'04+ owners: Want better throttle response?

[E.B. Cornburner]

Reading the thread on the '02 throttle body mod got me thinking yesterday, so I went out and looked at mine, and yes, there's some little "vanes" in there that I've concluded solve a twofold problem...First and foremost, they're in there to eliminate a "swoosh" or squeal from the throttle body under light throttle openings. Second, they're in there to help create a progressiveness to the throttle bore, so there's less of an abrubpt feeling as the throttle is opened. Well, as us throttle-by-wire owners already know, there's more than enough of a lag in the throttle response than most people like.

My solution is mind-numbingly simple. It can be approached one of two ways. First, let me explain the difference between the '02 throttle body and ours. The '02 had the "vanes" cast right into the throttle body itself. Ours do not. They're moulded into a little 1/4" thick spacer that sits between the TB and the intake plenum. What I did was simply take the TB off, pull off the spacer (which is also your TB gasket, and is for the most part reuseable) and remove the vanes from it with a die grinder. It's just thin plastic, and grinding them goes real quickly. Be careful.
The other approach will be concluded completely as soon as tomorrow. I ordered an aftermarket TB gasket from Carquest, which judging by its price (~$4) probably isn't anything special, just a regular old gasket. In this case, if I'm right, the spacer with the vanes could simply be eliminated altogether. Both ways will accomplish the same thing.

After putting everything back together, my first road test was very impressive. There's virtually no lag time in the throttle response anymore. Touch the throttle, and it's right there. Paired with a K&N drop-in filter, the power at WOT is equally impressive...By the precise calibration of my butt dyno, I'd say the combination is worth about 7-10 HP. On a 55 MPH kickdown, this thing pulls like a freight train now. Much improved over the stock TB spacer/paper air filter combo I was running previously. I can't say for sure which helped more, but since I did the filter first and didn't notice all that much difference, I'd be willing to say the modification to the spacer helped out a bit more.

What's more, is I have a feeling I gained a little MPG out of this as well! I filled 'er up last night with E85, then took off for a road test on a 55 MPH road with the cruise set at 58, and according to my message center, I was getting 18.2 MPG! All that MPG was lost when I headed back home and was driving it like a rental car! Hey...Ya gotta test both power and MPG, right?

Give it a try...I'm confident you won't be disappointed.

 

[abarkl]

What was your MPG before the mod? I wonder if I will find the same setup on my '03.

 

[E.B. Cornburner]

Was the '03 throttle-by-wire? I never really checked an '03.

From the one drive I took, I noticed about a .7 MPG gain, but I'll have to put some more miles on it to see if it stays consistent.

 

[trucku]

Great information

Gonna toss my thread link so people searching gets 2 bangs for the buck and can cross reference.
2002 throttle body mod..


I am seeing about the same gain highway.

 

[abarkl]

Was the '03 throttle-by-wire? I never really checked an '03.

From the one drive I took, I noticed about a .7 MPG gain, but I'll have to put some more miles on it to see if it stays consistent.

If I find out my '03 is not, would the mod make a difference.

 

[E.B. Cornburner]

If the '03 is not throttle-by-wire and has a cable, then follow the mod writeup for the '02 that trucku posted and linked to in this thread.

 

[04urban]

Hey E.B. Thanks for the Info. On your stock spacer with the vanes, did you use a new gasket or the old one? I kinda got lost there, between the new spacer and the old one. I want to try it too. Eric

 

[04urban]

Never mind i went back and read it again,, the vanes are in the 1/4" gasket,, And yes it seems very simple. Very quick and easy. Is there any downside?

 

[E.B. Cornburner]

Never mind i went back and read it again,, the vanes are in the 1/4" gasket,, And yes it seems very simple. Very quick and easy. Is there any downside?

So far, I've found no downside whatsoever. It really wakes up the throttle response from closed to ~1/3 throttle, which is the place most people use the most. It's also much more responsive when rounding a corner and getting back on the throttle...Before there seemed to be much more lag time before it responded, and now it's right there.

FYI, an '05 Mustang 4.0 doesn't use this vaned spacer...They have a similar looking throttle body bolted directly to the plenum. The gasket is a rubber O-ring style embedded right in the plenum. So the way I look at it, if it's good enough for a Mustang, it's good enough for our trucks.
Most Mustang owners want a nice responsive feeling vehicle anyways, rather than one that feels dull and lazy till it's really flogged which is probably part of the reason this part was never included on them.

If there was any one thing to say could be a downside, it would be the fact that you'll always want to stomp on the throttle to feel the extra power you've gained! Like I mentioned in my original post, the combination of the K&N filter and this mod really woke up the response and power of mine. One without the other may not yeild quite the same results, but would still be beneficial by themselves.

