1989GTATransAm

iTrader: (3)

Well it has probably been 15 years since any work/improvement has been done on the TPI intake manifold. BBK is suppose to come out with a new one but nothing yet as it is on the back burner.

I'm talking about the manifold and not the runners or plenum. The factory plenum can be opened up, cleaned up so I don't see that as an issure. There are plenty of runners on the market and the SLP's can be readily modified and reworked to your hearts desire.

So what needs to be done to the Edelbrock/Accel intake manifolds to improve them? Maybe just hog out the runners at the smallest cross sectional area to insure they are the same throughout the length? Do the runner port angles need to change where they meet the head? Just wondering what is needed to improve on the design?

One of my thoughts is to machine out the runners and weld in sheet metal runners of a better design. Of course the question would be what design? Open for suggestions. Would like to see one flow in the 280 plus cfm range.

1989GTATransAm

iTrader: (3)

No suggestions yet? I think what I'm going to do is "blueprint" my Edelbrock TPI manifold. Edelbrock claims that the runner intake hole is 1.750 inches in diameter. I know mine are not that big from previous measurements. So I will grind them out to 1.750 and try to maintain that diameter until the transition to the rectangle portion of the runner that meets the head.

When I get the manifold off I will measure the rectangle portion of the runners. I will see if they are smaller than the head. Depending on the dimension I will make sure the final opening is slightly smaller than the head opening and take that back to the transition to the 1.750" round portion. While I had the heads I made sure they were opened up to a Felpro #1205 intake gasket.

Hopefully at that point they will flow enough air to support my ported Dart Pro One 200cc heads.

Drac0nic

Been thinking that you can get a base and a set of runners for cheap enough, even knocking 3-4 inches off a stock diameter set of runners would have significant improvements. If I had casting facilities I'd make a set of runners that would be designed for a siamesed plenum. They would be an oval shaped tube for the length of the runner until they entered the base where there would be a divider at the last inch to reduce turbulence.

Guest

The whole thing needs to be raised up to flatten out the bend from the intake to the head. Without getting into the runners or plenum, thats about all you can do besides add material to the base for porting. Castings are thin... though better than stock.

You arent going to get 1.75" to the center of the manifold or anywhere close without welding. The shape transition starts about 1.5-2" in from the runner mounting flange and is done about that far from the head side.

1989GTATransAm

iTrader: (3)

Thanks Chris. I haven't played with my Edelbrock manifold as it is still on the car. As you know Don has the long block built up and ready for the install. I will have do some port work on it and go ahead and install it.

So it sounds like the Edelbrock Manifold needs new runners as it is narrow in the center and has to sharp on an angle entering the head. Maybe the trick would be to machine out the existing runners and install new tubular runners and weld them in place. With the proper shape of course.

Or just weld up the manifold and grind away with a new shape.

To DracOnic. That is pretty much what I have done with the first style SLP runners. I also increased the plenum area by extending it into the runners. See link for pictures. I will clean up the plenum and runners some more but I want to concentrate on upgrading the Edelbrock manifold this time around.

https://www.thirdgen.org/forums/tpi/...y+modified+tpi

Guest

Machine it to the size and shape you want and cover up all the holes later.

1989GTATransAm

iTrader: (3)

Yeah I have been doing some researching and thinking about it and I think you are right. I will do some internal measurments and the areas that appear too thin I'll just have material welded on and then grind away. That would be the easiest way to go. Thanks again.

Red Devil

Well, if I can find a stock base I think I'm going to try what me and maximus talked about a bunch of years ago... cut the damn tops off the runners and weld material into an oval shape a little into the transition. Catch now is of course getting the money and time and convincing ede to take on a little welding project. Bah... Maybe next year then.

Guest

I may still do that one of these days if I ever get really bored... and learn how to weld.

Red Devil

I can do the welding, but more than likely a bit, ok, really ugly using the mig. ede on the other hand... I swear he could probably weld steel onto water and still make it look good. That old bastid!

Guest

Well if I end up near EBF we may just have a project in the works.

Red Devil

If you end up anywhere near my neighborhood EBF instead of farther east, there is a list of projects begging to get started/tested/prototyped.

kdrolt

Look at the LS1 intake manifold. It is TPI.... with the defects dealt with. It also helps that the LS1 heads flow extremely well. That intake (as well as the one used on the Daimler Chrysler Hemi) is about the best guide for what-to-do that you could get.

