pbellone

I have a 1993 C4 LT1
I see there are 2 sizes of TBs. What is factory and is there an option worth doing for better performance? I also see the airfoil gadget. Snake oil?

QCVette

The stock one is 48mm.

Unless your car has a lot of mods, there is no need to go to the bigger throttle bodies. The gains will be minimal if any.

The airfoil is poorly thought of on the forum. It adds very little if any to the performance and adds the possibility of the retaining screw coming loose and being ingested into the motor causing a catastrophic failure. I tried one a long time ago and the seat of the pants there was no gain. However there was enough difference in flow that I got a hesitation on first throttle movement. I changed the chip and the hesitation went away. So it does do something, but not enough to feel.

In short, they both will lighten your wallet without much gain.

EDIT:

Just saw you have 2 posts. Welcome to the forum.

We like pictures too, so show us yours and tell us about it.

c4cruiser

The OEM throttle body is a 48mm size and it will work fine for a stock motor and for motors with some mods. If you have to replace the TB on your car, then a 52mm TB will work fine.

The "airfoil" is all but worthless. Don't bother with one as you will not see anything in the way of a performance increase.

If you want some mods for your car, I would suggest starting with headers and a true dual exhaust system. Do you have to have any sort of emissions testing where you live? With long tube headers, you can remove the cats and center resonator and install true dual exhaust with an X-pipe.

Also, it can't hurt to replace the plug wires and spark plugs. MSD and Taylor make good 8mm wire sets. Use Iridium plugs such as those from NGK or even AC Delco.

pbellone

Thanks for the answers. The car runs pretty good. It has 67k on it and is stock. I'm in the middle of getting it back to a reliable condition like replacing hoses, lines, and tune up parts. And in NJ we don't do inspections on vehicles over than like 20 years so I could get away with certain mods. Building a garage this summer so I can work more comfortably on it.

aklim

Word to the wise. "UP TO" is key. Send me your address and $100 in cash and I will pay you back in 2 weeks UP TO $500. See where I am going with this? I could send you $1 and still be within the "UP TO" stipulation. Good stuff isn't cheap because it doesn't have to be. Cheap stuff isn't good because it can't be. General rule I live by.

aklim

Help me out. In my county we don't do inspections on vehicles over 20 years either. How could you get away with certain mods? They don't inspect so wouldn't you be able to get away with anything other than exhaust where you are making a racket or the black smoke that a cop can nail you for?

As the priest joke goes, I'm asking this for a friend.

My $0.02, get the plugs, done with something decent but not exotic. Change them every couple of years. Flush anything fluid. Spray a fine mist around the plug wires when it is cold and when it is hot in a dark garage to see if there is any leaking. Check fuel pressure. Change brake hoses. I dump all my injectors when I get a new car for reman units because they will have some build up that I don't trust snake oil to remove.

ZEN357

Unless you are building the engine you will see very little if no improvement going from the stock 48mm throttle body to a bigger size.

aklim

Friend of mine did see the difference every day he drove it with the 58mm unit. You can feel it, or so I was told. Took it to the strip and consistently ran slower with it than on stock. Switched it around a few times to be sure but no joy. Still slower. I couldn't have laughed harder that day.

He did threaten to make me walk home if he heard another word about it on the way home. So funny. Never heard it being faster any more. Bought it from him later when mine was having issues. All for a song.

C3LT1

Kevova

If the engine only requires 600 cfm installing 750 cfm may cause a loss of performance. ECM calibration will be off a little, on initial acceleration due extra air. The main performance benefits are at 85% + throttle, when requires maximum airflow. One other possible situation is the outside of throttle body is usually larger than the stock one. Many times the stock air filter ducting won't fit over it.

aklim

You would not happen to have the list of those that DO NOT fit, do you? Years ago when I went from the Accel 58mm to the Holley 58mm one when the Accel one had issues, I did not consider it Just in case I have to do it again, I'd like to know what to avoid.

Kevova

I do not. I do have a 52mm on an LT4 intake I don't know who made it(don't have it's cover) but it's too big. I have read of others who have had similar condition with the larger throttle body.

aklim

I have a K&N 5050 conical filter so it is a c-hair looser but you just got me worried that if the bore were large enough, it too might not fit and who knows if they will still make what I have that does fit.