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I'm interested in how you selected the cam to go with the TPI intake. The cam I have now is a Comp Cam XFI special grind, but it was intended for use with the higher reving Mini-ram. I want the cam to be very obvious but with "reasonable" idle quality, and I want to get as close to the 500HP flywheel number as I can. The current cam has 112 lobe separation, gross lift is .546 intake, .543 exhaust. duration at .050 is 238 intake 244 exhaust, lift at .050 is .3640 intake .3620 exhaust. Roller rockers, roller lifters, 1.5 ratio rods. AFR 1038 heads, special grind 64CC chamber port matched to the 1205 gasket. I plan on having reasonable amounts of porting done to the intake, nothing like where you've gone (can't afford it:-) I know there's more to this but any suggestions on where to start or what to look for in a cam that will maximize the potential of the intake/engine would be greatly appreciated.
There are a ton of factors to consider when picking a cam. However, one of the major considerations is how it “matches” with the stall speed of the torque converter. At least you shouldn’t have to worry about that. Assuming that cam was “matched” to the stall converter with the MiniRam (or the stall speed was matched to the cam), the cam will not be too big for a 391 with the FIRST. I don’t know your stall speed, but it’s in the ballpark of the cam I’ll be running in the new 406 with the “MegaRam” and a 3,200 stall speed converter.
Current stall is 2800. This said, Precision Automachine is selling what they categorize as "A complete FFI TPI system" with FAST ECU, Intake, injectors, fuel pump, all wiring, sensors etc. One of their posted caveats is this unit must use a cam with no greater than 224 duration on the intkae. My cam is 288. Any idea why they would make that comment?
Badss, please ignore the question I posted previously. My duration at .050 is 238, not 288, and I talked to the vendore. he explained the comments. Sorry
Do you have any flow numbers from the ported first tpi?
If I’m not mistaken, Allen (1989GTATransAm) had the #1 port on an out of the box FIRST base flowed at 301cfm. In another post we determined that #1 or #8 should be the worst flowing ports – others are less restrictive and #1 and #8 would need a little help to equal the others.
Later he had the ported base flowed again on the #1 port after opening it up to a 1206 gasket with modified and ported SLP runners (only about an inch of the divider left) with the adapter he was running to mate up to the FIRST base flowed 311cfm.
I know it was a good bit of work put into Allen's FIRST, but I’m going guess that the base on mine opened to a 1207 with the entry openings around 1.92” with the fully ported and siamesed FIRST runners (about half the divider left) would more than likely flow in the 325cfm range.
So if we were to build a 355 with Afr 195 heads, street ports, the first system has the potential to be ported beyond the flow of the heads? Would this allow it to run to a rpm comparable to the HSR?
The short answer is yes to flow and no on the RPMs, but there’s more to building an engine for a street car than RPM capabilities.
The minimal cross-sectional area of the head sets the maximum RPM potential and the head flow determines the maximum HP potential for a given engine. Intake flow equal to or greater than the head flow helps to insure it will not limit the potential HP capability of the head. An intake with a minimal cross-sectional area equal to or greater than the head’s MCSA helps to insure it will not limit the RPM potential of the engine. HOWEVER, due to the physics involved, any intake runner length much over 3” on a SBC will start to reduce the RPM potential/capabilities. So, a longer runner will never be able to match the RPM potential of a short runner intake on the same engine.
When building a racing engine, as long as you’re not exceeding the part’s capabilities, RPM is king – it’s easier to make higher HP numbers at higher RPMs. For racing, big heads, big cam, steep gears, and high stall speeds are part of the “equation”. However, the “power under the curve” (a factor of shift point, stall speed, and shift recovery RPM) is a major consideration as well. You see a lot of tunnel rams on racing engines with runner lengths greater than 3”, so giving up some RPM potential for the extra power under the curve the longer runner length gives is not a bad thing even for a racing engine.
For a street engine, if you’re not concerned about the idle speed and vacuum and the stall speed and gear ratio, you can treat the build similar to that of a racing engine. However, most street engines are a compromise of idle speed, vacuum, stall speed, and gearing – the milder or the more compromised the build (smaller cams and lower stall speeds) the more critical that power under the curve becomes. Adding runner length increases midrange power but at some point it will take more power away from the top end than it can make up “under the curve”. That point will vary depending on different sized engines and with different transmissions. If you’re running a close ratio manual transmission, the shift recovery is higher than a wide ratio automatic, so you’ll have a narrower rpm band for the “power under the curve” (favoring upper RPM power). While making for a very spirited “driver”, it’s harder for a long runner intake like the FIRST to equal the quarter mile performance of a shorter runner intake like the HSR with a 5 or 6-speed transmission – especially with larger engines. However, it’s much easier for a long runner intake to equal and possibly perform better than a shorter runner intake with a wide ratio automatic and a “typical” 2500-2800 stall speed converter.