1989GTATransAm

iTrader: (3)

Was over at Dyno Don's today looking at the stock TPI manifold. Chris is right on that one. There is no runner transition where the TPI manifold meets the head. The runner is straight ahead and of course so is the runner in the head. So there is an angle say at the gasket where the two bolt together.

Not sure if the Edelbrock TPI manifold has taken this into account or not. One could add more metal in the area to raise the floor and put in a short side radiuss so to speak. Then grind the portion at the top of the runner where there is more metal to match and maintain the proper dimensions. That would ease the transition somewhat and make for better flow.

Regarding the LS1 manifold I agree it is a better design. Howeve I believe the ports on the LS1 heads are evenly spaced and not grouped together like on the first gen sbc. Anyways need to keep this thing looking somewhat like stock so the smog guys don't get excited. Adding a 1/4" of metal here and there won't raise a red flag if done properly.

Guest

There are only 2 bases that have anything other than a straight shot out of the intake base to the head, and thats the old/apparently now unavailable Accel base and the FIRST base which of course doesnt work with TPI parts.

BTW while you are studying parts, maybe you should take a look at how the throttle body transitions to the plenum (it doesnt), how the plenum transitions to the runners (it doesnt), and how the runners transition to the base (they dont either). A bunch of separately designed pieces that just happen to attach to one another.

1989GTATransAm

iTrader: (3)

I had been toying with the First intake idea. I had put it on the back burner. However the First intake might be the way to go. Then make a custom set of runners based on the fully siamesed SLP runners. Might even be able to modify my SLP runners to fit.

Maybe I would only have to modify the base section where it meets the intake manifold. Then I could use my modified factory plenum. That should keep the smog techs happy from the visual standpoint. Think I will give First a call tomorrow for more investigation. This sounds like the way to go. Thanks Chris for the information and ideas.

Guest

From what I've seen and read, there's almost no way you're gonna get a First base to bolt up to the stock style runners and plenum, even with Jerry's help. Probably have better luck trying to mate their runners to the stock plenum.

1989GTATransAm

iTrader: (3)

I have been spending a lot of time on the www.firstfuelinjection.com web site the last couple of hours. I actually think I can do it. Here is how.

The boss as I will call it on the bottom of the SLP runners is around 5/8" thick maybe a little more. Two each per runner for a total of four. This is the portion the bolts go through. I would then have four made up that match the first intake manifold. This would of couse match the bolt holes and runner holes on the First intake. By the way they claim a true 1.750 inch which I will question them about tomorrow along with the match up of the intake to the heads.

Next cut off the four 5/8 " boss's on the SLP runners. Then carefully line things up and tack on the remainder of the SLP runners to the new 5/8" boss's that match up to the First TPI intake. Then weld up and fill in any gaps that might occur between the First boss's and the SLP runners. Might take some welding but it can be done. Then hogg out the SLP runners to match the First intake runner holes. It should work. I will then use the First gaskets on the bottom portion of the runners and the Mr. Gasket ones that I already have for the top.

I love these projects. Hehehehehe. Got to get 400RWHP with TPI. I have a good friend in the aluminum business and a good friend with a machine shop so that will help. There should not be as much welding in comparison to what it took for my modified SLP runners.

BadSS

The FIRST is about as good as it gets for a true LTR setup on the old SBC. The base to head is more like the upper runner of a good high-performance dual plane intake as compared to the lower runners of a bad or factory dual plane for the stock TPI. The runner to base transitions are still not optimal,,, but they are at a much better entrance angle,, as can be seen in the first comparison picture below. There’s also enough meat there to shape the transition area a little more.

The rough ported FIRST with the stock TPI intake on top should give you an idea of the potential size difference of the FIRST. I've open up the base to approximately 2.7" cross-sectional area through the entire base,, which would be WAY overkill on most applications. Pictures don’t really grasp the size difference. Through the base,,, the ported FIRST looks more like an oval port big-block dual plane than a small-block TPI. The third picture has an as cast FIRST (stock opening 1204 gasket) with the FIRST I've opened up to a "semi-raised" 1207.

