Homemade 125" FED Twin-turbo SBC

Very cool build. Its not tasteless or ugly, its bad ass. Listen to the guys most on safety and design. My dad grew up in SoCal during that era and drove this style of car you are building. Plenty of crazy and not so happy ending stories from that time. I'm attaching a pic of my dad at Lions. Pretty sure you might have a ride like this in your future. Again, VERY bad ass!
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Welding the housing into the chassis is perfectly legal, in fact Davey Uyehara builds his nostalgia top fuel cars that way. If you do decide to weld it in make sure that you spread the load sufficiently on the lower rail. The way that your brackets are done now is not especially strong. The flat plate that is welded to the frame is in the middle of the top surface of the rectangular tubing and that is the weakest area. It would be better to have the plate aligned with the edge of the vertical face of the tubing, or even running down that face to provide more weld area. If you put an upright in the same theory applies--keep it close to one side of the rectangular so that the load goes into the vertical face as well.

Roo

 

Thanks for the info. Does Davey weld the rearend to the frame because its stronger?

 

Awesome photo! I have a set of wheelie bars that I plan to use, I would love to carry the tires a ways out but I would probably wreck it.

 

Do you spray it out of the hole or delay it?

 

If you want pictures of my Mark Williams chassis his rear connections are way more beefy than anything posted here and would be good to look at.

 

You are more than welcome to contact me, I check in on the boards a couple times a day. The recipe on that twin turbo 302 of mine is quite simple. From the bottom up is a stock '87 block, crankshaft, rods and pistons. The only work done down bottom is new main, rod and cam bearings as well as new stock replacement rings. I used ARP main bolts and ARP rod bolts. I did alot of massaging inside the block to remove as many stress-risers as possible, I didnt remove alot of material here I just worked out all the sharp edges and blended everything together. No girdle, no straps just stock block with ARP main bolts.
The heads are TFS twisted wedge 170cc that I did a minor cleanup in the bowls, the runners were left untouched, this was just a blending in of the valve job into the throat and cleanup in the bowls. The cam is a TFS stage 1 hyd roller and I took apart the factory roller lifters, cleaned and reassembled them then used them. I used a set of Comp roller tip rockers and used a final pushrod length of 6.550".
The intake manifold is one of those "Parker Funnelweb" knock-offs that can be had from ebay for $125. I ended up slightly enlarging the intake runners in the heads to remove a .040" lip and blended this about an inch into the port. The casting quality of these intakes is terrible so I spent about 3 hours cleaning it up and straightening out the waavy runners.
The carb is an old 650 Holley mech sec DP. I rebuilt it with a holley kit, solid floats, and vent tube extensions.
The turbos, wastegates and BOV were bought from ebay. The turbos are those generic T3T4 hybrids .63/.50 ar, they can be bought for $130 a piece.
This motor is in a 3242 pound fox Mustang with bone stock front suspension and just a set of lift bars out back. The trans is a Redneck built C4 with their 3500 converter and I run 3.55 gears in the rearend.
On used 10" circle track tires I have run a slip-sliding 6.29 at 112.22 mph in the 1/8th mile. If you were to duplicate this motor and put it in a REAL car, it should go into the upper 5s as long as the cars weight isnt much over 3000 pounds. The biggest issue with my setup is the stock suspension and junk tires, which is why its slow. I built the car for fun using junk that was laying around.

 

Yes please!

 

How exactly are you doing the carb for a blow-through setup? I have done some research on it before, but yours makes it sound a lot easier than what I have read before. Also what is your compression ratio and how much boost will you run with this setup? What type of fuel do you use?

 

I'm loving reading about this. I can't wait to read more about your twin turbo setup. I've been reading up on them and your carb setup info was most appreciated. Please keep us posted!

 

