When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
That intake will be under the hood at the rear, and protrude from the hood at the front. This is acceptable to Catorce, as he wanted no-holds-barred maximum output.
I am following this intake up with another one that will be canted nose-down at the front so that it will fit completely under the hood of a 928.
That intake will be under the hood at the rear, and protrude from the hood at the front. This is acceptable to Catorce, as he wanted no-holds-barred maximum output.
I am following this intake up with another one that will be canted nose-down at the front so that it will fit completely under the hood of a 928.
Well I'm thrilled with the results of our new manifold and this motor in general. I will let Carl tell everyone the good news when he returns from the dyno, but suffice to say this thing crushed it!
We expected to produce more HP at the top end than before (we finished at 602 HP) but we were really pleased that this
id not come at the expense of the bottom end. I lined up the engine dyno's from this motor with the stock manifold and with
the new manifold side-by-side so you can see the HP per rpm easily.
The new manifold started making more HP than stock at 4700 rpm, and never looked back.
We were also very happy that we had 28 inches of vacuum at idle, leading us to believe this manifold could be driven on the street pretty well.
We call our new manifold the "Hi-Rise 654" in honor of the 6.54L stroker motor it was designed for.
Looks nice. On your 6.5L motor, I would expect this manifold to start pulling ahead of the ported stock intake after 4500 rpm. But that guess and $2 will get you a cup of coffee at Starbucks.
Looks like I missed this by about 500rpm. The fabricated hi-rise manifold started pulling ahead of the ported stock manifold at 5000rpm, not 4500rpm as I guessed. The hi-rise pulled away from the stock manifold starting at 4700 rpm.
Is the engine redline 6700rpm? If it's not, and you can spin it higher, you'll make more power by doing so with this inatke. If the 6700rpm redline is firm, then I'm guessing you'd make a little more power with slightly smaller diameter runners on the hi-rise intake
150 hp over the stock manifold with a power curve increasing all the way to max rpm, simply fantastic! Finally, a real performance intake for the 928. The question is, why did it take so long?
It's amazing what a little bit of imaginative thinking, and resultant execution can accomplish - congrats to both of you.
Are you going to post the graphs of all the 6.54 runs together?
On a side-note, judging by the hp still climbing at 6,700 RPM on a 6.54L, the runner cross-sectional area is too big for a 5.0. Just guessing, the runner diameter at the base where it meets the head must be greater than 1.6 inches. No big deal and just an observation/speculation as this was designed for a 6.54.
I'm not sure why it took so long in general to make such a manifold...I can tell you from making the 3.6 cases that sometimes good idea languish for want of money or motivation even though the need exists. In my case, my gut told me the stock manifold was leaving a ton of horsepower on the table, and even the extrude honed one with spacers was not that exciting on a motor like this. Our particular manifold took a long time because the fabricator is known nationwide for manifold building, mainly for NASCAR and he has a long waiting list, even though the results are worth it in the end.
As far as pushing it further, I am not sure there is a need to. I won't push it past 6700 or thereabouts and I am sure it will make a handful more ponies but I think we proved the point, and a 510 rear wheel horsepower 928 that weighs mid 2600s will be just fine.....
Hats off to Carl and all his hard work, these are his calculations.
Hope yea don't mine, I plotted all three intakes to see all the curves overlayed with each other:
Too much free time?
It does help see what's going on.
__________________
George
90 S4 Grand Prix White (Murf #5 - 210 mph top speed)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM) http://928.jorj7.com
11-20-2017, 01:13 PM
