I have researched several sites and posts regarding the siamesing of the manifold intake ports on a TPI intake. All I have seen describes hours of grinding drudgery to accomplish this modification. It hit me before starting on that part of my '55 Chevy TPI conversion project of a way to eliminate 90% of this grinding hell. I have used this method on my TPI intake and was able to siamese all 4 pairs of intake passages in an hour! I had contemplated using a hack saw blade or a stiff back saw but the hand labor was still involved. Then it hit me...a Saw-zal with a 4' blade would make light work of the cast aluminum assuming I could control the angle of the cuts adequately. Turned out it was a peice of cake and cutting 4 inch deep wedges in these ports took about 30 minutes for all four pairs...combined! After cutting the upper and lower slits in the web I snapped the sliver out with a pair of channel locks. All that was left was to smooth the edges and it was done! If anyone is interested I can e-mail pictures of the steps. Not sure how to post them on here. My e-mail dtlong@atlanticbb.net This method could be used on after market runners as well. Hope this might help someone.

 

sounds like an alternative to the grinding

 

Siamesing is only half the battle. You also want the size of the runners enlarged. I hear golf ball sized diamter is good for flow. A sawz all can't do that. No way around it, grinding is inevitable for power.

 

There's still a ton of grinding involved! Enlarging the ports all the way through is key to making good power and it takes many hours to get the initial rough cut and then smoothing with sand rolls. There is alot of metal that needs to be removed from each port all the way through.
If I had to choose between siamesing or a good full opening up of the ports, I'd take the full port.

 

yeah thats true there is no way that a sawzaw can make the holes i got in my manifold

 

Siamesing the base and leaving the tubes segregated will most certainly hurt flow. What you've done is to create a pocket where velocity will be reduced, and turbulence created, effectively reducing cylinder filling. Siamesing of the base comes after siamesing of the runner tubes.

Siamesing of the tubes is not that difficult. You can use your saws all to cut the inner halves of the runners out. Then you need to weld aluminum sheet between the open halves to make a single oval runner out of each pair of tubes. Look at TPIS's work on this.

 

I know about doing the runners also. Just saved a bunch of grinding as a prelude to finish porting. Has anyone ever notched factory runners, formed the two tubes together and finished with JB weld? Aluminum is tricky to weld. How far into runners has been found to be most effective or are most modifiers attempting all the way thru with no center ridge to assist laminar flow.

 

SLP siamese runners cut horizontally through the middle. Port/siamese both pieces all the way through, weld back together. Best option IMO. A little center piece in between the runner ports at the base side can be left and smoothed before welding back together so the air enters the base smoothly, if you're not siamesing the base.

 

Internet lore has it a golf ball is the precision measure of hp.

I say if you can fit a mango through it youll make real power.







To the Op nothing wrong with a quicker way to do something even if it isnt popular. That would take a lot of time with a grinder. Now get the rest of it and post pics.
Hell even if you didnt like it its just a TPI base they are a dime a dozen.

 

Exactly! Funny stuff!
I'm aiming for a small grapefruit!

 

Try it first so you have some facts to back up your incorrect assumption.

 

I can't imagine why siamesing the base and not fully siamesing the runners would be a good idea. Why would you say try it first?

 

i was thinking a orange it has more sphere shape way better for flow.

 

Unless you try it and document the results, you have no factual basis to draw a conclusion. Whats worse is when you end up being completely wrong by doing so, like in this case.

 

Wow! Common sense tells us this isn't beneficial without siamesing the runners. I think you are looking for an argument.
Do you have proof that otherwise?

 

^^Max is correct. I'll admit I don't know anything about intake manifold harmonics and such but haven't you ever wondered why EVERY aftermarket intake manifold has individualized runners? They have kept all the runners segregated in all the LSx manifolds as well, do you see a common denominator?

The siamesed runners for TPI cars worked because the intake runners are so small that it didn't really hurt low end torque to much to combine them.

 

The SLP TPI runners work because they are somewhat larger than than the stock tpi and they are siamesed slightly for added plenum volume.

 

What Madmax isn't telling you is he has done all this in the past, probably one of the first to do it that I know of on this website. Look up his old posts, all the info is there.

 

Yes that to. And I hope the OP plans to 'knife' what he cut out with the sawzall.

 

I guess I should have retitled my initial thread as "EASIER" Intake Siamesing. I didn't mean to imply that the tuned port engine I am building is now ready for drag racing into the upper 10's or anything. How can anyone deny that cutting out a 3/16" thick wedge of cast aluminum 4 inches long and 3/4 of an inch wide in 5 minutes is not easier than grinding for hours on end to remove the wall between intake manifold passages? Port all you want after that but I just saved you 4 or 5 hours of mind numbing work. That was my only goal in posting my idea. My goal is not a 600hp behemoth...I just want a snappy 350 hp or so TPI engine for my heavy old '55 that looks good. I cruise not race.
Now that I have passed on the pleasantries...I have read posts on Corvette, Hot Rod and other chat sites where some have merely gasket matched, upsized their runner tubes with the steel ball technique and opened their manifold as I have and felt they had made performance improvements due to the notion that each cylinder is now fed by two runners rather than one. Maybe that is old school and has been disproven by dyno. I would like to hear from someone who has tried that technique and knows cuz I don't know. Again I am not looking for ground pounding power I just want to optimize a nearly stock engine. I have a 350 30 over, with headers, ZZ4 heads, a Chevy Hot Cam, roller rockers and a 52mm throttle body. I am also port matching everything and doing some smoothing here and there as I see fit. I am going to have a tune done on my ECM chip as well. Wife lost her job so the SLP runners will have to wait! Thanks ahead for any suggestions. My '55 is in this pic if anyone is interested.

 

Yeah, I do. Its almost 10 years old now. I'm not the only person with it either, but then again this is actual fact not theory and "common sense".

 

Could you enlighten me a little on the siamesed intake concept as to your findings? If you read my last post I am going to be a while without siamesed runners. I want to get this thing together as best as possible at this point. Thanks ahead...

 

Sounds easier to me. I almost tried that route first, but didnt have the appropriate tool that is what you were using. How was the blade kickback as you cut through? Or did you not have to go that far?

 

Search for my user ID and siamesed, or sort the TPI board by views and scroll down to the 8th post down thats not a sticky.

 

I just sprayed the cut with WD-40 as I went and cut into the convex curved side. The saw will only go in one way since the injector bosses pretty much block access from the other way. Never had a single kickback only used one blade also. Really the saw will only work one way... the direction can be seen in my pic on my facebook page. I could e-mail a pic of the direction I went in if you like. It really was easier than I expected as I also was expecting some kickback. I used a 5 inch blade which yielded a 3 1/4 deep wedge. I also turned the blade with the cut on the side of the foot away from the swivel.

 

Okay. I looked up your thread on this mod from 2001. Interesing stuff. Perhaps I was hasty in my judgement. Still, I believe a fully siamesed runner and base combo would be better. At high revs, you're still limited by how much air your runners can flow.

 

Good one!

 

Good work that would save hours of grinding to the same effect once done.

I think that you should be shooting for lemon size though, everyone knows they are the most aerodynamic fruit so it's gotta make more power.

 

Wouldn't a large banana fit the curve of the intake better yet? I think we have lost our focus here guys! Try my technique see what you think. I will post pictures of the wedges I cut out later. Then one can correlate how much time a chunk that big would take with a rotary grinder.