Write-Up: Building a Custom PVC Fenderwell Intake

so i stole my brothers, i went to his new house in the riv behind his uhaul and got everything unloaded

this was lastnight on the highway, my brother asked me how the intake was and i didnt really know until he asked

i punched it and put it into 2nd that stock pulley was screamin, i cant wait til i get a pulley and PCM...im sold that the new intake has great gains even from a 3 inch

or maybe a heat gun? i figure a Straight peice of schedule 80 PVC line bent, would not only hold up better but perhaps the intake airflow would be even less restricted by not using thes bulky couplings, perhaps even alow for a 41/2 inch pipe lined with fire guard for insulation? what are your thoughts?

I think you will end up with a reduced inside diameter at the bends, if you can even do it.

anything above 3.5" inside diam is not really helping IMO. the TB is only so large, and the car can only take in so much air at a time. also there is very little obstructions at the couplings b/c everything fits flush inside.
also, i dont think a heat gun will be near enough to bend pcv. my intake gets really hot in 100* FL stop and go traffic. too hot to touch, maybe around 250*, and its not enough to warp the PVC.

my 4" FWI came apart the other day and i was running an open 4" pipe without a filter for a few miles. i lots power due to heat, and my throttle response was worse for some reason. even if it had been sucking in cold air i dont think i would have felt any difference than if it were connected to the filter...even at WOT. (i know, really not good for the motor to go WOT w/no filter)

i'm not trying to shoot down your idea, i dont know much about how a pvc bender works so maybe you can prove me wrong?
and what is this fire guard you speak of? is that like reflectix? (sp)

Get some intake tubing already man!

Whats that like the 3rd time its fallen apart? lol.

i have it pcv glued and taped at that joint. i just cut the center piece too short when i made it. so when i launch the car and the motor rocks back, it pulls it apart. but i think i have it fixed right this time (said that the last few times too)

you may have seen fire guard near heavy electrical traffic, like EMT Tubing and or ducting, its an orange fireproffing rubber that you cant paint on that is smooth to the touch, about a 1/4 inch thick. if painted onto the inside of said PVC, ti will cut the inside Diameter, down to 3.5" anyway, and with it, the inside of the pvc would be the same temp as the intake, even if the surface of the PVC was on fire. it is similat to pyroseal.

I think I know the stuff you are talking about.

If its the same stuff we refer to it as innerduct.
We use it for conduit under roads and stuff when we make directional bores...

The PVC heater blanket will work very well for bending it.



Bert

BUT, what will that do to the ID at the bends?

dont picture a bend like if you were trying to bend an empty red bull can, picture a uniform bend like you would expect to see if pvc came straight from production with curvatures, the inside diameter change would be Minimal at worst. IMO slightly bent PVC with a small change in ID, would create less turbulance than 2 45 degree angles, because obviously, the shortest distance from point a ( your filter) to point B (your throttle body) is a straight line, the straighter you can make that line, the quicker and more efficently you can get outside air to cool your engine.

Lucas wrote:

dont picture a bend like if you were trying to bend an empty red bull can, picture a uniform bend like you would expect to see if pvc came straight from production with curvatures, the inside diameter change would be Minimal at worst. IMO slightly bent PVC with a small change in ID, would create less turbulance than 2 45 degree angles, because obviously, the shortest distance from point a ( your filter) to point B (your throttle body) is a straight line, the straighter you can make that line, the quicker and more efficently you can get outside air to cool your engine.

Another option might be to take a PVC "sweep" and use the heater blanket to make a slight bend in the sweep to make it fit.
The "sweeps" are used to gradually make a 90* bend, so picture a long 90...
Thats confusing as heck...

I think I would just use the rubber pipe that comes with the kit you can buy.
I had a similar set up on my GN and it worked great.
Bert

the silicone 3 to for reducer goes on the throtle body correct?

SuperRiv07 wrote:

the silicone 3 to for reducer goes on the throtle body correct?

thats how i ran mine.



pieced together myself for about $60.00 but i have a hook up at pep boys that gave me a discount, it would actuall run more like $120 but if your good with that here's what you need

1 - 4inch to 3 inch reducer for the throttle body
2 - 1 (45 degree) elbow
3 - 1 (20 degree) elbow
4 - 1 (90 degree) elbow
5 - 1 (6 inch) Straight
6 - whatever filter fits inside the fenderwell,

all pieces go together in that order, its a little cramped when you get to joining the 90 - straight and a little wiggling helps. And make sure you use the rubber gaskets that come with each piece to help reduce the risk of leaks.

set-up works great, car feels more responsive but its cool out today.

SuperRiv07 wrote:

the silicone 3 to for reducer goes on the throtle body correct?

The TB opening is 3.5". So you'll need 3.5" to whatever ID tubing you're going to run to the FW. 3" won't fit on the TB, and 4" is too big for the TB.

Jason wrote:

1 4" to 3" rubber reducer ......

I'm sure Jason meant 4 x 3.5 reducer, as the TB is 3.5"

i see well I guess i should have measured cause i just went and bought the parts needed and i bought a 3 to 4 rubber reducer gues i will have to return it

that looks nice as hell man but i only spent 25 bucks and got the pvc that i needed im a lil short on cash but when i get some i will build a custom stainless but for now im going with the 4 inch pvc

lyonsperformance wrote:

SuperRiv07 wrote:

the silicone 3 to for reducer goes on the throtle body correct?

thats how i ran mine.



pieced together myself for about $60.00 but i have a hook up at pep boys that gave me a discount, it would actuall run more like $120 but if your good with that here's what you need

1 - 4inch to 3 inch reducer for the throttle body
2 - 1 (45 degree) elbow
3 - 1 (20 degree) elbow
4 - 1 (90 degree) elbow
5 - 1 (6 inch) Straight
6 - whatever filter fits inside the fenderwell,

all pieces go together in that order, its a little cramped when you get to joining the 90 - straight and a little wiggling helps. And make sure you use the rubber gaskets that come with each piece to help reduce the risk of leaks.

set-up works great, car feels more responsive but its cool out today.

so i was looking over the photos of the pvc instal and my 45s ar a bit bigger, so my question is where did you buy yours i just went to home depot and got what the had in the plumbing section so let me know so i can return what i got and get the right shit before i start and then realize it aint gonna work and then im stuck with shit and out my money

You just have to shop around at some hardware stores to find pieces you like, if their appearance is important. Lowes, Home Depot, etc. Look in the Yellow Pages under hardware stores?

yeah true Im sorry to sound pushy im just excited about starting another project with my riv

No problem, I know where you're coming from. It sucks that no one sells a FW intake designed to bolt right in on our Rivs. I have the same problem with my 68 GS350, basically 2 vendors exist to source any perf parts from, and they mostly cater to 455 cars, the Buick 350 gets the shaft most of the time.

yeah it does suck but shit half the fun of working on cars is building custom shit

i just wish there were other people that lived by me to come over and we could make a day of customizing our rivs

Tell me about it.... I don't know any other Riv owners locally. But there is a local W-body group I've been involved with a bit. Truth is, there's so much help readily available here that it really simplifies working your way thru mods by yourself. If you get stuck, ask for help. Lots of us are online throughout the day/evening.

yeah thats true Im always loged in and usually home and when im not Im on line on my laptop in the car