Tom400CFI

Whoa! So what we have here is a massive missrepresentation of the truth...kind of like saying that you never complained about your car climbing hills on the highway. Huckabee? Trump? Let's re-examine:
...and you post links to someone's DIY modified TPI?? In what way do those links have ANYTHING to do with GM prototype TPI's, or research on the LT5??


Do you realize that those modified TPI intakes are guys trying to get TPI to behave more like an LT1 (or a mid length runner intake) by shortening the length of the runner? Do you realize they live in CA and have to pass visual and have CARB cert'ed parts...so the only way they can do that is to keep the same look on the outside, while shortening the functional runner on the inside...to move the RPM range up...to make more hp. You understand that if they weren't constrained that way, those same guys would be running an HSR or Miniram and long tube headers. You "get that"...right?

You should pay special attention to post #4 in the first link...and post #7 in the second link.


.

Phoenix'97

No, I don't "get it". Everyone was praising the superram as the next evolution of the TPI intake and yet the same performance seems to be achievable by opening up SLP runners. Also, you didn't read the first link, did you?

Customblackbird states, "they where made after a secret design that GM never put out...sum how he got the designs lol. basically its wats stated above. the cast aluminum SLP's are opened and ported completely then they weld in aluminum and make it look flush. again this acts like a larger plenum but at a cost that would say.... is it worth it? also the difficulty of welding cast aluminum. personally why not just get a set of stockers, cut the inter tubes in half and half cut the outer tubes then get a tig welder to weld in aluminum thin gauge sheet stock and come up with the same idea... it would prob cost less, easier to work wit, lighter, and would have that sexy fabricated look to it. thats what TPIS did to there siamesed runners, but u could create larger plenum area by following the design above."

Now, how true the story is, we may never know since GM would have tried to keep this a secret and burned it. Now, if an engineer smuggled this design out, it must have been a design worth replicating if GM wouldn't produce it.

Now you want a read about the LT5?

Demise of the LT5 Engine

http://www.corvetteactioncenter.com/forums/c4-corvette-zr-1-a/14104-demise-lt5-engine.html

pologreen1

Not reading this too close or giving much thought, but I'm not buying it.

I keep saying the word plenum to you.

In an engine build this is important and should be the same amount of cubes as the engine. The TPI is like 150+ or 180 IDR anymore.

Superram is nothing miraculous really... it's shorter runners with much larger plenum volume. An engine needs air to breath, if you have a shorter runner it will breath faster, and larger plenum it will breath deeper , if not you choke which is what you want.

real guys that did real test show the real flows on all these pieces, I found the info recently and it was done in the mid - late 90's. i disagree with the equal statement of those runners. Just not enough are to be equal.

you need all the choke you can get and your idea will be great on paper.

Tom400CFI

I DID read the first link. Your post about "GM's "secret design" made it seem like you had read an article from a credible publication. What you really read was some lore from a poster who types like this:
"sum how he got the designs lol. basically its wats stated"
^That basically = made up bull ****. It's not an article, it's not confirmable. I read it...I dismissed it. I'm waiting for the article from a credible source.



How true is it? Probably not true, but the "article" (the quote from an illiterate) that you cited isn't work jack. As for the design of the SLP runners...yeah, we all already know that they are better than stock; they shorten the stock runner and raise the RPM range (somewhat). Don't need made-up stories to make that case.




Well at least this was from something that was published. I've already read it...I own the book that quote was from.


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Tom400CFI

Oh yeah and...

Of course people praised the Superram; it uses shorter runners...similar to the SLP runners. But the Super ram works way, WAY better than the SLP runners. Opened up SLP runners? I think the Super ram is still better...but in either case, the goal is to reduce runner length in order to move the RPM range UP...the opposite of what you claim you want to do.

You should pay special attention to post #4 in the first link...and post #7 in the second link.

