S4 intake modification ideas
02-26-2008, 10:39 PM
#16
Nordschleife Master
Wheee! it's a good night for engine tech threads! I love this forum.
1) It would take some serious coin and time to make a "plastic" performance intake manifold. Injection molds are $$$$$ to get in the door and $$$ to modify each design interation (because it's going to take a few tries). And then the high-temp materials are $$$ by the ounce, usually a pain in the **** to process, and occasionally OEM-protected so unobtainium. Right out.
2) Aluminum: where it's at. If you can cut it, weld it, try it, cut it more, weld it more, and try it again all in your garage/machine shop then that sounds like DIY to me. My buddy is tossing around custom intake ideas for the 500cu Caddy motor going in his altered '40 Chebby street-rod, I bet he tries 3 or 4 designs.
3) ITBs like Hammer and Louie. 'Nuff said.
1) It would take some serious coin and time to make a "plastic" performance intake manifold. Injection molds are $$$$$ to get in the door and $$$ to modify each design interation (because it's going to take a few tries). And then the high-temp materials are $$$ by the ounce, usually a pain in the **** to process, and occasionally OEM-protected so unobtainium. Right out.
2) Aluminum: where it's at. If you can cut it, weld it, try it, cut it more, weld it more, and try it again all in your garage/machine shop then that sounds like DIY to me. My buddy is tossing around custom intake ideas for the 500cu Caddy motor going in his altered '40 Chebby street-rod, I bet he tries 3 or 4 designs.
3) ITBs like Hammer and Louie. 'Nuff said.
I at one time had a bunch of BMW M60 V8 manifolds and those are fairly cheap. Those had oval shaped ports as well but they maybe too small. Those run about $50 used.
I would think that an aftermarket ford or chevy manifold could be good. Although the LS engines have odd shaped intake ports. Or is that the truck heads, i dont know if they share the same design.
02-26-2008, 10:47 PM
#17
I have. And he worked it out. Its almost easier than trying to reinvent some huge aluminum tubed monster and finding out once its tuned for each cylinder there was no difference.
02-26-2008, 10:54 PM
#18
Nordschleife Master
Why not just make a plate for each side which bolts on to the factory manifold with a pipe leading to the front and either join these pipes together in the front and have the MAF and throttle body there, or have 2 throttle bodies and then join to a super MAF? you can then just block off the bottom holes on the manifold and not have to tear everything off to replace the ISV, or knock sensors as they could be left in the same location with a hose for the ISV leading up to the front.
02-27-2008, 01:38 AM
#19
Rennlist Member
Thread Starter
We actually did this. two throttle bodies too, but their werent any gains vs the stock set up. (actally about 5hp gain). the 2 into 1 pipe for the maf using the stock airbox system was a little rough, but it basically proved to me, that most of the problem is the runner size, and the abrupt curves.
I posted the PTG CF intake plennum pics. that 3.2 liter makes about 500hp and the runners are about 3" diameter each. (something much bigger than our intake runners .
mk
I posted the PTG CF intake plennum pics. that 3.2 liter makes about 500hp and the runners are about 3" diameter each. (something much bigger than our intake runners .
mk
Why not just make a plate for each side which bolts on to the factory manifold with a pipe leading to the front and either join these pipes together in the front and have the MAF and throttle body there, or have 2 throttle bodies and then join to a super MAF? you can then just block off the bottom holes on the manifold and not have to tear everything off to replace the ISV, or knock sensors as they could be left in the same location with a hose for the ISV leading up to the front.
02-27-2008, 01:43 AM
#20
Race Director
MK
Gumball is local and has the molds to the intake that Anderson and Fan run on their strokers....give him a call...maybe you can have an aluminum verison made fairly cheap? I'm sure others would buy it too if the price was right!
Gumball is local and has the molds to the intake that Anderson and Fan run on their strokers....give him a call...maybe you can have an aluminum verison made fairly cheap? I'm sure others would buy it too if the price was right!
02-27-2008, 02:05 AM
#21
Administrator - "Tyson"
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Why not just make a plate for each side which bolts on to the factory manifold with a pipe leading to the front and either join these pipes together in the front and have the MAF and throttle body there, or have 2 throttle bodies and then join to a super MAF? you can then just block off the bottom holes on the manifold and not have to tear everything off to replace the ISV, or knock sensors as they could be left in the same location with a hose for the ISV leading up to the front.
Here you go:
02-27-2008, 02:36 AM
#22
Nordschleife Master
Unless you can fab up a somewhat large production run of manifolds fr the 928 for less then $1000 then i say dont bother.
If it starts to go much over $1000 I think you would be mad to not just go for an individual throttle body setup where you then need to simply make plenums for both sides and plum them to an air intake source and filter it. I guess that setup runs what $2500-$3000, so i guess there is still a hole between $1000 and that, but if it got to be much more then that then i would just spring for the ITB setup which is the best of the best short of direct injection or something (which will never happen)
If it starts to go much over $1000 I think you would be mad to not just go for an individual throttle body setup where you then need to simply make plenums for both sides and plum them to an air intake source and filter it. I guess that setup runs what $2500-$3000, so i guess there is still a hole between $1000 and that, but if it got to be much more then that then i would just spring for the ITB setup which is the best of the best short of direct injection or something (which will never happen)
02-27-2008, 04:29 AM
#24
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Thread Starter
thats what we tried, and it didnt do much. I think we all can agree that the supercurved runners in that compact plennum are great for what they were designed to do, but dont maximize HP. something fabed up out of aluminum would be fantastic. im thinking something like what was posted here, but low profile so the hood shuts and attaches to the rear just like the stock set up.
mk
mk
02-27-2008, 08:34 AM
#25
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i would just spring for the ITB setup which is the best of the best short of direct injection
The stock manifold does a nice job on the stock motor. Actually works fairly well on modified car.
02-27-2008, 08:38 AM
#26
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The import tuner guys are able to produce manifolds like this for reasonable prices (even low volume) so hopefully something can materialize for the 928.
The 16V guys are ahead on this one, our runners are damn close in overall length / size compared to the S4's.
Last edited by hacker-pschorr; 02-27-2008 at 09:02 AM.
02-27-2008, 08:56 AM
#27
Three Wheelin'
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Variable-length runners.
BMW has their elegant snail-shell spiral designs on the road now, now THAT would take some heavy-duty R&D.
Mazda had a simple setup of sliding tubes for the 4 ITBs sticking out of the LeMans-winning 787B 4-rotor. I heard a video clip of that evil thing when they fired it up for Sevenstock, people were clamping their hands over their ears in pain when it revved - and it revved INSTANTLY.
That's the route I would explore: ITBs on sliding tubes, probably laying horizontally over the valve covers. The hardest part would be the mobile throttle linkages, but a little creativity may come up with something for that.
Yes, I am crazy.
02-27-2008, 10:33 AM
#28
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02-29-2008, 06:18 AM
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From what I remember, Phil Threshie did a lot of R&D in this area and came up with the carbon fiber intake manifold design which was further tweaked by Mark A. and crew. There was a long, technical article written on Threshie's R&D findings in one of the issues of the now defunct 928 Forums magazines. Probably would be worth a re-read before jumping into modifying the 928 intake plenum by the seat of someone's pants. It's unfortunate that Threshie's company imploded, seemed like a lot of good stuff was going on for awhile.