Twin turbo 4.0l

U

Unfalconbelievable

Well-known member
Hey there, my big girls nearly ready to rock again after more extensive engine mods and im excited lol had to tell sumone. Previously twin turbo'd on the stock bottom end it now sports 8.5:1 compression ratio with earlier 15cc dish pistons, ported and polished head (theres more work in that than u'd think, 40hrs it took me), 2mm oversize valves, custom ground cam with springs to suit, cleaned up crank and rods, 1.7:1 rockers off the earlier 3.9l and revised throttlebody. Next in line is megasquirt once i save the cash up after this build and 15psi boost with a 6300rpm limit. Heading towards 300-350kW at the wheels or 400-475hp in old speak. Should be pushing 400-500ftlb also. cant wait
 
Wow, sounds like you are doing alot of great work! I'm curious, what rockers are you using that have a 1.7:1 ratio?


Unfalconbelievable":3eh6sx1l said:
Hey there, my big girls nearly ready to rock again after more extensive engine mods and im excited lol had to tell sumone. Previously twin turbo'd on the stock bottom end it now sports 8.5:1 compression ratio with earlier 15cc dish pistons, ported and polished head (theres more work in that than u'd think, 40hrs it took me), 2mm oversize valves, custom ground cam with springs to suit, cleaned up crank and rods, 1.7:1 rockers off the earlier 3.9l and revised throttlebody. Next in line is megasquirt once i save the cash up after this build and 15psi boost with a 6300rpm limit. Heading towards 300-350kW at the wheels or 400-475hp in old speak. Should be pushing 400-500ftlb also. cant wait
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The rockers are ones my uncle gave me off the earlier 3.2 3.9 and 4.0l that ran the 11mm lash adjusters, apparently they are 1.7:1 as opposed to the later modle 1.5:1.... No pics just yet, its not quite all together and back in but after xmas i'll get some posted. I cant wait to drive it, even tho it wont be as good as before at first, due to the lower comp and same puny 4psi boost till i get the megasquirt. Also i have the stock cam advanced a tooth on the chain, more top end and a great note! At 3000rpm it sounds like another throttle bodys opened up, which is bout where the turbos spool
 
do these rockers bolt right on, or did you have to do any mods? thanks.

Unfalconbelievable":92ccprhf said:
The rockers are ones my uncle gave me off the earlier 3.2 3.9 and 4.0l that ran the 11mm lash adjusters, apparently they are 1.7:1 as opposed to the later modle 1.5:1.... No pics just yet, its not quite all together and back in but after xmas i'll get some posted. I cant wait to drive it, even tho it wont be as good as before at first, due to the lower comp and same puny 4psi boost till i get the megasquirt. Also i have the stock cam advanced a tooth on the chain, more top end and a great note! At 3000rpm it sounds like another throttle bodys opened up, which is bout where the turbos spool
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bolt right on with the pedestals and cam retainers. They are off the same design engine, maybe a 3.9l instead of a 4.0l but they are all interchangeable. Even the new BA's run the same sump and crank and smaller rods than the AU. The block is virtually unchanged except for the timing gear up front. My uncle owns a machine shop and we were going thru some book he had there and it said the earlier ohc sixes ran the 1.75:1 rockers so he tracked some down for me
 
The 4.0L is the OHC version of the inline six found in Australia.

Unfortunately, the head won't bolt onto ours over here in the States. :(

Other than that, a fantastic engine. To bad only a few are over here.
 
Yes you are correct, They are a dime a dozen down here in oz but. the cylinder spacing and port spacing are the same as the 250 x-flo but head bolts are different and the timing gear would have to be modified. Should have pics in the next couple weeks, as a daily driver its hard to get time to work on it but i'm running it in in NA form and then the turbo's go back on :twisted: tho only at the pissy 4psi till the megasquirt
 
a 95 xg falcon ute. Oh and I've changed my mind on the megasquirt, couldn't get any sense out of the ppl on that topic so I'm buying a microtech lt10. Shooting for 250-350 rwkW or 375-450hp at the wheels roughly in old speak. Getting a custom clutch built, sprung centre brass button with wave washers under the buttons making it a lil more street friendly but still capable of 500Nm of torque
 
Unfalconbelievable":3c0c1t9d said:
Pics will be on tonite in a new post, if they work. I've had trouble before
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Post them here please with this thread / topic. So we can see what you have done.
 
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