OK, I needed some high flow runners, but wanted to maintain the factory look. Some of us like the long tube look. The options are limited, AS&M are usually the choice, the ACCEL's are not bad. But all expensive.
I was just about ready to purchase a set of AS&M's when I noticed the measurements, and saw a few pics... Those are really long, in fact they are longer than stock! And they look it, they stick out funny.

I started to think, what if I built my own?

Here is what I came up with:
1. Cut the factory tubes off the factory flanges, port them to 1.75".
2. Purchase 8, 1.75" OD 6061-Aluminum 180degree Mandrell bends on a 3" centerline radius.
3. Fuse the new tubes to the factory flanges!

The AS&M tubes are 1.75" OD, but thiner than I could find. I found 16ga. which put my ID at 1.620" (AS&M ID is 1.654").
I made some guides for drilling the flanges out with a 2x4, and used a standard 1.75" hole saw. You could get them machined out, but I am trying to do this for less than the cost of some AS&M's.
Here are a few pics of my guides and a preliminary test fit of the tubes, notice the driverside has the factory tubes installed for comparison.

When I measured, these "Custom" runners will be a full inch shorter in length than the factory runners and a larger ID than the ACCEL's(1.615") and the SLP's(1.600").

More post's to come as I progress on the project.

 

A few more pics, again trying to compare to the factory runners installed on driverside.

 

Man they look GREAT!

 

that is awsome! deffinatly great craftsmanship

 

Wow would you make another set and sell them?

 

But how'd you attach the to the stock flanges? Joining steel & aluminum = Epoxy?

 

Are not they both aluminum? If so he can weld them on the inside and smooth them out. Great work. Very well done.

 

"2. Purchase 8, 1.75" OD 6061-Aluminum 180degree Mandrell bends on a 3" centerline radius"

I missed that part. Never seen aluminum tubes like that for sale. Where'd you get them? Welding aluminum is not a problem for me so.....

 

Looks awesome. I noticed when I installed my accel runners, how much closer the plenum sits on top of the egr valve. It's real close, and my AFPR screw touched the plenum before it was adjusted. Don't wanna go too short of you might risk clearance issues. But MAN, those looks smooth and you might have yourself a side business there!

Will

 

Those look really nice. I likey

 

Thats great man! Looks damn near factory, but custom clean. You are definitely on to something!

 

I purchased them from Columbia River Mandrel bends, http://www.mandrel-bends.com, $18.50 each.

 

I have not changed the height of the plenum, The shorter length comes from tucking the tubes in tighter to the fuel rails. But no EGR for me, it is going into my 63' Acadian, no emissions control on a 63'.

 

They are both aluminum, the flanges are cast aluminum. I have no access to a TIG, so I looked at other alternatives. The stock ones are bonded together with a high temp aluminum solder. So I went looking, Alumiweld (http://www.alumiweld.com/) seemed like it should do the job. I purchased one pack from Alumiweld, and have since bonded both sets of Runners using my Oxy/acetelyne torch. I will post some pics tomorrow. To ensure a seal, I am going to use thin coat of JB-Weld to fill any possible pin holes. That will be sanded down before applying "Metal-Cast" from Duplicolour to give them a powder coated appearance.

 

Oh and one more thing: I am using the Holley AFPR, it has a very low profile wheel to adjust instead of the screw. Check it out if you are having issues, it is part number 512-501.

 

Cool. You got the Part# handy? AL-16-175-300-180?

 

Yeah, those are the ones.

 

I don't think it would be worth it for the buyer. So far I am into these for $260:
- spare runners from ebay $25
- new 1.75" tubes $148
- Alumiweld $35
- shipping fro all parts $50

For me to want to sell more of these, there would have to be a mark-up to cover the time spent and turn a bit of profit. By that point you are in the price range of the after-market options. And with two kids and a job that involves lots of travel, the profit margins would have to be large for me to consider putting the time in.

But there is no copyright to my idea, so feel free to build your own set. It really has not been difficult.
The Alumiweld took a bit of practice to get it right. I did it with the plenum held in place by the stock runner on one side, bolted my flanges on the other side of the plenum and lower manifold. Then I popped the tubes in place and lined them up.
The trick I found was to apply heat to the Flanges, they are the thick part. Once hot enough the Weld rod just melts on to the Aluminum, its like a wax crayon that has been sitting in the sun.

If you had access to a TIG, you could replace one tube at a time welding it in the inside as suggested.

 

They look great! How do they run?

 

It will be a while before I get the motor to that point. And it will be impossible to say how much improvement I get from them as I have made several other changes at the same time. New heads, cam, high flow base, new TB.

 

Do you have an idea of how many cfm's they will flow? Nice work by the way, I may be looking at my next project!

 

How did you cut the stock tubes off the flanges? Basic cut to the tubes, then finished by grinding from the inside of the tubes to free them from the flanges?

