AU XR8 Engine specs

[5.6 litre]

hi just wondering what heads were on the 185kw xr8? and what are the differences between the series 185, 200, 220kw? sleep:

[xd5.8l]

220/250kw heads were the same.

200/185kw were just your standard run of the mill gt40's

The 220 heads got a port job, bigger STAINLESS STEEL valves. Milled for higher comp in 5L while left stock in 250kw to keep compression down.

[5.6 litre]

thanks what about the injectors are they all the same?

[xr8ute]

All AU V8's use GT40P heads (different to GT40), and as xd5.8l has said, the 220kw, and 250kw motors used modified GT40P's....

Most AU's ran 24lb/hr Bosch EV6 injectors (blue), although some very early AU's ran 19lb/hr Bosch EV6 injectors(orange). I beleive the 220/250kw motors ran a higher pressure fuel regulator.

Do a search for the difference between the 185/200/220 motors...it has been covered a million times already ;)

[5.6 litre]

:eclipsee_ thanks im new to these forums your help is appreciated

[12]

Originally Posted by xr8ute

All AU V8's use GT40P heads (different to GT40)

Not all AU V8's. Some of us lucky early T-Series owners got the SVO Y303 alloy heads. :

[howesy]

Originally Posted by xd5.8l

220/250kw heads were the same.

200/185kw were just your standard run of the mill gt40's

The 220 heads got a port job, bigger STAINLESS STEEL valves. Milled for higher comp in 5L while left stock in 250kw to keep compression down.

Original 250KW specifications as published.
Cylinder Heads
These are the same heads as used in the 220KW engine with modified combustion chambers.Increased valve sizes and 1.7:1 ratio roller rockers.

Compression
9.6:1

220Kw 9.1:1

[xr8ute]

Does anyone know what valve sizes the modified heads used?

[howesy]

[QUOTE=xr8ute]Does anyone know what valve sizes the modified heads used?[/QUOTE

250KW T3 engine

inlet-: 49.3mm dia. and lift at valve was 11.99mm
opens 17 deg BTDC
close 79 deg ATDC

exhaust-: 39.4mm dia. and lift at valve was 12.00mm
opens 64 deg BBDC
close 22 deg ATDC

[xr8ute]

So that will be 1.94" inlet and 1.55" exhaust. Thanks Howesy

[5 FTR 5]

Originally Posted by howesy

Original 250KW specifications as published.
Cylinder Heads
These are the same heads as used in the 220KW engine with modified combustion chambers.Increased valve sizes and 1.7:1 ratio roller rockers.

Compression
9.6:1

220Kw 9.1:1

The compression on the 220 is 9:5:1

[philstoj]

I bet you will be surprised to see what sort of porting the 220/250 GT40p heads got, bugger all really.... I dont think the CNC machine broke a sweat..
Those heads only got a larger inlet valve, 1.94", the exhaust was a standard GT40P 1.54".
The Y303 heads are just an alloy version of the GT40 head, same valve size and all, nice weight saving though.

[5 FTR 5]

Originally Posted by philstoj

I bet you will be surprised to see what sort of porting the 220/250 GT40p heads got, bugger all really.... I dont think the CNC machine broke a sweat..
Those heads only got a larger inlet valve, 1.94", the exhaust was a standard GT40P 1.54".
The Y303 heads are just an alloy version of the GT40 head, same valve size and all, nice weight saving though.

To true about the porting,I had a close look at mine when BPT where putting the upgrade cam in.The only CNC work is where the intake manifold connects with the head Bugger all done.

[xr8ute]

Originally Posted by philstoj

Those heads only got a larger inlet valve, 1.94", the exhaust was a standard GT40P 1.54"

Stock exhaust valve for the GT40P head is actually 1.46" (1.54" is standard on the GT40).