Need your injector size recommendation. All engine details inside!

[CoolAid]

This is for my friends 02 Camaro SS. Currently with his intake/LT set-up I have his stock 28.8s logged at 80% from 6k+. Now we are putting heads/cam to it and want to put some injectors in it as well before the tune.

Set-up:

-Stock cube (346) LS1
-MS4 cam: 239/242, .649"/.609", 111 LSA
-243 heads, semi-ported, w/ larger valves
-10.5:1 compression ratio
-79mm ported LS6 intake
-82mm ported TB with stepdown spacer
-SLP catless LTs

I am thinking atleast 42#s with that set-up, 60#s if he decides to put a 150 shot on it down the road. Any thoughts? Im just now learning about injectors and what to look for, best brands...etc....

Thanks for any help! :cool:

[TomH]

no clue on the injectors Coolaid... but good to see my heads are going to good use! ;)
unless thats a different friend lol

[thedak]

42's will be plenty.

[Oh4GTO]

I had pretty much the same setup (cam and heads) and I ran ford green top. Dont remember what the DC was but it was of no concern.

[CoolAid]

I guess were going with 60s. Tuner says he can make them live N/A and they are good future proofing if he decides to shoot it full of N20. Hes looking at the Siemens 60s that HSC has on sale.

[hardcore]

I guess were going with 60s. Tuner says he can make them live N/A and they are good future proofing if he decides to shoot it full of N20. Hes looking at the Siemens 60s that HSC has on sale.

I''m running 42's with all about the same suff... and N2o will have no effect unless he is running a dry shot...
on motor I'm only at 60%
on a 75 shot I'm at 82%
A 125 dry shot is realy big

[CoolAid]

Im assuming you have a wet shot and if your at 82% with a 75 shot that seems a little close no? I've read multiple places that the industry standard for maxed injectors is 80% and if he runs nitrous it will be atleast 100-150 shot.

[thedak]

42s are plenty with a wet shot.

60s are overkill on a 450 RWHP NA Car.

[wanablaze]

42s are plenty with a wet shot.

60s are overkill on a 450 RWHP NA Car.

+1. Unless he's going to run that large of a dry shot, go with the 42lbers.

[JoeMama's GTO]

480 RWHP on a 75 dry shot with 42lber's. I am not sure what fuel pressure the Maro's run but our fuel pressure makes 42's behave like 60's. Don't forget about the pump!

[hardcore]

Im assuming you have a wet shot and if your at 82% with a 75 shot that seems a little close no? I've read multiple places that the industry standard for maxed injectors is 80% and if he runs nitrous it will be atleast 100-150 shot.

no mine is a DRY shot 80% is fine as long as you AF is good.. I've been 11.5-11.2 so Rich for a 75 shot

[CoolAid]

Thanks for the input. :cool:

[05gto60]

480 RWHP on a 75 dry shot with 42lber's. I am not sure what fuel pressure the Maro's run but our fuel pressure makes 42's behave like 60's. Don't forget about the pump!

actually, our fuel pressure only makes them act like 48# to 50# injectors. it depends on what number you use for fords PSI, as ive seen different numbers posted

[leorou]

I own a 04 gto with about 64000 miles. I figure it's time to change my fuel injectors. I searched and found Mototron 60lb injectors. I don't know much about injectors, a little advice would greatly appreciated.

[spiceredm606]

what are your mods^?

[leorou]

No internal engine mods. just want something better than stock.

[Fenderplayer]

42s are plenty with a wet shot.

60s are overkill on a 450 RWHP NA Car.

is there any reason why he can't go with 60's? are they less efficient and lower usage levels?

[kenmosher]

No downsides to the 60s ... they have excellent linearity, good response, can run up to 500kPa differential across the injection and are VERY tractable at low flow rates. They are also very repeatable across injectors in both dynamic and static flow rates.

