Hello,
does anyone has done this?
When applying the camshafts from a 1985/86 Euro S2 (4.7l - 310hp) in a 1978/79 euro "normal" (4.5l - 240hp) 928, and without more modifications, what could be the expected gain in power and torq?

 

The 928S2 camshaft looks like this compared to a more sporty kind of camshaft.

 

And where to find those cams?
Tried schrick but it seems no one has "sporty" cams for the 928...

 

don't see why not. but if you can get the S2 cams, get the Heads and intake as well. the euro S2 heads are much better than the 4.5 ones

 

What is the source on the graphs?

Note doesn't show 79, shows stock 85 S2 and Webcams rewelded ? (oddly not listed on their web page).

 

Not sure how well Euro S heads work on the 4.5L with 95mm bore.

 

the EURO S , NEEDED bigger valves, larger intake runners, larger ports, bigger throttle body and higher compression plus dual exhaust ; as well as the bigger cams to get the 310 out of a 4.7.
Just doing the cams may well reduce torque at lower RPMs but the restrictive intake of your 4.5 would limit the high end horsepower.
Over the years I had several customers who did add S cams to an otherwise pretty much stock 4.5 and they ended up making more noise than anything else.

 

I do not have a graph of the 1979 4,5 liter factory cam but according to the specs it is of no major difference from the 1985 S2 cam.

The grind #458 was custom made for me back in 1996. WEB-Cam has several hundreds of profiles and many of them can be applied for the 928 engine. Here is a high lift race cam for the 2-valve engine for which I have run into a problem of not finding suitable mechanical lifters. Depending on the high rate of lift velocity this cam profile need minimum 42mm lifters or the lobe will run out on the edge of the lifter. The cam will be used for heads having 2.150" / 1.625" valves on 4.250" bore.

Ake

 

Last year I did build a Moto Guzzi V-Twin race engine for a customer. The bore is 95mm, stroke 78mm. Does it sound familiar? Yes, same as for the 4,5 liter 928 V8 engine. The Moto Guzzi pushrod engine having 50/40mm valves, 41,5mm carbs and very limited cam lift of about 11mm depending on small size lifters and the rocker ratio, is making good torque from about 3000 rpm, peak power at 8400 rpm and red line at 9250 rpm. When will we see something similar based on a 928 2V engine? Here is the power at the wheel.

Ake

 

I definitely think the heads need to go with the cams. I'm not sold on needing the intake and throttle. My US 4.7L with only the Euro heads/cams and a full exhaust makes 272whp, which comes out to 320 at the crank.

 

I have S2 cams, heads and runners - not cheap though.
Roger@928sRus.com

 

how much HP will installing Euro S LH cams gain in a 4.5L....about 40whp & torque.... A well running USA 4.5L CIS engine with full race exhaust makes about 220whp-230ftlbs......add euro cams will get you close to 260-275ftlbs....my 4.5L L jet engine with early Euro cams, Euro intake and some porting but stock smaller USA valves makes 265-289

 

If you didn't dyno the car (on the same dyno) then those numbers don't mean much.

 

Ugh, what a painful post, I just looked up my rewelded cam purchase for some details, bought them 1/2009, still in box. ;( Almost decided on not using slightly rusty used 944T valve springs.

I started with US 80 cams, worst I had since they were getting welded before grinding new profile. Base circle was reduced from 1.415" to 1.360" with a max intake lift of .506".

From the cam info sheet on the grind I picked.

Valve Timing Information
Engine: Set (2) Porsche 928 SOHC 16v - Hydraulic
Grind # 552/553

Intake Exhaust
Valve Lash 0000 0000
Valve Lift .506 .462
Duration 266º 240º
Duration @ .050 244º 222º
Lobe Center 110º 110º
Intake Opens 12° Before TDC
Exhaust Opens 41° Before BDC
Intake Closes 52° After BDC
Exhaust Closes 1° After TDC

A bit more info on various cams.
intake lift exhaust lift intake duration exhaust duration
78/79 .435 .395 227 216
80/82 .396 .350 216 206
80/83 usa .435 .395 215 203
80/83 euro .472 .432 223 215
84/86 euro .472 .432 228 219

Quite a bit of difference between them.

 

My car bone stock on the same dynapac did 180whp, so I believe the numbers.

The torque down low never budged after the head/cam/exhaust swap. If you overlay the two plots it just carries the torque out a lot farther. It only gained power over 4000rpm.