More like frosted glass lol. I get what your saying, so as the plan being a street car with the ability to go down the track, I think our engine plan should do fine. Love the look of the tpi setup
Does anyone have any real flow numbers for the FIRST as a complete assembly (perhaps with before and after porting figures)?
I just got mine ported and we weren't able to get anywhere near 300 CFM with the manifold bolted together as an assembly and ironically enough (contrary to what I've read here), the base appears to the be biggest bottle-neck out of everything.
Ports 1 and 8 are horrible (especially 8) and as an assembly, my average CFM across all 8 ports is only 267.
Flows with just the plenum and runners assembled, we were able to get a respectable 282 - 293 CFM range on all ports but once we bolted on the base, our average dropped to 267 (with #8 being the worst, coming in at 257 after porting- It was 221 before!). A big bottle neck.
Granted, I'm running a 1205 gasket vs a 1206 or 1207 but 300 CFM should be attainable with a 1205 (my current 195 heads flow 294 @ .550). The problem with the base are that the angle(s) in which the ports dump into the heads are all wrong and stifles the flow. Unfortunately, even with the bigger 'as cast' runners and ports, you can't port the base to flow real efficiently with the material available.
While I still plan to see what this intake will do on my 409 SBC, based on the flow of my heads compared to the intake, I'll be leaving about 70 HP on the table. While I am optimistic, my actual flow numbers are disappointing.
Does anyone else have any real-world numbers to share?
When porting the base on any of the manifolds we strive to change the angle so that it better matches the head. That includes raising the injectors and welding. The numbers I got were off of Joe Sherman's flow bench. Probably depends on how the flow bench is set up. When done I used a 1206 manifold gasket. I think BadSS may have went to a 1207 gasket.
When porting the base on any of the manifolds we strive to change the angle so that it better matches the head. That includes raising the injectors and welding. The numbers I got were off of Joe Sherman's flow bench. Probably depends on how the flow bench is set up. When done I used a 1206 manifold gasket. I think BadSS may have went to a 1207 gasket.
Thank you for clarifying 1989GTA-
I can totally see needing to raise the injectors and welding to improve the port angle but unfortunately, that is more effort and money than I really want to invest in this manifold.
I was just surprised to read all the threads touting "300 CFM base out of the box" compared to what we experienced. #8 only pulling 221 was especially disturbing- We expected 1 and 8 to be weak but not that weak.
Perhaps Ken can incorporate some of these changes in his next revision of the base casting.
Elm
It sounds like you all mounted the plenum opening to an adapter and blew through the intake for flow numbers. While I get that the air would be moving in the same direction, and in principle once “pressurized” there shouldn’t be a difference, but I can’t help but think there would be some variance. For instance with it upside down on the bench, I’d think there would be some variance whether the other ports were just taped or blocked off at the flange or if they were taped off at the plenum/ front of the runner (or something filling the other seven ports all the way to the plenum. Maybe not, but I’m sure there is someone flowing intakes like that could say for sure.
Plus with the blow through, I take it that no radius is used? With the intake bolted to the fixture, I’m sure a radius was/is used at the runner entrance – maybe Alan can confirm that one was used to get the 301cfm numbers they got. I know for a head that can make 20+ CFM, depending on how large a radius is used.
Still, your numbers were a little disturbing to me as well until I started trying to find some information on blow through flow testing on intakes. I ran across the following article: http://www.hotrod.com/how-to/engine/...ifold-porting/
With the intake flowed upside down an out of the box Performer RPM only flowed 216cfm and a Victor Jr only flowed 241 cfm (average of all 8 ports). When bolted to a 300cfm head, the RPM flowed 251cfm and the Jr flowed 247 cfm. Even through they flowed better bolted to the head, it is a still a little disturbing to see that kind of drop on a 300cfm head.
However, when they put it on the dyno the average HP from 3600 to 6600 rpm was 512HP (594 peak) for the RPM and 503HP (598 peak) for the Victor Jr. Porting the RPM they got a 297cfm average with just intake and 267cfm bolted to the heads – it only made 6 more peak HP (600) and averaged 510 HP (less that the unported version).
Long story short, I’m not so sure after doing a little digging that you (or me for that matter) have anything to worry about a winding and twisting intake like it is averaging 267 cfm across all ports. I would still expect your average power numbers to be insane.
