In the context of a 5.0L short block with Euro S heads where the pistons are going to be cut for valve reliefs anyway, so a bit more might be easy, is there much room for improvement on the Euro S cams?

The dyno charts I have seen showed the HP dropping fast above 5500 rpm, so it has me curious.

 

Any camshaft is only efficient over maybe a 500-1.000 RPM range above or below that it is less so. As with just about everything engine ( even car ) related it is a COMPROMISE...You can torque or horsepower when it comes to cam selection BUT you can not have BOTH. My old short stroke 2.6 liter RSR style mechanial injection 911 engine made about 40 HP at 4,500 RPM came on the cam at 6,000 RPM and we shifted at 8,500 RPM. I would downshift it when it dropped down to 7,000 RPM or so and at 10,000 RPM or so it would break things mechanical overrev if you hit third not fifth on an upshift....

 

Same question again

 

Define "improvement".
Glenn

 

I would guess that the flattening of the power delivery up top is do more the restrictions in the intake track than anything else. If you want to know for sure, retard the timing three degrees and see if you get more up top.

 

Good suggestion, Adam. Do you know where said "5.0L short block with Euro S heads where the pistons are going to be cut for valve reliefs anyway" could be found and an owner who wants to try out your suggestion?
Glenn

 

You may find improvement going to the US cams, as far as street driveability is concerned. Get some low-end torque that you'll use all the time, vs a few top-end ponies that you'll only see when you get above 5000RPMs. As Adam points out, there are some intake and exhaust issues that cause the roll-off right at the top. I don't want to stir up the Kibort discussion on torque vs horespower. But... The key is rear wheel torque available. You will drive through the horsepower peak some, then shift and drop below it again. To maintain max accelleration, you'll want to drop back into the fattest torque area you can. Gear spacing and shift points are decided by how this works out considering the change in overall ratio (and therefore available rear-wheel HP) when you shift. At what RPM's do you plan to shift? That will help you decide what in improvement is.

In my limited experience, the top-end power is handy for racing, when you are constantly in that narrow peak-HP band. At all other times, you'll be wishing you had decent torque to launch from stoplights and to keep the engine revs reasonable in normal traffic. Similar to Jim's 911RSR experience, I had a 246 Dino with the top end off a Lancia Stratos rally car. It screamed once it was rolling, but there was a tremendous amount of clutch abuse just to get it launched in traffic. After a month, the Stratos rally cams came out and the big-throat carbs came off. Even giving away 100 dyno horsepower with the change back, the car was more fun in daily driving.

Moral: Be careful what you wish for. Decide what you want the car to drive like when you are done, then do the things necessary to get there. The wrong cams can ruin an otherwise great driver.

 

Very well put dr bob.More is not always better.

 

Even after I stroked the 2.6 into a 2.8 and dropped it in a lightweight 68 911 shell 2020 lbs all up getting it moving from a stop on the street was a challenge but the sintered metal three puck clutch did not help much ! But the extra stoke and displacement moved the power band down some with the same Carrera 6 race cams.

 

I don't know how it is with 928 cams, I've been told the factory cams are all fairly mild, but on a 5.0L Ford block you can get a cam that improves on 3000 rpm torque enough to feel and measure, idles decent enough to pass smog, and still has solid gains above 5000 rpm, maybe shifting the hp peak from 5200 to the 5500 to 5800 rpm range, which seems just what I would like in a 928. Typically the key to good results is having a cam ground to your specific engine configuration taking into account every detail of the engine, intake, heads, and exhaust.

Just my opinion, but it seems to me that 928 cams are FAR from a highly optimized racing cam like Jim described. Fat torque from 2500 to 5500 is actually kind of common in a modern cam.

I am just wondering if anybody has experience down this road, since as Glenn says, no engine is handy to test on, and the lead time for having a cam ground after my engine build is started makes a cam change impractical. I would guess one of the hybrid's out there must have had the cam degree messed with, maybe one of the guys will chime in.

Could be the cam is plenty for the flow potential of the Euro S heads, intake, and exhaust, so improvement is pointless.

Could be regrinding the factory cams won't be a practical option due to cost.

Maybe some real answers will show up or I will find them.

 

the problem in your comparison is that you said Ford. This is a Porsche, Yeah I know they arent optimised for out and out HP, but your said Ford. I dont think anything Ford has EVER made was optimised for power, they worry about emissions and noise and all that boring crap.

You sure your not that guy that PorKen said you were with the "ford" nickname????? Sounds fishy

 

427 solid-lifter side oiler
351 Cleveland
351 Windsor
289 Hi-Po
2.3L SVO engine

Ryan, you spend way too much time telling Dangler he doesn't know what he's talking about, and then do it yourself just so you can keep bugging him. Why?

Matt

 

I've got a 91 Mustang, so the 5.0L Ford is just something I am familiar with the options on. Its a 5 liter V8 with 16 valves and 220 ish fly wheel HP in factory trim, seems legitimate to compare to a 83 US 928. The parallel goes further with the Cobra Mustang rated at 280 hp, and with typical ported heads, cam, and intake street motors are about 310 rwhp. Why should I assume the 928 16v has less potential?

Note to Dr Bob, Euro S has more torque than the US motor, but I am not sure if the rpm it peaks at shifts or not.

 

Yeah Matt they made some good engines, relax dude. 99% of their engines produced though werent made for sports cars. So they are made to do different things, like maximise fuel economy, or emissions, or something other then Power. Also I dont know what most the crap you listed is but i suspect its from the muscle car era in the 60's when everyone and their mother had an engine that made 350+ HP.

I knew he was talking about mustangs. There all all kinds of cheap things you can do to fords to get 50hp. Thats not the case with any NA Porsche. You can drop cams in a ford and make another 30hp on what would still be a fairly mild cam i suspect. Again, not the case with Porsche.

Again dont quote me on numbers they arent exact by any means, i never owned a Ford and dont ever plan on it either. But i suspect you now get the point i was trying to make.

 

I'm plenty relaxed, dude. I'm just totally perplexed as to why you actually make every thread he starts worse.

My point was: you're going to extremes and stretching logic just to make his posts about him and not the question. You said you didn't think Ford EVER made an engine for performance. Why?

Why phrase it that way when you really had nothing to add but just wanted to get in a dig (and be wrong doing it)?

Or you could have just said, "I think Ford and Porsche engine are too different to make that comparison." That way, you wouldn't make it a childish, personal attack yet again.

It's okay, every now and then, to let it go. You sem reasonable so I don't see why you have to stalk Danglerb and make something on the Internet so personal. Seems a waste of your energy.

Still relaxed,
Matt