 

[04urban]

E.B. I already have a KKM, That made a big differance, so this will only make it better (I hope) and response in cornering is what i was looking for most. I'm handy with the dremel tool, So I"ll try cutting the vanes and polishing the housing myself And the downside will be "as you said" keeping my foot out of it. But it should be well worth it Ill let you know how mine turns out. Eric

 

[04urban]

Ok I removed the vanes, (more or less port matched the spacer). I did not see much of an improvement in HP. But what i was really after was the responce time to throttle. It DID remove almost all of it to the point it is a well worth the mod. I put about an hour drive time into it, lots of stop and go, and cornering. The lag in responce is gone to the point you have to look for it
E.B. I think the extra HP you gained was from your change in filters. The same as i noticed when i went to KKM. I wonder how much of a differance it would be between the KKM and the K&N filter?
Anyway Great mod, I highly recomend it to any one that has a 04+ 4.0v6.
Thanks to you E.B.

 

[blitzk]

It's also much more responsive when rounding a corner and getting back on the throttle...Before there seemed to be much more lag time before it responded, and now it's right there.

UGGH!!! I might do it just because of that.

The lag around cornering is horrid!

 

[blitzk]

Ok I removed the vanes, (more or less port matched the spacer). I did not see much of an improvement in HP. But what i was really after was the responce time to throttle. It DID remove almost all of it to the point it is a well worth the mod. I put about an hour drive time into it, lots of stop and go, and cornering. The lag in responce is gone to the point you have to look for it
E.B. I think the extra HP you gained was from your change in filters. The same as i noticed when i went to KKM. I wonder how much of a differance it would be between the KKM and the K&N filter?
Anyway Great mod, I highly recomend it to any one that has a 04+ 4.0v6.
Thanks to you E.B.

I have a FIPK/KKM on my 04... I like it better then just the KKM kit, but it's not cheap to buy BOTH kits

 

[Curtis]

UGGH!!! I might do it just because of that.

The lag around cornering is horrid!

Holy crap! I thought I was the only one that had that Lag... its a PITA!
Why doesnt it happen when not cornering?

E.B - did you get your aftermarket TB gasket from Carquest yet?

 

[E.B. Cornburner]

The aftermarket gasket that Carquest listed for the '04 was wrong...Turned out to be the correct one for an '02 style TB/plenum.

I'm not out of the woods yet on a flat gasket. I'm thinking maybe one for a ~2000 Crown Vic 4.6 might work. I'll just have to get one and see if the bolt pattern on the TB is the same, which by eyeballing it looks close.

 

[ffdemoss]

The aftermarket gasket that Carquest listed for the '04 was wrong...Turned out to be the correct one for an '02 style TB/plenum.

I'm not out of the woods yet on a flat gasket. I'm thinking maybe one for a ~2000 Crown Vic 4.6 might work. I'll just have to get one and see if the bolt pattern on the TB is the same, which by eyeballing it looks close.

Keep us posted...thanks for doing the leg work on this.

 

[E.B. Cornburner]

Well, here's the moment we've all been waiting for...

The flat paper gasket needed to completely eliminate that plastic spacer and affix the throttle body directly to the plenum is exactly what I thought. One off a 2000 Crown Victoria 4.6L is the correct one. It's also the same on a '97-'99 F-150 5.4L.

Fel-Pro part number 61050, Ford part number F65Z-9E936BA. The Fel-Pro gasket is only 99 cents at AutoZone.

One thing that needs to be done if doing this, the bolts need to be shorter. You can do this by either obtaining bolts approximately 1/4" shorter than what's in there now, or simply just stacking 2 or 3 washers on the existing ones. The method you choose is solely dependent on your own taste...Some people don't like the "cobbled" look of multiple washers on a bolt.
If this isn't done, the bolts will bottom out in the plenum, and could possibly split the plastic.

Other than that, I can't think of anything else that would prevent this from being one of the easiest mods ever. I personally think the idea of exchanging that spacer with a simple gasket is easier and faster than modifying the spacer itself. Also, it's more easily reversible if anyone wishes to do so.
For the sake of arguement, that plastic spacer is only about 7 bucks right from Ford if a replacement is ever wanted or needed.

 

[JasonF]

Thanks for the information. I might give this a try when I get back home in a couple weeks. Anyone else tried this and noticed a difference?


Jason

 

[2005xltsport]

just last night, i switched out the vaned spacer with the fel-pro gasket...for comparison purposes, i kept my same air filter in...didn't notice much, if any, improvement...i'm thinking that the used air filter is already restricting the air flow enough, making the mod useless until i replace the air filter.....i ordered a higher flowing amsoil eaa air filter and will drop that one in as soon as i get it...will re-post findings after new air filter is in

 

[2005xltsport]

just last night, i switched out the vaned spacer with the fel-pro gasket...for comparison purposes, i kept my same air filter in...didn't notice much, if any, improvement...i'm thinking that the used air filter is already restricting the air flow enough, making the mod useless until i replace the air filter.....i ordered a higher flowing amsoil eaa air filter and will drop that one in as soon as i get it...will re-post findings after new air filter is in

okay guys/gals...i put in my amsoil filter and put the stock vaned spacer back in, once again for comparison purposes...i think i noticed more of a throttle response improvement due to the higher flowing air filter than the spacer mod...it didn't completely remove the lag, but it seems to shorten it slightly.....gonna try the spacer mod again and see if it improves some more