John Speake

Link didn't work for me.....

andy-gts

I heard taking the devek level 2 headers off and putting gregs new headers on gave 12 more hp

928er

That is no surprise on the headers. The devek header collectors were 1960's technology. Collectors are the most important part of header design.

andy-gts

just got word the oil problem is a thing of the past and the dyno for the engine was over 600 hp during tuning on the dts dyno.

John Speake

Some people are just plain greedy :-)

blown 87

Just Wow.

andy-gts

I think he was just comparing as the level 2 header design is a known baseline.

Just another question.....remember the POWER BROKER , he made some snakelike headers but I havent been able to find them for a while

928mac

OVER 600!! holy, I hope some money was saved for trans suspension and tires.

Hmmm what do you do to get traction, as ladder bars and a pinion snubber wont work.

hacker-pschorr

Now we're talking!!! Very nice.

A long time ago there were two very similar 928's on the same dyno both doing some tuning with similar (pre-shark tuner) software.

The car with the DEVEK Level 2 headers made more overall and peak power than the car with the "snake" headers.

I would stick with Greg's if I were you.

John Speake

That was Tom Cloutier who made those systems, some years ago...

AO

Awesome! Nice Mp3 too. Thanks Rob.

Can't wait for the final story.

GregBBRD

Here's the highlights.

Oil system is much better. We had some "visual modifications" done, so that we could watch what was going on. At 7,000 continuous rpm's there is still a bit of "splash" coming out of the valve cover breathers. this is a "local" problem that requires a bit more thought.

Crankcase pressure and valve cover pressures were always the same...which means that the crankcase now keeps "communicates" with the heads.

Anyone that didn't think that there was much oil being "stuffed" into the heads (looking back in this thread Kibort and Louie were doubters) has another think coming...it's incredible.

The dyno tuning session was long. Remember that we are running this engine on weasel **** (91 octane street fuel), which means tuning needs to be approached slowly and carefully. You have to start rich, without much timing, and "work" your way towards the prize.

Here's the highlights (no hero runs...this is exactly how the engine will be tuned), with the Devek Stage 2 headers that Andy owns:

Peak torque: 501 ft lbs. It was above 500 from 5,600 to 5,900.
Peak horsepower: 604 at 6,700, with horsepower over 600 from 6,600 to 7,000
The engine makes over 400 ft lbs from 2,000 to 7,000.
It makes over 450 ft. lbs. from 3,800 to 7,000.

My headers made 512 ft lbs. It was above 500 ft lbs all the way from 5,300 to 6,200! An incredible 1,000 rpm spread.
My headers made 609 at 6700. Over 600 from 6,300 to 7,000. Stupid power.

Once can "bench race" engines forever. Here's the reality: The heads moved enough air through them, with the intake attached, to make 575 hp. NO matter what cam, no matter what compression, no matter what fuel, no matter how big the engine is...the limit of a naturally aspirated engine is the airflow through the heads. What does this mean? this means that this engine has over 100% volumetric efficiency all the way from 5,900 to 7,000 rpms.

I know that the entire huge group of "internet" engine engineers think that all engines have volumetric efficiency way above 100%....but the reality is that very, very few engines ever get above 90%...and even less get anywhere near 100%.

For the 928 engine to make 700 or 750 horsepower, the head airflow would need to increase by more than 50%! That is not possible, with this casting and valve sizes.

Shark_Week

very nice work Greg

blown 87

Well Done Greg.

Randy V

So does that mean that Andrew got pwned?