Phoenix'97

You "think" the Super Ram is better? Well, thank you for your opinion. As per that forum, even with the SLP runners opened up, the function of the long runners is not diminished, so says the poster. Even then, for my build, keeping the SLP runners as they are should be more than enough for what I plan to do. The poster has high power production goals whereas I am more concerned with my daily driving experience and occasional launches from green lights. I don't demand massive torque on the low end, but something to get me going, something to get my rear feeling like it will swing out with the pedal mashed down to the floor, and something that throws me in my seat good enough to make me happy! I am talking mild, MILD, power here compared to what you guys are making.

So, I have the vision down for what I want to do, the question then becomes if I can make it happen with that TPI intake and what the engine builder and tuner has to say to give me what I am seeking, my own version of a General Motors production car tuned for the street but more powerful than what I have now bare bones stock LT1 with poor low end torque.

Tom400CFI

Hey! You're welcome! That IS what you came on this forum, looking for right? Opinions from people who know about this stuff?
And you DID say...



How likely do you think that is? You shorten the runner, raise the RPM range, but with no consequence? I mean, I KNOW that shortening the runner is the right thing to do for more power, but come on. There is no "magic" in the SLP runner.


Man...you know what would perfectly meet those goals? A stroker or gears.



Really? I have a stock LT1. Something might be wrong with your motor if it's not making similar power to mine. Wait...didn't someone already say that?


...but with more low end tq than a stock TPI....right? You know, ~300 lb-ft at 1000 RPM isn't what most people would call "poor low end torque"

Did you pay special attention to post #4 in your first link...and post #7 in the second link?

Kevova

There was a lot research with TPI in the eighties. There have been a few threads where people came across some one off manifolds, runners, and plenums. The ridiculously long runners which killed a lot of the l98 performance. There have been links to a lot of information in regards to the TPI if you read the. If the gen II engine would have been slated to be installed in trucks there probably would have been a dual runner intake with the internet of a high flat torque curve. It had already was decided that was not going to happen. L31 would bridge the gap until the LS went in pick ups in 99 ( 00 C/K) There is a sbc/LS block not for the Gen II. Being hung up on 25 inch runners and the TPI. There are several companies making tubular front subframes for both drag and road racing. They are lighter and stronger than the stock one. Lowering the engine will lower the center of gravity, should improve handling. You most likely need a shallow road racing style pan. Subframe is 600. Btw the ls deck height is about .200 higher than the sbc. To hybrid an lt1 will take a one off custom block.

GREGGPENN

I have a vision!

It's too bad you don't know how to work a clutch to get anything UP TO and including burn-outs with the CAR YOU ALREADY HAVE!

Even if (in 5-10 years) you figure out how to cut, modify, and/or stuff a TPI under the hood of your car, what are you going to do about the god-awful weird-looking wrap-around rear wing on your car? Or the short wheel base?

You should just SELL that car and buy one already equipped with a TPI. Win-win....

Tom400CFI

Totally.

AgentEran

You just dont know how this $hit works.

Phoenix'97

http://www.corvetteforum.guru/module...=10259&forum=1

cuisinartvette Posted on: 2009/11/13 18:57
Deck height should be the same, the rest is dictated by intake. LT1 intake should clear about any hood.

Who is telling the truth?

Phoenix'97

Haters will always be hating. That is fine. I am using a totally different philosophy for my performance goals!

GREGGPENN

This is one of the most important statements in this thread. MOST guys do consider horsepower over torque. I'm one of the few that went the other way...but did so in a manner HOPING to capture some of both.

That 1989 TransAm guy (from 3rd gen) obviously had some of the same thoughts I had...along with people looking to supercharge or build stupid-powerful setups with extra power EVERYWHERE. The point I'm trying to make is people sometimes do shoot for mid-low and high-rpm power. There were guys that siamesed bases, tubes, and modified plenums. People have tried just about everything -- including what that 89TA guy did in 3rd gen. He wanted to know if/how well fully-siamesed large tubes would work.

