Gain 100HP with an intake manifold change?? - Cross post from Ferrari Chat
03-10-2016, 12:57 PM
#106
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That manifold is a work of art....no wonder they cross sectioned it to show it off!
The rectangular cross section allows them to make the runners much larger in size and still fit together in the available space. Those things are absolutely huge in size at the entry and then gently taper down to the size of the ports (which are also huge.)
I'm guessing that this car has more than 5 gears to choose from and that they are close ratio gears, so that they can keep the engine in the higher rpm range. I'm also going to guess that they have variable valve timing over the entire rpm range, to help the port velocity and cylinder filling efficiency....otherwise this thing would be really lame on the bottom end and through the midrange.
"Let's trade some low and mid range torque for horsepower on the top end, because we have lots of gears that are really close together to compensate." We can throw in some variable cam timing to make up some of the losses, but we will never get back to what the engine would do with a smaller port and runners.
Not so good for a 928.....
The rectangular cross section allows them to make the runners much larger in size and still fit together in the available space. Those things are absolutely huge in size at the entry and then gently taper down to the size of the ports (which are also huge.)
I'm guessing that this car has more than 5 gears to choose from and that they are close ratio gears, so that they can keep the engine in the higher rpm range. I'm also going to guess that they have variable valve timing over the entire rpm range, to help the port velocity and cylinder filling efficiency....otherwise this thing would be really lame on the bottom end and through the midrange.
"Let's trade some low and mid range torque for horsepower on the top end, because we have lots of gears that are really close together to compensate." We can throw in some variable cam timing to make up some of the losses, but we will never get back to what the engine would do with a smaller port and runners.
Not so good for a 928.....
if you look at the dyno run here, you can see if we used a 928 gear box, the RPM would be from 6600rpm to 4500. the vantage gear box (maseratti)
keeps the RPM from 5500 to 7500rpm. not a huge differecce and you can see the average HP that results. bottom line, its not much of a trade off. the intake will help our cars in a HUGE way. if optimized as you will probably do, im sure it will be even better.
also keep in mind that this is a very narrow bore stroker. the stroke is greater that our GTS's, at 89mm and the bore is only 86mm, more than 10% less than our 4.5 928s. so, that is a HUGE reason why the engine is less torque. 4.3 liter vs our 5 liter. the intake would give exceptional gains on our car
again the gear ratio drop in say 3-4 gear shift is 78% of the RPM with the vantage with 3.91:1 rear end, vs 71% of the RPM for the 928S4 2.2:1. the result is 7500rpm to near 6000rpm, and s4 goes from 6600rpm to 4600rpm
as a note. I have shown two dyno runs.... one with the flappy not working on the original cams, and the new 85 cams before I had the timing set. this shows the S4 intake and resonance advantages to mid range torque.
03-10-2016, 01:09 PM
#107
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Mark, Mark you not only want to suggest how to build it......but ALSO WANT TO SET THE PRICE !! So Han's flanges are about $1,000 some alloy tubing and the Salsbury 4850D plenum for $100 add on a single mustang throttle body just might hit your price point..... some assembly required 
03-10-2016, 01:15 PM
#108
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Mark, Mark you not only want to suggest how to build it......but ALSO WANT TO SET THE PRICE !! So Han's flanges are about $1,000 some alloy tubing and the Salsbury 4850D plenum for $100 add on a single mustang throttle body just might hit your price point..... some assembly required
3-4 K doesn't sound reasonable? yes its a guess on my side, but it also is a price point im acceptable with. call it "market research" Jim! Gezzzz!!
what would you pay? 10k 20k... im sure its going to cost Greg this much to do the first one....right.. but if he can produce a lot of them, maybe the next runs go for a lot less. (plus being able to recoup his devel costs)
Carls really nice intake runners are $2500? so we are talking finishing the job here. (that seems like the most expensive part anyway)
you don't think there is anyway to adapt an existing work of art to our cars?
by the way, where is the salsbury intake .. I cant find a picture anywhere
thx
03-10-2016, 01:20 PM
#109
Captain Obvious
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Mark,
"....will commission..". There is no "will". Either you do or do not, everything else is BS. Put the money behind it.