The second picture shows the massive size difference between the fully ported FIRST runner on the right (1.9" inside diameter) and a gasket matched set (a little over 1.75" diameter) on the left. If you’ll note height wise,,, the stock base flange on the runners can’t cover the fully ported runner openings. Width wise,, you would have to get rid of the EGR tube and weld the crap out of it. It would definitely be VERY labor intensive for a set of SLPs. Anyway,,, you can weld the crease in the bottom of the FIRST runners to siamese them.

There might be a little hope in modifying the plenum to work,, it's basically the same width but the linkage might be tricky since the edge of the runners would come right to the bracket pad – might have to cut and weld in an extension piece. Actually,,, it might be worth cutting off the front of the TPI plenum and welding it to the FIRST to use the “stock” type throttle body not bring attention to the obviously different mono-blade throttle body it comes with - at least that would be how I'd approach it if I really wanted to try and pass it off as a "stock" TPI.

Guest

Hey Bad SS, thanks for posting the pics. Had not seen those yet. Hope you dont mind I borrowed one...

If you really wanna mate the runners to the base, well take a look:
Note where the first set of runner tubes fall, and then where the second set falls. They dont line up with the factory set on the spacing from the front set to the rear set. I know its a picture, but notice the bolt holes from the manifold (a known fixed spacing) arent off much at all. You'll need to address that.
Notice also the location and angle of the flanges for the runners where they mount to the base. I'm pretty sure they are more vertical and are closer to the edge of the manifold but I've never measured one up. Take a look at the base-head bolt holes again though, you might see there is a difference there as well. I think its a can of worms... personally.

Speed costs money, how fast do you want to go?

Just noticed, if you're lucky... when you cut those pretty SLP's to be far enough away from the base runners, they might just be far enough to the inside to fix the spacing depending on how fast the runners taper inward, I've never really looked at that before.

1989GTATransAm

iTrader: (3)

Attached is a picture from the First website. Notice how close the center holes of the stock runners are to the ones on the First intake. They virtually line up. This is what I'm banking my calculations on.

Drat it. Wrong size photo. To tired tonite to fix it.

Thanks Bad SS for the posting the pictures and information. Going by calculations the 1.75" diameter with the corresponding 2.4" CSA would do my motor just fine. Peak torque should be right around 4800rpm and flow enough air to support the 276CFM that my heads flow. If I can pull it off that should give me the horsepower I'm looking for.

Chris we can talk about my project at the Christmas dinner. See you there.

MikeH

iTrader: (10)

BadSS..Ive read your posts on that intake before. That base looks much better in design then does the Accel, edlbrock, ect. The entry angle to the head is much better.

I know the base is the restriction on my superram even ported.The runners are maxed out. Wonder if that first base could be made to work with the superram runners and plenum. Didnt get a chance to read the whole post or research it but i will.

1989GTATransAm

iTrader: (3)

Talked to Ken today at First Fuel Injection. I ordered the First intake manifold/base, the fuel rails which are required for the First manifold and the gaskets. The project is officially underway.

By the way BadSS has a good point. If I did not have the modified SLP runners I think the easier route to go would be to use First runners. You would have to cut off the flange that the four runner tubes go into and make up a new one that would bolt onto the GM intake. Then reweld the runners up to the new flange and weld and grind as necessary. This is if you want to keep the thing stock looking.

Kevin91Z

iTrader: (1)

Holy crap Allan, here you go again! A little weight reduction and your car will hit the 11's!

Shagwell

For stock appearing and still gaining the performance, I agree with BadSS's idea of moding the plenum to end up with the factory TB. Looking at port line-up, I'd probably go with reworking the FIRST plenum to accept the factory TB. If you want all the gains the FIRST intake has to offer, you need the large, shorter runners that it comes with.

Eveytime I see that intake I want to get it and I don't even have anything to put it on. It's just soo sweet looking.

1989GTATransAm

iTrader: (3)

Hehehe. Yeah I think the weight reduction would start in the drivers seat area. The First Intake Manifold has all the features I have been looking for. By the way it cost less than the others on the market.

1989GTATransAm

iTrader: (3)

Madmax and BadSS. My rough thinking right now is to cut back the SLP runners about 1 1/2 inches from where they meet the base. Then have an adaptor piece 1 1/2 inch thick or what ever dimension to make it fit properly made up with the First bolt holes drilled in and with the proper outside shape of course.

