I have been looking around at other posts regarding this topic and have seen some people saying the 310cc injectors that come with the kit are fine for 240ish hp...I was just taking to a guy with a dyno near me and he said 310cc injectors are only good for 175whp (200bhp)...I thought this was a little odd because the kit is pretty much 200hp from the factory...so if he is right my intake, exhaust and header would put me over the limit of the injectors and thats not including the 2.7" s/c pulley and alt/crank pulley I have...the guy at the dyno shop said I should get 440cc injectos and said they were good for 260whp...I asked him about the 370cc injectors and said they would only handle 225whp (250bhp)...The guy is used to working on turbo'd hondas so I am wondering if this is the case with our cars with the m45...I thought turbo cars required more fuel the the m45 requires (but I could be wrong)...so I am wondering what everyone thinks about what this guy is saying...I am planning on taking my car there to get him to dyno it and check my A/F...its $75 for an hour on the dyno and he can check my A/F for the same price...so I think that might not be a bad plan to do anyways, just so I know what I am running for whp and A/F. If anyone has some experience in this that would be awsome.

You want less than a 80% duty cycle. A completly stock 2.4 with the kit and included 310cc injectors will have about an 80% duty cycle. So basically if you plan on making more power than stock you need bigger injectors.

This was found in the "What is a fuel system" sticky at the top. This link will help you calculate the injectors you need.
http://www.rceng.com/technical.aspx



Edited 1 time(s). Last edited Wednesday, May 21, 2008 9:13 PM


FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

mine ran lean with the 2.4s/c injectors 13.0 at wide open

i switched to the 2.0s/c injectors , and droped into the mid 11's at 35psi fuel pressure (hpt wasnt out then)

I was running 93% duty cycle at an AFR in the low 12s with them and only putting down 185whp

just buy my cobalt ss injectors in the F/S classifieds lol



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

so I did the calculation and found that if I had 230hp I would need 414cc injectors so the next size up is 440cc...so I am estimating I have 230bhp so that would be around 200 whp...I am thinking I am gonna get my car dynoed June.12 to see what my whp is and what my A/F is...they guy at the dyno shop said he could do a tune on my car for $720 at the most for one day...I am wondering if I got 440cc injectors how hard would it be to tune my car for the new injectors...I am pretty sure the guy can use HP tuners but he is not really familiar with the program as he deals mostly with honda/acura and thinks it may take him a little longer to tune my car...he charges $150 for the credits and $85 an hour for a dyno tune...would you be able to tune the injectors fairly quickly using HP tuners...anyone have some experience tuning for larger injectors...any help would be great

$720 ia outrageous for a dyno tune on your car.,.. Credits will only cost him $99.98. Hell, we usually charge $400-$500 for a dyno tune(complete package) for NA or facotry boost. Find another shop man.... We are in STL, but the dyno is booked for the next 3 months... Too many boosted F/Y bodies and Vipers (these tunes are $750-$1000)



P&P Tuning
420.5whp / 359.8wtq

It seemed a little steep...but he said that would be the most it would cost...if it only took him 3-4 hours to tune it, it would only be $450...he was just saying its a harder tune and takes him a little longer...but I'm not looking for huge HP gains I just want to get the car running so its not lean...so do you guys think 440cc injectors are what I should be looking at, I was thinking the RC ones but not sure if I need new connectors or they are compatible with the stock setup. Any help would be appreciated.

I was quoted about $725 for a tune at the local dyno place as well. I thought it was ridiculous.


2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero

oh yeah... most dyno shops are freaking outrageous when it comes to tuning.

i was quoted $350 to JUST raise my rev limiter at one locally.



Riddle me this... riddle me that...

I guess you got to pay it if you want to get a tune and since shops know people will pay they get all they can out of it. I was wondering if some 440cc injectors would be hard to tune on a 2000 LD9...I really only want to run the bigger injectors efficiently and possibly raise some limiters, not looking for huge HP gains...any help would be great

The injectors will be fine. With hpt you can compensate for the extra fuel thats not needed. If you have or know someone with hpt you could see about renting a dyno, which my friend did with his neon and paid only $100 for 2hrs.

I honestly dont think youd realy need 440cc's, as you can see most of the m45 guys even with smaller pulleys/meth are still on the stock sc injectors or just a bit larger. Im putting in ljs injectors with are 378cc and use the stock clips, the fuel rail bolts just have to be slotted a bit since the injectors sit shorter. And a wideband is a must have.

