4K Intake Manifold Modification

[NinjaMekanik]

Hello Guys,

 

Question on the 4k intake manifold. I'm fitting a weber 32/36 and have an adaptor plate. As i don't know as much about carby stuff i thought id put the question up here.

 

My adaptor plate is an oval shape however the ports (i guess you can call them that) on the manifold where the original carby bolts up is two circles, one smaller than the other. My question is, if i remove the centre of this to make it the same shape as the adaptor plate will this help or hinder air fuel flow? Photos show what i mean.

 

The part shaded in red is what i would be removing.

Before

After

Edited November 8, 2012 by NinjaMekanik

[Twinky]

You probably should take it out, if you have access to a die grinder. I wouldn't just hack it out.

If you do have a die grinder then try to keep the same port angles all the way along the adaptor

plate and through the manifold plate. By keeping the manifold with the twin ports you would have

some turbulence at that point because of the air leaving two ports from the carby, then to an section of free space

and then have to travel through the two ports again.

 

I don't think the difference would be that noticeable in a stock situation but if you have a mild cam and exhaust then yes there

would be a noticeable difference especially in the top end. Not that you would see a power increase or at least a small one but

it would be allot smoother in response.

[NinjaMekanik]

Yeah have extractors ready to go in at the same time and will be doing a cam regrind when i put the 5 speed in.

Yeah i was thinking the sale thing about the turbulence but ive heard that in some situations it helps? i don't know how true that is....

May need to get a die grinder as i was planning on using an angle grinder and do it as neat as possible but i spose you can only get so neat with an angle grinder..

[19914afc]

You'll need to remove the manifold obviously so I would put the extractors on at the same time.

[Twinky]

You could possibly use an angle grinder and then sit there for a couple of hours using a flat and half round file to neaten it all up.

But I don't think you'd get a disc small enough on an angle grinder to cut the section out and not gouge anything else out.

Or you could get a small coarse round file and file out that middle section instead of using the grinder, then go on and the the flat and half round.

Might take you two days but if you have good hand skills it should't be too difficult.

[NinjaMekanik]

yeah thats the plan. have extractors now, might have to do a sneaky drive to the exhaust shop with nothing past the collector on the extractors :ninja:

Cam regrind will be done at the same time as the box later coz ill take the engine/trans out.. from what ive heard doing the cam with engine still in is a prlck

Edited November 8, 2012 by NinjaMekanik

[NinjaMekanik]

You could possibly use an angle grinder and then sit there for a couple of hours using a flat and half round file to neaten it all up.

But I don't think you'd get a disc small enough on an angle grinder to cut the section out and not gouge anything else out.

Or you could get a small coarse round file and file out that middle section instead of using the grinder, then go on and the the flat and half round.

Might take you two days but if you have good hand skills it should't be too difficult.

 

hmmmm not the most patient of men tho. lol

[snot35]

Previous owner of my car which came with the same setup removed those bits with an angle grinder. Crap job done, the disc is too big and whoever did it over shot leaving a gap to the outside which they then fixed with silicon.

 

Get yourself a die grinding bit if you can. Even if you put it in a power drill you should be able to do a pretty neat job. See if you an get a bit designed for ally as it won't clog as much. I wouldn't be too worried about the whole turbulence thing, I doubt it helps and even if it had been designed in there it would have been for the carb that you've just ditched. Clear it out, get it tuned when all the mods are done and you should be a happy camper.

[altezzaclub]

Drill two lines of 3mm holes into it, about 2mm apart. Then run a 4mm drill down the same holes to chop the walls out and tap it with a hammer on a knife or sharp screwdriver. Then file the ragged edges flat or use a drill with an alloy cutter in it. Same rotary burr tool you use for porting alloy heads, you could do the whole job with one.

 

I do it all the time to make big holes in panels.

Edited November 8, 2012 by altezzaclub

[NinjaMekanik]

sweet. cheers guys sounds good.

 

Same rotary burr tool you use for porting alloy heads, you could do the whole job with one.

I do it all the time to make big holes in panels.

If i buy one i might use it to port my head then as well. How easy is that to mess up Altezza?

[altezzaclub]

Using the cutter is easy, but knowing how much to take off is the difficult part...

 

I just matched the inlet ports to the Lynx manfold I was going to use, without opening them up any further down the throat.

 

http://www.rollaclub...the-girls-ke70/

 

Get a conically curved cutter, that is the most useful.

Edited November 8, 2012 by altezzaclub

[NinjaMekanik]

ok sweet. thaks man :thumbsup:

[B.L.Z.BUB]

my mate has a manifold with this done and an adapter welded on that may just need a bit of tidying up. If you get stuck or mess it up let me know.

[GJM85]

Had mine machined out. Wasn't expensive.

[Evan G]

those alloy bits for the die grinders are good for removing material BUT DO NOT try porting with it! use the double cut bits. leaves a better finish and less chance of error