Upgrade C4

[CaptDale - is secretly British]

A few months ago I picked up a nice used 58 mm throttle body for my Corvette. I had yet to install it as I was diagnosing other issues and did not want add another variable to the equation. Since I have mostly figured out those problems, I thought it was time for a fun upgrade.

Dirty old 48 mm body next to the shiny 58 mm body.
More air = moar poooooower baby
But really there is a nominal increase in power according to dyno sheets and nonsense like that, but what I am more interested in is the quicker throttle response and likelihood to rev faster. Should make the canyons just that bit more fun.

Also looks pretty good on there minus where I messed up the fresh bit of paint I pit on that top cover, oh well.
Plus it is CARB legal so I don't have to change it back every 2 years or pay out the nose for it to be CARB legal.

Lately I have been hunting own a MAF problem where at idle it reads less than nominal air volume. I've been through 3 MAFs so far trying to see if it was the old MAF that was the issue or not. Sadly new MAFs even from the manufacture are crap shoots in quality. So hard to tell. Did a smoke test and no visible leaks of unmetered air. Man I wish I could just pull the motor, build a 383, put in a new wiring harness and just rule out a lot of possibilities.

Anyway, that is where we are with the C4 at the moment.

[jminer]

Looks good - solid fix that is also an upgrade!

[trivet]

@captdale-is-secretly-british
Very cool - post your impressions once you get to open her up. I considered a very similar upgrade on one of my past vehicles, but never got around to doing it. I always wondered what difference it would have made.....

[CobraJoe]

Nice Upgrade. I love the snappy feel of a "oversized" throttle body, even if it doesn't add much power.

[MM54]

@cobrajoe said in Upgrade C4:

Nice Upgrade. I love the snappy feel of a "oversized" throttle body, even if it doesn't add much power.

It does make a big difference to the feel of the car, even if the numbers stay the same. I put a 70mm tb from an e-series van on my last crown vic (stock is 65) and while I assure you it made zero additional anything, the increased rate of throttle opening helped make it at least feel like it wanted to get on the move.

[CobraJoe]

@mm54 I did the same upgrade to my '96 CVPI when I was in college. Replaced the stock TB with a Mustang sourced one.

It was a very satisfying change, even if it didn't help on the top end.

[chan]

No such thing as too much throttle response!

Are these model-specific?

[CaptDale - is secretly British]

@chan They would be engine specific, but technically this is Corvette LT1 specific in CA due to the CARB number.