Is it hard to tune for the SS S/C injectors over the stock 310cc injectors? Also, what all needs to be modified to the SS injectors to get them to work in an LD9? Just the fuel rail bolts, and do they use the exact same injector connectors as a 2000 cav LD9? Just wondering whats the HP rating on the SS s/c injectors? Is it around 225 whp at 80% duty? Any help would be great

Matthew Jollymore wrote:Is it hard to tune for the SS S/C injectors over the stock 310cc injectors? Also, what all needs to be modified to the SS injectors to get them to work in an LD9? Just the fuel rail bolts, and do they use the exact same injector connectors as a 2000 cav LD9? Just wondering whats the HP rating on the SS s/c injectors? Is it around 225 whp at 80% duty? Any help would be great

They connect just as the stock injectors do. You just need to modify the rail. I'm running these injectors. Tuning these injectors are no different than tuning any other injectors.



FU Tuning

Is it a lot of work to modify the rail to get these to work on the LD9? And I am wondering if the 370cc injectors from the SS s/c are the stock size or from the stage 2 kit? I'm not sure if you can just get the injectors from GM, probably be cheaper to get some RC ones unless I can find some used ones or a smashed up SS s/c in a junk yard.

the 310's have been too small for my motor the day i put them in lol

I'm running LSJ cobalt injectors now and if i want to put a shot on the car i'll need to upgraded even those.

Matthew Jollymore wrote:Is it a lot of work to modify the rail to get these to work on the LD9? And I am wondering if the 370cc injectors from the SS s/c are the stock size or from the stage 2 kit? I'm not sure if you can just get the injectors from GM, probably be cheaper to get some RC ones unless I can find some used ones or a smashed up SS s/c in a junk yard.

Is there any way to get these injectors to work without modifying the fuel rail, so if I decide to upgrade again my rail would still be stock...and how much work is it to get the rail to work with the lsj injectors?

BOOSTED / JMdecals.com! wrote:the 310's have been too small for my motor the day i put them in lol

I'm running LSJ cobalt injectors now and if i want to put a shot on the car i'll need to upgraded even those.

My S/C build loved the 310 injectors.

I'll get all the mods I have for my car put on and then head to a dyno to see my A/F...I have been looking around at injectors to see what is available for the LD9...I know the lsj injectors work with a little modification to the rail but I am debating on leaving the rail unmodified in case I go with a few more mods in the spring...I was looking around and found that racetronix has a 37lb/hr injector(which is around 400cc)...I'm not familar with injectors and am wondering if these are any good and if I would need an injector adapter to get these to work on my car...the only other mods I would be looking at for HP would be alky injection, larger TB, and a tune...I am wondering if I should go with the lsj injectors or go with a 400cc or 440cc injector to be safe...wondering how much time/effort it is to modify the fuel rail for the lsj injectors...any help would be appreciated.

The lsj injectors should be plenty good enough for what the m45 can do. All you have to do is slot the 2 bolt holes the hold the fuel rail down about a 1/4 inch. You have because the injectors are shorter than stock, and this allows the rail bolts to line up with the bolt holes. Heres a pic I found:



Im actualy about to do this right now with my dremel.

MP45 kit injectors: 310cc
LSJ injectors: 370cc

That's not a big increase.. I'd get at least 440cc or higher. if I were to spend money on injectors.. that leaves room to grow (small pulley, meth, nitrous, P&P'd everything, etc.)


2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero

Yea lsj's are 378cc to be exact I believe, not much bigger than the 310's but if someone doesnt have hpt these arent too hard to adjust with an afpr or whatever.

I got my lsj injectors for $10 with only 3k miles on them, plus they use the stock connector incase you do ever decide to switch back or whatever.

I know this is not recommended....but if I got the SS s/c 370cc injectors, would I be able to drive my car for a few hours without getting a tune done...I would want to get them installed and drive to get my car tuned on a dyno...from my understanding my car would run rich doing this? As long as the car will run I may have to end up doing that.

It should run ok, but not sure how it would idle just from the fuel pressure being changed. You would run richer, but if your leaning out that would help some and wouldnt be too bad.

will you run less lean with alky injection?...I am thinking about getting the stage one cooling mist kit and wondering if that will help my A/F due to decreased temps?

wondering if anyone is running/know of racetronix injectors...they have some 37lb/hr injector (which I think is around 400cc). I'm wondering if thesee would work with my car...any help would be appreciated