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Auto to Manual Conversions - Good, bad or ugly ??

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OK guys,

I need your thoughts on auto to manual conversions.

More to the point of buying a car that has already had the conversion done oppose to buying a car that was manual from the factory.

What are the bad points and what should be looked out for, both short term and long term (resale value etc..)

Basically I'm sort of in the market for another R33, one has come up but it has had an auto to manual conversion done.




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No idea,

I don't see how there can be much of a difference really?

As long as they are the genuine Nissan Manual Parts...

Same parts,

Same car...

same ride... as long as a proper installation job is done I don't see how there can be that much harm. I plan to get my auto converted...

But how did you know it was a conversion?

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G'day Jive,

I did a little bit of home work. :rant: The car that I'm thinking about was originally imported by a fella that used to post up on SAU. He sold it to someone else, and now that new person is selling it. I found the original owners SAU nick name, matched up the pictures and they were the same car. And in one of the posts that the original owner posted up he said that it had an auto to manual converstion done (takes breath...)...

Apparently the conversion was done by a good workshop in Sydney, so it wasn't a back yard job ;)

The only things I can think of that may have an effect on the car is maybe the dash (the auto has lights saying D, N, R etc... (I think!), and I think the ECU's are different.

Anyone else got any thoughts on this ?


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The ECU should not cause to much of a problem, but it should be replaced for complete effiency. The auto ECU will slow down the fuel pump when it is 'expecting' a gear change. a manual ECU will not. But i mean if your going to go for perofrmance you'll will most likly get an AphexiFC or something later on anyway. The auto lights in the dash must be disconnected other wise the car will never start. As im sure your aware an auto car has safty's to make sure the car will not start while in anything other than park or N

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yeah i'm currently questioning the CPU on mine, as my car has had a conversion done in the past. I've heard the timing can be altered differently by the auto computer due to the fact that it thinks its always in P or N.

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hey guys

i had the conversion done in my old car (R31 GTS-X) put an R32 gearbox into it... conversion was fine...i drove an original manual GTS-X and didn't feel much different..i left the auto ecu and diff in and seemed to run fine....about the

P-N-D thing..i kept the selecter swithch which is about your palm size tucked away under the dash and made for a cheap immobiliser..just switch so it thinks its in drive and well, no start.. just taped it in Park instead of paying a sparky over $100 to hard wire it and hehe would really confuse people trying to steal it but anyway that my experience.

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ive done 2 conversions on silvias i cant imagine a skyline is much different and they are great you cant even tell if the jobs done right.... A few things make sure the fork slave cylinder is matched to the clutch slave cylinder... what i mean by this if the they say 15/16 both should be the same the other it could be is 3/4 but thats more on sr20 silvias!!! Also im unsure but some clutch arrangement use proportioning valves like i said im unsure if r33's do but r32's gtr's do!!! If a r33 pedal box was used then there should be no other dramas... oh also make sure if they got a tailshaft made it fits in really weel cause ametures usually mis measures tailshafts when getting them made!!!!! Dont try to hunt down the auto computer its better left all in there and connected... on the silvias i just open circuted the wires that are for drive so theres no lights comming on and such!!!

Hopes this helps jay!!!

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If you do it correctly, there is no difference in how it will drive, and i dont see why it should effect resale. As long as the inhibitor is looped so the car always thinks its in N (as far as the engine is concerned) it will run fine. I had been running around on the standard diff/ auto ECU for ages till i changed to a IMPUL ecu, and it went fine, my gearing actually worked out slightly taller than a factory manual, so im thinking it must at least have a 4.1 in there..

Auto ECU runs slightly more advanced timing, so you need to be careful with boost, but 9/10 a manual conversion car will be faster than a factory 5spd due to the diff and ECU. This is the case with 32's anyway.

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  • 3 weeks later...

Best to replace the ECU with manual one so it doesnt reduces power when it thinks it should shift gear. Second you may be right for converted car to be running a bit faster than stock cars due to auto's 4.3 taller diff ratio helps better in acceleration compared to the manual's 4.1.

Reliability should not be an issue as they're both have pretty much the same internals apart from gearing ratio. For GTS-T at least both manual and auto has viscous lsd out of factory (or A-LSD as option). In Toyota Soarers they are different cause only manual soarers comes with lsd but not auto ones but I could be wrong. You gotta thank Nissan for using lsd in both manual & auto skylines!

You should not have issue with fuel consumption and final top speed as the difference in ratio is only about 4%, but that small difference could mean a few millisecond faster down the drag strip ;-) 1st & 2nd gear may feel a bit stronger too but i doubt many would feel it.

Leave the diff u dun have to change it if it's not broken. Driveshaft for auto & manual has different length so it should have been replaced during conversion anyway. U can get away with ECU but best to swap it with manual ECU. Wiring looms are the same so it's an easy job to swap it.

So Jay.. dun worry about it, if it's done properly (take it up on a hoist and examine) and everything is in place then it should not be a problem at all.

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