CobraSteve

New member here, so please be patient with me. Recently acquired a Lola replica with a 1988 13B turbo 2 engine. I have stripped all of the fuel injection, turbo, exhaust manifold, and intake manifold from the engine as I am trying to simplify it. I prefer reliability and simplicity over performance. Please suggest the proper intake manifold for a wrap over intake and Weber side draft carburetor set up as my hood clearance is minimal. Please remember my engine is a four port design and I have not seen a wrap over intake for this four port engine which was initially turbocharged.

lduley

iTrader: (1)

You can use a 4 port lower manifold on a n/a engine far as i know, you just may have to modify it for the upper. You may be able to make a 12a 4port work also, but that will require some modification to mesh with the 13b.

I don't know Frankenstein engines that well so what i said may not be useful at all. One way would be too look at the the different manifolds and how they mate up to the keg. I think racing beat offered a 4 port carb setup, but its been awhile since i looked at their site to know for sure

Siraniko

iTrader: (13)

If you can have someone make a 12-a to 13-b tii adapter plate, you can use a 12-a one piece sidedraft manifold.

peejay

What you will need to do is port match an OEM '86-88 6-port lower manifold to suit the Turbo II block, then use an 18101 upper manifold. The center port will line up with the block, unlike a GSL-SE lower. You will also have to add an extension to block off the air injection port.

It will take a lot of epoxy and will look like this:



As far as I have seen, the only carbureted manifolds for the TII block are for Holleys and downdraft Webers, so this is your best bet albeit labor intensive. I have maybe 8 hours in this lower. Putting the N/A injection manifold on my T2 block (nonturbo) was a huge benefit, and made me wonder why Mazda bothered with 6-port engines at all.

CobraSteve

Thank you to all of you who have responded. I was hoping there was a standard, off-the-shelf, intake manifold already being cast from aluminum, but if I have to modify or fabricate an adapter plate, so be it. Are all of you 100% certain there is not already a standard manifold available on the market?

Siraniko

iTrader: (13)

The onlh aftermarket available is holley or downdraft IDA. The aluminum plate is available at mazdatrix but without port and bolt holes. Robert at rotary shack has adapter plates but none for tii. im still trying to convince him to make one for tii.

Im gonna be heading to a local shop next monday if they can make one for me as i also need a an adapter plate for old school 13-b to tii. I will pm you.

Siraniko

iTrader: (13)

Come to think of it, you can use the tii LIM and rb dellorto UIM. You just need to oval or slot the outer bolt holes.

peejay

The T2 lower has its flange much higher and the carb will sit very high.

Personally, I wonder if the downdraft setups wouldn't fit. They clear the same area that the Turbo II engine does, after all.

CobraSteve

I may ultimately go with the downdraft set up and have to cut a hole in the hood. I resist doing this as the car's construction is similar to that of an aircraft or a boat. It is a combination of fiberglass, high-density foam, cherry wood, and epoxy.

CobraSteve

Additionally, Racing Beatpart number 16494 for the Weber 48 IDA downdraft carburetor has provisions for only six holes, whereas my engine is set up for seven holes. The seventh hole is located in the center near the top of the bolt pattern and Racing Beat part number 16494 has a provision for a bolt hole to be drilled, but is cast solid. Local friends of told me I do not need that seventh bolthole, but common sense tells me Maza engineers added the additional bold for extra insurance to ensure a tight seal between the manifold and the engine.

Further, I am told the Weber 48 IDA has an approximate height of 7.25 inches including the air horns. I am curious how much higher the carburetor mating surface on part number 16494 is when compared to the top of the engine. It appears to only be 2 inches from the photograph, but every inch counts, and I must also remember to have a minimum of 2 inches clearance above the carburetor air horns.

Siraniko

iTrader: (13)

I will measure the total height of my IDA from engine but if your concern is the air horn, that can be modified where it can go horizontal

CobraSteve

Does somebody manufacture an air horn with a 90° bend in it? Granted, the radius of the bend would probably come up to the height of the existing air horn, but then I would not have to worry about the additional 2 inches of clearance required for proper airflow.

peejay

I don't think anyone uses that seventh hole but Mazda. They went for decades without it and the nonturbo engines never used it either.

They may have put it in there because of turbo pressure forcing the intake away, compounded by the much narrower (and thus more flexible) shape of the turbo intake manifolds.

I think I "fixed" mine by putting a small freeze plug in the hole to seal a potential vacuum leak.

CobraSteve

To seal the hole, can I also use a Loctite sealant and an Allen head bolts which would be recessed way from the machined surface?

peejay

I didn't seal the hole in the block, I sealed the hole in the T2 lower. Ran it with only six bolts, never an issue.

Siraniko

iTrader: (13)

Search the net for jay-cee enterprises in santa ana ca. Call them and ask for Jack. He should be able to give you advise

CobraSteve

Thank you to everyone who is trying to help. JayCee appears to specialize in VW items, but I will give Jack a call to see if he can help. So far, I have not gotten a clearer picture of which direction I want to go. It appears as though the wrap-over idea I had utilizing a sidedraft Weber will not work without utilizing a custom adapter plate, and the vertical downdraft setup may be my only option. I'm an "old school" sort who does not want fuel injection, anything computer-related whatsoever, etc...just trying to keep it simple as possible.

Tom93R1

iTrader: (2)

Atkins told me at sevenstock that this would work with the turboII intake ports.
84-92 13B N/A Rx7 Wrap Over Manifold...

I'm not sure how neatly it will line up, it will still need work to match the secondaries correctly as on this manifold they lean in to match the 6-ports.

I really wish somebody made a good manifold specifically for the turboII as that's what I am running in my REPU. Currently I am set up similar to what peejay did but mine doesn't look nearly so nice.