My very, very DIY tripower intake mod.

First Fox

Well-known member
OK guys as some of you may know, my turbo Fairmont is receiving some new parts and in the quest to improve the horrible fuel distribution of the log head, I am working on a tripower modification and it will also be turbocharged. To my knowledge this has yet to be done. 8)

I am building this myself with only the use of hand tools and welding equipment, in other words no machine work. I am not a huge fan of the Offy intake for our small sixes and am too cheap to pay the price for one anyway. A big issue with the Offy adapter is it would raise the carbs enough that hood clearance would become an issue and I am not going to hack up my hood just to use a ready made adapter that is mediocre at best.

Instead I am completely plagiarizing an idea from Powerband in which he made an adapter from box steel that is removable. Unlike his design though, and in order to help in my quest to keep overall height in check, I am mounting my new plenum on the SIDE of the stock log.

This new plenum will be made of scrap steel tubing and of course will be to removable if need be to swap to other carb combinations.

Just wanted to share and as always to encourage others that although it may not be the "right" way to do something, it still has a chance of working and more importantly keeps the hands and mind busy and helps us all to learn. :beer:

Pics and more info to come.
 
FF'

I really like the idea of a Side-Mounted removable plenum for the log head . Considered removing the outside (1/2) of a stock log runner and building a bolt-on other half plenum that would bolt on to the head's half (open) runner. THis could allow for swappable carb or FI platform and plenum sizing. Glad my early effort at a simple versatile plenum for the log may contribute to a more practical configuration. Eager to see how your forced induction plenum setup evolves . GMTA' ( :roll: ) ...





more technically savvy builders discounted the idea of my home-fabbed large plenum for 'drivability' but I've found the beta-test 2X4 tubing and big 2BBl setup (NA) to be more 'streetable' than the original Offy setup and consistent at the track .

... the blueprints and machine shop:
. . . . . .


have fun
 
:beer: sounds like it will be a great start to a better intake system First Fox :nod:
 
Powerband, I really like your setup with the square tubing. I wonder if you might shave the TOP of the log and set the plenum directly on top of it. You would have unrestricted flow along the length and especially in the outermost intakes. Of course you would on the side too. I'm thinking of how you would clamp and seal it. Top mounting would be completely flat and you could use U-bolts, similar to the Offy rig.
 
My intent is to use square tubing as well but of a smaller size to keep the plenum area down. The piece I have in my pile is 1 1/2 inch and I will weld three carb flanges to that tubing. I am basically shaving the log in half to give a flat mounting area around the circumference and cutting the side out of the square tubing. I will use several bolts and nuts through the side of the stock half-log and through the new tubing plenum using a hand made gasket sealing the outer circumference of the log.

This way, instead of the three small holes of the Offy adapter I will have the entire length of the log to feed the cylinders, but ultimately the carb bores will be the restriction I believe. If that's the case, the beauty of this design is that I can make another plenum with 4 carbs. Or 6... Or 36 model airplane carbs if I feel like it. (y)
 
ludwig":3in0jgj7 said:
Powerband, I really like your setup with the square tubing. I wonder if you might shave the TOP of the log and set the plenum directly on top of it. You would have unrestricted flow along the length and especially in the outermost intakes. Of course you would on the side too. I'm thinking of how you would clamp and seal it. Top mounting would be completely flat and you could use U-bolts, similar to the Offy rig.

ludwig,

... another interesting idea that needs research, maybe you gave someone the motivation to make it happen, are you good with a sawzall ?

... clamping and sealing an intake manifold is a challenge but could be similar to typical bolt on intake methods with gasketed surfaces..


have fun


( btw , later intake runners aren't really flat , they are on two planes meeting at center carb port)
 
There was a great deal of talk several years ago on this forum of sawing the log off and leaving the intake stubs in place. This would (theoretically) allow a plenum of the type you have to be mounted directly to the intakes on the side. One fellow posted some pics of his intake manifold after he had sliced off the log with a diamond saw or something.

The problem here is the attachment of the plenum - brazing, bolting, welding, whatever. Each one has its own significant difficulty. In your situation, I could see a series of holes across the bottom of the box where it mates with the log.

Powerband: Hot Rod magazine showed how somebody built a sheet steel plenum box for a large block 8 and mounted three Stromberg-type throttle bodies on it. It was an EFI setup but the mag said it worked great. I don't see why we couldn't do that here somehow -- and you are the closest to the solution yet.
 
FYI: If you want to seal an intake, look into a sealer called PRC. We use it on aircraft and there's nothing like it. I'd almost use it on a boosted intake... Within reason. It's amazing stuff.
 
