Extremely long time lurker here. 99% of the time I find what I'm looking for by searching here or google so I dont post much. At all really lol

Anyways, on topic. When talking to a buddy with a BB 32 valve the other night he was starting to make fun of our "cookie cutter combos" after a few drinks
"All of you run a set of heads, a fast intake, and a custom cam and all make '450' hp" He actually got kinda pissed when I asked how it felt to be beaten by the same cookie everyday hahaha

When i got home and thought about it some more, he is right to a short extent. Even some of the experts here have said things indicating it. Pat G made the point that everyone has very similar power peaks that are forced by the intake and the best you can do by changing the cam is extending it or making it a 'double hump' power curve.

Ford 5.0 guys have a plethora of intakes to choose from with many varying runner lengths, letting them change their power band or better match their cam/intake for different power bands. My buddy had his intake modified to shorten the runners cuz they were holding his 8200rpm B-headed motor back (yes 8200. I've verified from a twEECer in the pass. seat).

That brings me to the my question (sorry for the long read btw). Would it completely muck up the flow of a FAST to change the runner length an inch? You could even use the inch taken out of the runner to raise the floor under the runner like cobra guys do so they don't lose the wave harmonic.

This is all speculative by the way, I don't have the money to buy 2 FAST intakes to try this out on my upcaming H/C build. I just thought it would be a cool idea for guys who have limited space but wanna rev to have an option other than a fast since we can't fit a single plane/4500 real well (mines just cool on the street so a FAST is fine)

 

Btw since i put this in the wrong section like a scrub, could someone switch it over to external??

 

I was really hoping someone in the know would have some thoughts on this.....

 

Who says we don't have many intake manifold options. There are single planes available, holley has both high and medium rise intakes.

Then there are some more exotic custom made sheetmetal intakes or even a dual throttle one.

If you want top end power like him, get a single plane or holley high rise.

 

Are you wanting to add an inch or take away an inch on the intake? I'm pretty sure people who run highly milled heads have to mill the intake in some cases to get the runners to line up.

 

Did he mistake the LS1 for the LT1 that actually does have a pretty small intake selection unless you convert gen 1. Hell the LT1's only aftermarket option the Edelcrap has been shown to possibly HURT power.

LS market is flooded with options by comparison.

 

One of our main restrictions is the vehicle platform. We simply don't have the under hood height. Even switching to a fast92 I notice a huge amount of decreased cowl clearance during installation. Most people aren't willing to lose their wipers to run a different intake. That's another reason why new intake choices are slow to come to market.

 

Agree with that ^^^. It's just hard to make something that's going to fit and get the job done. Right now, the FAST setup is the best option for someone who's not wanting to hack up their car.

 

That is one of the only reasons I was asking this. If you have a truck its not really a problem but I refuse to hack up my 30k mile car for a couple hundred more rpm. Its a car thats gonna be mostly street with some late night highway runs. When my dad takes his car to Hutter in a few weeks I'll see if he'll cut me a deal on back to back testing with a modified fast. That is if he doesn't think I'll just be ruining an $800 piece of plastic...

 

It is some expensive plastic.

 

haha yea it is but hopefully taking a .5-1 inch out wont ruin the shape of the runner. What I was thinking was to cut the bell of the trumpet off and then cut out the desired amount of runner. Then get both cuts perfectly flat so they meet up correctly and epoxy them back together. It'd be really cool to here Tony Mamo or Brian Tooley chime in on this since I know they both know quite a bit about that intake

 

I thought the same thing since I've owned mostly Mustangs.

But I'm willing to cut into the cowl but as others have said most are willing to.

I really wanna try the LSXRT

 

Thats supposed to be a badass intake. Like I said though I wanna be able to drive the car without fear of rain or anything, plus the car is pretty clean. I just think it would be a cool alternative for people who don't wanna run a vic jr/4150 set-up. I probably wont be able to get numbers until august sadly

 

Fast intake and ~7000ish rpm may be the "Cheap" limit for these cars. I dunno how much these other setups cost, but getting an LS breathing to 8k+ might be out of most peoples pay grade.

 

No doubt lol Im lookin more at 72-7500 tops. I dont wanna have the double hump in the power curve though which is what happens when you try to push a FAST that far it seems. If I **** up the intake i'll just buy a new set of runners for it and put it back the way it was. I'll have turned down LS3 valves, morel lifters, and a solid valvetrain set up so hopefully that range wont be out of reach for me

 

Altering a FAST for an inch is going to be expensive and lackluster.

The reason we don't have many different intake styles is because F-bodies have poor hood clearance. Given the clearance of a fox body, there would be 3 times as many choices out there.

And there is nothing wrong with the 'cookie cutter' mods. Its a cheap, simple set of mods that net you more power than the supercharged GT500 had when it first debuted.

Btw 450 HP is a bottleneck because the stock 78mm throttle body only flows enough CFM to support about 525 HP N/A. Once you hit 450 or so you run into the land of diminishing returns.

 

The FAST 102 has removable intake runners for just this reason and they can be modified fairly easily. It would take a lot of R&D to see what would be optimum for your set up. I would start by only taking a 1/4" off at a time and see where it gets you and document the power curves. Once you go too far you'll find out where your ideal target is you can purchase a new set of runners and modify them to that length as you will have probably gone too far in removing material during testing on the originals. I will tell you that runners aren't cheap. I've seen them range from $60-$70 each. Also don't forget as you take off material you lose the bell shape to the end of the intake runner. You will need to recreate that for optimum results.

Lonnie

 

By the bell shape do you mean how its flared at the end or the shape of the runner? If you mean the flared end part im going to cut it off first and epoxy it back on to the runner I've shortened as I figured it was important. Its nice to know someone repsected in the industry doesn't think this is completely crazy

 

I suppose the biggest reason why there really aren't many options for runner length in the FAST intakes is that it isn't necessary. The shorter runners will show benefit at higher RPMs that are not as easily achieved as they are on the Ford OHC motors. We are limited by our valve train and wallets. Can we get to 8k, sure. But you are talking a perfect and REALLY expensive valve train.

Maybe you want to make more torque. Queue the LSXRT. Sure it's a truck intake but the longer runners and plenum volume make for great low end torque assuming you have the room to fit one.

Another reason there isn't a "short" runner version of the FAST are all of the cheap single planes you can get. The Vic or Vic jr are great choices that easily support the flow of the higher RPM's. So again there really are plenty of options for all achieveable RPM ranges. They just won't all be a FAST style plastic intake.

Then you have the ITB's from Jenvey, Harrop, Kinsler and OBX? Expensive but great idle and you can make them any length you can fit. Think Mazda LeMans beast that got banned.

If I were staying N/A I'd almost consider trying the OBX. If they didn't work, queue the lifetime warranty.