I have to pay the welder(s), the machine shop, Dr J and buy the materials. I could have saved a bunch by doing the porting myself on the intake manifold instead of paying Dr J but I hate doing that portion of the work.

I am trying to build this intake system to a certain specification as dictated by the mathematics and input from certain people who I respect in the business. The intake manifold and the plenum were not designed for this large of a cross sectional area and a lot of rework is required to make it happen. I had to build the runners from scratch. If I had used the intake system now on the car it would not have cost near as much. The First intake manifold would not have required any welding and machining for example.

It could be that this experiment might be a total failure with very little if any gain. If that happens I will just re-evaluate things for my next move. On the other hand I could gain 30rwhp with a lot of power under the curve. Maybe even a 10.99 second car in the quarter mile. We shall see which way the chips fall.

 

Going back through this thread admiring your work. Man those runner are gorgeous.

 

Bring it to the low altitude, no humidity tracks and you may get there if your up in the 450-460whp range by then. Thats what it will take

 

I was thinking of taking it to Famoso in Bakersfield, California somtime in November/December. It has better air than the tracks around Los Angeles.

 

The intake manifold is back from Dr J. We were going to flow it with the runners and plenum attached but do to some weld in the areas where the runners attach we could not do it. However Dr J did flow the intake manifold by itself with some interesting results that I had not thought of.

With a small clay radius it flowed 335cfm. With a larger clay radius it flowed 345cfm. Sooooooo, the cfm flow is highly dependent on the radius used on the inlet side. After the manifold gets machined again, allowing the runners to be attached I will get it flowed with the runners and plenum attached. That means the radius in the plenum will have a big affect on how much this thing will flow. Of course the runners will have their effect also.

Dr J also stated that his intake manifolds opened to a 1206 gasket typically flow in the 335cfm range as this one did. The 1206 port opening being the restriction. It will be interesting to see how the runners and plenum affect the flow. Dr J normally flows single and double plane carb manifolds and has a good feel for them. By the way the 1206 gasket opening is the smallest CSA on my setup.

 

Very nice! With that "necking down" of the runners to the 1206 ports to the intake valves these should be some interesting results.

 

Happen to have a pic of this? I'm always curious with port modifications such as this...

 

No I don't. Heads are on the car so I can't take a picture.

 

heres the vane on a set of AFR 235cc heads

 

Couple of progress pictures. One showing a stock manifold for comparison. Going out to the machine shop on Monday to work on the plenum and the base. The runners are virtually done. By the way carefully look at the Accel base on the bottom of the stock manifold. You can see how much weld was added in order to get the CSA needed. The top of it is covered with weld. After the machining and some tidying up on the ports I will post some more pictures. The port openings into the head will be 1.275" X 2.170". Just a tad smaller than the port opening of my AFR 195 heads in order to give me some wiggle room. The openings into the base as shown in the picture are 1.875"+.

 

I like the vane. My Twisted Wedge have a vane also. It helps to create turbulence as the air enters the combustion chamber in order to prevent stratification of the air fuel mixture.

Be sure to keep your hands and feet clear of those huge runners so not to get sucked in.

 

That vain in those 235cc AFRs is designed to reduce the turbulence,it seperates the air from crashing in the bowl at high lift, directs the air to use or stay to that side of the bowl and shortside.I developed this in our heads and it looks like AFR copied my design.If you remove it you will lose alot of air flow at .550 lift and up and the port will be very turbulent.

 

What heads do you do? This vane design has been around for a good number of years. Its nothing new. Many claim it does nothing but improve flow on a flowbench but doesnt make more power on real running engines.

 

The heads that i developed this in are A.P racing Heads,they are in the weld tech catalog,they cnc them for us.Ask around alot of top circle track racers use this head and they make a ton of power.I developed this 12 years ago,we have this in a 18 and 23 degree head as well as a sb2 head.I also put something else in a different part of the port.Our 23 degree,235 cc runner flows 360cfm @.700 lift.18 degree head flows 397cfm,sb2 flows 430 cfm.I also made a ls1 head which we never ended up making that flows 355cfm with a 2.00 intake valve.

