DraygenX

I ran across a thread awhile back in which someone removed the secondary butterflys on the throttle body. I'm taking my throttle body off this weekend and getting it ported and was wondering if anyone has done this and what the throttle response/accel/HP effects were?

RotaryEvolution

iTrader: (30)

unnoticable on an n/a, minor power gains on a T2, most people say the work to do it is not worth the gains.

DraygenX

yeah I remember reading that but I've got to break it down anyways for the port so I figured why not, I'll have to update you once I get done sometime next week. should be interesting to see how the port/removal goes. I'm upgrading my injectors to 550cc so I figured the more air the better

NZConvertible

You cant port the TB unless the #2 secondary throttles are removed. This page explains how to do it. Note that you can leave the thermowax and fast-idle linkages in place, and just remove the double thottle system. As for gains, don't expect much on an NA...

http://fc3spro.com/TECH/HOWTO/TBM/tbm.html

That's not how EFI works. The amount of fuel injected is based on the measured airflow, so increasing airflow (only a tiny bit in this case) will not balance out the ridiculous amount of fuel the bigger injectors will flow.

Why are you upgrading the injectors? The stock injectors can flow ~250fwhp worth of fuel, so unless you're near that (i.e bridgeport or turbo), this is a waste of time and fuel. You will only loose power unless you have some way of tuning fuel mixtures (fuel controller or standalone).

DraygenX

I have a apexi fuel management system and the 550's are only going on the secondary rail, I'm keeping the primary's stock. Dores anyone know any good write ups on doing the porting so I can get a better idea what's going on? And btw thanks NZ for the link, it'll help alot.

NZConvertible

But why are you putting those injectors in? Like I said, unless you have a bridgeport or turbo you don't need them. You will gain mothing from having them. By "Apexi fuel management system" I pressume you mean the S-AFC? The S-AFC is not sophisticated enough to iron out the transition with different sized injectors, so you'll get a little hiccup every time the secondaries come on. If you need bigger injectors this is an acceptable trade-off. If you don't, it's not.

For the porting, do a search. There have been lots of threads on this, with plenty of pics too. Once you've seen a pic the rest of it is pretty self-explanetory.

DraygenX

had a set of 550's laying around, roommate was going to use them when he did his turbo upgrade but that never happend, he ended up getting a jdm S5. well the injectors I figured I'd try since I had them and if they didn't make a difference then oooooh well, easy enough to take back out. I'll look into the porting, I have an extra intake so it's atleast good for a "learning experience" lol

NZConvertible

Just letting you know there are no gains from putting in bigger injectors unless your existing ones physically can't pass enough fuel to keep mixtures safe. If you put them in and tune them properly, you will notice no difference (except maybe that hiccup). If you put them in and don't tune them properly, you will actually lose power. Plenty of people have learnt that the hard way.

uRizen

iTrader: (2)

I have my throttle body out right now and was about to just remove the secondary plates and shaft and leave the fast idle cam in place.

Do I need to actually remove the thermowax assembly from the back of the throttle body if I'm just pulling the shaft and plates out? From reading the how-to, it doesn't look like there's anything holding it on in the thermowax side so if I don't have to yank that out, all the better.

As far as vacuum lines go, can I just remove the ones that go to the little plastic deal with the two nipples on top (it controls the little vacuum actuator on the front of the TB) then cap off the nipple on the manifold, or is that vacuum line required for the fast idle cam in any way?

Thanks for any tips!

Mint87RX7

ok guys, when swapping an entire s5 lim,uim,plenum, and tb i ported everything and took out the butterflies. everything was worth it except the tb. i have an n/a so yes like karack said it was way more work than what its worth. its harder to get your idle solid and runs like complete **** when its cold. its may have given me a little bit of power only because i ported everything i could get a grinder on but if i did it again i would not have touched the tb. im going to pull it off in about and hour so i will post some pics of mine if you would still like to do it and want an example.

uRizen

iTrader: (2)

I just got back from the garage. The secondary shaft does pull out if you remove the actuator and the plates. I didn't have to crack the thermowax assembly open and all that's left is to tap and thread a plug in the shaft hole.

The only question left regarding the plate removal is if I should cap that vacuum line or leave it connected to the little plastic bit.

I would normally leave the plates in there, but the actuator hasn't been doing it's thing since I got the car and I even removed an plugged the vac. line going to it at one point to see if it made any difference in my idle and what-not and it didn't, so this is all just a part of my simplification process.

Mint87RX7

well heres mine, i could have taken more out but i just wanted to smooth it out since our throttle bodies are already huge

Mint87RX7

heres one with a little bit of side view so you can see what i did with the center of it
[img=http://img152.echo.cx/img152/7074/dscf00022hy.th.jpg]

uRizen

iTrader: (2)

Sweet, that's quite a bit larger then normal. I wish I had the time to do something like that. Even though it's not worth the time with my cirrent engine, it would one more thing to add to the list.

Did you do that yourself, and if so, what tool did you use?

Mint87RX7

the porting itself takes no time at all, that probly took me like an hour. its the butterfly crap thats a waste of time, you have to get all the parts off the tb without stripping those little phillips screws and then tap it out and find the bolts to fit in it. i used a normal carbide allinum bit and then used sand paper rolls to smooth it, then crossbuffs to get it to shine, then rubbing compound and a super fine buffer disc to make it realy realy shine. but the porting alone is easy, just go slowly to keep it smooth and make sure you dont put a hole in it

Mint87RX7

not to thread jack but i have a question, when i took it off i saw a small puddle of gas on top of my uim. i had somebody rev it up while i looked at it and the fuel rail is not leaking and i have new o-rings for the injectors, i also put rtv between the plastic black thing that connects the tb to the plenum. any ideas where the fuel is coming from?

uRizen

iTrader: (2)

Did you check the clamp on the secondary fuel rail?

I had something similiar last time I removed the UIM and it was because I had the clamp sitting at the top of the hose.

I moved it down a little so it was right above the lip on the rail line and it stopped leaking immediatly.

Mint87RX7

it just looks as though its dripping from the throttle body, i just found a buncha vac lines on the spider that are open so the fuel is the least of my worries lol. time to start another thread