View Full Version : Larger throttle bodies...

07-09-2002, 02:33 PM
Just needed some info on what exactly a larger throttle body would do and how it would work, and possibly, which would be the best for an 89 5spd

-Any info is greatly appreciated, Thanks for your time!

07-09-2002, 04:39 PM
IMO it's not gonna do all that much, if anything if your motor is basically stock. I have a 90 SC with a 70mm BBK/SCP TB, it might have added 5 HP but I really can't tell any difference. Maybe if you had the heads worked, replaced the MAF with a larger one, and changed the fuel injectors to larger ones it would be worth it. Also if you have not changed the MAF it's only a 55mm on an 89, so installing a larger TB would really do nothing for you, since the MAF needs to be at least the same size or bigger than the TB to work properly...I think that's how it goes, but I could be wrong. Either way a good cold air induction system, or a raised top (if you don't already have these) would get you more bang for your buck. I'm no mechanic, I'm only speaking from what I've done to my 90 5 speed, and from what I've read, and been told. They are needed when you perform heavy mods to the motor to get the fuel/air mix into the cylanders faster than the stock system can provide. Not to say you can't do it, just that you might expect more than what it will get you. Good luck with whatever you decide.

07-09-2002, 04:56 PM
thank you for the info

07-09-2002, 05:19 PM
Glad I could help. So far I have a Mac CAI, a BBK/Edelbrock 70mm throttle body, 70mm modded MAF, Walbro 190LPH fuel pump, 10% OD pulley, complete manifold back performance exhaust with a pair of Borla mufflers, and within the next couple of weeks I'll have the raised top, and ported exhaust manifolds. I really thought the throttle body would do more than it did, but at least it's there if I do more engine mods. Have you done any other mods to your 89 yet? If not one of the first things you can do is pull out the air silencer. It doesn't cost anything, and it's easy to do. Feel free to email me if I can help....just click HERE ([email protected]) to do so. Any pics of your SC? I have an 89 5 speed parts SC too...not much left to it though! I also have a book with most of the part numbers for our SC's....not all of them, and many parts are no longer available new, but it helps just the same.
SC Ya,

Phil Kuhn
07-09-2002, 07:12 PM
I added a 70mm BBK throttle body a few years ago and had the inlet plenum port matched and then immediately dyno tested the mod.


I added +9 rwhp on a blistering 85 degree day with my mildly modded SC.
This was the best HP adder I've done to the car and it cost $240 + $30 for the dyno runs.

There've been guys spend a lot more than that to get 10HP

'93 5-speed
48K miles