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Xu9J2 Compression


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24 replies to this topic

#1
mostormxu9

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Hello everybody.

 

Does anyone knows how much is the compression of xu9j2 engine?

 

Thanks.



#2
jackherer

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9.3:1



#3
mostormxu9

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9.3:1

I mean compression pressure.

How much psi?



#4
Anthony

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For a compression test? I guess you should see around 175-180 psi for a healthy engine, but compression testers can vary significantly in terms of accuracy!

#5
dcc

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You'd be most concerned over the cylinders showing the same pressures

#6
mostormxu9

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For a compression test? I guess you should see around 175-180 psi for a healthy engine, but compression testers can vary significantly in terms of accuracy!

thanks man.

i want to use xu9j2 head cylinder with xu9 2c internal for turbo conversing.



#7
mostormxu9

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Does anybody knows the xu9j2 camshaft profile?

lift?

duration?

...

 

and as I said i want to use this head by turbo.

Is it necessary to do some modify on it?



#8
petert

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I assume you mean DKZ? Don't quote me, but I think it's 226º @ 0.050" on the inlet, max lift 0.445" and 218º @ 0.050", max lift 0.405" on the exhaust. ie the inlet lobe from the D6B and the exhaust lobe from a DFZ. Thus it has considerably less overlap than a D6B cam which has identical inlet & exhaust lobes.



#9
B1ack_Mi16

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DKZ ain't that the 205 Gentry engine?

 

The XU9J2 I thought was the one used in the 1987 and 1988 405 GRi with 125bhp. Same looking (probably exact same engine?) as BX GTi engine.

 

D6D seem to be the engine code.

6y0qo154.jpg​



#10
welshpug

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that is also what I would presume a j2 to be, downdraft high port long intake high torque engine.

dkz is a 9JAZ ?

#11
petert

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No idea then.



#12
mostormxu9

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DKZ ain't that the 205 Gentry engine?

 

The XU9J2 I thought was the one used in the 1987 and 1988 405 GRi with 125bhp. Same looking (probably exact same engine?) as BX GTi engine.

 

D6D seem to be the engine code.

6y0qo154.jpg​

Yes I have this head.

But I bought just the head and intake.

I dont know the exact code.

Is it necessary to port and polish the inlet ports?

I heard that the stock port is a little narrow and if you port it you will get better performance.

How much boost is safe for this head and block?



#13
B1ack_Mi16

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Anyway for compression I suggest you measure the head CC's if you just bought the head and it is not mounted to the block.

And do the same with pistons etc.



#14
petert

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Take the cam out and measure the lift of inlet & exhaust lobes. You'll then be able to make reasonable judgement.



#15
Thijs_Rallye

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dkz is a 9JAZ ?

 

Yes.

 

This head/intake runner combination is from a D6D engine if I'm not mistaken.



#16
petert

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Specs.

Attached Files



#17
mostormxu9

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Anyway for compression I suggest you measure the head CC's if you just bought the head and it is not mounted to the block.

And do the same with pistons etc.

I will measure it tonight and will tell it.

The pistons cc is 6.



#18
mostormxu9

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The cc of head cylinder is almost 48 ml.

So with piston and the gasket we have almost 55 ml velocity for combustion chamber.

Is it enough and suitable for turbo?



#19
Thijs_Rallye

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compression ratio = (Vstroke + Vcompression)/ Vcompression

 

Don't forget the headgasket volume.



#20
mostormxu9

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compression ratio = (Vstroke + Vcompression)/ Vcompression

 

Don't forget the headgasket volume.

ALMOST 9.2:1

Is it ok?