 

Wow! Thanks for correcting me. Learn something new everyday.

 

Okay, got the plenum and the base back from the welder. Here is a picture of the plenum with the new bottom welded on. I am increasing the volume of the plenum. Next up is to extend the back about 3/4" and then make a monoblade opening in the front. Hopefully Friday I will be back out to the machine shop for further progress.

 

You know, I considered doing that myself, but after looking at the pic, it has me wondering how well that would work if you were to fully extend the plenum rearward, run a crab cap dizzy, then.run the runners only as pairs...spreading the top tubes apart, and relocating the vac ports between the first and second passenger tube pairs.

Curious, why the vette plenum? What are you going to use that vacuum for?

 

The plenum is the 90-92 style for the speed density set up. One could do that with a different distributor but there would be other complications. I have considered making my own plenum and may yet do so. There is enough room to extend the back out around .75" or so with the present distributor..

I am finished at the machine shop(maybe). I thought the only welding I had left was on the backside of the plenun. Then while doing some finish work on the ports I found a small hole and thin spot between ports 5 and 7. So do I weld, epoxy or what???

I had jury duty today and will go back tomorrow. If I get assigned to the case then maybe 10 working days. Another delay.

 

Confirmed I will be on Jury duty until maybe the 2nd week in July. That will slow down things considerably with my project.

 

Don't these people understand? This is more important than some dumb trial. There are people waiting to see this project completed!

 

Hahahaha. Well I am working on it this weekend. Actually it should not be to much longer. I have the majority of the things done.

 

Cool. Can't wait to see it! Keep us posted and the pics coming.

I always wanted a tig welder to do more of this myself. My MIG just doesn't have the power to lay down good welds with aluminum. I hear you on the porting though, I love when its done and I can make it flow but damn I hate doing it.

 

Here are some more progress pictures. One shows the plenum looking in from the throttle body. The front has now been opened up to accept my monoblade TB. I have one side pretty well blended in but need to do the other side along with blending in the top and bottom sides.

The other picture of the plenum shows the 3/4 in spacer I have added to the front to increase the cubic inch of the plenum. I need to get it up to at least 45% of my motor displacement so I need the plenum to have 166 cubic inches. So between that, the bottom lowered and the back blown out I should make it.

The picture of the intake manifold shows a couple of ports where it bolts on to the head. With the additional welded there is plenty of room for the Felpro 1206 intake gasket. Before a 1206 would not seal at all. I am pretty well done with the base as I only now need to clean up the out side weld area so that it looks like it came from the factory that way. Just some minor clean up of the ports. I will also get all the runners coated on the inside with a ceramic heat barrier to help keep the air cool.

Edit: By the way the opening from the base to the head is 1.275" X 2.170" as shown in the picture. That is slightly smaller than a Felpro 1206 as per the instructions of Tony Mamo from AFR because the AFR 195 Competition head itself is slightly smaller than a Felpro 1206 gasket.

 

That thing is frickin sick!!!
You're like a mad scientist!!!
I can't wait to see this thing in action... (not literally)
Finish up and start postin some Dyno Vids and Numbers!!!!

 

I think it's a little crazy and you should abandon this project immediately and send all the pieces to me for disposal. If they end up on my car, you can deny any knowledge.

 

GTA Sammy, I like your discription.

ASE Doc. Hahaha, this intake system is going to stay on the car come hell or high water.

This experiment could turn out to be a failure. The numbers on paper and the dyno simulation programs look really, really good, however the dyno has a way of bringing in reality and the final say on what works and what does not work.

 

Yeah. But my old school sense of what makes air move tells me it's going to be a screamer. I'm so happy with my motor right now, I can't really concieve of building another one anytime soon. Just the tuning work I've been doing this summer has brought out some very pleasing results. I can hardly believe this is the same motor I built 11 years ago. In a community of hot rods, my car stands above the crowd. I blow by Hemi Chargers and they are helpless to keep up with me. This is a long runner TPI engine. What you are doing takes what I've done to a much higher level.

