track results after fitting head

well finaly got out to wiilow bank tonight and gave the old au a run .i was pretty disapointed to say the least .the best i could crack was a 15.03 @93mph.must of done about a half dozen runs from 15.03 /15.1 .
something must be wrong i can't see how i can loose 4 tenths and 2mph from from fitting a ported head .unless the old one was something special .
guess i'l just have to go over it and double check everything .
catch ya jake

[Casper]

Its most certainly possible. There is more to porting a head then just making everything bigger. If the profile isnt correct then the efficiency of the head can actually get worse rather than better. It may be worth asking whoever did the head what sort of profile changes they actually made.

headsense did the porting and is definately one of the best in the buisness ,i got the flo figures for the head and there definately on the money .i
ts still running the streetfighter cam .maybe the manifold or headers don't line up to the head properly ,the head i got ported was off an au series 1 .we dialed the cam into the exact jmm specs .
it's still runnig the standerd injectors ,after i got the retune done i asked if they were maxing out and they said they were fine .
it's all to confusing to me its gone from 159rwk at 5400rpm to 157rwk at 4900 rpm you could realy notice the difference at the track trying to wind it out in 3rd took forever .
it seems something restricting the flow its strang how both figures are so close , the new head has picked up a crap load more torque you just put your foot down and go compared to the old one.

[Stav]

Bugger!!

[blueoval]

Originally Posted by Nik

headsense did the porting and is definately one of the best in the buisness ,i got the flo figures for the head and there definately on the money .i
ts still running the streetfighter cam .maybe the manifold or headers don't line up to the head properly ,the head i got ported was off an au series 1 .we dialed the cam into the exact jmm specs .
it's still runnig the standerd injectors ,after i got the retune done i asked if they were maxing out and they said they were fine .
it's all to confusing to me its gone from 159rwk at 5400rpm to 157rwk at 4900 rpm you could realy notice the difference at the track trying to wind it out in 3rd took forever .
it seems something restricting the flow its strang how both figures are so close , the new head has picked up a crap load more torque you just put your foot down and go compared to the old one.

Wait about a week and then get your head retentioned. See how that goes.

[Stav]

I reckon that the chip may not be spot on.

[jonbays]

Originally Posted by Nik

well finaly got out to wiilow bank tonight and gave the old au a run .i was pretty disapointed to say the least .the best i could crack was a 15.03 @93mph.must of done about a half dozen runs from 15.03 /15.1 .
something must be wrong i can't see how i can loose 4 tenths and 2mph from from fitting a ported head .unless the old one was something special .
guess i'l just have to go over it and double check everything .
catch ya jake

Probably just the day at the track high humidity temp or something.

93mph sort of tells me this is a true 150rwkw engine in an AU though.

Bu thats tuning cars for you the first gains are always the easiest then it gets harder the faster you want to go.

[xr8ute]

Damn...thats unexpected. As jonbays said, maybe just weather at the track that day or something.

What rpm where you shifting at?

What rpm where you shifting at?[/QUOTE]


5500rpm ,i tried short shifting at 5000 rpm and made no difference ,it was a lot hotter and more humid than the last time i ran .
the best 60 ft i could get was 2.144 launching at 3800 rpm (missed 2nd gear that run)the last time iwas there runnin the original head i got a 2.065 launching at 3500 .

[Stav]

I think that theses engines love the cooler weather. My best 0-100 time was in 15 degrees. Now with the heat rising the car feels a tad down on power. The further south you go the quicker your car will run..

[EvilChief]

Originally Posted by Nik

What rpm where you shifting at?

5500rpm ,i tried short shifting at 5000 rpm and made no difference ,it was a lot hotter and more humid than the last time i ran .
the best 60 ft i could get was 2.144 launching at 3800 rpm (missed 2nd gear that run)the last time iwas there runnin the original head i got a 2.065 launching at 3500 .[/QUOTE]

damn you guys can launch at 3800rpm, id love to have done that ...

i could only launch from 1500 before it became spin city ...

times match i ran a 14.9 at 93.33 mph with a 2.2 60ft, got a 9" sucker in the rear thou & stock ecu :