Then drill two 1 1/4" holes in the adaptor centered on the First intake holes. Next step would be to bolt the SLP runners to factory modified plenum. Bolt the adaptors to the First intake. Then slide the factory plenum/SLP runner assembly over the First intake to the correct height and position. Then tack weld the SLP runners to the assembly.

Take the assembly off and finish welding the adaptors to the SLP runners. Again as much weld as necessary. Then the grinding and blending process and maybe more welding begins. Anyways I'm retired now and have the time to do this.

By the way with my 355 setup I'm thinking of sticking with the 1.75" runners in the manifold as this gives a cross sectional area of 2.4 square inches. Any other thoughts on this let me know. Also this should make my total runner length around 13 inches. The exact number will depend on the runner length the First manifold. Head about 6 inches. Manifold maybe 6 1/8 inches. Figure 1 inch for the adaptor piece/SLP runner after the blending.

Tony89GTA

iTrader: (7)

Since it sounds like you have the fab skills why don't you make like a superram setup out of it, you know like fab your own runners and make a boxed plenum kind of like a superram. I bet that would hall a$$, and then at least it will rev to more then 5k.

That FIRST intake base looks sweet how much did they charge you for that and the fuel rails?

BadSS

As soon as the batteries charge in my camera I'll snap a few shots of a stock plenum and SLP runners sitting in place on the FIRST base. There's about a 17-degree angle opening for the runner to base and about a 6 or 7-degree angle at the plenum to runners for the loosly bolted assembly to "fit" on the FIRST. I tell you,,, it lines up a lot better than I thought it would,, and might not be all that hard to fab up like you're talking about doing,,,, which would be similar to a how a spread-port header adaptor works,, just thicker. In fact,,, after you get the "adaptors" on the intake,,, if you put the right cut on the SLP runners,,, it looks like it won't be all that hard to do since your SLP runners are fully siamesed.

MikeH

iTrader: (10)

So they sale just the base? How much did it run you? Didnt see a price on the website.

Mike

1989GTATransAm

iTrader: (3)

BadSS you did what I was going to do when the First Intake arrives. Thanks for the advanced information and the pictures. I was hoping that the First Intake was cut at the same angle as the stock one. If not it won't be that big of deal. Got to cut it anyways so just at a slightly different angle. Maybe I won't have to cut back on the SLP runners as much to make the transition if they are reasonbly close. Thank you for your help and previous posts/threads/pictures on the First Injection which I have reread.

Tony what I have already done is very similair to the Accel Superram in effect. I have extened the plenum out into the runners and that greatly increased the plenum area. Also siamesing the runners extends the plenum down to the intake manifold. So my runners are a couple on inches shorter than the Supperram.

Ok guys the price of the First intake manifold was $185.00 and $115 for the special fuel rails. Kenny threw in the 4 gaskets needed for the intake. I don't know if this is a special deal or not as he said he had one that he could sell me for that price. So naturally I jumped on it.

BadSS

No problem. I hope you can get it to work. It looks like you'll have to do some plenum work to get the spacing right enough to center the runners to the base port - the driver's side needs to go back,, and the passenger side needs to move forward. With the runners centered,,, the big oval siamesed runner feeding the shared intake ports should work fine. Here's a few pictures to get you thinking about the plan of attack.

BadSS

Three more. It looks nice,, always liked the SLP look. I wish FIRST would remove the creases from the castings (at least on the bottom side) so they could be easily siamesed. There's only a couple guys around here that are willing to weld that crease up for me and they're both concerned about them rolling inward.

BadSS

Happy Thanksgiving you all.

Allen, do you see fabricating a new plenum or seriously modifying the existing one? If so,,, I'd cut the base flange straight off the SLPs and weld to the adaptor to give the airflow a straighter shot. This will "roll out" the SLPs away from the plenum. Maybe cut off the t/b mount, split the plenum in the middle, bolt to runners,, then fill in the blanks and weld back the t/b mount??? It'll be a slight pain, but looks doable for sure.

1989GTATransAm

iTrader: (3)

Thanks BadSS for the pictures. They are a great help for the planning until the manifold arrives. That last shot looks like how the finished product will be. By the way what is that bolt for on the top side of the First manifold?