Everyone seems down on the old Offy setup , but NO ONE has made as much power and gone as quick as my old combo ,AND it had MUCH more in it , sorry but that square log may work great for EFI , as it only has to move air , BUT using it in a Carb setup will not work in the RPM range that works with the Log head , looks neat , but that's all , IMHO
 
FalconSedanDelivery":19wv06cc said:
Everyone seems down on the old Offy setup , but NO ONE has made as much power and gone as quick as my old combo ,AND it had MUCH more in it , sorry but that square log may work great for EFI , as it only has to move air , BUT using it in a Carb setup will not work in the RPM range that works with the Log head , looks neat , but that's all , IMHO


For the record I am not trying to outdo the offy adapter in terms of breathing or overall performance. My only problem with it is the price as I am inherently cheap and I can hack up a head for next to nothing. Even if I ruin it, these heads are virtually free. I also like the idea of being able to experiment with different carb combination and plenum sizes and that can't be done with the Offy. I dont think either if us are going for looking neat as much as it being "workable" and "modifiable"... Tunable if you will.

Whether or not the square plenum will work well has yet to be proven, for me anyway. I have seen some very square looking wet, sheet metal intake manifolds before and far be it for me to tell the guy who owned it that it didn't work. This idea may be unorthodox and far from optimal, but that doesn't mean it won't work. Unless someone has tried this and failed miserably, I for one will press on with it and as always will report if it sucks.

There is never a shortage of people that will tell you something will never work but are amazingly absent when it does.
 
FSD makes a good point, if just moving air fine, but a wet A/F mixture seems to work better with round or oval ports.
Prime example, the big block chevy performs better with the oval port heads rather than the rectangular port heads.
With your turbo deal any combination will be better than the naturally aspired intake.
Whatever it will be better than the stock log head. Bill
 
I will be here, and the first to acknowledge if I am wrong AND , I am not trying to tell people that it wont work at all , just that design wont work BETTER than the Offy setup , in the rpm range that suits the Log head , Trying things is what Hot Rodding is about , but I am also trying to help others save time and money , as a quote from an old movie , Just because you can doesn't mean you should , it applies here as well :beer:
 
Actually SD, I have gone just as fast as your offy with less. I did it using the same head that you used but I used home made adapters with 1 7/16" hole. Not the choked down small offy. I would have went larger but Ak Miller was pushing the small Holley carbs for the end carbs and that's what the throttle bore size was. I tapered the adapter to the 1 3/4" YF carbs. Picked up 3 tenths over the small Holleys. I fully agree with you. There's nothing wrong with the tripower but, I prefer full bore adapters. Screw that O ring crap. Bore it out. Gasket it with Permatex no. 2. Ninety thousandths is all I needed to seal. Position the adapter closer to cylinders 2 & 5. Forget trying to get it between the ports, its not necesary. The full bore is better.

I fully agree with Falcon Delivery. There's nothing to gain with the late manifolds by hacking the log off and nobody has gone faster by doing so. That I know for a fact.

I don't see how you will gain any more hood clearance. The farther you get away from center, the less clearance you'll have. I would save yourself a lot of grief and make up some custom low profile tripower adapters. You'll only have to make 2. I'd just lower the engine mounts.
 
Hello group,

I am digging through my file of old photos. I started on a project with a head that I milled the whole top of the log off. I was planning on just a piece of flat steel on the top an using two Holley/Weber two barrels. My friend with all the machinery (milling machine, lathe, ability to weld cast iron, etc) died, and the project ended.

I'll post pictures - if I can find them. The casting "Flash" in the ports was amazingly restrictive! Just to be able to grind out the casting flash would be a GREAT flow improvement - that would not be achievable with an Offy adapter or a homemade tri-power like on page 35. The Ford 6 Cylinder Performance Handbook has one picture of the casting flash on page 22.
 
Re the casting flash, that could be taken care without opening the log - by using extrude honing -- if only you wouldn't have to go into escrow to get that done. Boy, is that ever EXPENSIVE.
 
wsa111":1wgylog9 said:
...
Prime example, the big block chevy performs better with the oval port heads rather than the rectangular port heads.
With your turbo deal any combination will be better than the naturally aspired intake.
Whatever it will be better than the stock log head. Bill

You are discussing something there that I am very familiar with and with which I have a lot of experience as well. Your comparison is apples and oranges as you are talking about the cross sectional shape and size of a port, not a plenum where velocities are relatively low. And even with that being true, it is not the port SHAPE difference between the two that makes a difference in power or more accurately airflow, it is the overall AREA of the ports. The rectangular BBC ports are much larger than the oval ports and that's where the added airflow and loss of port velocity comes from, not the shape difference between the two styles. There is also a ROUND port variant of BBC heads as well known as "peanut" ports heads, and they have even greater port velocity as the ports are VERY small. And while they make terrific low speed torque, they won't flow enough air to rev past 4000 rpm. Also, the oval port heads indeed do NOT always out perform the rectangular port heads. They are intended for medium speed engines and they excel in those application. The large rectangular port heads excel when reving to 8 or 10 thousand rpm and the peanut port heads are the way to make diesel like torque in a tow rig. Its all about application, same as with a lot of things we discuss.

