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Manifolds

3K views 31 replies 9 participants last post by  Soxx 
#1 ·
Is there any DYNO proven advantage from changing from the droopy ea/ed manifold to the ef manifold. Ive heard the ef ones are better for low end, but the Ea-EB ones are heaps better for top end pull.
I can get these manifolds easy as ,just woundering weather it would be woth the effort to change.
 
#29 ·
would i be mistaken.... the eb's dont run knock sensors???? but the later ef's do, do the el run one??? ... M not sure if they do run one....

Anther thing ive found with my eb falcon, with over 18 deg of base timing it wont ping, is this normal, once you cam these motors up.... should i keep winding it up till it pings, then back it of.. i alway run mobil synergy and nothen else..
Its driven me crazy because when i set it to ten degs after setting the ecu off, it feels a lil lazy, but the more i wind it up the better it seems to go, but i dont want to go to far...
 
#30 ·
EF onwards had knock sensors.

You can run more advance because of the less dynamic CR with a bigger cam. Things get complicated when you start talking static and dynamic CR.

You can wind it up a long way, but cylinder pressures can become strange if the timing is advanced too far and you will lose power. You should be able to feel that anyway.

My DEV5 runs best at 8 deg, but it has 9.8:1 static CR.

Rick.
 
#31 ·
i under stand..... can i put it this way, a motor with a stock cam but 10:1 static comp might ping on any thing over 9 degs? but a motor with th e same static compression but with a much wilder cam can run 15 degs, is this because of the overlap of the cam.

I should have realised this my 250 i built runs 11.5:1 comp, with with a 260 @ 0.050 cam, so it doesnt deteonate on premium unleaded, if i used this comp with a standard cam it would prob detonate....
 
#32 ·
INJECTED250 said:
i under stand..... can i put it this way, a motor with a stock cam but 10:1 static comp might ping on any thing over 9 degs? but a motor with th e same static compression but with a much wilder cam can run 15 degs, is this because of the overlap of the cam.
Yes, and because the valve is open longer it gives less time to build up compression. That's why a bigger cam really wants higher static CR.
I should have realised this my 250 i built runs 11.5:1 comp, with with a 260 @ 0.050 cam, so it doesnt deteonate on premium unleaded, if i used this comp with a standard cam it would prob detonate....
Definitely.

Rick.
 
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