Here is what I plan on doing. I plan on keeping the plenum and at least 3/4 of the upper portion of the SLP runners as is. The rest is as follows.

Cut the bottom flanges and more off the SLP runners. Maybe cut back from the face of the flange 1 1/2" on the bottom of the runners. This dimension will be determined by how much of a transition I have to make. Make up what we will call the adaptor plate and the exact thickness will be determined by what gap is left.

With the SLP runners bolted to the factory plenum I will then center it to the best for all four areas. Then tack weld the SLP runners to the four adaptors that are bolted to the First manifold. If I have to add a 1/4" of weld to the outside of the SLP runners in certain spots so be it. Then start the blending and hogging out procedure. If I happen to grind through in a certain area I will just have more weld added.

From what I can tell in you pictures this should work. When I have everything in hand I can make a better call. With the say 1 1/2" thick adaptor plate plus the welding on the outside of SLP runners I should be able to make a smooth transition from the First manifold into the SLP runners.

Regarding your project. If you have the crease welded up you need to have everything bolted together to keep the runners from warping. Then you could siamese the runners down however far you want. I would do some study on wave tuning to get the proper length of runner. With my 13 inches of total runner I'm about where the LS1 346CI motor is. A good place to be for a good blend of torque and horsepower. I hope to be able to rev this thing to around 6300rpm before the power really drops off. Maybe peak horsepower around 5700rpm.

BadSS

Thanks Allen. I asked the guys here about bolting the system together and welding the creases, but they both said they could still pull in and as soon as it was unbolted they may not want to line back up. Fortunately Ken over at FIRST said that if that did happen he could fix them for me,,, so I'm going to get that done this week. I've spec'ed it all out, 2.68" cross-sectional area and about 15" total runner length is where I need to be.

You’re going to have to do a little porting to get a 2.4” minimal cross-sectional area in the base. The runners are all not exactly the same. This posed no problems for me when I ran it box stock on my “400-horse” 355,,, at least the color on all the plugs were consistent,, but it is something I had planned on fixing for the fully ported project,,, and will do before bolting the other FIRST back on the 355. I have a feeling you’ll want to do the same thing,, so here’s a little heads up.

These are rough estimates since I haven’t made molds of the runners yet. Runners 5, 6, and 8 have an as cast minimal cross-sectional area of about 2.05” (1.17w X 1.75h) at a pinch point as the runners make a turn into the head opening. The rest are as cast at about 2.20” (1.21w X 1.825h). The transition area goes up to around 2.5” in all but #1 (correction)and #8,,, where it is as cast around 2.35”. #8 makes a dip down to clear the distributor as opposed to machining the top of the runner for clearance. It looks a little narly, but there’s plenty of material there to smooth the runner transition on that port and get up to the 2.68” I went with since almost half the port is below #6 (so you can use all the area to grind for that half of the port),, although it started getting a little thin at a couple spots. It’s also a little thin in the lower half of #1 (correction) due to the water passages in the intake,,, so be careful there. I got it to 2.68”,, but was getting a little worried. I concentrated the majority of my porting on the top of the port and “over-sizing” the outside walls adjacent to the short-turn pinch point going toward the heads.

The base to runner openings are cast larger than 1.75",,, closer to 1.85",, most are not perfectly round,, smallest point on the two I have was 1.82" and the largest was 1.91,,, using an average of 1.85” you get about 2.68” area – you can get this area a lot larger than 2.68”. I had not touched the runner openings on the base for the rough cut port in the pictures (that’s why they don’t look perfectly round,,, they’re as cast). Of course increasing the area of the intake tract as you move toward the plenum is pretty much what you want to do. There is a lot of potential in these FIRST intakes and I’m happy to see someone else that’s going to be able to tap into that potential. I have no question in my mind that you'll be able to achieve your planned goals!!!!

Oh,,,that bolt is to block off the the EGR crossover tube opening that would run from the base to the plenum. The plenum has a block off bolt in it as well.

Have a good one, Kevin

1989GTATransAm

iTrader: (3)

About the EGR cross over at the bolt. I had an idea that is what it might be as that is why I asked. I'm considering places for the EGR. I have some ideas and that area is one of them along with mounting the EGR on the Plenum. Would take some more maching but I have a mill and lathe in my garage. I will let my friend handle the adaptor pieces for the SLP runners as he is a very good R&D machinest. Might have to seriously modify an EGR valve. Hahaha.

