new but they will cost more then double that much.

I don't think I have read anywhere in this thread an actual Litres per 100 kays figure on how much the 3.8 in a Magna uses. Can anybody provide a figure?

I don't think I have read anywhere in this thread an actual Litres per 100 kays figure on how much the 3.8 in a Magna uses. Can anybody provide a figure?

My AWD....untuned 3.5 = 12.2. ........... then with exhaust & tuned 3.5 = 11.6........now with tuned & worked 3.8 = 11.6 still.

Its different for every car... That's probably why.

It wont be much different from a 3.5. Maybe a little more economical when driven gently

Reading about 3.8s fairly frequently. Not many give details though. Where should I be looking if I'd like an idea of cost, and how many kms a 6g75 has (can you even get them new)?

Theres a crate motor in S.A. atm for 3k.

I don't think I have read anywhere in this thread an actual Litres per 100 kays figure on how much the 3.8 in a Magna uses. Can anybody provide a figure?

I had a rough figure in an earlier post, but it was deleted.

For the record the below is all for a 5sp TH wagon (weighs about 1515kg, or equivalent to TJ sedan I'm told), and they are based on close to a full tank, and with a consistent mix of highway driving and city (probably 2/3 highway at a guess).

All my 3.5lt fuel usage figures are in my old log book, but from memory it was always around the 10.5lt per 100km range, I don't think it ever went below 10's.


After fitting the stock 3.8lt (but with HM headers and exhaust, and a 98 tune), a good example is:
594 km on the trip
Ave speed 55.1km/h
used just over 59 lt fuel (98 Octane)

Ave usage per 100km according to trip computer spot on 10 lt/100km (actually calculated a little higher doing the maths)


Modified 3.8lt with cams, HM headers, exhaust and a tune to suit cams, but this time a safer 95 tune.
608 km
Ave speed of 55.6km/h
Used just over 61 lt fuel (still running on 98 octane though despite tune)

Ave usage per 100km according to trip computer 9.96 lt/100km (actually calculated a little higher doing the maths)


As I stated though previously how you drive is the big variable.
For example I know the cams I'm using have led to a slight increase in fuel use, and when I first had them running and was using the extra power regularly I saw a larger increase, around mid-high 11lt per 100km, but as you can see above if you drive it more sedately the figure drops down to similar to the stock cam figures.

3.5 to a 3.8 conversion is very similar, you fit the 3.8lt and initially drive around having a great time and using the extra power every chance you get, and the fuel use will be up on the 3.5, then your driving style settles back down to normal and you discover it the fuel usage is no more (or likely less) then the 3.5lt.