ESU

I have been thinking of boring my TBs up to 2in but not sure if I will see any positive result or if it may even be harmful. The car is a mostly stock 82 with 63k miles. I have rebuilt and rebushed the TBs. I also added an 85 fuel pump and bumped the pressure up to 14 or 15. I wiped a cam lobe a few years back and since a stock grind wasnt available I had to go with a slightly hotter cam from comp cams. I am also running true duals. I was wondering if boring my TBs out to 2 inch would compliment the engine as it sits now or am I just throwing my money away? My thought was the engine was breathing a little better with the cam and exhaust and that bigger TBs would be beneficial.

rmm82

I'd call the Dynamic Crossfire Injection folks ( http://www.crossfireinjection.net ). They are very knowledgeable in this area. If you haven't done so already, I'd swap out the heads (I have a set of trick flows on mine) and purchase the Renegade from the DCI folks. They are great people.

ESU

Tried that, never really heard back from them and I had them re-bushed by them and purchased some things from them.

rmm82

Sorry to hear that, sometimes DCI gets busy. Back to your original question (keep in mind that I'm not a mechanic, just been doing my own work for many years), IMO, I'm afraid that given your current configuration (e.g. mostly stock), you'd be wasting your money. Those stock heads are poor performers, the intake even worse. Changing those two items were the best thing I did (oops, almost forgot - also installed 3.73 gears). Now I can actually smoke the tires from a stop.

ESU

I agree that the heads and manifold are a definite problem but I have no thought of changing either. Just thought I might reap a benefit from a simple item like the TBs. I really didn't think it would help but figured I'd ask some others their opinions.

augiedoggy

Think of it this way if you plug a small thin $2 lamp cord into your wall outlet and then plug a larger heavy duty cord into that do you think the cord will deliver more power/amps? The answer is no because the small cord is the restricting factor and bottleneck in the system just like you intake and heads..... main reason I sold my 84... there are a bunch of aftermarket intake companies claiming to make intakes for these but you have about as much chance at winning the lottery as actually aquiring one it seems..... at least thats the way it was for me. Some people order and prepay and wait years for manufacturing run of them. The stock intake flows under 600cfm if I remember correctly.

ESU

Yep, seems like those manifolds sell out before they ever hit the shelves. Guys have talked about being able to work/port/bore the manifold to give better results?

jdp6000

If you google it there are a few sites that give instructions on how to port the factory manifold. There is a guy over on corvette fever that has a thread on all of this. He ported his manifold, bored the TBI's, used heavier injectors, better heads and cam, etc etc....

Jim

hugie82

You might see another 500 rpm before it drops off with the 2" TB bore job. To get the full effect, you'll need to get an X-ram, Renegade or a lot of porting! To open up a stock manifold will take 10 hours and about 2 pounds of aluminum will need to be ground out.
All this work will give you very little at low rpm if anything at all but top end may get you close to 6500 rpm. The stock set up is what makes our cars fun. The low end torque is a blast, so most of my engine improvements are targeted for 5000rpm and down. I would say the best bang for the buck is a nice set of aluminum heads. nothing else will wake up any CFI. The bump in compression, better heat management and low rpm flow (velocity) is where the torque is!

corvettenorway

flow is torque !! full porting job of the manifoil = flow !! porting or better flowing heads = flow !!! headers and better cats = flow !!!!

augiedoggy

I get what your saying but dont really completely agree.... as long as you improve the engine flow path (tb,manifold,heads and exhaust you can easily improve your powerband across the board....
My 84 was torquey but it ran out of steam LONG before 5500rpm.... and most seem to measure between 165-190hp at the rear wheels on the dyno stock.... Not very good. TPI delivered better torque from its long runners..
As long as the owner stays away from driving anything with more power he would be happy but Like I said my employer bought us 4 cylinder camrys and once I drove that I was disappointed at the power output of my old vette... (it was a z51 so handling was still awesome compared even to my 74)
I drove it happily unaware for over 13 years though...Despite all the talk about crossfire reliability the car had 104,000 miles on it and all I needed to replace was a starter and an alternator.... ran like a top.
My 74 on the other hand it about to get a 400hp/414tq engine transplant so I can at least keep up with the modern stuff. It wont be the fastest but at least it can hold its own on the road.