I feel differently about the power drop with regards to meeting emissions. A couple of decades ago this was the case with things like EGR, excessive inlet manifold heating for better homoginisation, air injection exhaust manifolds ect, however the current way of thinking is to achieve better emissions via a better burn, and in doing so, helps to increase power outputs. You only have to look at the chamber differences between the XF and the E series to know what Im talking about there.

A funny thing that RPD found when testing several BBM manifolds with cams is that most times the power was fatter accross the midrange with the runners open, and we tested different points from idle up to 4000rpm opening points.

Thats my 2bob

And if you do choose to go BBM Tocchi... I just happen to have a full conversion here inc. EL GLi auto ECU from a EF Falc that you could have for a price.. if your interested PM me because I probably will forget to check this thread..

I've been told by a few people that the earlier manifold was better for turbo applications though?

The thinking for log being better for turbo is that dual runners have little/no advantage for boosted engines and the pipework is easier with the log.

Ive heard the log style is better for LPG systems as it provides better flow, if ur goin for the most power out of LPG as u can

With the polution side of things, notice how they have gone back to the EGR system again, even being fitted to diesels, and cats fitted to diesels too. The Govt is the one that pushes the vehicle manufactures, along with the EPA, to make them better their emissions. So the companys will do what they can to achieve the emission std and still produce power.
The XH ute in the lower models had a log manifold, and the XR6 version had the BBM setup. Ford never issued fuel consumption figures for the XH vans & utes, or the XG range either. The Govt made the car makers have those stickers on the window, you know, the fuel consumption ones, but the comercial ones didn't at that time.

Not quite sure what the logic was behind this. I would've thought a BBM would've been beneficial on all XH models, considering the engine was all EL (including camshaft - according to the ford manual).
I wouldn't have thought continued manufacturing of the EA-ED log manifold + associated induction parts would've cost any less than just drawing from the existing EF/EL parts.

thanks for the offer, but im going to buy an actual AU engine (i wasnt sure if i wanted to go log manifold or BBM). im pretty sure ill go with BBM

just to let you know .. if your using a au bbm in anything other than a au the air charge sensor is different and is not compatable with e series as it has the map sensor combined with the air charge sensor..and the el air charge sensor doesnt fit the au manifold...
when i first did my bbm conversion i couldnt get it to run right with the au air charge sensor.. so i had to go out and get a el bbm....

i think the bbm at the standard 3800rpm is to high. not that i have played with it much, but under full throttle it labors a bit around 3000 till it opens and goes fine again.

but then again, ford would have used that intake runner formula to figure it all out so you'd expect for stock it'd be not too bad

I think everyone with the exception of RPD who has messed around with the switching point has found that 3800 rpm is spot on. Personally I found that the crossover point is 4000rpm, below 4000 there is more torque on long runners and over 4000 your better off with the short runners, however you get the best transition with the runners at 3800rpm.

The other thing worth keeping in mind is that changing cams changes the dynamics in the intake manifold. If you have drastically different intake valve timing then the ideal switch point will move.

thanks for that. im going to be using AU engine, bbm, etc but running it with an auto EL ecu.


would the opening at 3800 be almost too 'late' in the rpm range with a turbo application?

The BBM doesnt do anything for turbos. Personally I would pull the butterfly's out completely, they are only going to get in the way.

And as said above, if your using any e-series ECU, get an EF or EL BBM and sensors.

what is it with pulling the butterflies out of bbm manifolds ? if your goin to do that send it to me n ill send replace it with a log manifold.

You have lost any gain with the bbm with takin the butterfly out. if you can't switch, either tune for power or torque, you can't have both.

The only problem with the log manifold allbeit a small one, is the offset of the throttle body being closer to number 1, with forced induction it's a moot point also the "log" makes more room for the blower. if you have forced induction why bother fcukin round with stock manifolds ? if you want serious performance get a custom manifold made if thats what horns u up. but the highest point of that would be just so you can say "look at my custom manifold,doesn't really do s**t but it looks tough"

You want serious power ? you get what you pay for. if your buying an au engine,throw in a cam, cold air induction on the cheap & a nice exaust (not a poofter f@rt, no back pressure, gay sounding pos)

Ford motors respond well to decent modifications, the bbm, on an ea would benefit from long runners because they don't rev. a more broad rev range like that of the au would probably benifit from a log manifold or standard functioning bbm. Ford spent millions in R&D to develop that manifold & change over point & chances are you can't match that financial input.

Ever looked at the BBM of a factory BA/BF turbo - you guessed it, butterflies removed.

Here is a picture of a (Tickford) dyno printout.

It shows the ED XR6 (log manifold) vs EF XR6 (BBM).

The SOLID lines are EF XR6 which clearly makes plenty more grunt (torque) lower in the dial. The dotted lines are ED XR6 which makes a fraction more power at peak, but looses out between 2 and 3 grand.

Interesting graph. Especially as Ford claim 164kw peak for EF and 161kw peak for ED.

 

 

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