Random header thoughts

[Jim Green]

--- Michael Gough <mdg3369 at mac.com> wrote:
> The tube designs are MUCH nicer than the log
> designs. Logs are great if
> you're making a manifold for a naturally aspirated
> car. It's easy, and the
> gains from going from N/A to turbo are so huge that
> nobody cares if the log
> design isn't the best. However, on a car that
> already has a turbo, and a
> somewhat decent (well it's better than some)
> manifold, going to a log
> shouldn't be an option. In "Turbochargers" by Hugh
> MacInnes (great book
> BTW), he mentions that on a highly tuned BMW turbo
> motor, switching from a
> log to tubular manifold increased power output by
> over 100hp. So please go
> the tubular route.

OK

> Another idea. I've been looking over the stock EM
> pretty well (comparing it
> with the AAN manifold too) and I'm noticing 2 major
> issues with the stock MC
> manifold. The first is that the wastegate doesn't
> vent gas from all
> cylinders, only the back 2 or 3. The second thing,
> is the collector. The
> collector vents cylinder 1 by itself out of one of
> the large outlets. The
> cylinders 2 and 5 come out of the smallest, top
> outlet, and cylinders 3 and
> 4 come out of the other large outlet. I always
> thought the small outlet was
> the single one, but upon closer examination, this is
> not the case.
> And I have no idea where I'm going with this
> now...Just don't do a log
> design :)

OK

> I haven't started on my collector yet, but
> it's going to be very
> similar to a 4-1 collector. Since I'm (probably)
> using a KKK turbo, I am
> going to start with a piece of 2" pipe, tube,
> whatever, and then cut the
> sides out of 5 pieces of tube, and in the end, I
> hope to end up with
> something that looks a bit like a 4-1 collector, but
> with the tube for
> cylinder #3 in the middle of the other 4 tubes. I
> don't know how well space
> will permit this, but I'll try!. Also I've decided
> to go with schedule 10 1"
> pipe with an ID of 1.1" The idea size would be 1.3"
> but the only thing with
> this ID is 1.5" tubing with a .095 wall (still can't
> find any of this) The
> reason I'm going with the 1.1" schedule 10 pipe
> instead of 1.25" schedule 10
> pipe with an ID of 1.4", is that the smaller tube
> should help keep up
> velocity at low RPM, and I figure that it'll be a
> large improvement over the
> stock manifold (with the restrictive collector) that
> it should give good
> results. I haven't completely made my mind up on
> this, but I'm probably
> going to go with schedule 10 1" pipe.
> Another idea for someone with too much time on their
> hands and no money, You
> could try cutting off the collector on the stock
> manifold and making a new
> one...There's nothing inherently wrong with the
> runners, they're fairly big,
> the major problem I see is the collector. So get out
> the metal cutting band
> saw and make a new collector!

OK Already!  Seriously though, I just went out and
took another look, your right, that thing has to go.
I may just take mine off one weekend, and grind out
all of that crap that splits in into three sections,
and do a little porting.  You can't tell me they are
there to direct the flow based on the rest of the
manifold.  Both my junk manifolds are cracked on those
ribs anyways, so they can't be supporting anything.
My dremel tool is going to hate me for this
one........might be time to invest in a real grinder.
I thought about doing all this the last time I had the
motor out, but I was sure I'd have a header soon so I
didn't worry about it.  Now I just don't feel like
spending the time and money on it especially since I
just recieved my BIRA brackets in the mail:)  These
are a much needed upgrade since the car is seriuosly
fast, and I almost melted my stock brakes doing 0-60
runs tuning the ignition.  Then I can get this damn
thing on the track

=====
Jim Green
'89 90tq 034EFI, Haltech IG5
http://www.geocities.com/jeg1976/car_home.html

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