Strosek Ultra

Some call it split overlap when the intake and exhaust lobe centerline is at equal degrees at both sides of TDC on a cam lift diagram.
Åke

justaguy

Cams were installed straight up with the stock separation. Is there any thing to be gained with cam timing or do you merely shift the torque and horse power peaks. I have adjustable cam gears ( not installed) but both cams are tied together so both intake and exhaust would be advanced or retarded in unison. I don't know enough to play with the overlap of the cams and it seem one tooth on the sprockets would be a significant change.

Captain_Slow

This is very interesting... I've often thought this and a more modern intake would be the biggest upgrades to "modern" for the 928.

GregBBRD

Those are great results! Very doubtful you will find anyone making that kind of power with a 5.0 engine....I'm certainly not aware of any.

Be sure and let us know how it performs on the track....that's what really matters!

x98boardwell

Great results! Is there a process on the coils on each plug process and what modifications are needed? Seems like a great upgrade on its own!

Congrats on those numbers.

docmirror

As a general rule, lobe spacing does just shift the HP/Torque curves on the RPM scale. There are other things at work, but it depends on if one moves the int, or the exh, or both, and which way they go. Most cases(but not all), reducing the overlap by advancing the int cam will improve low end torque at the expense of high revs. But - a word of caution before everyone gangs up on me, there are a bizillion affects when lobe separation angles come into play.

I used to test cams for EMPI on their air cooled VW engines and we would spec a much different cam for engines going in the microbus, vs the cams going in a sand rail. Different jobs, different cam lobe separation. Same idea with boat cams, because they have no ability to shift, as the prop pitch is fixed. Need a cam that will work for 1600-5400 with a smooth band. Special profile, which is why when one orders a marine engine from a car maker, a lot of things are different, specifically the cam profile. Very few V8 cars run for hours at 3600-4000 RPM fixed throttle.

ptuomov

The LSA is what it is (114 for the S3 cams) and you can't change that with those cams. You can however advance or retard them.

The factory installs the S3 cams significantly retarded in S3 (not 114 on both intake and exhaust, but something like 120.5 on the intake and 107.5 on the exhaust). Presumably retarded installation is ok because the heads flow so extremely well at low lifts that the maximum piston speed air flow demand is met with the 5.0L engine with all reasonable cam phasings so you're not paying a low rpm penalty and you'll get better high rpm ramming effect with later IVC. Pure speculation on my part, though.

Porken has done a lot of experimenting on these, so he might know how to install them for the best average power.

Raceboy

I installed VEMS with VAG coil on plug (the short ones) on my friends 928's (Euro) with 4.7 16v engine back in 2006.

Since then done several VEMS installs on 928's. Nothing unusual.

Soon there will be Plug and Play VEMS kit available for 928 EFI models (both 16v and 32v).

Strosek Ultra

Was it not a 5.0 liter 380 rwhp build made by Jim Morton and owned by Dennis Kao some years ago?
Åke

SwayBar

The Holbert car first started doing 335 rwhp a loooong time ago, so this is nothing new...

Chris Lockhart

What does "VAG" stand for? TIA.

Raceboy

Volkswagen AG

Chris Lockhart

Ahh, OK. Thanks.

IcemanG17

nice dyno numbers......