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New 928 Intake plan based on Aston Martin v8 Intake Manifold

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Old 07-11-2017, 04:42 PM
  #31
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Don't forget the valve cover breathers.
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Old 07-11-2017, 04:55 PM
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Originally Posted by hans14914 View Post
Single-plane cross-runner intake manifold will work on an 87+ car with the stock hood with either a front mounted, or bottom mount throttle body. Here is an early proof of concept that shows it all fits using my old flanges. Its also easy to make this into a twin plenum with dual forward facing throttles.

Making a 928 intake is not that hard.... making one that fits everyone is. Good luck with the Aston mods. It will be interesting to see how it comes together.
G]
The reason that the idea is so attractive to me, is that its proven technology on a similar spec'ed engine. we have seen how sensitive the 928 engine is to intake mods.
Next, why build , easy or not, when it is already invented and available. sure, if this works, im sure a LOT of folks would want one. to build it from scratch.. good luck! (see Hackers Econ lesson above) But, for a few of us, it would be amazing. PLus, i dont see a need to introduce any other complexities. keeping it near stock is my motto. stock TB, stock Fuel rails in stock positions . this way, its more of a near bolt on affair, anyone can do.
the key is your manifold adapters.... then rest seems pretty simple. the magic is in the interior of the intake. look at those massive bell mouth inlets.

the size of the intake is exactly the same as the s4 intake. the only issue with the mods, is making the 8 runners from the intake plenum to the adapters.

Originally Posted by dr bob View Post
Most one-off efforts run into stumbles that turn into face-plants. If a factory manifold can be modified without having hard turns in the last few inches to the flanges, and all the other stuff can be made to work, then kudos to you for taking this on.

That said, some pretty savvy fabricators have been working at this for a while, and find that the time needed to get all the things to fit is pretty significant even after the design is done.

The dr bob prediction is that the effort should be spent on a design that can be 3D printed. Mustang and Corvette manifolds are plastic and seem to survive OK. If I wanted to do some modifying, I'd be looking hard at 'murican pieces in plastic as a starting point, so that glue can be used for fit-up rather than welding as your metal AM piece will require. I'm guessing you haven't done any TIG welding on cast aluminum parts before; it's not something you casually learn on at home or pick up from watching yeau-toob shorts. Tell me if my assumptions are wrong.
Bob, i certainly wont do the TIG welding. and i want it to be such an effort in fitting, that the aluminum intake can be used, but not damaged in the process. finding the angles and mounting on flanges like the lower intake manifold adapter is an idea.. that way, the artistry would be in mating the two adapters. seems like a MUCH easier challenge than building something from stratch, even soemthing that is just a bunch of curved tubes, that are in no way, optimized for any engine. my prediction, is that this intake would provide as much of a gain to our engines as it did for the little AM V8 which only has 4.3L and puts out 330 -370rwhp. (as much as the holbert motor with 700cc less displa. and no smog) this is near 75hp -100hp more than the stock S4 motor). the 4.7 liter puts out 100hp more....with no other changes than displacement. compared to our 928 4.7s, even euros? thats 100hp more. cams and valve size are near the same... sure, ECU timing and other things will make up some differences, but the MAIN diff is this amazing intake. the Mustang is doing the same thing with their Boss302 intake.

Originally Posted by V2Rocket View Post
port spacing...IIRC the AM engine is derived from the Jaguar V8, right?
so it's got ~96mm bore spacing vs the 928's 122mm...

you can buy/borrow an AM intake and measure runner length and taper, you say the ports are about the same at the head.

at that point it's making 8 identical bent tubes and fitting them in a box that fits under the 928's ample hood room.
Jim Bailey might have one of those Salisbury plenums for sale...

Greg and Jerry are taking a long time because they want to be very careful and make their work PERFECT, whether for themselves or potential customers. but if you just want a go-fast part for your race car and your own curiosity, "how hard can it be"?
the box has the head room, but the runner spacing worries me. you found the jaguar V8 specs? i wonder if he heads are the same? anyway, how do you think the 122mm vs 96m bore spacing works, when i just measured the total intake feet (tubes) to be only 27mm differnce... this means the spacing has to be less than 7mm per runner. what am i missing? Ill go measure the spacing in a few hours (center of bore to center of bore and compare)

by the way.... are there any modern engines that use the intake bore spacing as our 928??? the hemi? if there was, maybe that manufacturer has a trick intake that is of this new generation design.

below.. AmV8 intake vs the plastic mustang design.
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Old 07-11-2017, 05:17 PM
  #33
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From the perspective of fabrication, you can use Hans' intake stubs and build a very similar AM box by cutting holes in two straight pieces of sheet metal for the runner cutouts, and tack them onto a rounded bottom for the intake. That is a good start while you figure out runner lengths and angles. Tapering is the key to increasing velocity from the bellmouth.