 

Almost done with the plenum. Just need to get the back pieces welded on for the extension. I won't be able to get to the welder until next Friday. I am virtually done with the intake manifold. I have been blending in the welding that was added to make it more "factory like" in appearance. So we are getting real close. The runners have been done for some time.

I just did some calculations on my plenum volume doing actual measurements. It will be around 172-175 cubic inches. That is about 46-47% of my engine volume. This is from Grape Ape Racing.

"Grape Ape Racing recommends the following guidelines for plenum volume: V-8's sharing one large plenum do not work well as far as resonation-effect tuning, but the optimal tuning size would be 40 to 50 percent of total cylinder displacement. For a four-cylinder, 50 to 60 percent of displacement works well. For three cylinders or a six with twin plenums, each plenum should be 65 to 80 percent of the displacement of the three cylinders being fed. For engines operating closer to 7,000 to 7,500 rpm, reduce plenum volume by 10 to 15 percent."

So I am just about right where I should be.

 

This thing is going to be a beast... TPI to the max. I know "extrude honing" is very expensive but imagine applying it to you're set up? It makes me grin!!!

 

I think we're a bit past extrude honing.

 

I was re-thinking what I suggested yesterday... it wouldn't really be cost effective. It's just that this set up makes my go into insanity-mode

 

I got the plenum back from the welder today with some of the extension at the back welded on. I took some photos to show my approach on how to extend the plenum. Now I will cut out the other 3 pieces and have them welded in next Friday. Hopefully this will be my last week on Jury duty as it really puts a crimp on things. Here are the progress pictures.

By the way the extension out the back was badly needed to have more clearance for runner #8 to draw air from along with the extra volume. I would have liked to have extended the rear wall further but I need to have ample clearance for the distributor.

 

Yes, I can see the difference in the photo through #8 runner opening. That will help prevent air starvation to that runner.

Dark Minister, I didn't mean to shoot you down. Extrude honing is a fairly effective means for smoothing and providing small increases of cross section on cast runners where manual or CNC porting is not practical. Extrude is generally done as an alternative to manual or CNC porting. The trouble with extrude is that it's difficult to control where material is or is not removed. You can't really create a specific runner cross section using extrude.

1989GTA has taken great pains to create a particular cross section in this manifold base that supports the large(2") tube runners, and the intake port entry of his cylinder heads. He could not have done this using extrude honing. It had to be done either by hand or by CNC. As you can see reading through the thread, there was also a great deal of welding involved to modify the base, as well as the plenum, to allow for the massive runner cross section.

 

"1989GTA has taken great pains to create a particular cross section in this manifold base"

That is true. In this case Extrude Hone would not be of benefit.

 

very impressive project. Subscribed

 

I had an unexpected day off from Jury Duty so I put the time into finishing off the plenum. The only thing left with the plenum, base and runners is to blend in the exterior welds so they appear factory and then to have everything coated with a thermal ceramic barrier coating. Gots to keep the air cool as posible. I will also have the whole thing flowed. So things are almost done. Here are some more pictures.

 

And some more pictures of the plenum.

 

looking good man... that plenum looks even better than my FIRST plenum.... cant wait to see the end results

 

Thanks. I believe the First does have a little more volume.

 

yes it does.... its only and inch longer and a tiny bit wider but from the looks of your pics i see that ports are larger in size than the FIRST runners ports.... impressive to get all that power from a gm type tpi setup....

 

Yes the ports are larger than an out of the box First. However when I was inspecting a First intake system it appeared to me that you could possibly open up the First to a 2" diameter on the plenum. Then of course one would need the runners to match. The base looked like it could be opened up to 2" inside diameter also where the runners attach. Plenty of potential.

I think I have pretty much gone about as far as one can with the factory plenum and the Accel base. I have busted though the base in many places and some places are on the thin side now. I would not want to open up those areas any further.

