5.4 DOHC Buildup

WABWare said:

Well looking at modding my car. I'm surprised on how cheap building a 5.4 DOHC motor will be..... How much hp will the stock 5.4 block hold up too and the navigator parts for the 5.4 are cheaper than the 4.6 cobra heads.... I know the cobra heads flow betteer......but a good port job will fix that........Any suggestions when considering this buildup...........!!!!!!!!

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Where are you getting a 5.4 DOHC Engine from? Is it a Navi engine? I'm sure it certainly isn't the 00 Cobra R 5.4

WABWare said:

Well looking at modding my car. I'm surprised on how cheap building a 5.4 DOHC motor will be..... How much hp will the stock 5.4 block hold up too and the navigator parts for the 5.4 are cheaper than the 4.6 cobra heads.... I know the cobra heads flow betteer......but a good port job will fix that........Any suggestions when considering this buildup...........!!!!!!!!

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well assuming you can tune a 5.4 to the same specific output as the 4.6 it is quite easy to work out a ruff figure.

A s/c 4.6 Cobra unit will give 400rwhp no worries, which despending on how you rate the drivetrain loss (a grey and arguable area), some say 15% so 400/.85 = 470bhp crank

as its 4.6 litres, 470/4.6 = 102bhp/litre

So with 5.4 litres, 102 x 5.4 = 551bhp crank

And as extra proof the Ford GT uses a variant of the 5.4 (aluminium block, twin screw blower) and that is rated at 550bhp.

Of course the cams, heads, blower type and psi level will affect output, and block, pistons and all the other internals will affect durability.

If your looking at n/a then 75bhp/litre is a sensible target or 405bhp crank.

You could tune it to silly levels of corse where 100bhp/litre is possible n/a although rather revvy, and 200bhp/litre from an FI setup.

I am pretty sure I read somewhere that lightnings start blowing up at around 600hp. Not sure, but I think that is accurate.