One thing I will tell readers (since the OP won't be interested in this) is that ALL these methods of siamesing -- in attempts to get the same thing as an LS intake -- found out it's not the same. (OK...even if not shooting SPECIFICALLY for LS performance, we're talking about the effort to get your cake and eat it too! )

Joining long runner tubes via siamesing: at the bottom, by removing runner walls, or at the top isn't the same (as good) as an LS intake. For people that don't know, intake reversion is what you're trying to take advantage of. (Look it up). When you siamese, you interfere with those pulses. You disrupt how they behave and I think you can partially diffuse them. This is NOT the goal.

I looked CLOSELY at all methods of "cheating the system" to build a custom (reasonably-priced) intake that would leverage TORQUE -- along with power. And, I was more interested in sub-4500rpm performance...for short city bursts. It's a street car...so what can I say?

I spent hours and hours and hours porting the SLP setup I have. By enlarging tubes and siamesing at the TOP, my goal was to properly feed a stroker. If you look at the harmonics of reversion, there are lengths where 2nd, 3rd, and 4th order harmonics occur. It was always MY impression that lengths BETWEEN these harmonics were a waste of tubing in pursuit of longer/shorter characteristics. So, the length of MY SLP intake targeted hitting one of those harmonics, adding plenum size, and (not so uncoincidentally) leaned heavily on what Lingenfelter learned with the superram. It's runner length wasn't an accident. Nor was the larger plenum size...which helped to feed 8 runners without much interaction between runners.

Short explanation: Don't believe these siamese attempts to build runners. The best you can say for the approach...is the disguise. Intakes and runners built (by companies with the money to do testing) are far more likely to serve your purpose. The LSx intakes have thought and purpose and physical design and space considerations all built-in.

I paid attention to every siamese effort I found here, on 3rd gen, and on the internet before my build. I embarked on what I did DESPITE knowing a larger tube FFI or HSR would create more TQ/HP. Since then, I've continued to look for and observe the results of siamesing efforts -- in addition to looking for FFI builds. Though the later seems oddly rare, it can be explained by the cost of the HSR...OR the fact good enough builds don't lack for torque -- even with short-runner intakes.

Most importantly, I can't say I've EVER seen a dyno from a siamesed intake (bottom, middle, or top) that I thought couldn't be at least equaled with an non-siamesed solution. If you're shooting for torque, a large-tube TPI is really a good option for a 350....as demonstrated by our member "TA". I would also suggest an FFI is the best solution for larger CI engines. In both cases, runners maintain inversion pulses without interference from other tubes.

ANY intake can be improved via porting (enlarging) and/or radiusing inlets/outlets. But I've never seen evidence that siamesing (i.e., as shown in the 3rd gen links above) is worth the time/money spent.

I'm not saying this to talk anyone out of an unusual build. I'm just saying the odds of creating something better (than "stock" intakes) isn't good. Conversely, the odds of creating something not QUITE as good are very high.

rocco16

If you don't want "more acceleration", why do you want more torque?

Torque is what produces acceleration!!

I don't think you really understand this whole power-producing process.....

AgentEran

And another vote for:

You just dont know how this $hit works.

B757captain

It's like watching a slow-motion train wreck. Or a really, really bad movie. I couldn't stop reading. Now all I can say is:

a: Can I get my money back? Or at least the 2 hours of my life lost due to morbid curiosity?
b: UFB!!

Tom, Gregg and all the others: BRAVO!!

Phoenix: What is wrong with you?? Seriously.

pologreen1

You got that right. It's called uneducated goals. That usually leads to something though.

More than likely a botched car for sale, a cut open hood, or a person that does not ever come back to post real results of their build, or a car unfinished from running out of finances for it.

These threads have gone stale, start some new thread content.

Maybe putting a 2.59 gear in for better MPG or something really off the wall.

Phoenix'97

You guys need to have some faith me.

PatternDayTrader

Pheonix - Start new content and make it both interesting and helpful; unless your just here to perpetually jerk people around.