You and Mongo and the "bouncing off ideas". It's easy to bounce off ideas when you have no idea what you are talking about. Even worse when the ideas comes from some " internet research". Fn' bench racing.
"....will commission..". There is no "will". Either you do or do not, everything else is BS. Put the money behind it.
You and Mongo and the "bouncing off ideas". It's easy to bounce off ideas when you have no idea what you are talking about. Even worse when the ideas comes from some " internet research". Fn' bench racing.
03-10-2016, 01:20 PM
#110
Rennlist Member
That manifold is a work of art....no wonder they cross sectioned it to show it off!
The rectangular cross section allows them to make the runners much larger in size and still fit together in the available space. Those things are absolutely huge in size at the entry and then gently taper down to the size of the ports (which are also huge.) they are close ratio gears, so that they can keep the engine in the higher rpm range. I'm also going to guess that they have variable valve timing over the entire rpm range, to help the port velocity and cylinder filling efficiency....otherwise this thing would be really lame on the bottom end and
I'm guessing that this car has more than 5 gears to choose from and that through the midrange.
"Let's trade some low and mid range torque for horsepower on the top end, because we have lots of gears that are really close together to compensate." We can throw in some variable cam timing to make up some of the losses, but we will never get back to what the engine would do with a smaller port and runners.
Not so good for a 928.....
The rectangular cross section allows them to make the runners much larger in size and still fit together in the available space. Those things are absolutely huge in size at the entry and then gently taper down to the size of the ports (which are also huge.) they are close ratio gears, so that they can keep the engine in the higher rpm range. I'm also going to guess that they have variable valve timing over the entire rpm range, to help the port velocity and cylinder filling efficiency....otherwise this thing would be really lame on the bottom end and
I'm guessing that this car has more than 5 gears to choose from and that through the midrange.
"Let's trade some low and mid range torque for horsepower on the top end, because we have lots of gears that are really close together to compensate." We can throw in some variable cam timing to make up some of the losses, but we will never get back to what the engine would do with a smaller port and runners.
Not so good for a 928.....
the vantage using a wide spaced gear box like the 928 and a giving 71% of the RPM post shift results in:
370hp down to 310hp or an average of 340hp. (with S4 gears) (with Vantage gears that number goes up to 355rwhp)
the S4 is 320 down to 250 with the flappy working or average of 270rwhp
In FACT, the shape of the curves are near identical... might even favor the vantage.
the vantage peak hp of the vantage is 20% greater than the S4... with the S4 gears, its average would be 25% greater than the S4 engine. proves that the intake is even BETTER regardless of the gears!
EDIT: surpringly Greg, the gear spacing for the Vantage is actualy wider until you get to 4th gear.. 4th 5th and 6th are .8 apart. but 1-2-3rd gear are almost the same as the 928... there goes that theory!
Last edited by mark kibort; 03-10-2016 at 02:01 PM.
03-10-2016, 01:31 PM
#111
Rennlist Member
Mark,
"....will commission..". There is no "will". Either you do or do not, everything else is BS. Put the money behind it.
You and Mongo and the "bouncing off ideas". It's easy to bounce off ideas when you have no idea what you are talking about. Even worse when the ideas comes from some " internet research". Fn' bench racing.
"....will commission..". There is no "will". Either you do or do not, everything else is BS. Put the money behind it.
You and Mongo and the "bouncing off ideas". It's easy to bounce off ideas when you have no idea what you are talking about. Even worse when the ideas comes from some " internet research". Fn' bench racing.
Yes, I will put up the cash.. greg and I have to hug it out first. I don't think he wants to build one for me... could be wrong... but I have NO problem with greg. he takes the bantering too seriously here. we see eye to eye on much more than just clutch adjustment and oiling issues!