Looking at some LS engine sheet metal intakes, the aftermarket ones cause a noticeable loss of torque for benefits of gaining HP at the top end. For a car like the S4 where the cam profile is suitable for lower end power (which it should for street use), this would be a performance killer. We would never make full use of the intake unless we all run track days.
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Old 07-11-2017, 05:33 PM
  #34
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not sure where you're measuring...
from the front of port #1 to the back of port #4 is ~16" or more on a 928 head. youd need to chop the AM intake between the runners and add material to space it out evenly, or run angled connectors from the AM top to the 928 head.

the closest "mainstream" engines were the chevy and ford big blocks...
IIRC, 928 is 4.8", BBC is 4.84", BBF is 4.9" bore spacing.
928 DOHC ports are centered on the bore so they have the same spacing..

Originally Posted by mark kibort View Post
the size of the intake is exactly the same as the s4 intake. the only issue with the mods, is making the 8 runners from the intake plenum to the adapters.

the box has the head room, but the runner spacing worries me. you found the jaguar V8 specs? i wonder if he heads are the same? anyway, how do you think the 122mm vs 96m bore spacing works, when i just measured the total intake feet (tubes) to be only 27mm differnce... this means the spacing has to be less than 7mm per runner. what am i missing? Ill go measure the spacing in a few hours (center of bore to center of bore and compare)

by the way.... are there any modern engines that use the intake bore spacing as our 928??? the hemi? if there was, maybe that manufacturer has a trick intake that is of this new generation design.
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Old 07-11-2017, 06:51 PM
  #35
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Originally Posted by Mongo View Post
From the perspective of fabrication, you can use Hans' intake stubs and build a very similar AM box by cutting holes in two straight pieces of sheet metal for the runner cutouts, and tack them onto a rounded bottom for the intake. That is a good start while you figure out runner lengths and angles. Tapering is the key to increasing velocity from the bellmouth.

Looking at some LS engine sheet metal intakes, the aftermarket ones cause a noticeable loss of torque for benefits of gaining HP at the top end. For a car like the S4 where the cam profile is suitable for lower end power (which it should for street use), this would be a performance killer. We would never make full use of the intake unless we all run track days.
i dont think me or anyone i know can make a box full of runners that would even remotely compete with the fully factory produced AMintake.

as far as using full HP. these runners in the AM intake are tappered and should provide decent torque, but as you know... to me, that has no value. even on the street. when i want more power, i use the engine where it is designed to make power. if it is 5k to 6k,, thats where i floor it... otherwise, im cruising!

Originally Posted by V2Rocket View Post
not sure where you're measuring...
from the front of port #1 to the back of port #4 is ~16" or more on a 928 head. youd need to chop the AM intake between the runners and add material to space it out evenly, or run angled connectors from the AM top to the 928 head.

the closest "mainstream" engines were the chevy and ford big blocks...
IIRC, 928 is 4.8", BBC is 4.84", BBF is 4.9" bore spacing.
928 DOHC ports are centered on the bore so they have the same spacing..
Ill measure again tonight. bottom line, the difference was 1" spread among the entire 4 runners. I guess, the AM intake was then 15" and the 928 is 16"... (again, ill check tonight) so, that means its not going to be a huge issue to make new runners angled outward slightly to make the runners fit the wider center points of each of the 4 runners.....
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Old 07-11-2017, 07:24 PM
  #36
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One of my concerns is that Aston Martin intake is designed to compliment the cam profiles of that 4.3L it sits on.

With that being said, does the AM V8 utilize variable valve timing?
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Old 07-11-2017, 07:30 PM
  #37
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Originally Posted by mark kibort View Post
i dont think me or anyone i know can make a box full of runners that would even remotely compete with the fully factory produced AMintake.

as far as using full HP. these runners in the AM intake are tappered and should provide decent torque, but as you know... to me, that has no value. even on the street. when i want more power, i use the engine where it is designed to make power. if it is 5k to 6k,, thats where i floor it... otherwise, im cruising!


