Hay all guys. Those of u guys who have done the 380 conversion on there magnas. I know there seems to be a pritty obvious torque gain. But how's the top end power compare to a 3.5l?

On dyno day in Sydney few months ago, best n/a magna we had did 133kw at the wheels, stock ralliarts did a bit better with 137kw. Compare this to two magnas with 380 motors, one did 157 another 160 (i think????, Ben & Brendan correct me if im wrong), you will see people claim you can get much much more out of either 3.5l or 3.8l, however its important to remember that cars were ran on the same dyno on the same day & as such it is a good comparison of what the difference between the two is.

Even more those 380 motors put my supercharged setup to shame as i only did 150kw, yes i did have a really REALLY bad tune, when i took the car to another tuner & believe he used the term "pathetic" when describing it.

Lol my car was faster than andrei's charged magna.

You get your tune fixed yet Andrei? What power are you making now??

3.8 keeps pulling to redline while 3.5 dies in the arse up top.

hahaha, i had it dynoed, on that dyno it did 175 on LPG only, tuner never done factory ECU flashing on a Magna so he adjusted LPG only, so it still drives like shit on petrol, again i wouldn't look into that dyno figure too much, it would be good to take it back to same one to see the real improvement. Also since its impossible to adjust timing with LPG ECU im still driving on spark for petrol, so further gains can be made if im to take advantage of 110 octane of lpg.

I've driven this blokes car and it really does pull till 6500. I kept shifting before 6 and he was like Wtf r u doing dickhead lol.
Ih8hsv said his car only lasts till 5500 though, difference is bens runs the 380 manifold and a tune.

I've driven this blokes car and it really does pull till 6500. I kept shifting before 6 and he was like Wtf r u doing dickhead lol.
Ih8hsv said his car only lasts till 5500 though, difference is bens runs the 380 manifold and a tune.

I would have thought this to be true, that the 380 manifold is better as it closes in at the last few runners at the far end. However, some people are saying that the magna manifold is better :|

I've driven this blokes car and it really does pull till 6500. I kept shifting before 6 and he was like Wtf r u doing dickhead lol.
Ih8hsv said his car only lasts till 5500 though, difference is bens runs the 380 manifold and a tune.

So the 380 manifold dosent have as good top end as magnas manifold? It's wierd that the 380
Has better top end the peak power is at 5250rpm. Ralliarts is at 5500rpm witch should
Make the 3.5l have better Topend. Who knows?

I would have thought this to be true, that the 380 manifold is better as it closes in at the last few runners at the far end. However, some people are saying that the magna manifold is better :|

The 380 manifold is good for 5kw top end trust me its been tested. The magna manifold isn't terrible but only the 380 manifold will release the potential of the 6g75. After driving bens car with 6g75 engine and manifold +tune it is a 13 second car.

The 380 manifold is good for 5kw top end trust me its been tested. The magna manifold isn't terrible but only the 380 manifold will release the potential of the 6g75. After driving bens car with 6g75 engine and manifold +tune it is a 13 second car.

Oh true. If the 380 manifold gets the most out of the 6G75. Everyone should use them when doing there conversion. How's much power does bens car have with a tune? Is everything else stock other than tune.

Oh true. If the 380 manifold gets the most out of the 6G75. Everyone should use them when doing there conversion. How's much power does bens car have with a tune? Is everything else stock other than tune.

The 380 manifold needs to be drilled to fit the magna throttle body so most people cbf and they just use 6g74 intake. This also looks stock so keeps people out of cop trouble.
Ben has a free flowing exhaust (2.5inch mandrel bent) and a pod sitting in his engine bay(not ideal) power estimation is 165kw from the man himself.

The 380 manifold is good for 5kw top end trust me its been tested. The magna manifold isn't terrible but only the 380 manifold will release the potential of the 6g75. After driving bens car with 6g75 engine and manifold +tune it is a 13 second car.

That's what I thought. I think maybe the comments that I've seen in the past have been more along the line of: drop a 380 engine in to a magna with magna exhaust and intake and it flies. Maybe not so much the intake side, but I know the 380 engines go well when the exhaust has been freed up of restriction (read: catalytic convertors)

My mate from the supaloc race team said that the 380 manifold makes so much more sense just looking at it, he said it gets tighter at the far end to improve flow to the end runners so the cylinders up that end don't starve of air at high revs.

That's what I thought. I think maybe the comments that I've seen in the past have been more along the line of: drop a 380 engine in to a magna with magna exhaust and intake and it flies. Maybe not so much the intake side, but I know the 380 engines go well when the exhaust has been freed up of restriction (read: catalytic convertors)

My mate from the supaloc race team said that the 380 manifold makes so much more sense just looking at it, he said it gets tighter at the far end to improve flow to the end runners so the cylinders up that end don't starve of air at high revs.

Yep the manifold itself is a much better shape. It is also angled perfectly so you can put a good cai on your intake by moving the battery to the boot.

That's what I thought. I think maybe the comments that I've seen in the past have been more along the line of: drop a 380 engine in to a magna with magna exhaust and intake and it flies. Maybe not so much the intake side, but I know the 380 engines go well when the exhaust has been freed up of restriction (read: catalytic convertors)

My mate from the supaloc race team said that the 380 manifold makes so much more sense just looking at it, he said it gets tighter at the far end to improve flow to the end runners so the cylinders up that end don't starve of air at high revs.

Did back to back dyno testing of 3.8 upper intake vs 3.5 on my modified 3.8.....3.8 is definately better.....about 5kw & 5nm.

There maybe a different outcome on a standard 3.8 though.

Did back to back dyno testing of 3.8 upper intake vs 3.5 on my modified 3.8.....3.8 is definately better.....about 5kw & 5nm.

There maybe a different outcome on a standard 3.8 though.

I would be even better on the normal 380 setup, because of the better ignition system etc.

I would be even better on the normal 380 setup, because of the better ignition system etc.

Yeah maybe....but i meant that i got those gains with a modified 3.8 with cams, etc. etc. A standard 3.8 in a 3rd gen. may get better or worse gains than that......wont know till someone does a back to back with a standard motor i suppose! :P

Wonder what it would do for a 3.5?

Yeah maybe....but i meant that i got those gains with a modified 3.8 with cams, etc. etc. A standard 3.8 in a 3rd gen. may get better or worse gains than that......wont know till someone does a back to back with a standard motor i suppose! :P

Oh I see. What cams are you using? What other modifications?

When I've upgraded my wife to a wagon one day and I've got my TF back, I plan to put an LSD and a mild 3.8 in it.

An ex member of this forum said it gained 4-5 kw on a 3.5 aswell. can't comment on reliability of source but it sounds about right.