It sounds like you all mounted the plenum opening to an adapter and blew through the intake for flow numbers. While I get that the air would be moving in the same direction, and in principle once “pressurized” there shouldn’t be a difference, but I can’t help but think there would be some variance. For instance with it upside down on the bench, I’d think there would be some variance whether the other ports were just taped or blocked off at the flange or if they were taped off at the plenum/ front of the runner (or something filling the other seven ports all the way to the plenum. Maybe not, but I’m sure there is someone flowing intakes like that could say for sure.
Plus with the blow through, I take it that no radius is used? With the intake bolted to the fixture, I’m sure a radius was/is used at the runner entrance – maybe Alan can confirm that one was used to get the 301cfm numbers they got. I know for a head that can make 20+ CFM, depending on how large a radius is used.
Still, your numbers were a little disturbing to me as well until I started trying to find some information on blow through flow testing on intakes. I ran across the following article: http://www.hotrod.com/how-to/engine/...ifold-porting/
With the intake flowed upside down an out of the box Performer RPM only flowed 216cfm and a Victor Jr only flowed 241 cfm (average of all 8 ports). When bolted to a 300cfm head, the RPM flowed 251cfm and the Jr flowed 247 cfm. Even through they flowed better bolted to the head, it is a still a little disturbing to see that kind of drop on a 300cfm head.
However, when they put it on the dyno the average HP from 3600 to 6600 rpm was 512HP (594 peak) for the RPM and 503HP (598 peak) for the Victor Jr. Porting the RPM they got a 297cfm average with just intake and 267cfm bolted to the heads – it only made 6 more peak HP (600) and averaged 510 HP (less that the unported version).
Long story short, I’m not so sure after doing a little digging that you (or me for that matter) have anything to worry about a winding and twisting intake like it is averaging 267 cfm across all ports. I would still expect your average power numbers to be insane.
BadSS,
Thank you for chiming in. While I am still somewhat optimistic that the intake will give my my desired result, the flow numbers produced were less than expected.
Yes, the intake was bolted plenum down to the flow bench and yes, an adapter with a 3/8" radius was used. Since this intake is somewhat awkward to flow, it was really the only option without having to create all sorts of custom fixtures.
Based on the link you provided, it appears sucking vs blowing through the manifold is irrelevant when measuring flow:
"While some perceive this flow procedure with misgivings, intuiting that the flow bench is blowing into the manifold while the engine sucks, from the standpoint of airflow volume the only thing that matters is the pressure differential across the manifold. The bench and the intake manifold runners don't care which side of the flow system is providing the force creating the pressure differential."
Originally, we expected the plenum and runners to be the bottle neck so we were quite surprised at the numbers that came back when all assembled.
Personally, I would be curious to see what the base would flow on it's own but I didn't have the time and resources to create a custom fixture to test it by itself.
We did observe that when short tubes were attached to the 'head' side of the base (to mimic a head being in place) that it did marginally improve the flow numbers.
"I’m sure a radius was/is used at the runner entrance – maybe Alan can confirm that one was used"
That is correct.
Interesting that in the above picture the air would be flowing backwards.
The Superflow bench in question can 'suck' or 'blow' so nothing is backwards. It's also seems that the direction of flow is somewhat irrelevant as a restriction is a restriction based on the article provided by BadSS: http://www.hotrod.com/how-to/engine/...ifold-porting/
Unless someone has an identical test scenario and fixture to contradict the numbers we've recorded, I am inclined to believe they are what they are.
I agree in principle there shouldn't be a difference and don't think there would be with a single stand alone "pipe" in a blow through verses pull through flow. However, I’m also rather convinced that you can’t compare the flow numbers for intakes flowed in different ways.
I guess the point I was trying to make was the article only got 216cfm for a Performer RPM using the blow through fixture/method. I’ve never seen a published number less than 275cfm for an RPM, and typically they’re indicated to flow in the 285cfm range. I tried to find something from Vizard or McFarland on intake flow numbers and could only find where Vizard said the Air Gap RPM dropped flow around 4.7% on a “racing head”, but the article didn’t give the head flow to see what that might be. Assuming 300cfm, that would be around 286.5cfm,, kinda in range with the other published “pull through” numbers for the RPM style intakes.
I did find a porter that published his “blow through” flow numbers and an out of the box RPM Air Gap flowed 210cfm, Victor Jr 237cfm, World Products Motown 255cfm, Super Victor 271cfm, and the Street Dominator 283cfm.