The shape of the PLENUM or the log in this case isn't going to slow velocity down nearly as much as port shape. Whch is nitbbeing changed at all. A larger plenum tends to favour high speed performance at the cost of low speed torque but the shape of the plenum runner or the log itself, is not going to lower overall airflow much if at all. Booster signal and idle quality , probably, but overall airflow, I doubt it.

And as far as the hood clearance, I assure you it is an issue for me and there is very little clearance even with my homemade carb hat. The carb hat needs to be taller than it is not shorter, and if I even add an inch to the carb with an Offy adapter, I will have to make my new carb hat shorter still and that is definitely a step on the wrong direction. I can mount the new plenum lower than the stock carb location is now.

Lowering engine mounts is not an option as there is priceless little room between the pan/k-member and rack and pinion. It ain't gonna happen without some major work.

And FSD, chances are the V8 crowd probably pulled the "just because you can..." thing with you when you decided to build your six in the first place. I for one am glad you ignored them and did our own thing. Just like I am doing. :beer:

By removing the side of the log, it should allow me at least some access to cleaning up the intake ports. :beer: Extrude honing one of these heads is like putting a silk hat on a pig.
 
It took a long time to build My 6 ,it started when I was 17 ( 1977)and had a 66 Mustang with a 200, there were Few parts back then , but when the guys at the local speed shop said you cant make one of those engines run for crap , well low 14's at 91 aint too shabby and There was low 13's left but Life ( Finances ) made me sell all the 6 stuff I had , and actually the engine now is with Powerband , Good Luck with your Project
 
FalconSedanDelivery":3beyg82m said:
It took a long time to build My 6 ,it started when I was 17 ( 1977)and had a 66 Mustang with a 200, there were Few parts back then , but when the guys at the local speed shop said you cant make one of those engines run for crap , well low 14's at 91 aint too shabby and There was low 13's left but Life ( Finances ) made me sell all the 6 stuff I had , and actually the engine now is with Powerband , Good Luck with your Project


Any modifyer should only be interested in what precentage boost you get with each modification.

Powerband, yeah!, FSD's engine is the best naturally asperated log head engine ever. No one else has a 220 hp flywheel 250 I6 using stock Ford parts. Thats 2.2 times the stock approx 100 hp net rating, without a turbo.

The point is that FSD got that even with the most constrained Offy intake and car throttle body size restrictions, the FalconSedanDelivery 66 Mustang set up made power. Even with very restrictive porting.


Any thing that fits underhood and improves carb port area on an beyond the stock Offy set up, will provide solid gold power increases.


First Fox, your really on the right track...Box section log intakes all the way....

As for other posters, yeah, casting flash is an issue, but how come Crosely's direct mount 500 cfm Holley 2-bbl can make 205 flywheel hp from just 200 cubic inches? Answer. Carb Port area was opened up.

Increase the size of the carb port area, and you gain performance. De-dagging the ports becomes less of an issue when you have a straight shot to ports 1 and 2, 3 and 4 and 5 and 6. Remove the 90 degree bends.

Ak Miillers weld on intaked 67 Mustang mods proved that the Ford six responds to pure carb port area increases and less bends. 1.5 times the power just there from geometry and area improvements.

The log cna be a dog for flow, but the best manifolding reduces the total hea loss. The best maniofold and carbueration is the one that produces the lowest cfm loss. If your intake ports only flow 165 cfm at 28" H20 with the log cut off, then you do the bare minimum mods to make the whole pacakge flow 165 cfm at 28" H20 from the manifold.

It classic Holman Moody Cleveland Rat roster or Smoley Y intake maniifold design.

Pure carb port area increases and Less Bends
 
FalconSedanDelivery":1zrz5vf8 said:
It took a long time to build My 6 ,.../ and actually the engine now is with Powerband , Good Luck with your Project
? ... just "for the record" - I'm not sure what FSD meant, FSD's engine was not gotten by me. My current various projects are all self-(home) built, in the pursuit of similar power achievements ...

have fun



Powerband
 
Back
Top