tpi runners

[White96ZQ8]

Would it be possible to make shorter runners for a tpi intake? Well I know its possible, but for the sake of making more top end power would it work? Im sure any small change in runner length would be a a difference. I have a tpi intake collecting dust and it would be a good canidate for my crate engine, but dont want a low end torque monster. Its just an idea. What do you guys think?

[Chevhead89]

there are tons of aftermarket runners for them. and no you couldnt really make them shorter. to much angle to be much shorter.

[White96ZQ8]

Oh, do any of the aftermarket ones improve top end power? I have never really looked into them maybe I should.

[White96ZQ8]

http://www.compcams.com/Community/Ar...?ID=1737510521

[Crew Cab Sonoma]

you could siamese the adjacent runners in
the base.

[1low86blazer]

ur best bet is to go with the tpis mini ram intake to make top end power, thats the same intake i wanna do on my tpi swap when i finish getting everything i need.

[White96ZQ8]

Quote: Originally Posted by Crew Cab Sonoma

you could siamese the adjacent runners in
the base.

Not being a smart ass at all, but what would that do?

[White96ZQ8]

I wish I could afford a tpis mini ram, if I could then I would in a heart beat.

[Crew Cab Sonoma]

siamesed openings in the base prevent the tubes from becoming an airflow
restriction, by allowing the base to draw from two tubes simultaneously.
at least that how the theory goes...
of course the base can be a restriction itself if it isnt ported out thoroughly,
or use an aftermarket base.

i had a mini ram on my Corvette. for the money spent on a new one,
WAY overrated.....
the performance gains didnt come ANYWHERE near justifying its cost.

one day, when i get around to building another engine for my the vette,
it'll be a TPI with siamesed aftermarket base, and stock runners...

[Chevhead89]

you have to be careful tho when siamesin the runners. the airflow is very picky. so far the best results i have heard of was takin like 5 inchs out. look at thirdgen.org. thats a great site on the TPI. there are some true masters of TPI on that forum.

[Maverick2664]

Quote: Originally Posted by Crew Cab Sonoma

siamesed openings in the base prevent the tubes from becoming an airflow
restriction, by allowing the base to draw from two tubes simultaneously.
at least that how the theory goes...
of course the base can be a restriction itself if it isnt ported out thoroughly,
or use an aftermarket base.

that makes perfect sense, i wonder why i never realized that before... i couldnt figure out what siamesing the base would do if the runners are still seperate anyways, i never thought of it pulling from 2 runners... now i know

but yeah, head over to thirdgen.org, just about everything i learned about TPI came from reading that forum, those guys over there really know their shit, and a number of them have access to dynos to prove what mods do what

[Maverick2664]

hey crew cab, how much do you know about TPI's? im knee deep in the middle of building one and have a question that i havent been able to find answers for

I am building a supercharged 383 TPI, and i am wondering how i should setup my intake, obviously i am going to port as much as i can, but would siamesing be best if im keeping the stock runners? i know when N/A the game is air velocity and vacuum... but when you have positive manifold pressure everything changes

should i siamese or not? and should i look into aftermarket runners? the only reason i want the stock runners is for looks, they look way more badass than any aftermarker ones, but if theyre going to kill a blower setup, than i may have to rethink

[junk racing]

if it were me i would go to an LT1 intake...go too www.lt1intake.com He machines them too fit a sbc and they are still cheaper than most aftermarket tpi runners alone.

[junk racing]

Okay i apoligize he has since went out of buisness, go too google and search LT1 intake conversion, popular hotrodding did a write up on it as well as many others.

[Maverick2664]

no thanks, i know of the lt1 intake swap and i dont want it, never was interested in it... that and id have to drill for the distributor

[junk racing]

with a turbo or blower you dont really have too do anything as your forcing air in the motor, i would run a split duration cam favoring the exhaust side and a wide lobe seperation for that blower, it will help to expel the exhaust in the chamber more efficently. If you port your intake the heads become the restriction, if it was me id just clean up the casting flash on the heads and intake and boost it. just my .02

[Maverick2664]

oh i know all that stuff on the cam, and the heads im using flow pretty damn good, and i will be porting them more, i just dont know if i should do anything with the runners, or if in stock form they are fine

[junk racing]

you can clean them up, id port the tb opening for a bigger tb, port match the intake too the heads and just run it like that...my 25th anniversary camaro ran damn good with these few simple things done, but it also had TFS heads, custom cam, and a 175 shot with full bolt ons...... 7.80's on motor 6.90's on the jug

[White96ZQ8]

I will look into the siamesed base, something like an edelbrock or accel. I read in a car craft article about 4th gen vettes that the accel runners and plenium really increase the hp peak.

