Before we begin, I'm relatively ignorant and still in the thick of learning all the basics in the automotive mechanics world (engineering student, I do this becuase it's fascinating and a lot of fun). While Having TSTC (Texas state technical college) near me, I have a readily available supply of machine shops and machinists. That being said, from my understand the low rpm power band of the intake system on tpi's is due to the long distance the air travels in the intake, and that this promotes high low end air velocity, while it chokes at high rpms. If you were shorten the runners, this would raise the effective rpm range? Similiar to the Arizona marine and speed tpi style intake? Idk if it would be cost effective, but having the runners shortened seems as though it would raise the power band a bit. Though due to their size they are still restrictive. Any input? Feel free to criticize my ignorance and lack of understanding, as I hope your responses will lessen them. I also would like to find someone with a stronger fluid dynamics background and use my mechanical experience and CADD abilities to design some Siamese sheet metal runners much cheaper than most on the market, maybe with air foils at the base end of them. Once again, I just want responses regarding the absurdity of my thoughts to increase my ability to think independently. I did some reading on this recently, and any corrections on flawed facts or logic would be awesome. (Yes I do understand the intake is restrictive by nature, especially on a 350), thanks everyone

 

Sorry I wrote a book up there, but I felt it was necessary.

 

Biggest flaw in your theory is how to shorten the runner length with the radius they have from the plenum to base ?
what would you do ;use 2 90 degree bends welded together?

This is the best you can do to improve a TPI runner
https://www.thirdgen.org/forums/tpi/...owing-tpi.html

You might take note of BadSS's comments in this thread about long runner vs ......performance.
https://www.thirdgen.org/forums/tpi/...ed-accell.html

Have you read this article showing the relative strengths and weaknesses of short vs long runner intakes?

http://xtremecarzone.com.au/index.php?showtopic=386

Particular study the graphs showing where the TPI based intakes die but the short runner keep going ( giving up bottom end to do so )

 

Interesting, I'll read those over

 

There is a welding professor at tstc that's good enough welding aluminum with a TIG welder that he can weld a coke can together that he cut in half. My idea would be to make a template with a thin peice of sheet metal that could be fab'd and welded in. I don't like the 90' bend idea as it seems you would lose a lot of low end due to the sharp bends reducing air velocity. Ideally the shortened intake would be a proof of concept for the rpm range adjustment. And the Siamese sheet metal runners would best accompany a Siamesed intake base. Hopefully the volume of air allowed by the larger sheet metal runners would help account for their length on the low end while the reduced length and volume once again would improve the rpm range, while I do understand there is still a little low end torque to be lost, hopefully it is relatively neglegible compared to the high end gains. There is a professor with a doctorate in mech. Eng. I am relatively good friends with at school. And I'll be in another of her classes on Monday. I'll see if she's interested in helping.

 

I still don't see how you can connect the ports on the base to the ports on the plenum by a shorter distance ?
A shorter runner requires a straight shot at the intake port from the plenum without a 180 degree turn ( as per a short runner intakes )

 

The shorter runner may be a total fail, but I don't see why it couldn't be raised from about 4600 effective rpm to 5000 or 5200, which seems much more streetable to me. Siamese runners and a Siamesed baseplate would also probably be necessary. Might not be, but a large weakness seems to be the crossover in the baseplate. That adds a pretty good distance for the air to travel. I think that would probably be the best part to replace, but I don't think that's the cheaper solution I'm looking for. This might be a complete fail, but I think it's worth a try. If I have the money, I'll give it a shot. Mostly just a project. Plus if I am able to turn some positive results and bring that to my engineering professor. I think she would have to give me some credit for it somewhere hahaha.

 

There is not real good way to shorten the runners on a TPI intake. Siamesed SLP runners are as close as you can get.

Otherwise, you have to go with a stealth ram as shown above, a mini ram or a super ram, all of which have shorter runners.

 

There is a member on this forum, a couple of months back, that built his own runners using 180 degree bent tubing he bought from a supplier. He used bigger tubes and made the runners shorter, noticeably shorter. But, yes, he did have to modify the fuel rails in order to clear the shorter runners. Maybe he will chime in on this thread.

 

Ok for personal use if I find that the shortened runners don't give me what I'm looking for, do any of the aftermarket "ram" style intakes not require aftermarket fuel rails? All that I've seen have. And $190 for fuel rails is a lot more than I feel like they should cost.... Mine is a budget build. When I have my 880 block and 906 heads ready (.030 over, DIY p&p, deck height zeroed, and valve springs as well as a valve job) the only other things I'm doing are flat tops, balanced rotating assembly, mild cam, and the intake and headers/exhaust. Already got the block and heads and headers. Also the 880 is a short block, so I have crank and rods. Lots of little stuff left out. That's just big picture.

 

You say you are into engineering ; make your own

http://www.summitracing.com/int/sear...rder=Ascending

 

Only the out of production , only available used Super Ram intake; the perfect compromise of short and long runners benefits
Notice how they achieved a shorter runner by using a 90 degree into a much enlarged plenum

 

Interesting. I'll keep an eye out for a super ram. As far as making my own. Monday I'll have access to my CADD software again! (Solidworks) My engineering professor said it would be best to talk to other "car guys" about designing it. As it was "out of her expertise". Kinda sad to hear from a lady with a doctorate in engineering with over 300 college hours -.- ....... Anywhoo, I'll see what I can figure out. Anybody willing to be accosted with random questions on occaission over an unknown length of time? Hahaha. Also it seems less and less like it be be overly effective without siameseing the baseplate.

 

These runners contrary to most believers, produce in excess of 430 ft. lbs. of torque to the rear wheels of my "355" @4900 and just over 300 @3500.
With a measly 400 HP @5800. (notice no loss at low RPM's)

So having something like this is a good thing.

 

To respond to vetteoz's remark, take note I'm an engineering student haha, not a degree holder yet haha. To make your 355 produce that power, what all was necessary to do to the intake? I see runners, what kind of porting siameseing etc? What else is in it? Compression? Cam? Heads? I have vortec heads btw, porting those seems about the best thing without going aftermarket. $$$$$

 

Another note, the 906 heads are 1.94 I, 1.50 E. Anyone got a ballpark on what 2.02 I and (some size larger exhaust valves) would cost? Anyone have a special favored size for valves? I understand really huge valves hurt you down low. Any opinions on the stock rear end? I hear 450ish tq is all their good for if your mean to them....... Guilty...

 

The problem with the base is the restriction just before the entry into the head.
We weld up that area before porting so the roof can be raised thereby reaching flow #'s such as 300-340 cfm, which is required to make that kind of power.
No siamese ports on the base.


Head work is expensive.
Just get alum. heads with those size valves, best investment.

Not much to be gained changing valves on those heads.

 

Vortec head mods 101

https://www.thirdgen.org/forums/tech...mods-info.html

 

Thanks for all the help fellas! Especially the welding of the base before porting. I've never welded aluminum, nor do I consider myself an excellent welder. I do a couple practice beads on my cracker box and use it for projects. But I got a buddy I think could! Very cool. I can take time to work on this until I get a new ECU anyway. School starts back in the morning tho. Blehh. Good luck guys! Thanks!