 

I used the 2x4 guides pictured and a hole saw. I ran the hole saw through the 2x4 guide to keep it centered. The Hole saw was 1.75", which is much larger than the stock tubes, so the tubes just fell out once the hole saw made it through to the other side.

 

Alright, here are a few pictures of the completed Runners on the bench and installed. Notice how close the are to the fuel rails, I had to grind the rails a tiny bit to get the clearance.

 

A few more pics...

 

No Idea, I have no access to a flow bench. I don't even know anyone local who has one.
The closest comparison would be the Accel Runners.
The Accel's measure:
Length - 6.625"
Diameter - 1.615"
Flow - 243 cfm

My runners measure:
Length - 6.250" (3/8" shorter than Accel's)
Diamter - 1.620" (only slightly larger than Accel)

If anything I would expect them to flow more than the Accel's, because of the smoother bore of the tubing, unlike the Accel's Cast finish. Accel's that have been Etrude-honed flow 275 cfm.
It's all guessing at this point.

 

Very nice work, I agree they should flow more with the better finish. I just put about 20 hours into smoothing the interior of my SLP's. I like yours better.

 

For anyone still interested, I got the engine running, and it runs really strong. I am running an Accel Thruster with a dual sync Distributor, so I still have some tuning to do. But the car pulls hard, really hard, keeps pulling to 5500 rpm. It will be interesting to see how it runs when I get the tuning dialed in.

 

Keep us posted. Tuning can make a big difference.

 

Looks great! If you got 1989GTATransAm interested you gotta be doing something right

 

Great project.

I had thought about doing the very same thing to replace my dented stock runners. Same tube size and supplier I was looking at too.

I was going to make new flanges and start from scratch but cutting apart a stock set like you did could work too. Probably take about the same amount of time either way but I could add a little meat in the thin areas to strengthen things up a bit.

 

2 questions

#1. what's the best tool to use to cut off the factory tubes?

#2. Exactly how do you bend the tubes or if you order them like that exactly how & from where?


Thanks in advance!!

 

How did you know you were centered on the flange opening with the hole saw? Did you cut through the 2x4 from the bottom or top?

 

Nice. Get a bulk deal on tubing so you can get the cost down and sell them! I'd be in for a set! Would be willing to send my stock ones so you'd have the flanges already!

 

Wonder if 2in tube would work really wanna try this

 

That is going to depend on the rest of your combination. I think it would be to big for a 305 as an example and maybe most combos if your only turning to 5500rpm.

Be prepard to move a couple of bolts in the plenum area and a couple on the base. You will also need some welding and machining with the new bolt locations and opening up the holes to 1 7/8". I would have to check my thread when I did it for more details. I think you can get away with 1 7/8" tubing without to much hassle.

 

This is a pretty nice idea. I wonder if increasing these runners would make any difference on a stock LB9. ** Corrected ** from reading other posts, anything helping airflow will help, even an LB9. :-)

I plan on picking up a spare complete intake manifold w/ the runners and plenum setup to port and tinker with.

 

Great job! What heads are those on the motor?

 

Ijust talked to my cousin who is a machinist (for Ford Racing) and he said it would be no problem to machine my flanges! I should have this done for the first autocross of the season in may! Thanks OP!

 

Any updates on this? This sounds like a fun little side project for me.

 

First time I'd seen this, and I really like the idea. I'd been having thoughts of trying to use a 3D printer to play with different runner configurations. Part of the design would be dependent on how large the intake manifold can be ported out to, and then working backwards from there. One of my concerns was how well the printed part would hold up to underhood temps. But if they worked long enough/well enough to try some different configurations on a dyno, it could be well worth it before taking it to metal. Between the prebuilt radius piping, and a shop with a waterjet, once you've found what works, it would be fairly simple to just put that combo together. There is even the potential of a custom plenum, so that larger tubing could be an option without having to add material.

 

Beautiful craftmanship. I would be in for a set.

 

 

WOW i wish i had this knowledge....

 

 

In for tuning/power updates, if any.
I have several sets of runners and it would be a fun project.

 

I think the op has left the building.

 

SELLING IT!
Well, Its been fun. I never got the car on a dyno, but it ran really well.
I am however moving on to bigger and badder things. So I am selling this set up. I'll post it in the classifieds when I get time, and maybe on sleaze-bay. But I though I would give advance warning to anyone who was following the build. I am selling:
- The lower intake (edlebrock 3817, Vortec base), egr block off plate
- My high flow runners
- Stock rails with holley adjustable regulator and -AN adapters
- The heavily ported upper plenum and aluminum dizzy cover
- 58mm twin blade billet TB with modded IAC housing (no coolant passage)
- IAC, TPS, MAT, MAP sensor, stainless hardware and thermostat housing
If I didn't list it, then its not included.
If you are interested send me a PM with an offer.

https://www.thirdgen.org/forums/engi...ml#post6073572

 

What afpr is that and what kind of piece is that on top of it?

 

The piece on top is the adjustment wheel
https://www.holley.com/products/fuel.../parts/512-501