The carb that I built for this FED motor is a traditional 650 mechanical secondary Holley with acc pumps front and rear. These carbs are very common and can be bought used but good for under $75. The mods really dont differ much from a full rebuild. You should make a simple lapping board with 400 grit sandpaper to help straighten warped main body, metering blocks etc. Doing this is very easy and helps seal an old carb, and its standard practice even when rebuilding a carb for stock applications.
I used a standard Holley rebuild kit that comes loaded with different power valves that can be used for fine tuning later. The only real mods are cutting off the choke tower and epoxying the choke linkage hole, drilling out the power valve channel restrictor holes in the metering blocks. Drilling the PVCR holes is something that needs to be done by trial and error, as in take it to the next size from stock and try it and increase the size until you get it close. Doing this helps you to use a smaller main jet which really is the goal of tuning blow-thru carbs. The smaller the jet, the better A/F ratio during cruise, compensating fuel from the power valve circuit helps to do this and you are not using the power valve circuit until engine vacuum has dropped below the PV vac rating. I found that with my blow-thru carb on the Mustang liked a 3.5'' power valve and small #65 primary jets with larger jets out back but I cant remember the size.
You need cheap solid floats so you dont crush the hollow ones from the factory, jet extensions in the rear bowl will help you to not uncover the jets under hard acceleration which there will be plenty of that when your done, I still remember the first time I launched the car under boost off the transbrake, it ripped both front tires off the ground and cut a mid 1.40 60' time.
Vent tube extensions are worth their weight in gold. You pull out the short little vent tubes and replace them with 5/16'' brake line that will run out to the inlet of the carb hat, put a flare on the ends and epoxy them into the main body. When velocity picks up inside the carb hat, air will stack up against those flared ends of the tube and actually force a slightly higher pressure into the bowls. This makes the main jets think they are bigger than they really are, that slightly higher pressure in the bowls makes a big difference and doing that alon made me have to come down 5 full jet sizes up front. This helped alot in cruise and slight throttle opening.
If you guys want to know more about this blow-thru stuff just ask. I learned alot after building and tuning my first one and Im more than willing to share all I know about it. If you really want to dive into this subject then cruise on over to www.theturboforums.com , there is a wealth of knowledge over there and those guys got me started on the blow-thru carbs back in '07.

 

I will warn you guys to the biggest drawback to a turbo setup. Torque and broken driveline parts. Check this video and the associated damage picture below. http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=102_3946.mp4

 

Either of those engines would be intresting in something like this (120"wb hard tail)


Or my old O/T pro street Pinto wagon I used to have (I had a single 88mm turbo on a 302 with a 4 speed, blow-thru 650 Holley, 15 psi of boost, it was loads of fun)!

 

Hey Jim, thanks for the info on the Blow-Through set up. With any luck I will actually put one of these set ups to use at some point here.

 

Got the pictures, having download probs

 

I wouldn't worry too much about that kind of thing with a dragster, Jim. What breaks parts like that is weight... Your dragster will have a lot less inertia to overcome than the Mustang.

I have to argue against welding the housing into the chassis. All due respect to Davey, et al., but it will be more of a pain in the ass for not much savings in effort. Go with a design like the one McTim pictured. Move the plates out to or near the outer edges of the frame rails. That way the load is bearing on the vertical wall of the tubing. The plates will be too far apart, but there is nothing wrong with running spacer blocks in between drilled to match the mounts.

Notice how most of the axle brackets make a full circle around the tube? That cuts the shear load on the weld surface way down. You have to cut the ends off the housing to install that kind of plate, but you can make them 2 piece and overlap them for more weld surface. Use a minimum of 1/4" thick plate for the axle brackets. 3/8" would be better, not because it needs the strength, but for extra bearing surface on the mounting bolts. Make sure the shank of the bolt is long enough to go all the way through the entire assembly, so nothing is riding on threads. If the rearend gets free it will likely destroy the car, not to mention injure you, so don't even think about trying to cut any corners there...

 

Let's see some pictures of the Mustang making a good run!

Sam

 

Your advice is well noted, thank you.

 

We didnt take many pictures of the car, just a few in the burnout box. We did however tape alot of the passes. I will dig up a few and post them here.

 

http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=102_3944.mp4
This was a 6.29 pass.

 

http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=101_0844.mp4
This was a 6.50ish pass. Probably a tuning pass as its alot slower than usual

 

http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=101_0847.mp4
Mid 6 sec pass on 7 pounds of boost.

 

http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=102_3893.mp4
6.34 pass against a nitrous 408 who went 6.29

 

http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=102_3892.mp4
http://s263.photobucket.com/albums/ii137/Mitchell302/?action=view&current=102_3888.mp4
A couple mid 6 second passes on 7 pounds of boost.

 

I put in 6 hours tonight out in the garage. I finally decided on a turbo layout and header design, actually they are log manifolds. My original plan was to build a set of tubular equal length turbo headers but after a couple mockups it was very clear that I needed to build something much more vintage. All the pictures of the early twin turbo cars I have seen all had some sort of log manifold on each side, I have never seen any old turbo setups using tubular headers.
So I decided on a pretty basic design that I think is going to flow better than the traditional front exit log manifold. The 2 center exhaust ports will dump straight into the T3 flange and the outer 2 tubes are going to turn a smooth 90 degrees and meet up with the other 2 tubes. I need to cap the ends of the log but Im going to wait until I finish blending in all the sharp edges inside with my die grinder. The end caps will have a smooth 90 degree contour so the 2 outer tubes will make the turn without running straight into the opposing wall.

 

That's almost art! Except for the billet tops on the BOV's, it looks like pure early 60's... almost

Here's a thought. Get a couple folgers coffee cans the right size to fit over the billet, and have someone paint 'em like old oil cans.......... Nevermind...

 

Cool!

And thanks for sharing the videos!

That stang runs hard!

Sam