All these intakes were tested in the Hot Rod and Car Craft dual plane and single plane intake shootout on the same test engine, but used a smaller cam and carb on the dual plane shootout. Kinda sucks that they didn’t use the same cam and carb, but it’s understandable since most people wouldn’t use the same cam and carb with the different style intakes. Still, not that you can compare the dual plane and single plane power numbers, you can on the single plane - Peak HP and Peak TQ, was:
Air Gap (210 cfm) – 474/508 (232/240-.540/.559-112 cam and 750 carb)
Victor Jr (237cfm) – 523/507 (248/256-.613/.613 – 106 cam and 850)
Motown (255cfm) – 534/508
Super Victor (271cfm) – 523/506
Strip Dominator (283cfm) – 543/514
What this tells me is that the upside down blow-through flow numbers don’t accurately reflect what the intake would flow when bolted to the heads nor can it be used for an indication of the power it would make. If it did, the Motown (255cfm) would have made less power than the Super Victor (271cfm) and the Victor Jr (237cfm) would have made a lot less power than the Super Victor (271cfm) and it made basically the same power on the dyno. Incidentally, the cross-sectional areas are increasing larger on the intakes above that made more power – the cross-sectional area and how well the intake transitions/directs flow to the heads have a lot more to do with the power it makes than the standalone flow numbers (regardless of flow direction - unless it is flowed while bolted to the heads).
Anyway, I agree, the numbers are what they are, but I’m thinking you should feel pretty good that the FIRST flowing on average of 267cfm, more than the Motown's 255cfm and is right there with the 271cfm from a Super Victor. At least I feel a lot better about it now - lol
BadSS,
Thank you again for your insight and perspective-
I guess we all (myself included) tend to get wrapped up in the numbers vs actual observed performance. I know dyno numbers are another one of those metrics that folks often get wrapped up in the actual number vs using the number as a reference.
The biggest frustration in the aftermarket area has always been the lack of standards for testing and the lack of documentation on HOW they tested. Trying to compare camshafts, carburetors, throttle bodies and intakes from one vendor to another is difficult since everyone seems to measure their product a little different than the other so a true apples to apples comparison is virtually impossible unless you do it yourself.
Unfortunately, I probably won't be able to report back on my actual performance with this manifold for another year as I still have a lot of other work to do regarding the fuel system, wiring and PCM tuning.
But you guys will be the first to know my results!
I really didn’t want to post anything else in this thread until I had the engine running in the car, but family and personal health issues along with a new job has all put a stop to the hot rod project. Health issues seem to have subsided so hopefully I can start tinkering around and maybe have something to report over the next 6-9 months.
That said, this post fell victim to the photobucket extortion and I’ve had a couple people ask about the pictures that were posted. So here they are with some inserts from the original text.
Here’s a shot of the intake flange - left side after welding,,, right side after smoothing things out and blending it in. The intake can be ported out to a 1207 gasket, but my heads were ported to put them in a "semi-raised" position and the intake needed a little additional metal at the top of the port.
Top half of the picture below shows the ported FIRST base on top of an unported FIRST. Bottom half shows the inlet side of the ported FIRST base. I haven’t touched the as cast opening yet – it is right at 1.85” ID
I wanted to fully siamese the runners to about the halfway point. So, I had the center creases of the runners welded. Here’s a picture of the front and back welds - I threw in the old ported FIRST runner to reference how large the bottom openings will end up being.
Here she is mocked up with the welded runners. There was some concern that the runners might warp,, but everything fit, sealed, and lined up perfectly (Self Racing Heads did a bang up job on the welds).
Here’s step one completed on the first pair of runners. I knew it was going to take some time,, but man,,, these runner have a ton of meat to remove.
Finished top half porting of the runners. I was more than just relieved to get them "done" - lol. It probably took about 16 hours on them,, literally removing 1/2lb from each runner. I wish I would have taken a picture when I weighed them,, my buddy didn't believe it until he saw the difference on the scales for himself.
I smoothed out things on the outside and shot one with black primer to get a preview of a finished runner – figured the welded runners would be more of a tip off that it wasn’t just a 305 TPI under the hood.
Again, I hope to be able to provide an actual update over the next 6-9 months.
This is bad ***! I am definitely following. I have a First laying around I planned to run with a procharger while I build a dart block and send out a superram to be ported for the new setup.
Like you BadSS, I've run into a bit of bad luck health-wise the last couple of years and have not been able to get my project on the road yet either.
Treatments are going well so I plan on getting this thing running this Fall by hook or crook!
