my mods are basic bolt-ons with xe 230/236 cam. i have stock heads but with 2.00/1.56" manley race flo valves. i am looking at getting bigger injectors and a 52mm tb for this setup. i will get custom programming but i just want to know if i will feel/see a difference running bigger injectors with this motor. i also eventually will install some fully ported heads on this same engine.

thanks

thomas

 

you will only see gains from bigger injectors if you are running out of fuel- which i personally doubt.
fuel isn't like air-

you get as much air in there as humanly possible-
you add one part fuel for every 12 parts of air you cram in there.

less fuel and you will run lean/hot and have a world of problems

More fuel and the combustion wont be optimal netting less power

so in other words, if you aren't leaning out, dont get them. 24# injectors are pretty stout. worst comes to worst, you may want to bump up your fuel pressure a bit.

 

so what about if i did the injectors along with a 52mm throttle body? or are you saying that with my stock heads i don't need it

thomas

 

52mm tb = drop in puddle in the grand scheme of things

your REAL restriction is in your heads. so even if you can cram it into the intake manfold, the heads cant "suck it up" anyway

kind of like having a 4 lane highway turn into a 2 lane highway and back into a 4 lane highway. making the 4 lanes into 5 or 6 lane highways wont help, you need to open up the 2 lane segment

 

i understand what you are saying now. i will look into heads before i worry about the tb. i will probibly get the injectors though since it seems like a reasonable price.

thankss

thomas

 

To put it in perspective ....

I'm having to upgrade my 24# injectors because they are MAXED OUT at 6K RPM, but I need to go above that. My car has heads and cam and about 475hp. That's how far you can push em.

 

mike,

i have the same cam as you. do you think that with ported heads i will need the injectors then? do currently take my car past 6k (around 6250). so does this mean that i will need bigger injectors too? our mods are very similar except for the heads

thanks

thomas

 

HOW PORTED is the real question

 

~280's on intake
~200's on exhaust

 

My heads are 257 int / 203 exh @.6

Also, after installing the heads and cam, when I went from the stock TB to the 58mm it made a big SOTP difference, so consider that too.

I logged data and made some WOT passes, shifting at 6K. It's a good thing I didn't rev higher because at 6K the injector duty cycle was 102%

 

mike,

what do your heads flow to allow you to make 475 hp? i hope that we are talking at the crank right? what does that setup make at the wheels ~400??

thomas

i just saw that you posted, sorry!

 

who ported those heads? do you think you could make more power with this cam if you had better flow#'s or would it not make that big of a difference? have you dynoed yet or are you numbers based on estimation?

thomas

 

DAMN,
hope your velocity and low lift numbers follow suit

 

they are from a local porter who has done several sets of lt1 heads with good results. he told me that he had good low lift numbers as well, i wrote them down but i can't find them! i will double check the lift numbers throughout the range though before i send my heads to him.

thomas