4.5 to 4.7 swap

[XLR8928]

Does anyone know if I will run into any issues running my 4.5 L jetronic FI, and 4.5 flywheel on the 4.7 engine I'm building?

I'm using euro cams, tubular headers thru a 3" exhaust system with a flowmaster muffler, K&N air filter, stock C.R., total ignition timing to be set at 28deg.
Any estimates on power output?
-Kerry.

[Pete R]

I did the swap but used CIS. The question will be is if there is enough headroom in the L-tronics to read and flow enough gas at high rpms and not lean out.(which I don't know, CIS worked fine)
You'll probably be around 240-250hp

[paris]

I might be wrong but I thought a 4.7 engine puts out 315hp

[Pete R]

Originally Posted by paris

I might be wrong but I thought a 4.7 engine puts out 315hp

A full 4.7 84-86 Euro with pistons, heads, cams, intake, throttle body ect is only 310. Adding cams and exhaust to a normal US motor won't get all that. Maybe 20hp over the normal 230hp if the engine is fresh. Just a guess really though, don't have dyno #'s

[XLR8928]

My motor is an '83 4.7 (rated at 234hp). I figured a euro cam, headers, 3" exhaust, no cat, and 5deg increased ignition timing would be worth at least an extra 25 or so h.p., or around 260hp.

[Pete R]

Originally Posted by XLR8928

My motor is an '83 4.7 (rated at 234hp). I figured a euro cam, headers, 3" exhaust, no cat, and 5deg increased ignition timing would be worth at least an extra 25 or so h.p., or around 260hp.

I'd buy that

[riber.bentsen]

Originally Posted by Pete R

A full 4.7 84-86 Euro with pistons, heads, cams, intake, throttle body ect is only 310.

Well, Porsche were always conservative with their performance numbers. Some have measured (late) 4.7 euros at around 340 hp.

[Xlot]

Originally Posted by riber.bentsen

Well, Porsche were always conservative with their performance numbers. Some have measured (late) 4.7 euros at around 340 hp.

Yep - a local manual '85 S2 (4.7L LH2.2) put down 206rwkw (276rwhp) on a Dyno Dynamics machine.

For comparison, that is more than a stock 91GT (267rwhp) and manual 89S4 (260rwhp) both put down on the same machine. And the GT and S4 were both post-intake refresh so had all working sensors etc.