I have been able to get everything assembled and I've even been able to fire it up but the tune on my 0411 PCM needs a bit of work before I can take it on the road.
This isn't the finished product but it's good enough to run this way temporarily.
Elm
The intent was to fully port the intake for a flat-top 406 with old-school Dart “Race Series” 220 CNC ported heads and a solid roller cam. As fate would have it, I had to abandon the project and haven’t been able to get back on it until recently.
The heads were CNC ported with a semi-raised runner program opened up to a FelPro 1207 gasket. While the FIRST will cover a 1207 port without welding, it needed a little extra material added to the top of the flange to be able to cover the “semi-raised” ports of the Darts. Here’s a shot of the intake flange - left side after welding,,, right side after smoothing things out and blending it in.
The base intake porting is done, except for the final clean-up and port alignment for the head and runner openings. Top half of the picture below shows the ported FIRST base on top of an unported FIRST. Bottom half shows the inlet side of the ported FIRST base. I haven’t touched the as cast opening yet – it is right at 1.85” ID so it won’t take much to finish it to the planned 1.9” ID. Pictures really do not do this thing justice,,, it looks more like a big-block intake in person – especially after the porting!
I wanted to siamese the runners on the FIRST, but the creases in the runners will only allow you to “notch” siamese the runners (similar to how the SLP TPI runners come out of the box). Here’s the link to the page of a thread where gbayfisher “siamese” notched the FIRST runners about 2” for his AFR383 build – starting at post #707. https://www.thirdgen.org/forums/engi...-383-a-15.html
Here’s a picture from that thread showing his port-work – nice job by the way!
While notching the runners will add a few hundred RPM to the FIRST, I wanted to fully siamese the runners to about the halfway point. So, I had the center creases of the runners welded. Here’s a picture of the front and back welds - I threw in the old ported FIRST runner to reference how large the bottom openings will end up being.
Here she is mocked up with the welded runners. There was some concern that the runners might warp,, but everything fit, sealed, and lined up perfectly. The plan is to blend in the welds and paint the runners with a black epoxy or crinkle paint. It looks pretty good as is (Self Racing Heads did a bang up job on the welds),,, but I don't think I could pull off “It’s just a little ole 305 TPI” with it looking like this!
Stay tuned for pictures of the siamesed ported runners and plenum. It may take a while for the updates, but the “MegaRam” TPI will definitely happen this time around!
Can somebody help me with stage 4 porting and Siamese work?🙏
Thanks for bringing this post back to life and reminding me how long it’s taken me to get the car back on the road.
I’ve started and had to stop numerous times over the years. I’ve made some progress on the car over the past couple months and it’s going to take a few more months before I’ll be able to get it running. That’s assuming nothing major pops up like it has in the past.
OK, I don’t know what Stage 4 porting is, but I’m going to assume you’re talking about a full tilt boogie port job. You also said you were interested in Siamesing.
I can tell you, to properly Siamese the FIRST’s runners, you’ll need to find someone to weld up the inside and outside creases as far down as you want them siamesed. I ported mine all by hand, but if I had to do it over again, I’d find someone that could mill out the majority of the runners and then I’d finish it off by hand. Just the mill work alone might be relatively expensive, but it would cost a small fortune to pay someone to do the runners all by hand. I did it for myself, but I sure wouldn’t do it for someone, even if they paid me a reasonable amount for my time, which I doubt anyone would want to pay that much.
The base is cast with an approximate 1.85” opening at the runners and around a 1204 opening at the heads. However the native port size near the exit and throughout the base is approximately the size of a 1206 gasket. The casting makes a relatively sharp bend into the 1204 “as cast opening” about 1.5” from the exit. It doesn’t take much to open it up to a 1206 sized gasket opening, which could be overkill, depending on the build.
Base runners 1 and 8 need a little work, but not much. It’s possible to open up the base exit to a 1207 sized port (and the base runners’ cross-sectional area to support it) for a balz out 406 or 434.
Anyway, I can’t help you with who can do the work, but hopefully the information will be helpful in finding someone.
What are you building? The reason I ask is the thing as cast with just some port matching to a 1205 without any other grinding can feed a pretty healthy 383 or even a fairly healthy 406. You just have to match up the cam to the heads, cubes, compression, and physical limitations of the long runners. I’ll also add that it’ll typically need a different cam than you see most using for a typical GM based TPI.
This thing is a lot different that the typical GM style TPI in that it’s actually possible to open it up too much for some builds. Meaning you could kill off more power “under the curve” than you could make up on the top end.
05-20-2014, 03:19 PM
