Carburated IR Intake Manifold

[frnkeore]

I've written about this in my Member Project but, I though many others might be interested in doing this.

I bought the TR off Brent's JJ and while doing machine work on it, I found that the bolt pattern, for the top plenum, was the same as a 4500 Dominator carb and looked like one would fit the lower manifold ports. I found a 8896, 1050 cfm carb, at a swap meet, about 3 mo ago and confirmed that they will fit w/o any throttle interference to the manifold but, I thought it might flow better if a spacer was used, to straighten the transition, to the TP runners. So, I made two 3/4" spacers, with 2.03 bores.

Another problem that reared it's head, was the intern, progressive linkage. They make a 1/1 & 2 styles progressive, my 8896 has what they call a "soft stag", the other is "Staged". The Staged is for 4v application and the Soft staged was developed for 8v applications ans starts opening the secondarys, at 15° as opposed to about 37° of the staged linkage. Now the easy thing to do, is to replace the throttle linkage to the 1/1 but, those little things, believe it or not, are up to $75 each......

I decided to try a a slot in the spacer, about .20/.30 deep & angled to connect both sides, for that first 15° of opening. 1/1 linkage, uses .028 squirters and progressives linkage, use .035's so, I'll replace the secondarys with .028 and leave the .035's in the primarys and see how it works.

It seems more than a coincident that the Weiand TR has the 4500 bolt pattern for the 4150 plenum, did they ever sell a upper manifold for the 4500 carb?

Here are some pictures.

[blykins]

I've done this before, but it was on an 8.200" deck Weiand tunnel ram.  The dimensions are a little different, but I was able to cut the lower base down a little bit and then Tig weld two shear plates on top.  Sold it to a member here, should be pictures floating around somewhere.

I think it's just coincidental. 

The only 351C tunnel ram style intake that accepted Dominators was the Edelbrock UR-19 I believe.

[Gaugster]

It's very cool to read about innovative combos like these. I hope it works as expected. I'll have to read up in the project forum.

[428kidd]

Very cool Frank!

[jayb]

Dominator carbs will fit on the Weiand 351C tunnel ram plenum, and also on any intake manifold that has the two bolt patterns for mounting a 4150 carb in either direction.  It turns out that if you just install the Dominator carb at a slight angle, so that it uses two of the holes from each bolt pattern, the holes line right up.  I did this on all the intakes that I designed for my cylinder heads, so I could run Dominators on any of them.  The picture below shows my 8V intake with dual 4150 bolt patterns.  So, with these hole locations a 4150 carb will fit on straight, or at 90 degrees, and a Dominator carb will fit straight on, just canted a few degrees one way or the other, and also crosswise, just canted a bit one way or the other from 90 degrees. 

I believe that the Dominator pattern on the base of the 351C tunnel ram is there because some people wanted to use the base of the tunnel ram as an individual runner intake, with one barrel of each carb dedicated to a cylinder.  But IR intakes require a really, really big throttle butterfly, so I'm not sure if it ever worked very well.

[My427stang]

Frank, are you eliminating the plenum and having all 8 barrels open in sync?   Technically that's the only way to make it at true IR, however, as Jay pointed out, it takes more airflow per runner than if you have the plenum contributing.

My last IR build, although healthy at RPM, did pay a bit of a fine with torque in the 3000 rpm range.  With that I am more of a plenum fan, however, with the car you are building, you may want to kill a little on the bottom for drivability

[blykins]

There were actually "IR" Dominators made for this setup.  They were 6214's. 

[frnkeore]

This intake adapter and Weiand TR, opened a big door for me. I originally wanted it because I had suggested it to Brent for his JJ project and it made a big difference. I also have Jay's intake book and I was impressed how well the 48 IDA's did on the 427 engine, giving the highest average hp. My engine is 15 ci smaller than that engine and the 2" throttles are 6% larger than the Webers but, where it may fall down, is I'm going to be cammed for about 800 rpm higher. Hard to tell where it will fall.

A little basic math says that I need 8.5% more air than the 427 but, I'm increasing the throttle area by only 6.5%. If this all works out, I can go to the 2 1/8, 1250 cfm and gain 12.5% (19% in cfm flow) over the 48 IDA Webers. That would only need slight porting to match the intake opening. I could also go to the 2 1/4 throttle but, that would take a lot of work on the spacer and manifold, not to mention the $3200 for the carbs. The other option is to use a open spacer and create a plenum under each carb.

When I get it on the dyno, I'll do a AB test with the original plenum and twin 660's and see how that compares. If given enough time, I could throw in open spacers, too.

