FredR

That a different manifold arrangement would benefit the stroker motors was never in doubt to my way of thinking given the output of ITB motors. What might be interesting is how this manifold performs relative to ITB setups - rather well I suspect.

As mentioned earlier it would also be interesting to see what if anything this manifold develops on a stock S4 5 litre motor. I have a feeling it might be worth 30 hp although what it does across the full rpm band might also be of interest.

Either way, a nice achievement from Carl's team and even better as and when contained within the bonnet.

hans14914

Carl,

I remember those well... I think I still have the original trade magazine they were featured in somewhere in my collection. FYI, SLS printing is coming to the desktop this year. There is a Spanish company VIT and Formlabs here in the US - both supposed to have complete setups under $12k this year. Not big enough for a full manifold, but will be a nice size for other parts.

Very interested to see how the rest of the design finishes out. Keep us posted.

andy-gts

why re invent the wheel, didnt simard make some itb and just make arrangement to put them on your stroker......I thought your carbon fiber intake was for itb set up.....

Cheburator

Andy,

Mike's ITBs were a work of art, but I am certain they would have been pretty useless on a stock displacement motor. We tried with BMW throttle bodies on a high compression, Colin's cams, ported + 968 valve heads, 5.4GTS motor and got to about 360Rwhp with runners similar in length to the ones that Mike had. Decided to do it properly, played around with some software - swapped longer runners - Boom! 434Rwhp... I think we still hold the title of the most powerful stock size NA 928 motor...

Carl's manifold looks like it will work well even with a stock motor...

FredR

A,

That is interesting- if I understand what you are saying correctly, enhanced or optimal runner design can add in the region of 60 rwhp. Some time ago I raised a thread to try and understand why the specific power output of the stock motor was seemingly quite low. There was a school of thought that suggested the stock manifold was optimal for the design. Of course maximising peak output does not make a motor optimal but if you have dyno curve for that build it would be interesting [to me at least] to see what it looks like compared to stock power/torque delivery.

Trust such is of interest to this thread.

andy-gts

I think itb are responsible for a bout 50 or 60 hp, that is what devek and simard suggested , I have a taylor drilled crank and always wanted to have an itb on a 5 liter with perfected cams that greg brown could make and see what that baby puts down....that would be cool and since the sharktuner can now tune itb based on manifold pressure it would be so easy !!!!

andy-gts

BUT I thought the purpose of this thread was to optimize his stroker for best HIGHER rpm power numbers.....didnt Carl use that nylon intake he made with itb's I dont remember seeing his numbers for that intake set up !!!!

Carl Fausett

Intake runner length is an important element of the complete intake manifold design. Without going into the Helmholtz effect and other physics, it can simply be said that shorter runners favor top end power and longer runners favor lower-end power.
That is an over-simplification, if you want more info on this topic there are many threads that discuss intake runner lengths on the Renn, as well as many fine books on the subject.

Some other considerations when designing an intake manifold include:

• the use of bell-mouths
• intake runner taper
• whether all runners should be the same length or not
• whether the application is to be boosted or not
• throttle body diameter
• throttle body location
• plenum size
• number and location of plenum planes
• balance tubes
• fuel to be used
• injector placement

andy-gts

I wonder how much Gregs head porting helped the itb set up,,,,probably alot.....

andy-gts

sorry not trying to confuse things Carl,,,,,you search for new stroker intake is for racing or general use......sorry trying to get back on track !!!!

Catorce

Part of what Carl is trying to do is to make a "ready made" intake manifold that fits under the hood and significantly boosts power. A manifold that you can just buy and bolt on, like every other performance manifold for V8 engines. Sure, ITBs might make more power, but the complexity required to select, install, and tune ITBs is formidable. I think Carl can get most of the way to ITB power with a simple bolt on part, the likes of which is still not really available in the 928 world.

Carl Fausett

I never installed ITB's on those GF-nylon intake runners Andy. I was building for a boosted application, and elected to go with a pressurized plenum.
You are correct that we discuss itb's on the product page for those intake runners, and they would work well for that.

If you are interested in the story about that particluar intake manifold, it is a .pdf and is downloadable here https://928motorsports.com/installpd...oldarticle.pdf

I am attaching below a couple pics of it when it was finished. It made between 900 and 960 BHP depending on camshaft timing and phasing.

John Speake

What software was that then ?

NoVector

Just wanted to say that looks bad ***. We now return to our regularly scheduled broadcast...

Strosek Ultra

Carl´s single plenum manifold is showing a power increase from 4700 rpm and up. Below that the stock dual plenum manifold with its tuning flap is stronger. This is what we call the balloon syndrome, if you increase power output at one end, the other end will go down and vice versa. In order to overcome the balloon syndrome car manufacturers have developed advanced solutions like variable cam timing systems and variable length intake manifolds. Then we have the question of what kind of engine is to your liking, a stockish engine with good low end torque and less top end power or a more sporty engine having a huge power increase at the upper end. I prefer the latter which usually makes the car much more fun to drive.
According to my point of view all high performance NA engines should have an individual throttle valve at each intake port. Not only the increased air flow but also the possibility of using hotter camshafts with more overlap and still being able to maintain good driveability at lower rpms is a great advantage.
Alex has installed a set of BMW M5 ITBs on his car with excellent power. With the long air horns removed the engine was a disappointment. The same thing happens if the air horns are removed from a M5 engine. Correct tuned intake tract length is of vital importance.
Åke