Bishop648

Whats a good throttle body to throw on a s4 n/a?

j9fd3s

iTrader: (3)

stock one works great

Bishop648

Ok then another question.I read a few years back when i got my 86 gxlthat the older s4 block improved performace by tapping x amout of holes in the butterflies inside the throttl body.since i got a s4 in my 88 do the same rules apply or is it worth my time to do the throttle body mod and plug up the outer casting holes i dont need?

Dak

I would not drill any holes in the butterflies. You could remove the the first set if you like(the one closest to the intake tube) but I don't know how much it helps on a N/A. Seems mostly the turbo guys do it. I've been thinking about doing it myself. I think if you can get the screws out and just remove the butterflies but leave the rod you could keep all your cold start stuff in tact. Won't flow as well as with the rod out but then you then have to seal up the holes in the side of the throttle body where the rod was. I think the extra set is there for saftey. To keep you from applying full throttle until the engine is warm. They won't open till the coolant is at a certain temp.

Bishop648

I think i have a project for this weekend now.

fidelity101

iTrader: (11)

https://www.rx7club.com/rotary-car-p...-702539/page1/

your welcome

Dak

I just wanted to add that after digging around this weekend while trying to fix my idle I screwed up. I discovered the double throttle is also there to smooth the transition to WOT. This is also mentioned in the link to the FC3S pro site that was in fidelity101's post. That says it only effects it below 3000rpm. If you floor it suddenly below 3000rpm you will get a bog per the link.

I have a spare T.B. I got about halfway done with this mod years ago(just need to clean up and polish the porting and fill the holes) I am tempted to finish and install it. Just not sure I want to ditch the cold start stuff as I do drive it some when it is cold in the winter.

fidelity101. How does it start and idle when it's say 20 degrees outside?

fidelity101

iTrader: (11)

I never experienced the bog. I had sticking secondary throttle plates and a bad thermowax and removing those fixed my bog issue.

The secondary plates never affected cold start for me, I drove around Northern Michigan in winter with it too and would experience 0 degrees or less. Its EFI, as long as your battery is intact its going to start and idle fine.

Hell it starts "fine" now with the carb but its because of a lack of compression I use "fine"

Pettersen

iTrader: (1)

I experienced the bog when i had a turbo engine, but never had it bog below 3000 running NA. I think that is becuase the air velocity rises alot faster on an NA than on an Turbo, because of the IC and turbo..

Pettersen

iTrader: (1)

double post...