throttle body/plenum advice

[RareBreed]

Question for all you early 4.6 2V owners. I'm looking to add a throttle body & plenum on my '98 PI 2V 4.6. I have been looking around at several options, but I need to get some advice from any of you that have already added these to yours. I have been looking at the Prof Products combo and the Accufab combo as well. The dyno shop that is near me advised to go with the Accufab, as it will support upwards of 500 HP if I decide to supercharge it in the future. The Accufab is a great piece, however the price is a little steep. Any of you out there have advice and or preferences between the two?

please help a fellow member out with some thoughts/suggestions!

 

[blown98gt]

i went with a BBK 75mm TB and just ported my stock plenum, although my goals were to try and keep my car as "stock" looking but that was before i slapped a blower under the hood

 

[RareBreed]

I had a BBK 70mm on my '86 that I sold and it was ok, but I know the mod motors are a different animal. I want to make sure that I make the right choice without going broke in the process. I autocross it and do some on track events, so I don't need to go overboard on the cost of the bolton's.

btw, I see your screen name is blown 98GT, what blower are you running?

 

[Tbuck07]

BBK 70mm on my 97, with a trickflow upper plenum. Do it, youll love it. Thats what I have.

 

[Marvin97]

I've heard some bad stories about prof products throttle bodies sticking open..

 

[JDwhite98gt]

BBK has their new one out its a throttle body and upper plenum molded into one piece. Throttlebody opening is 78mm and i think its about 250 bones

 

[GDawg]

Before I bought my blower I bought a MAC 75mm TB. It was crap!!! So I sold it on Ebay and bought a 75mm Accufab. I have had no problems with it and it worked out great for my blower!

 

[DropTopPony]

I would not use Professional Products parts if they were free.... just my opinion though!
I used to have the C&L plenum with my BBK 75tb. On all the tests the Plenum/TB combos are all within a few HP of each other so find one at a good price and buy away. I see then on ebay all the time go for @$200 for the set and thats accufab.

I like that new BBK 78mm combo piece that just came out.

 

[RareBreed]

lots of good advice. I have not seen the BBK unit yet, I will have to check that out. As for the Accufabs on e-bay, I have not seen any of those lately but I will check them out. Pro Dyno in advised to go with the Accufab because they will support allot of HP, but for what I am doing with this, I could get away with a less expensive option. I do not see a supercharger anywhere in the near future and for reliability, NA would be better for me.

I will check out the BBK unit and e-bay for the Accufabs.

thanks for the advice :headbang:

 

[duff daddy]

i have the trick flow 75 u/p and the ford racing 70mm t/b

 

[WarHorse]

My upper is still stock but ive seen the accufab TB and Plenum's and they look great, I also like the trick flow plenum just wish they made a matching TB. Ide like to buy a set but until i do a PI swap i dont think ide get any power at all.

But ide suggest not going cheap, ive heard a few people say Professional Products run kinda cheap.

 

[Willis_98GT]

c/l 75 plenum accufab 75tb

its a awesome combo, you'll love the throttle response you gain.

 

[RareBreed]

thanks Willis! I read a few other threads about the same topic and you had replied to those that if you have the PI swap the gains will be more noticeable. i already did the PI swap when i had to do a rebuild after a rod bearing failure. i put on a set of '04 PI's from an F150. i hope the combo does make a bit of difference considering the cost as I have not put a tune in it either. i also hate the way the 4.6's take so long to drop RPM's after you lift from a free rev. i am used to my old GT40 5.0 in my '86, where it was instant. will the TB/Plenum help with that?

 

[duff daddy]

your idle adjustment screw on the throttle body may be too far out and thats causings it to hang slightly more then normal...

 

[RareBreed]

thanks for the heads up Duff.... I looked at the TFS combo in Summit today and it runs about $250. will I have any issues with the 75MM if I opt for that instead of the 70, since I am running a stock MAF? also, I was advised to pick up a used a 90MM Lightning MAF instead of buying a new unit as it can be adjusted accordingly as the performance mods are done.

any thoughts / advice?

 

[DropTopPony]

If you are staying N/A then your stock MAF is plenty big enough. Its 80mm.

 

[Willis_98GT]

thanks Willis! I read a few other threads about the same topic and you had replied to those that if you have the PI swap the gains will be more noticeable. i already did the PI swap when i had to do a rebuild after a rod bearing failure. i put on a set of '04 PI's from an F150. i hope the combo does make a bit of difference considering the cost as I have not put a tune in it either. i also hate the way the 4.6's take so long to drop RPM's after you lift from a free rev. i am used to my old GT40 5.0 in my '86, where it was instant. will the TB/Plenum help with that?

Yeah, my idle drops instantally

 

[duff daddy]

thanks Willis! I read a few other threads about the same topic and you had replied to those that if you have the PI swap the gains will be more noticeable. i already did the PI swap when i had to do a rebuild after a rod bearing failure. i put on a set of '04 PI's from an F150. i hope the combo does make a bit of difference considering the cost as I have not put a tune in it either. i also hate the way the 4.6's take so long to drop RPM's after you lift from a free rev. i am used to my old GT40 5.0 in my '86, where it was instant. will the TB/Plenum help with that?

Yeah, my idle drops instantally

if it doesnt drop then your idle adjustment screw is probibly way out on the throttle body... i have a lightning maf my stock one lasted and worked just fine with my ported heads and pi cams and intake you will be fine on a stock one

 

[GDawg]

thanks Willis! I read a few other threads about the same topic and you had replied to those that if you have the PI swap the gains will be more noticeable. i already did the PI swap when i had to do a rebuild after a rod bearing failure. i put on a set of '04 PI's from an F150. i hope the combo does make a bit of difference considering the cost as I have not put a tune in it either. i also hate the way the 4.6's take so long to drop RPM's after you lift from a free rev. i am used to my old GT40 5.0 in my '86, where it was instant. will the TB/Plenum help with that?

Yeah, my idle drops instantally

if it doesnt drop then your idle adjustment screw is probibly way out on the throttle body... i have a lightning maf my stock one lasted and worked just fine with my ported heads and pi cams and intake you will be fine on a stock one

The problem with my MAC TB was that it didn't close all the way no matter how you adjusted it. Maybe same problem. Once I bought the Accufab the drop in rpms was instant...!

My throttle response is pretty sharp...


.

 

[LI98GT]

i have the trick flow 75 u/p and the ford racing 70mm t/b

I have the same combo and am very happy with the results on top of PI intake/PI cams (stock NPI heads). You may want to check out the test that was done a while back at modulardepot showing that only a few hp seperated the crowd. IMO, stay with a quality brand and you should be good to go.

http://www.modulardepot.com/articlesp.php?aid=38