924Board.org

[MikeDanger]

anyone make one? If not i have been thinking about how to make my own, of have some made. I have to take my head off due to bent valves.
I found that my stock manifold hade a huge crack in it. so its not going back in... But its such a pain to remove the stock turbo/manifold...
so I want some thing better and easier to work with.

does anyone have any ideas as far as making headers??
Im going to toss the CIS... and make it EFI(one way or another) and ill be using a more normal turbo, like a garret or mitubishi.

this is the main thing i need to do before i put the thing back together.

if i can build a good header thats not to expensive ill be making one for my other 931 and if anyone else is interested....


I have thought about cutting up some bursch headers, but i dont know if that would work since it would have to go forward instead of back and also the cross member would be in the way.

I have been staring at my engine/bay(with head off) for hours trying to figure something out...

Maybe some of you could give it some thought....
Thanks
Mike

[Peter_in_AU]

if you go EFI then you have a clean sheet.

I figure you have two design options, turbo up front as per standard 931 or turbo on the intake side as per 951.

951-style would give you more freedom for turbo choice and would be a lot easier to work on in the future and might be cheaper to build the headers as the design would be more conventional with gentler bends. Down-side would be all that heat under the sump and on the intake side.

Might be an idea to take the 931 manifold to a performance exhaust shop and get an estimate to build something similar from steam pipe.
_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

[MikeDanger]

well at first i was going to move the turbo to the other side but make the pipe still come forward and around the front of the motor. But then theres the AC pump, i kinda wanted to keep the AC. now if i was going ot make a new intake (which would be nice but im not putting that much effort into this) it would be easier.
but i will be removing the pop up lights.

I think the stock manifold tottaly sucks, so i want to make headers. coppying the stock manifold wouldnt be that hard, but if im going to bother with it might as well do somehting better.

Problem is room is tight. I ahve to figure out whether the turbo will be on the top side or the bottom.
though i did see that 951 in exellence that had the turbo where the windsheild washer tank is.

I sorta wish i could just take some regular headers and bolt the turbo to the end of it, but then the turbo would be back behind the motor.

see if you can come up with some good ideas

[-nick]

hey Mike,
check out the maximum boost book (i can't say enough about it). there is some excellent info in there on making your own manifold. peak performance considerations involve finding a way to integrate the wastegate a little better into the manifold among other things such as turbo placement that you're talking about. the current setup has the turbo and wastegate on opposite ends, which is far from ideal.

garrett and other turbos offer lots of benefits over the antiquated and expensive kkk units. you're definately headed in the right direction. setting up an efi is, however, a pretty expensive proposition.

i hope this helps and i wish you luck. i think the stock manifold is not the best design either.

-nick

[MikeDanger]

Actually i have/had Maximum boost its a great beginner book, but felt it wasnt indepth enough. I have found a better book which actually has the Map of a our turbos. problem with trying to make the perfect header is complexity and space. Id like to get a 2 into 1+2 into 1-into 1 though a 4 into 1 would be OK, still way better than and stock one. id like to keep turbo relatively in the same area. I make be using a turbo with a built in WG, so that would save room and complexity.

just still need to figure out exactly how to plumb this.

The EFI wont be so hard im going to take it off a car with a similar motor, like a turbo eclipse most likey.

[1982Porsche924]

Sucks about the whole 3 bolt pattern on the stock turbo manifold, I was just hanging out at the machine shop today, and they said they can make the stock manifold a 4 bolt pattern for around 100 bucks. I've been looking into the 931s lately, and it seems to be a good option for anyone that wants to upgrade turbos. AznDrgn and I have been discussing some ideas, and one that might work would be taking the stock manifold, chopping off the last 3/4 inch, and fabricating a plate that would bolt up to a new turbo. Purchase a 951 gasket, line it up with a 3/4 inch steel plate, drill the holes, then cut out a big hole for the exhaust, weld the sucker to the manifold, and it might work.
_________________
1979 Porsche 924 "S"
Engine: Euro pistons, Light Flywheel, Weber TB, Bursch Header, Cam Wheel
Suspension: Front coil-overs, adj sways, Solid bush. Thicker tors. bars, 5-bolt, BBS rims
Body: Fiberglass widebody kit, 931 Nose

[MikeDanger]

Dude, dont even bother messing with the stock manifold. The factory turbo is actually fairly decent for the 931, if you were going to upgrade it just for the sake of upgrading the turbo it better be a turbo thats worth it.

Im just going to be taking a turbo i find on ebay. hopefully i can find something like a t4 for 200 bucks or so.

plus the stock one being bolted to the block and next to impossible to get to, im sure the stock manifold also make it run hotter than a header would.
the stock manifold seems like it was the easiest was to add a turbo with out much redesign effort.

[Wolf1]

You mention using the EFI from an eclipse, this may prove to be quite challenging. Unless you plan on running an aftermarket stand alone EFI control, the 931 does not support the required inputs to run the DSM computer. I believe a simpler system to integrate into the 931 would be from an 84 T-bird turbo coupe. It uses an airflow meter, a baro sensor, an oxygen sensor, and a hall-effect ignition stator. You could even use the T-bird turbo if desired, 10psi integral wastegate. With a boost controller you could go as high as desired. Oh and the engine and ECM wiring is totally seperate from the main vehicle harness, which makes it very easy to swap into another vehicle. Just a thought, thats probably the system I will use on mine.
_________________
88 951 stone gray
80 931 Red and surgically enhanced
72 914 (old toy) $old
2 1/2 924's for spares..

[epsylon]

there is a shop here in town, axis engineering, that specializes in making custom turbo setups for non-turbo cars. i have seen some wicked cool cars come out of there. i am going to be taking my 931 over there, once i get some of the bugs worked out of it first, and see what they would recommend and what they charge for work.
_________________
'82 931
'78 928
Howell Henderson
South Padre Island

[mrobbo612]

I made up a custom manifold to take mitsubishi tdo4 turbo after my turbo required new exhaust housing and turbine blades. The reason I chose a tdo4 turbo as used on WRX was that there are numerous performance options available for future upgrades . The tdo4 will spool up 6psi boost from as low as 2100 rpm and is capable of running 18 psi boost to 6000 rpm there after boost falls away to 15 psi at 6500 rpm. To fabricate the manifold is a very precise and time consuming option as i retained the locating rings so all ports in the manifold must line up exactly. I did away with the external waste gate and used the waste gate fitted to the tdo4 exhaust housing. Both compressor and turbine housings had to be spun on central core and water lines plumbed in to the cooling system.The turbo is still located in its original location and a modified actuator bolts to the water pump to control the waste gate operation. My car runs sequential electronic fuel injection and digitial ignition controlled by a motec ecu performance since the efi and turbo upgrade has improved substantially even at factory boost levels and at light throttle loads.If you are not able to do the work yourself be prepared for the expense as there is around 3 days work in fabricating the manifold,modifying exhaust and wastegate system,modifying oil and water lines to turbo,modifying oil return line to sump and oil cooler lines, and fabricating hoses and pipes from air cleaner and to intake.There is around 5 days work in converting the car to efi plus road and dyno time to tune it .If your still interested contact me and i can give you a list of components and operations required and some pictures of the finished product

[epsylon]

wow, sounds like are great car. i would be interested in seeing some pictures of the setup.
_________________
'82 931
'78 928
Howell Henderson
South Padre Island