EvilWS602

Hi guys. I've been building a 418 stroker with cathedral port heads. I swapped from the FAST intake to the MSD Atomic Airforce to see how it does in comparison. I installed the MSD and LS2 fuel rails. I used the fuel rail spacer to shim the rail up for my LS6 length 42# Racetronix large body injectors. They were extremely hard to get down in the boss and seemed bound up and would not spin or twist in the intake once the rails were bolted. I've been fighting a partial misfire with the fuel trim levels different form one bank to the other. Injectors may just need to be serviced being they sat up for a little while but some one suggested they possibly could be in a bind being how tight they are in the intake.
I contacted MSD and they recommend LS3/7 length injectors for that application. So I figured I just order new and services my current ones and reuse them on diffent build or sell them.
I ordered new Racetronix 42# short injectors which measure 34.5mm o-ring to o-ring which Racetronix said they use for the LS3 application.
I went to install them last night without any spacers under the fuel rails and they are not long enough to seat in the injector bosses of the intake. I can see daylight all the way around the o-ring.
So. Who has done an install with this intake and what length injectors was used. I need at least a 42# injector. What suggestions or combinations do I need to get proper fitment on this application.
Any and all help is greatly appreciated as I have been going round and round with this for months now.

The Alchemist

iTrader: (19)

I was the first to have the MSD cathedral port version, and I had issues with injectors as well. I have ID1000s, and have the extender on them to get my fuel rails to fit right. I had to modify the spacers as well with some shims, and ended up using a 2010+ ls3 injector oring for the bottom of the injector.

wannafbody

iTrader: (2)

Wow, that shouldn't be an issue with a $1000 intake

EvilWS602

You would think. Then you would also think that when you call their tech support on that $1000 intake they could give the the right information. They told me LS3/7 length injectors which are clearly to short. Found a buddy with the LS2 length injectors we mocked up to test fitment. They fit like a glove. Even felt and could hear them seat in the intake. Really disappointed that the MSD tech support couldn't even point me in the right direction on their intake installation.

EvilWS602

Through a lot of trial and error I have been figuring this out all on my on but I really hope I have about got finally.

98CayenneT/A

I used gtp Bosch injectors with a Ls2 fuel rail and purchased a $30 spacer kit that includes the o rings and I had zero issues.

EvilWS602

My tuner and I know guys that have used the extensions and had no issues but I was advised not to use them if I didn't have to. What length are those injectors? I believe the LS2 length or 52.78mm or 2.078 inch mid length injectors should do the trick. If I am in able to return the ones I got or get to much hassle I will get those extensions and give that a shot.

98CayenneT/A

The gtp injectors are 74 mm

98CayenneT/A

This spacer kit with the gtp injectors and Ls2 fuel rails was perfect.
https://m.summitracing.com/parts/msd...SABEgJZB_D_BwE

98CayenneT/A

Here is where I bought my injectors
http://www.ebay.com/itm/like/1821856...&ul_noapp=true

EvilWS602

Hum. Interesting. We had a set of the FAST spacer but figured they had the be the same size. I used them and spaced my LS2 rail up but my LS6 length 42# injectors felt bound up. Had to force them down to even get the bracket of the rail down the the spacer and get the bolt started in the intake. Trying a route without the spacers hopefully. The spacers can slightly throw geometry off though we have done it without any issues in the past. I'm just trying to set the up as it was intended just to rull out any and all issues I may encounter.

boostwhipped24

Anyone have any updated info on what injector you guys are running with this intake.

EvilWS602

LS2 length injectors work. Have LS2/3 rails and LS2 length injectors, seated perfectly.

ramairws6

iTrader: (33)

Fore Innovations rail and be done

corvettestar

hi i know this is old but what injectors did you use? I’m stuck now as old injectors are loose and not long enough. Thanks

gagliano7

He used LS2 length injectors.

corvettestar

Is this ok for injectors to sit? Do injectors have to be flush? Thanks . This mad intake manifold is a pain, had to cut good amount of fiberglass from my c5 just to install it plus a new water pump which was already new. I hope I don’t need new injectors. I spoke with several shops and said this is fine injectors done have to sit flush . I don’t know

wannafbody

iTrader: (2)

Injectors aren't going to sit flush with the bottom of the intake.

corvettestar

so is this ok?

G Atsma

Yes, it is....