 

yea the runners for the first are huge..... when i looked at the FIRSTs base ports you can visuallly tell that they are much larger than any of the aftermarket gm tpi bases... it would take some serious porting and welding to match the FIRST base.. i thought about the idea of porting the plenum ports and runners but i wanted to see what it does out the box.... so far im pleased and it outshines my old tpi for sure....yea i see.... i dont think you can improve on that plenum any more... your not going to use the FIRST base with this build.... are u using the accel base instead....

 

Agreed. The talent of some of the fabricators on this board is simply amazing. Subscribed.

 

I'm liking the project big time! I was wondering why you didnt move the 2 vac ports on the pass rear side of the plenum out to the edge like the rear extention and to where the runners bolt on? No big deal, just wondering. I know it cost to make small changes.. Looking real good!! cant wait 4 the dyno numbers!!!

 

"are u using the accel base instead...."

Yes. I had an Accel base available from a friend and after measuring it carefully it appeared I could reach my goals using it. It turned out I could but with a lot more work than I had originally intended once I got into the project. One of the reasons I liked the Accel up front is the ports are probably the straightest of all the aftermarket bases plus I liked the port entry into the head the best leaving the First out of it which also has a very good port entry.

Well, it turns out most of that went by the way side. The Edelbrock may or may not be a better choice as it is thicker in some areas but again the only way to know for sure is to open one up like I did.

The First would be by far the easiest to open up as no welding would be involved. However it does sit a little higher and requires work in other areas to pass California smog.

One other thing I want to say again is how important the entrance area from the plenum to the runners is. I tried my best to make a nice radius entry all the way around but do to the increase of the size of the runners it was not always posible. So I had to make the entry as smooth a posible. On port 1 for example the top of the port entry is actually the roof of the plenum. So compromises had to be made and on the dyno will tell what effects that will have.

As to the two remaining vacuum ports I figured I could reach my goal with out moving the ports. It is certainly an option for a person to do and I will look into it and weigh the pros and cons of doing so. That option may also help in feeding ports 6 & 8.

As to long tubes making power. I know of one entry in the Engine Masters Contest that used long tube runners and came in 3rd place. So it is a viable way to go. One just needs to get the proper cross sectional area which will insure the right CFM and airspeed. I can only hope I have done that.

 

Update: I re-visited the idea of make the plenum larger where the two fittings are located. The problem is that is where my adjustable fuel regulator is and I need access to it. If I came out to far it would interfere with the Schrader valve on the fuel rail where you check for fuel pressure. Both of those could be addressed, however I think I will just leave it as is.

 

if it was me i would get this
http://cgi.ebay.com/ebaymotors/TPI-T...iveQ5fServices


take the regulator out, make your own custom fuel lines like i did with the first and install a aftermarket regulator mounted on the firewall or something that way you can extend the plenum and have easy access to adjusting the regulator or couldnt you just relocate the bolt from the top to possibly the side.... i hate how the adjustable regulators have that stupid screw right under the plenum to where you have VERY limited access to it..

 

I have my fuel pressure regulator mounted on the radiator support. But I still do use the schrader valve to check pressure.

 

Well, I will be going to the Holly(cross my fingers) adjustable fuel regulator. It has the wheel on top for adjustment instead of the screw. Hopefully I can reach in and turn it with my finger. I have all the parts available including a fuel rail so I can mock everything up on the bench and see how much I can move that portion of the plenum out and still have access to adjust the fuel pressure regulator and access the Schrader valve.

I really like the idea of moving that portion of the plenum out. It would possibly give even greater air flow access to ports 6 & 8 which I am all for. So I will give it another hard look see. Even if it is only half way I will do it.

 

Okay, I gave it a hard look see by doing a mock up. It is certainly doable and I will procede. I probably won't bring them out all the way but more likely 3/4's of the way. Here are a couple of photos I took of the area. You can see that the plenum sits up about 1/4" higher do to the bend radius. This is not a problem as the First base is about 3/8" higher were the runners bolt on. So the plenum will be virtually the same height as where it is on the car now.