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Re: plenum volume



| A plenum full of other questions.
| I've seen a few people who have mentioned removing the EGR tunnel. Even
| though both sides share the common plenum I wasn't sure if there was
enough
| crossover between the two sides to see an improvement by doing so.
| Do you feel there is a lot of sharing between the two sides?

Purpose is to increase volume, and yes.

| I have been considering removing the lip on the swirl plates that cuts in
| toward the fins and maybe reducing the size of the blades by 1/8" or so.
| Have you done any mods to the swirl plates, their angles or size?

Don't touch the swirl plates!!.  Just make sure the deflectors are at
uniform angles.

| I like your idea of unshrouding the ports by cutting back the roofs, but
| what do you mean by opening the outside pockets?

Cut out some metal that ain't needed.  Look closely where water jacket
thermstat area is.

| When you went to the larger butterflies did you have any work done to the
| TBI opening?

Nope.   Just spaced the injector heads up some.

 I was talking to a local shop that does carb and machine work,
| and he seemed to think that enlarging the butterflies without working the
| radius would limit the full flow benefits of the larger butterflies!

Has he build a cross fire that rins 13's with ease???.

| On camshaft selection. I was talking to a gentleman at Lingenfelter
| Engineering a while back and was surprised by two things. One, when I
asked
| his ideas on my X-fire project he didn't immediately tell me to use it for
a
| boat anchor. Second, out of two cams they carry (214 @ .050 duration and
224
| @ .050 duration) he recommended the larger and said not to use the
smaller.
| Since most of the time (after the boat anchor response) the
recommendations
| I get are to go 202 duration or smaller due to the "crappy small ports" I
| was surprised. His feeling was that the longer duration is a
benefit(within
| reason) on the X-fire. His feeling was that due to the long runners and
| small port size they don't flow as much are as quickly and need the
| additional time open to fill the cylinders. Since you seem to be running a
| cam in this range I was wondering if that was your thinking as well?

Yep, 224 @ .050 both sides 470" lift, 110 centers.
Grumpy
|
| Thanks for the feedback.
|
| By the way, I saw the various post on this list and hope you are doing
well,
| and wish you a Happy New Year.
|
| Sincerely,
|
| Kevin R
|
|
|
|
| I have sone extensive porting mods to the cross fire manifold.  Making a
| 1/4" thick spacer for the lid made a large difference (BTW, I'm running a
| 355 CID).  Much better high rpm breathing.
| Also, ground out the ERG tunnel.  Opened up the outside pockets, and cut
| port roofs back 1/8" also.   With enough cam 2" butterflies also help.
|    BTW run it with a 1227747.  I some wotk but with the info from
| programming 101 makes it real sweet.
| Grumpy
|
| Kevin R
|