F-150 Manifold Testing/Journey

[BmacIL]

Do some VCT tuning for each manifold and watch the CJ destroy the 18+ intakes. Period. Same goes with the GT350 intake against the 18+.

CJ yes, but the GT350 is very small gains over the 18.

Sponsored

 

[WildHorse]

CJ yes, but the GT350 is very small gains over the 18.

Then how do you ex[lain the Bullitts gains? Cheers bud.

 

[Notagain]

Ive said it once ill say it again CJ over all especially a ported one.

That being said. Ported 18 is best bang for buck but itll never be better than a CJ.

 

[MasterCylinder]

Yeah I figured the the runner length was the deal but I know a lot of companies have employed the use of IMRC type built in manifolds where it artificially makes the runner longer. I know Volvo and Dodge (multi-air) for sure do it. That or if someone would make a custom one with variable runners (ig: porsche).

http://www.autozine.org/technical_school/engine/Intake_exhaust.html

 

[BmacIL]

Then how do you ex[lain the Bullitts gains? Cheers bud.

Funny you should ask. Just so happens that I've discussed that very thing with a development engineer of that engine. Most of it is from the intake and the tune for that intake. The Bullitt is indeed rated at 480, but the normal 18 GT is a tad underrated at 460. The GT350 manifold in particular was done more for marketing than anything else. To fully take advantage of it, you'd need to do cams, something they weren't prepared to do. This is why they didn't raise the rev limit beyond the standard GT.

 

[Mustang_Lou]

How many people have the CMCV working vs locked out? Can the OP insert a poll?

This is the F150 mani thread ... you getting mixed up with the '18 mani thread maybe??

 

[Dr. Norts]

This is the F150 mani thread ... you getting mixed up with the '18 mani thread maybe??

Ah shit. Yup. Sorry about that guys/girls.

 

[EFI]

Nice.

Really makes me wonder if there is a way to fix the 6-6.5k drop off. I feel like it has something to do with the IMRC chambers. =/

Simple...just port the F150 manifold. It should show similar gains that the '18 manifold saw.

In the picture below, you can see the ported manifold carries the power better and doesn't drop as quickly. It also makes the same power at 7300 as the non-ported makes at 7100.

IMHO the ported F150 manifold will carry the power the same as the stock GT manifold (to about 7000rpm) but make more of it and have huge gains down low. For those of us only revving to stock redline and those that live their lives more than 1/4 mile at a time that's the manifold to get. Sure in a pure out drag race the 18 or GT350 or CJ would pull it, but on a road course/autox type car the meaty bottom end torque will make for much more explosive corner exits and the only time the others will be better is on the straight away.

 

[WildHorse]

Meanwhile the guy carrying 1000 more RPM with a stock GT intake coming outta the corner is gonna go right by you. Leave 3000 rpm racing back in 1917 where it belongs.

 

[VooDooDaddy]

Nice.

Really makes me wonder if there is a way to fix the 6-6.5k drop off. I feel like it has something to do with the IMRC chambers. =/

From what I remember, the theory on an intake manifold with longer runners (F-150) is that the incoming intake charge of air develops significantly more velocity and inertia as it moves toward the intake valve and cylinder because it has a longer period of time to make the journey. When the intake valve closes, this higher velocity intake charge (compared to the other manifolds) has to come to a dead stop and when it does tends to "bounce back" thus slowing the intake charge of the next cycle which hinders airflow into the cylinder at high rpm.

 

[VooDooDaddy]

Meanwhile the guy carrying 1000 more RPM with a stock GT intake coming outta the corner is gonna go right by you. Leave 3000 rpm racing back in 1917 where it belongs.

Not if the guy running 1000 rpm lower is making 40 more ft/lbs. of torque. Torque is what gets a car moving from a dead stop or from low speed. On a road course there are typically 12 - 15 corners to come out of and maybe 2 -3 straight aways. They guy making more torque will have 5 times as many opportunities to gain ground vs. the top end guys who depend primarily on straight-line speed.

On a 1/4 drag strip; the CJ, 2018 GT, or GT350 manifolds would be the ones to get.

On the street or a road course, the F-150 manifold is the one to get.

 

[EFI]

Meanwhile the guy carrying 1000 more RPM with a stock GT intake coming outta the corner is gonna go right by you. Leave 3000 rpm racing back in 1917 where it belongs.

How does one "carry 1000 more RPM" coming out of the same corner given equal cars otherwise? Unless you carry more speed (meaning you have better suspension, tires and aero) you can't just carry and extra thousand RPM whenever you choose to.

But let's look at an example. Corner is taken at 65mph for 2 equal cars and drivers.

Car A has an F150 manifold and is sitting right at 5000rpm in 3rd gear. Car B has an '18 manifold and can either be in 3rd also or have to do an extra downshift to 2nd and be at 7200rpm. If they both stay in 3rd, car A has a 40rwtq advantage and will carry more or similar power for another 1700rpm. Advantage F150 manifold car. If Car B downshifts to 2nd at 7200rpm, he has the advantage but only for 2-300rpm which will be gone in a split of second, at which point the driver will have to upshift. Even if he is the fastest shifter in the world, it still takes half a second for the shift to happen and then he is right back down to a power disadvantage in 3rd. All the while, car A is accelerating hard while Car B is shifting. By the time Car B gets back into its power band over 7000rpm and have a power advantage, car B is already 2 car lengths ahead.

It will take along straighaway for Car B to catch up, and like the other guy said...most road courses have 3x as many slowish corners than they do fast straightaways where the '18 manifold will shine. Car B will have alot of ground to make up by the time the 2 cars hit a straightaway if it keeps losing 1-2 car lengths every corner.

 

[Dr. Norts]

How does one "carry 1000 more RPM" coming out of the same corner given equal cars otherwise? Unless you carry more speed (meaning you have better suspension, tires and aero) you can't just carry and extra thousand RPM whenever you choose to

Easily. You shift gears or you have different rear end gear ratios.

So yes you can.

 

[WildHorse]

Some of you guys are putting way too much emphasis on torque.

 

[Mustang_Lou]

Each manifold has it's own advantages for how YOU drive ...end of story. No need to try and convince each other 1 is better than the other overall.

We all agree for a street-driven car the F150 is better. If you're racing where you're in the upper rpm, then it's not. Done.

Sponsored