When is a bigger throttle body necessary?

[bluebeastsrt]

VMP, they'll be sending it to me soon with a Rev X tuner and the '18 ported manifold.

What do they recommend? I spoke with Lund about the same subject. They told me to just skip the bigger TB. It doesn't offer good street manners. And in their opinion. Wasn't worth the tuning headache for the small bump in power the TB offers.

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[JJR512]

What do they recommend? I spoke with Lund about the same subject. They told me to just skip the bigger TB. It doesn't offer good street manners. And in their opinion. Wasn't worth the tuning headache for the small bump in power the TB offers.

I actually didn’t ask them about a bigger throttle body. After several recommendations to use a ported stock TB, that’s what I asked about. I asked if using one would require a tune update, and they said it shouldn’t.

I don’t really understand why it wouldn’t, actually.

 

[bluebeastsrt]

I actually didn’t ask them about a bigger throttle body. After several recommendations to use a ported stock TB, that’s what I asked about. I asked if using one would require a tune update, and they said it shouldn’t.

I don’t really understand why it wouldn’t, actually.

I'd skip that and do an E85 tune. Probably costs about the same. And you'll gain 5 times the power from E85 as you will with a TB. Provided you have access to The fuel in your area.

 

[GregO]

Bret @ AFS states in bold on his webpage that PBD and VMP are the few that tune his 5 axis CNC TB without issue.
The OEM TB’s are inexpensive, find a good takeoff from a SC swap and have a spare just in case.

 

[1MeanZ]

I have the Ford Power Pack 2, and I’m convinced the only reason Ford uses the bigger TB is so they can use the GT350 intake tube. And no the GT350 does not just bolt on to the 15-17 intake, Ford uses an adapter. Drivability is great with the Ford tune, but I’d say the power gains are based on the CAI and the tune, not the bigger TB. In another thread we were discussing how aggressive the ignition timing is, I suspect Ford is pushing the tune pretty hard, and that’s the bulk of the gain.

 

[KellTrac]

I have a 2016 GT with PP2. Otherwise its mostly stock save for Roush Mufflers.

I ported and modified the inlet and swapped out the GT350 TB for a custom 95mm TB. It was a bit of work to get it all working...BUT it does drive amazing with the PP2 tune. Logs also show a MAF lb increase from 42.5 - 42.6 range, to now 43 - 43.5. Not much gain...but I am simply preparing for a highly modded 2018 IM. I have a theory that the ported 18 IM is severely restricted with the stock 80mm TB that everyone uses. We shall see how it plays out.

 

[KellTrac]

Some additional images. It was a PITA to get the GT350 coupler to fit BTW.

View attachment 423734 View attachment 423736

 

[GregO]

I have a theory that the ported 18 IM is severely restricted with the stock 80mm TB that everyone uses.

The Coyote's OEM 80mm TB flows 927 CFM.
AFS modded OEM 80mm TB flows 1177 CFM retaining the OEM sized blade / aperture.
Personally I don't see the 80mm TB creating restrictions with the CFM's listed.

 

[BLUE DEVIL]

I believe your theory about the 18 manifolds, both ported and stock, would provide better numbers with a larger Throttle body. I am waiting for the tuners to get enough logs and successful tunes without drivability issues, before going to a ported 18 manifold with GT350 TB. Until then I am sticking with the Ford Power Pack 2.

 

[KellTrac]

The Coyote's OEM 80mm TB flows 927 CFM.
AFS modded OEM 80mm TB flows 1177 CFM retaining the OEM sized blade and aperture.
Personally I don't see the 80mm TB creating restrictions with the CFM's listed.

Thankfully Ford doesn't agree and they blessed us with the Cobra Jet manifold that has a larger throttle body opening.

 

[KellTrac]

Any stock Coyote engine with supporting bolt on modifications (exhaust, intake and tuning mods etc) will make the most average upper RPM power with a CJ Manifold. The primary difference between the Boss302 manifold is the larger throttle body opening. The other difference is the slightly larger upper plenum.

That speaks volumes, literally..

 

[GregO]

Thankfully Ford doesn't agree and they blessed us with the Cobra Jet manifold that has a larger throttle body opening

My comments are specific to the 80mm TB and Coyote 2015-17 running at near stock redline.

 

[KellTrac]

My comments are specific to the 80mm TB and Coyote 2015-17 / 2018 manifolds ported or unported running at near stock redline.

Well yeah. That's not my plan. I would think most who install a ported 2018 manifold (likely with lockouts) are simply looking to get the most power possible at whatever RPM gives them the best performance.

Once you start modifying power levels with higher flowing components and modifying what Ford engineered into their intake manifold - you can throw the stock sized throttle bodies in the trash. It's not really debatable that they (larger TBs) pay dividends in terms of power and performance. Tuning and driveability is a different story however. Lol

 

[KellTrac]

Nothing against Brett, I love his work and have spent thousands with him. But the problem with that example is that one, he sells port work and two, you can't compare Apples to Oranges.

What was the CFM requirement for the engines you or him have tested? Was VE the same? Was a similarly comparable "system" tested with an 85+mm TB? IE; 120mm+ larger CAI with proper air filter and port/shape work on the TB *and* the manifold inlets modified to be similar in size comparison? Was the same ported 87.04mm IM opening used for both TB tests?

What I have found is just because a calculator says you need XXXX cfm doesn't mean that going more won't gain power. My cars have always shown a power increase from opening up the inlet side even when a calculator says otherwise.

The OP has a 15-17....What is the CFM of his stock IM? It must be MUCH less than what the engine requires...since any offering available will improve his power output significantly. ;)

 

[KellTrac]

Also not sure if you caught my post earlier. With only swapping from a ported GT350 TB to a non ported 95mm TB...no other changes at all, my MAF flow increased a bit. Back to back testing within 45 minutes. That's with a mostly stock vehicle. I wasn't expecting any flow increase to be honest. Based on my testing results on previous S550s, my car is seeing around 5 more horsepower now. Not a big deal, but very promising for what I have planned.

I'll let you folks continue. I'll be back eventually with some additional information and results as I get them.

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