[frnkeore]

There were actually "IR" Dominators made for this setup.  They were 6214's.

Yes, they also made the 1/1, 1150 cfm, 6464 but, I got this first 8896 for $200 and the matching one for $300.

I would have rather had the 6464 but, the price was right.

[My427stang]

I'd love to see the A/B test.  I did two engines, one single 4 and one 8 stack with 2.25 inch bores and MUCH shorter runners, but other than intakes and carbs were the same.  The IR engine was down 30 ft lb peak but up 8 HP peak and carried 200 rpm farther.  The beauty of the TR is that you get some runner length though which i think is critical. Not a real A/B test but only the intake was different between the two.

Just to clarify, I had to reread it a few times.  Correct me if I am wrong, you are eliminating the plenum to make it IR, but cutting balance slots in the spacers to allow transition with carbs that are not 1:1? If correct, will likely work on the dyno at WOT for peak testing once all 4 are open, but will be fussy in use.  I suppose it would tell you if it warrants buying more expensive carbs or kits to covert.

What is the overlap with the cam you chose?  Overlap is funny with the IRs, they want it for power, but don't like it until up top.

[frnkeore]

Just to clarify, I had to reread it a few times.  Correct me if I am wrong, you are eliminating the plenum to make it IR, but cutting balance slots in the spacers to allow transition with carbs that are not 1:1? If correct, will likely work on the dyno at WOT for peak testing once all 4 are open, but will be fussy in use.  I suppose it would tell you if it warrants buying more expensive carbs or kits to covert.

What is the overlap with the cam you chose?  Overlap is funny with the IRs, they want it for power, but don't like it until up top.

Ross, yes.

The primarys open 15° before the secondarys start. That only amounts to about 3/16, vertical movement (I have to actually measure it) and then decide how much to cut the opening. The angle of that cut, will be appox what the throttle angle will be. I'll be happy with it, for now, as long as it doesn't spit back. I can always apoxy it up and get the $75 links, if not.

The overlap is 82°, 294/302 duration.

[My427stang]

Just to clarify, I had to reread it a few times.  Correct me if I am wrong, you are eliminating the plenum to make it IR, but cutting balance slots in the spacers to allow transition with carbs that are not 1:1? If correct, will likely work on the dyno at WOT for peak testing once all 4 are open, but will be fussy in use.  I suppose it would tell you if it warrants buying more expensive carbs or kits to covert.

What is the overlap with the cam you chose?  Overlap is funny with the IRs, they want it for power, but don't like it until up top.

Ross, yes.

The primarys open 15° before the secondarys start. That only amounts to about 3/16, vertical movement (I have to actually measure it) and then decide how much to cut the opening. The angle of that cut, will be appox what the throttle angle will be. I'll be happy with it, for now, as long as it doesn't spit back. I can always apoxy it up and get the $75 links, if not.

The overlap is 82°, 294/302 duration.

The trick will be if the accel pump comes on fast enough and the dyno operator opens the throttles slow enough.  I'd say it'll work for testing especially if the dyno operator is ready and goes easy. 

As far as the cam, it'll be interesting, assuming solid flat?  Likely overlap is a little lower at the valves  than compared with an equal hyd roller at 82 degrees which will be in your benefit.  I haven't played with big solids and TFS but it will be interesting and should love to operate up top

[blykins]

Last big SFT TFS head combo I did had 86° of overlap.  Was a 465 and pulled past 7500 on the dyno.

The newer heads just don't need a lot of overlap and it makes it even trickier trying to work with an individual runner intake.  At the very least I would run a shear/anti-reversion plate but I think the cam would benefit from a little less overlap. 

[My427stang]

Giddy up...I say if you trust the work, light it up and find the HP peak!

[TomP]

I would try it using just the thickness of the spacer as the plenum for that first 15% throttle. I think the air will find it's way in. At part throttle there won't need to be much airflow and at full throttle it should act as an IR but with a little mixing.

 I noticed when I had a carb base plate screw fall through my 390 that several spark plugs were smashed flat and evidence of the screw marks in several cylinders. The F427 has a divided upper and lower plane of the intake. One screw , but it damaged five cylinders? Three on the upper plane and two on the lower...hmmmm. There is only a small notch (for 3 barrel carb) on the intake otherwise upper and  lower planes are divided. Somehow that screw went into a cylinder, bounced back out the intake valve and got sucked into another cylinder by way of that 1/2 by 1" notch under the carb multiple times.