LS1 Cobra

Hi All, Sorry this is probably a bit long winded but I'd apreciate any advice you can give...

I've got a 99 model LS1 crate motor in my Shelby Cobra replica. It's got the 853 heads with center bolt covers.

I bought a MS4 cam a while back and thought it would wake it up a bit. I was thinking I'd wait till I got some good heads before installing the cam but lately I've been thinking I'd just throw the cam in and see how it goes with the stock 853 heads. It's been sitting on the shelf for a year and I thought I'd have some fun over the summer.

I've already installed a dual spring, Ti retainer and molly pushrod package from TSP and I'm running Yella Terra 1.7 ratio rockers as well.

I'm running my own 1 7/8 long tube headers, Edelbrock Victor Jr and 1000CFM 4 barrel T/B. I've also got ARP rod bolts and an LS6 oil pump to go in.

I'm running a Bosch 044 fuel pump and SARD adjustable pressure reg, it's a full return system.

I'm already running a basic speed density tune and I'm going to have to get it retuned with the new cam.

My question is: Are the stock 28 pound injectors going to be up to the task or should I replace them before the tune? What size/brand injectors would you reccomend I run for this combination?

What sort of RWHP figure should I expect it to make?

I'm running an M6 with 3.9:1 gears.

Here's the motor pretty much as it sits at the moment. I've had this pic up on the forum a couple of times.



I've just done a few more mods to the water pump setup.



Thanks.

Michael

MRZ28

iTrader: (15)

WOW.. that is a SWEEAAAT setup you got there..... ok im done drulling now. As for your post, I use the SVO 30 lbs. I have never had any problem with them, and they are more than enough injector for My H/C/I setup.

Black FormulaLs1

iTrader: (10)

+1 for the 30lb SVo unless you plan on running some giggle juice....then i would go with the 42lbers..

LS1 Cobra

So 30# SVO injectors are the go. That's onle 2# more than the stock 28# injectors or are they rated differently?

Cheers

Michael

SOMbitch

iTrader: (8)

Yes they are rated differently. GM fuel pumps run more pressure (58-60lbs.) so they are about 36lbs. on an LS1 setup. I think Ford runs in the neighborhood of 45 lbs.

bww3588

iTrader: (49)

if they are stock 99 injectors, they are 26lb injectors not 28.5. the 98's and 01-02's i think were the only ones that got the 28.5's. that said, i went with bosch style 39lb injectors off ebay.

LS1 Cobra

I picked up a LS6 manifold that came with some 28.5pound injectors so I fitted them prior to the first tune.

scidav87

iTrader: (16)

i use lucas 42# unjectors, no problem, its all in the tunning how big you go...for the most part. Just don't go crazy big.

SIC LSX

iTrader: (10)

SVO 30's red top will be fine and cheep and so Will SVO 42's green top! I have SVO 42's and stock 99 heads with tsp 231/237 cam. I got 42's on a deal and i will be good when i add mods down the road. Make sure you car has the injectors tuned b4 you add them or you will wash you rings out!!! Remember SVO injectors are 5-6 PSI more with our fuel pressure so the SVO 30's are more like 35-36lbs

LS1 Cobra

OK that makes sense. I was wondering why anyone would only jump from 28 to only 30 pound.

So 42# green top SVO injectors are OK and would give me enough room to move up later If I built a stroker or something.

They will be able to dial them back enough when they tune it? Or is it best to choose an injector that's maxing out just above your peak HP, I mean is there a point where the injector works at it's peak efficiency?

Thanks

Michael

SIC LSX

iTrader: (10)

Yes it is ok! I have a smaller cam and mine are great and have been in over 2 years! I get 25-28mpg on hwy!

fatdave

iTrader: (6)

im running #42's on my set up got them with Nasty's stage 1 setup Great stuff and a great price. Just nice to know that I wont have to mess with the fuel system if I decide to do anymore work to the motor