03-10-2016, 01:40 PM
#112
Official Bay Area Patriot
Fuse 24 Assassin
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Fuse 24 Assassin
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Let's get something clear in this thread. I am in no means an 'expert' on intake manifolds. However, I do have numerous books at home I used to learn about manifold designs when I was doing my ITB project for the 944. You need to have a grasp of the concept and the whole purpose one intake is designed in order to meet the proper respiration requirements of the engine. Yes I am tossing around ideas with Mark, but I do know that THIS WILL NOT BE A CHEAP INTAKE MANIFOLD IF DONE RIGHT. However, price ranges of $2500-$4000 would just be ridiculous for a production manifold that would be better spent on cams, injectors and Sharktuning.... or in my case, that figure is my 4L60E swap I want to do with 3.90 gears.
On a side note, there have been some tuners out there who have designed their own sheet metal intake manifolds that have made more power than the factory manifolds. I'm not saying that a 'sheet' manifold is the solution to gains on this car, but if you don't know what you're doing, you can easily reverse course the opposite way, losing 50HP rather than wanting to gain it. Porsche knew what they were doing when designing the 928. Some have had better luck designing intakes for it, and some just said 'screw it', slap a blower on, and problem solved.
On a side note, there have been some tuners out there who have designed their own sheet metal intake manifolds that have made more power than the factory manifolds. I'm not saying that a 'sheet' manifold is the solution to gains on this car, but if you don't know what you're doing, you can easily reverse course the opposite way, losing 50HP rather than wanting to gain it. Porsche knew what they were doing when designing the 928. Some have had better luck designing intakes for it, and some just said 'screw it', slap a blower on, and problem solved.
03-10-2016, 01:45 PM
#113
Archive Gatekeeper
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Perhaps everyone should return to their garages, play with their 928s, and wait to let Greg and Hans do their thing? Probably a better use of everyone's time...
I'm really excited by what they've got cooking, they're a great team to make it happen.
I'm really excited by what they've got cooking, they're a great team to make it happen.
03-10-2016, 02:00 PM
#114
Rainman
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in the time since this thread started, somebody could have fabricated a rough but functional prototype manifold...
i like the look of the lexus LS400 intake manifold, check it out...
i like the look of the lexus LS400 intake manifold, check it out...
03-10-2016, 02:16 PM
#116
Rennlist Member
I think we are on to something with Carls intake .. it only needs a box.. heck, we might even be able to use the entire lower TB and MAF areas with air box, if we mount that to a plennum that fits carls air box.... think about that one for a second.
you take the stock bottom of the 928 S4 intake. its pretty good. big diameters, decent throttle body and the maf is right there. to mount to the stock air box..... makes this a bolt on affair.... THEN, you take Carls box'es and mate them to it. sure the short runners will not be optimal, but im sure it would be a HUGE improvement.
03-10-2016, 02:18 PM
#117
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The aftermarket parts business is frankly often more about looks than function....much like fishing lures which are made to look good to fishermen not fish !! Part of why I proposed the extruded aluminum plenum based on the readily available Salsbury 4850D.......it may not be flashy or cool looking....
03-10-2016, 02:27 PM
#119
Rennlist Member
I'm guessing that this car has more than 5 gears to choose from and that they are close ratio gears, so that they can keep the engine in the higher rpm range.
"Let's trade some low and mid range torque for horsepower on the top end, because we have lots of gears that are really close together to compensate."
Not so good for a 928.....
PLUS, look at the HP torque crurve. from redline to 70% of redline (post shift in a 928) the VAntage has 81% of its HP. the porsche 928 for the same % drop in RPM, has 78%. its better than the much larger 928 engine.
sure, much of the lower end gains could be due to variable valve timing. but dont forget we are talking a stroker (89mm) engine with 86mm pistons.
any intake would be a blessing for the 928, even one made from sheet metal. you cant get any worse that we have with the S4 intake. However, there are things that are good about it. i do like the MAF, and Throttle body with the lower "U" area feeding the plennum with two large openings. Im thinking we need to bolt something to that..... Carl? can you fab something up to your runners and plennum design??
03-10-2016, 02:28 PM
#120
Rennlist Member
The aftermarket parts business is frankly often more about looks than function....much like fishing lures which are made to look good to fishermen not fish !! Part of why I proposed the extruded aluminum plenum based on the readily available Salsbury 4850D.......it may not be flashy or cool looking....