I recently read in Chevy High Performance about TBI Blue Printing. They took a 92 305 tbi, and sent the the throttle body to Jet to have them "blueprint" it. In the article it says that the stock throttle body is a victim of mass production, and that the injectors can be off with each other by 15%. Supposedly, Jet rebuilds the throttle body and makes it better than stock and flow matches the injectors. On the Chevy High Performance test car, the owner said the car Idled way smoother and had better throttle response.

I contacted Jet and this service costs $200, and if you want an adjustble fuel pressure regulator it costs $75 more.

I just wanted to know what everybody thinks about this, or if anybody has had it done. Is it worth it?

 

The injector matching is good for a smoother idle but won't gain you much power. $200 is a bit steep. You can can pull your TBI unit off yourself and clean it really good with carb cleaner and perform the ultimate tbi mods to it. You can also make sure that the little screens on your injectors are not clogged with anything. This pretty much does the same thing that they did in that article but they took the whole thing apart instead. Save your $200 and go buy a can of carb cleaner and pull the unit and do it yourself.

 

well said Shifty. just think that $200 could be better spent else where like headers, a cam or something that'll gain you more HP. the TBI is pretty simple to dismantle thus you could do just about everything yourself if you have the common tools.

 

i had the same results for free by swapping injectors with some better ones a friend gave me...


edit:
oh, and you can buy new injectors for less then $200

 

i saw that article and though: "great, some f-body tbi content". after reading it, however, it's obvious it was nothing more than added value for an advertiser.

they didn't even bother with before and after track times and/or dyno runs. that's especially disappointing knowing that primedia (the company that owns EVERY car magazine now) owns their own dyno facility.

 

Where can you buy new tbi injectors? Are there performance tbi injectors on the market? If so, are they bigger? Do they pump more fuel?

 

different size injectors flow different amounts of fuel. for a 305, you don't need to increase injector size till you get into some SERIOUS mods, and then 350 injectors will be more than enough.

there are a number of places where you can get flow matched injectors. one that comes to mind is turbo city.

you can increase fuel flow without going to bigger injectors by installing an adjustable fuel pressure regulator. better yet is a vacuum adjustable fuel pressure regulator, which has lower fuel pressure at idle and part-throttle and more fuel pressure when you need it at wide open throttle.

do a search on "vafpr" and/or "afpr" to learn more. click on the top down solutions link at the top of this page ... they sell a vafpr kit.