I wish I could go with an lt1 intake, but I have vortech heads, and lt1 intakes cant be used with those heads.

Im a member on thirdgen.org and I have been doing alot of searching and reading over there.

[Maverick2664]

Quote: Originally Posted by junk racing

you can clean them up, id port the tb opening for a bigger tb, port match the intake too the heads and just run it like that...my 25th anniversary camaro ran damn good with these few simple things done, but it also had TFS heads, custom cam, and a 175 shot with full bolt ons...... 7.80's on motor 6.90's on the jug

well i must be doing something right, ive done all that already... i opened up the front of the plenum to match the big throttle bodies, i got rid of the "walls", i matched the runner openings, and i got rid of all the extra material between runner ports

i havent gotten to the lower manifold yet, but i planned on doing just what you said, smoothing and port matching... still thinking about siamesing though

the supercharger im going to be using is an F-1 Procharger

[Maverick2664]

Quote: Originally Posted by White96ZQ8

I will look into the siamesed base, something like an edelbrock or accel. I read in a car craft article about 4th gen vettes that the accel runners and plenium really increase the hp peak.

I wish I could go with an lt1 intake, but I have vortech heads, and lt1 intakes cant be used with those heads.

Im a member on thirdgen.org and I have been doing alot of searching and reading over there.

that seems to be the general consensus over there... that the accel parts are the best flowing long tube tpi setup, the problem is that they stopped making them a while back, so theyre getting hard to find

theres dyno results floating around somewhere on thirdgen for before and after siamesing the base, you lose low torque and gain high end power, forget the numbers, i think it was somewhere between 15 and 20

[ArtosDracon]

You can make shorter runners, seen it done only twice, but it has been done, not that entirely much due to clearance and keeping it a smooth bend, but it can be done. Casting a set would make it even easier than just using as tight of a mandrel bend as you can find or make, but never seen anyone try it. I remember reading on a forum(can't remember which, probably thirdgen) when I had my thirdgen 305TPI about someone doing siameses runners from the base all the way up to the intake with some oval tubing, and him being rather surprised and how poorly it worked out on his engine, I think it was just a 350 though.

A 383 will pull a fair chunk more air, but supercharging completely changes thigs. For a supercharged build I wouldn't siamese the runners just because it will increase plenum volume and give you a shorter, sharper boost profile because of the added plenum volume it will create. I would keep porting to a minimum, just smooth everything out so you don't have any bad turbulence and leave it at that. More porting and doing the siamese in the LIM would be more detrimental on a turbo build, but the same does technically apply to a supercharged build because it will take more air from the superchager to increase the pressure inside the plenum before hitting the intake which will slow down boost production, push the same psi higher up the rpm band, though only slightly. Unless you're using BIG heads and a BIG cam, the extra flow wouldn't at all be worth it.

[Crew Cab Sonoma]

Quote: Originally Posted by Maverick2664

hey crew cab, how much do you know about TPI's? im knee deep in the middle of building one and have a question that i havent been able to find answers for

I am building a supercharged 383 TPI, and i am wondering how i should setup my intake, obviously i am going to port as much as i can, but would siamesing be best if im keeping the stock runners? i know when N/A the game is air velocity and vacuum... but when you have positive manifold pressure everything changes

should i siamese or not? and should i look into aftermarket runners? the only reason i want the stock runners is for looks, they look way more badass than any aftermarker ones, but if theyre going to kill a blower setup, than i may have to rethink

lets just say i was siamesing TPI bases before there was any talk of it
on thirdgen...
i havent had any dyno test to back it up, but i do have over 600
dragstrip passes worth of experience with my 86 Corvette.

yeah, on a stroker, and/or blown engine i would definetly siamese the
base if you plan on keeping the stock runners.
and you have to cut deep into it either, just two inches in should be plenty.

if you focus on porting the base, and siamese it, IMO, there is not much need
for larger runners. a ported/siamesed aftermarket base would be of greater
benefit.