Ill measure again tonight. bottom line, the difference was 1" spread among the entire 4 runners. I guess, the AM intake was then 15" and the 928 is 16"... (again, ill check tonight) so, that means its not going to be a huge issue to make new runners angled outward slightly to make the runners fit the wider center points of each of the 4 runners.....
Mark...go back to post 15. Center runners will move very little, end runners need to move 1/2" minimum. Might get tight if you keep the runner length the same without kinky bends,
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Old 07-11-2017, 08:54 PM
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Didn't this discussion already happen?

It got pretty stupid.

Although the Salisbury intake idea was pretty cool.

https://rennlist.com/forums/928-foru...rari-chat.html
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Old 07-11-2017, 09:03 PM
  #39
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Originally Posted by Tass 928 View Post
Mark...go back to post 15. Center runners will move very little, end runners need to move 1/2" minimum. Might get tight if you keep the runner length the same without kinky bends,
good point. so the outer runners will have a bit of a bend or angle... shouldnt be insurmountable.

Originally Posted by Mongo View Post
One of my concerns is that Aston Martin intake is designed to compliment the cam profiles of that 4.3L it sits on.

With that being said, does the AM V8 utilize variable valve timing?
yes, the engine does have variable valve timing, but he cams are close to the 85 gt cams in lift and duration. i think, worst case,there might be a lack of mid range torque, but that would be true of the CF intake as well. (already used successfully.. and plenty of power!) i wouldnt worry about it, mainly because of the extra displacement... with 6.4 liters, it has too much torque anyway. a little drop in the mid range wouldnt be a big deal, for gains up top

Originally Posted by Mongo View Post
Don't forget the valve cover breathers.
oh yes! all two of them??
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Old 07-12-2017, 04:14 AM
  #40
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I had a checklist when I did my ITB setup with a chopped 944 manifold. Checklists are good.
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Old 07-12-2017, 04:20 AM
  #41
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I just did some measuring. the AMV8 intake has the runners with a center to center distance of 4" the 928 intake is more like 4.75... over all from #1 to #4 its 12" for the Am intake and 14" for the 928.

the height of the entire intake, is near the same at about 7.5" and so is the width of the intake runners from side to side. the intake itself is very close to the same size as the S4 intake. lapping off the runners near the body and welding on some runners at an angle that would spread the runners out by .5" per runner, will make it work.. lots of ports on the intake for breathers and vacuum..

I should have it soon and will start planning this project out.

Hans, making another run of lower intake manifold adapters??
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Old 07-12-2017, 02:08 PM
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If the difference is 2 inches one and four must be angled enough to move one inch each. 2 and 3 only need 1/2 inch each of offset. Also note that Han's adapters need the pipe to enter straight not an angle....
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Old 07-12-2017, 02:31 PM
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Mark,

How much money do you have put aside for this?
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Old 07-12-2017, 02:50 PM
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Originally Posted by Imo000 View Post
Mark,

How much money do you have put aside for this?

100 meeellion dollars! (Said in best Dr. Evil voice)
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Old 07-12-2017, 02:58 PM
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Originally Posted by Imo000 View Post
Mark,

How much money do you have put aside for this?
not much, as this will not be very expensive. the hard work has been done by AM, the trick is just spreading out the feet or attaching new feet to the intake. i have a machinist, welder and CNC all ready to go. i figure if i can make this work, we will can 5 of them for the list if anyone is interested.

Originally Posted by James Bailey View Post
If the difference is 2 inches one and four must be angled enough to move one inch each. 2 and 3 only need 1/2 inch each of offset. Also note that Han's adapters need the pipe to enter straight not an angle....
It doesnt look like hans angle will be an issue. i have to see when i get the intake on the jig, what the angles actually are (inward). as far as attaching the runners, they will angle into the plennum. maybe I buy the cad drawings for one time use and make the changes or pay Hans to change that portion which would be ideal. pre -angled would solve that problem.

the 1st runner will space forward by 1". the second runner will be positioned forward by .3" . that will put their spacing at the same as the 928 intake , of 4.7". then the 3rd runner will have to move rearward .3" and the 4th runner will have to move rear ward by 1". something like that.

There is plenty of length to work these angles and not be too disruptive to the flow direction. im worried manly about the connections as it has to be relatively smooth however, the sizes are so much larger than the S4, i dont think imperfections in the runner tubes will be as much of a flow problem as the huge bell mouths and plenum size will provide advantages. maybe we cut the runners and cannibalize them, cutting them flush with the plennum and cutting the feet off. to make new runners in the new positions. maybe we make flanges and use rubber adapters to join.
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