This totally freaks me out but what I'm being told is that these new SIEMENS Injectors are capable of these flow #s BUT are also able to flow better than smaller injectors at lower rpms and needs etc etc.

Ami being fed a load of or is this siemens injector as much hype as they say. We were planning on running delphi #42 but they're out of stock and wont have them for a while.

> fully built 388 forged everything that will revv 8k

 

Ouch, thats allot of injector. Especially for NA LT1/L98 types.
Are you being told this by Racetronix?

 

Two things:

(1) Yes your being fed BAD information if they are saying you NEED EITHER of those injectors sizes you mentioned. Best running 383 on this board is running 24# injectors. Several others running the same thing.

(2) Your motor will NEVER see 8k and make any decent power. Unless you have -15, -12 etc heads on it or better.

 

theyre not saying i NEED them. theyre saying that 1) the 42#s arent available.. and 2) that these can be used for my app without tuning issues because of the new design of these siemens injectors 3) that if i ever use a big shot of n2o or supercharge it... which i doubt i ever will.. i dont have to switch injectors.

ski im not looking to make power to 8k. looking to make a peak around 6800- 7200. i wanted it overbuilt so it can handle up to7800 or so without blowing to pieces.

 

Have you looked at 36's? They are probably still over kill, I am only at 76% DC at 6800 RPM with my combo, but they should provide plenty of head room.

 

The new 60lbs siemens/motron injectors do have excellent quality. I've used them in totally stock engines but with some sort of forced induction. If they are tame enough to work in a small displacement, stock cam application they will surely work for you

however


They are almost twice what you need. I would suggest getting a set of 42 SVO's.. They are commonly avaiable and have very good characteristics (not as good as the 60's believe it or not but your splitting hairs there)


Don't be afraid to use the proper sized injector for your car. With a good tuner you won't have any issues whatsoever

 

Alvin that seems to reflect exactly what ive been told. that these new Seiemens injectors are designed to work with stock cars and something to do with emissions - i can't remember. I know i can get delphi injectors from racetronix in #42. From what ive been told they are a better injector than the svo. Im no expert so i dont really know which is better.

i believe there is a Siemens #55 injector as well. if he still insists to use them i will ask to get those instead of the #60s. i wanted to ask up here to see if these injectors were some sort of 'miracle' injector that he makes them sound like.

 

apparently his supplier is Jack at racetronix... If he says to go with them ....

 

Mike, I am going to give you my opinion for what its worth. IF your tuner says to use xx injectors use them. That way if there is a problem with the way the car runs it is his problem to figure out. If you mismatch the parts (at least in his opinion) then he will blame anything wrong with the tune on that. I have no idea who you are using, but if he has experience with these injectors Id trust him. Oh and good luck in being happy with the power you will be making. I have yet to talk to anyone on here who is satisified!! It seems like we are for a little while and then we start looking for a little more.

 

Thanks for the email DieL,

In summary of the email:

The 60# injectors are WAY overkill for your application and most likely MUCH more $$ than a good set of 24# injectors.

OVER INJECTING your motor is not going to do anything for you, that "extra" capacity is not going to do anything but cost you a lot of extra money to have sitting there.

As previously mentioned, people can talk any "tune" they like; but results are where the rubber meets the road.

85vet 383CI motor 11.0@125MPH
Ralph 406CI 10s
SKi 406CI 11.0@123MPH
Corkys 406CI 10.9@125MPH
Beachbum 383 low11s
Corkvette1 434CI 10.2@130+mph
Corvette0096 383CI mid11s

There are a few things common among these setup; most important common denominators pertaining to this topic are these are some of the quickest C4 cars here in the forum, and they are all running 24# injectors.

To me the answer is obvious - don't mess with success!

some other fundamental things to remember with picking your injectors.

HP dictates how much injector you need. HP is based on airflow. The fuel is the easy thing to get.

So comparing to the above examples, chances are you are not going to be making any great amount more power than these other 383s and most likely we can all bet without regard you will not be making more than corkys 434 running bottom 10s. Hence the equation/decision becomes VERY simple.

The above people running/owning the mentioned setups are no dummies when it comes to this stuff - which the exception of me - so if there was power/a reason to go with bigger injectors they all would have them.

 

I fully agree i may not be putting the same or near power #s as the others mentioned nor am i claiming so. i am also not being told i NEED these injectors. Like i said earlier we initially planned on using 36s and then 42s but they dont carry them. racentronix is telling my builder that the siemens injectors, even though they are #60, are BETTER for my application. He also said that they are especially better for higher rpm motors not because they CAN provide huge amounts of fuel but because they have faster opening/closing speeds and better nozzle designs etc. He pretty much said that these injectors are BETTER than stock injectors even on a stock motor.

he wants to go with them so i said fine but he agreed that if there are any issues that can be traced back to them they would be changed no questions asked.

on the bright side they're black injectors. matches with my black heat dispersmant treated lt4 intake and fuel rails

 

So you've already bought the 60's? If you haven't I would still reccomend picking up a set of 42 SVO's. They will be big enough to do whatever you want yet they aren't the latest and greatest nor are they the biggest so they can be had for a few hundred less than the 60's. The 36's would be a good option too as that is more than enough for most NA applications. Its really pretty tough to max out a 30 lbs injector on motor alone but it is possible.. You really aren't going to max out a 36lbs.

If you've already gotten the 60's don't worry about it. They are clean injectors. I actually have them in one of my personal cars and a 700 RPM idle in a 355 still does quite nicely. It actually passes emmissions with flying colors and still runs a good 104mph in the 1/8th


Whatever you do I would put at least a 30 on the car. I wouldn't think of going anything lower.. I mean after all.. GM had to know what they where doing with a 28lbs injector in the LT4 and a 42 lb injector in the new Z06.

 

i dont think he has gotten them yet. The short block is finished and all the head/valvetrain parts are in.. just waiting on new valve locks i think it is. he sounds pretty convincing about using them so i agreed. I do have a lot of $$ in motor and the rest of the car i built around it over the last 3 years i figure i may as well take his word.

On a side note he also said that we should use lash caps. initially i believed it was because of a geometry issue but he says theyre better and will make it more durable for higher rpms.

At this point I'm wishing i just sold it and bought a c6 or an 03 z06. Either way if im not happy with the car when its done it'll be on ebay

 

thats exactly the way i look at things as well. im hoping ill be happy with it when its done. Its been 3 years with no motor in it... and im not nearly as hyped about it as i used to be. in fact im at the point where im so fed up with waiting i want to sell it before i drive it

 

I thought you had it finished years ago? Didn't you have RWHP #s listed at one time, around 488? Maybe it was someone else.
Why so long?

I don't understand how 24# injestors can be used on a LT motor like this, isn't that stock size?