Thank you again for information regarding the runners inside the manifold. That is good info. It seems like tall and narrow is the way to go regarding runners these day. So like you I will try to raise or lower the runner port to get the right CSA where possible.

Sounds like I will have an opening of around 1.85 inches where the runners meet the manifold. I can live with that.

I saw in your post from a couple of years ago where you marked a Felpro 1205 gasket on the manifold. Fortunately it looks like the bottom side where the short side radius is needs more work. This will help in the transition angle from the manifold to the head. That is where the Edelbrock and factory manifolds have none. So that is good news as I will be using the Felpro 1205.

As I posted above I order the fuel rails from Ken. This is another area I will investigate and see if I can make something along the lines of the factory unit. From your other post I know there will be clearance issues. Hopefull nothing a little engineering can't solve. Again thank you for the great information and help. Allen

1989GTATransAm

iTrader: (3)

Ok I think I have the EGR valve figured out. I will take the stock one and cut the ears of off it where it mounts to the base. I will chuck it up in a lathe and machining up from the bottom where the ears were I will cut it to the proper diameter to be threaded. Should be able to get a good 3/8 to 1/2 inch of thread.

On the side of the EGR valve that goes to the vacuum I will drill a hole and put in a short piece of tubing. With a hose attached to that I can run this to the plenum. Meanwhile I will have to put the hole in the proper place on the EGR port on the First intake manifold where the bolt is. Then thread the hole and screw in the EGR valve.

That should lower the EGR valve enough to clear the bottom of the plenum. I can also shave some off the top of the intake manifold if I have to lower the EGR some more. So basically I will modify the EGR valve so that I can screw it into the First manifold.

Orr89RocZ

iTrader: (20)

i dont think much can be done to the stock style TPI base setup...except making the runner holes bigger and maybe at a better angle to the head intake runners.

also i'd like to see siamesed bases and the runner holes fully polished for smooth airflow.

then make big oval runners to the plenum...thus making effective runner length smaller.




OR

i'd like to see individual plenums with shorter runners and individual throttle bodies. that be cool. not sure how you'd hook up the throttle cables tho.

1989GTATransAm

iTrader: (3)

The big oval on the runners is a done deal. Here in Southern California I know of 3 sets. Now working on the best base and fitting those runners to it.

1989GTATransAm

iTrader: (3)

The First TPI intake manifold arrived today. Like BadSS said it is a quality piece. I'm looking forward to working with it. It addresses all the issues that are wrong with the other aftermarket manifolds.

I will start another thread on how I will mate my SLP runners to it, how I did the EGR and the fuel rails. BadSS already did a good job on how to port it. My motor is only a 355 so I will not make my CSA quite as large as his.

Hopefully this will be the final part of the puzzle to get 400rwhp NA from a TPI system and 355CI.

smallblock383

Its good reading all of these threads to this post. I went through all of this bullcrap a few years back when I had my 383 built. I honestly came to terms with scrapping the TPI and going to a miniram. For all the work, machine time, and buying bigger runners, throttle bodies, and lower plenums, it was just shy of what the miniram cost me.

1989GTATransAm

iTrader: (3)

Some of us like to be a little different and go into uncharted territory. I'm not aware of anyone who has mated the First intake to the SLP runners and factory plenum. At least successfully.

Taking to Ken I know some have tried. The First intake has a great runner design. You can open it up to support a 400 cubic inch high performance street motor. Maybe one of the best features is the transition from the manifold to the head. It has a very good short side radius and top radius.

Im going to have the guy that ported my heads do this part. He has a lot of experience working on the ssr in the heads. By the way the factory and the Edelbrock have no short side radius. Just angles into the head. I believe the ssr part is as important as opening up the cross sectional area of the runners.

1989GTATransAm

iTrader: (3)

Most likely my last post on this thread as I will start a new one with the new parts and machining. The First Intake manifold is now at the machine shop and I had a good discussion with the machinist. What I'm having done is not hard at all to do just some time.

Having the adaptor plates made up for the SLP runners and the stock fuel rail manifold set up modified to fit the First intake. Also fitting the EGR valve. If one did not need the EGR or wanted to use the First fuel rail assembly it would be that much easier.