I ran a few searches and read a bunch of inconclusive stuff. It was mainly arguments that never came to an end.

There were a bunch of guys saying they were running stock injectors that were maxed out, but were not having any problems. It is my logical understanding that if you constantly max out an injector, it will break. And if it does break at 6,000 rpm, it will cause a lot of damage.

My question.... I am running stock injectors right now with a ~400rwhp setup. Using the .07 calculation (450fwhp)(.07), that puts me right around 36# injectors. Is that what size I need? What is the best brand?

The reason I am asking is because there is a guy offering to sell me a brand new, in box set of Bosch 36# injectors for $140. As a matter of fact, he has two sets. So if anyone needs a set, let me know.

Also, I still have not found actual dyno results saying that a bigger-than-stock throttle body would improve hp on a 450fwhp application.

 

36 should be fine ,even 30 are I think enough.
The bosch are rated a bit different and put out a bit more at lt1 fuel pressures .You can get a bit more out of injectors with an adjustable fuel pressure regulator also but raising pressure can I think make tuning a bit more difficult.

 

I got my pcm tuned for 24# svo injectors. However, I only have 24# stock injectors. Would this throw my tuning off?

 

Ya can make 500FWHP with 36's @43Psi and 86.8 DS.

 

Maxed out injectors may not consistently feed all cylinders as factory allows for a 10% variance in a set before it is considered bad. If no other that is a hell of a reason to step up.

On the TB want proof hook up a vacuum gauge and tell us what sort of vacuum you have at WOT especially say over 5000rpms, oldschool carbed rules were for a street car anyting more than 1.5" was a restriction, .5 on a race motor since we can't practially oversize a TB since it is dry unlike a car we can aim for the race goal. This info can be viewed with any datalogger too.

 

Would I consider my car a race or street car? If I set the vaccum to racing specs, will that hurt performance on the street?

How big do I need to go on the TB and how much power should I pick up?

 

I have close to the same specs as you and I was recommended to the 36's myself, although I was fighting for 32's for the sake of gasmilage, but I'm not quite sure how much different the two would be. Guess the only way to get better gasmilage is to put a piece of 2x4 under your gas peddle to keep it from hitting the floor so much :-P

 

Go big as you can go, 36's aren't bad, 42's and 50's are better. That way you wont need to buy a bigger injector in the future. Keep in mind that the stock pump isn't good enough for large hp, if you go larger than 30# I think its time for a booster pump or racetronix kit.

BTW properly tuned injectors will get the same gas mileage regardless of rating. There is a minimal impact on fuel usuage or drivability until you go larger than the factory ecm can handle. Its all about tuning.