* I used to work for MotoTron and was almost soley responsible for getting these injectors introduced to the automotive aftermarket. They were originally a custom spec'd injector for some really wicked Mercury Racing offshore blown powerplants and were custom made by Siemens for Mercury/Synerjet.

They were awesome injectors (I used them on my GN motor and it made 650HP+ and over 700 ft/lbs of torque ... and still passed Colorado tail pipe sniffer emissions!), but a bit pricey until we took the plunge and started ordering 40,000 pieces at a time. MotoTron also sold them thru Edge Products (who I also worked with), but now MotoTron has been sold to Woodward Governor and Siemens is selling them directly.

[GTO 05]

No downsides to the 60s ... they have excellent linearity, good response, can run up to 500kPa differential across the injection and are VERY tractable at low flow rates. They are also very repeatable across injectors in both dynamic and static flow rates.

* I used to work for MotoTron and was almost soley responsible for getting these injectors introduced to the automotive aftermarket. They were originally a custom spec'd injector for some really wicked Mercury Racing offshore blown powerplants and were custom made by Siemens for Mercury/Synerjet.

They were awesome injectors (I used them on my GN motor and it made 650HP+ and over 700 ft/lbs of torque ... and still passed Colorado tail pipe sniffer emissions!), but a bit pricey until we took the plunge and started ordering 40,000 pieces at a time. MotoTron also sold them thru Edge Products (who I also worked with), but now MotoTron has been sold to Woodward Governor and Siemens is selling them directly.

Seeing you worked for Mototron, do you have good spec sheets on the Siemens 60's ?

Didn't you also work on the Dashhawk project ? what happened there ?

[JS1965]

I went with the LS2 rated injectors now
Going to put them in this weekend
57LB RATED AT 58PSI

I might wanna spray a 100 dry down the road so that why I went with them

[kenmosher]

Seeing you worked for Mototron, do you have good spec sheets on the Siemens 60's ?

Most calibrators/resellers were given those specs, flow rates, on/off times, etc. ... I'll see if I can attach the a drawing that has the basics. Due to my noncompete, I don't think I can hand out the detailed specs (yet). In the lower right hand corner of the attached drawing are the basic calibration info. Keep in mind, this was for OUR version ... I *think* the ones being sold by Siemens now are the same, but if they've made any changes this may not be correct, although I can't imagine why they'd do that.

Didn't you also work on the Dashhawk project ? what happened there ?

Yep, DashHawk was my baby ... did pretty well, but with the downturn in the economy MSD cut a BUNCH of the engineering staff (including myself and my team) end of last year. I won't say anything negative, but I've got a real problem with what they did on many levels.

We've started our own deal now, with products due out this summer.

[Steel Chicken]

...

Yep, DashHawk was my baby ... did pretty well, but with the downturn in the economy MSD cut a BUNCH of the engineering staff (including myself and my team) end of last year. I won't say anything negative, but I've got a real problem with what they did on many levels.

We've started our own deal now, with products due out this summer.

Thanks for the PDF's!
Do you happen to know the actual minimum PW for those injectors? (not just the turn on time, but minimum reliable PW)
Would it be min on time + min off time?

And the dashawk is a great product, heard what happened with that...sorry to hear how it worked out. Keep us up to date on your new project!

[kenmosher]

They were tested and flowed down to 1.5 ms and "rated" at 2 ms.

That said, Bruce Plecan (may he rest in peace) reliably drove them down into the 1ms range on his GN. He was very impressed with how little "jitter" they had even at very high differential (across the injector) pressures.

[Steel Chicken]

They were tested and flowed down to 1.5 ms and "rated" at 2 ms.

That said, Bruce Plecan (may he rest in peace) reliably drove them down into the 1ms range on his GN. He was very impressed with how little "jitter" they had even at very high differential (across the injector) pressures.

Very cool. 2ms is the on + off, and what I assumed, but personal experience is they do indeed work ok at <2.

Nice to hear from someone who actually knows as opposed to e-experts!

Thanks again!

[adamsgto2004]

good thread