holdenhunt Posted December 25, 2011 Report Share Posted December 25, 2011 Ok guys so I recently did a cam swap using a 222/224 on a 112lsa. The setup is currently running fine but I am wondering if upgrading my injectors to slightly bigger ones is the right next move. I have full boltons and also the BBK 80mm tb, will the 8.1 injectors be sufficient? I dont want to get to radical or expensive on the price because I plan on staying NA and the only other changes I might have in the future would be a better set of heads. And will the stock fuel pump be sufficient with an injector change alone? I am also curious as to how much hp I will gain with these injectors. Quote Link to comment Share on other sites More sharing options...
NTMD8R_SS Posted December 25, 2011 Report Share Posted December 25, 2011 42lb 8.1L marine injectors will do the job. Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted December 25, 2011 Report Share Posted December 25, 2011 (edited) the marine injectors should be enough for that cam and a decent set of heads. If you go with a larger cam that requires more rpm and a set of good flowing heads that will increase the shift points even more and you'll run out. But if you plan on staying with that cam, do the marine injectors. I've been able to run 12's NA on those injectors and my buddy ran low 13's on a NA set up. A mild upgrade would be a set of green top SVO injectors, but they are not plug and play. The stock fuel pump will support more then most think it will, don't bother spending the money, you'll just be wasting it. I don't think an injector change will up your hp at all with that cam and stock heads. Define full bolt ons? Electric water pump? 160 stat? e fans? intake upgrade, 90mm or larger? Headers? aftermarket roller rockers? Under drive pulley? Ram air? Merry Christmas Edited December 25, 2011 by shadowsniper3006 (see edit history) Quote Link to comment Share on other sites More sharing options...
holdenhunt Posted December 26, 2011 Author Report Share Posted December 26, 2011 Ok so i see i misdefined full boltons, I have longtube headers and full exhaust, BBK 80mm tb, ram air intake, and a160 t-stat. And if im not gaining more hp by swapping out these injectors then i guess I may have asked the wrong question. I am looking for the next cheapest way to add more hp while also adding more room to grow on for future mods. I know the common weight shaving strategies but dont want to do any of that I want my truck to be practical. And i plan on keeping the truck NA. Thanks for the help! Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted December 26, 2011 Report Share Posted December 26, 2011 (edited) I'm sorry, I re-read everything and maybe I misunderstood. If you have the marine injectors now, you can keep them. If your on stock injectors, then I would upgrade. Its not going to add any power, but you'll be able to get the injector timing back to where it should be by having a lower duty cycle. Besides what I said before, you could add heads, thinner head gasket, true roller rockers, did you have a stall? Short tire on light weight rims is also a nice gain Sent from my SAMSUNG-SGH-I897 using Tapatalk Edited December 26, 2011 by shadowsniper3006 (see edit history) Quote Link to comment Share on other sites More sharing options...
holdenhunt Posted December 26, 2011 Author Report Share Posted December 26, 2011 I dont have a stall yet but im awaiting funds to build a tranny and do the stall all at once so thats next on the list, i also dont have the injectors i was just wondering if they would be ideal, and as far as doing the heads what would be a good choice with this cam? And would it be worth the dough to port and polish the stock ones? Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted December 26, 2011 Report Share Posted December 26, 2011 (edited) Its always worth while to add a set of great flowing heads. A set of great flowing heads can support large cams with out choking them off, or flow more air with a smaller cam and keep your power band and driveabliy in check with out the downsides of that larger cam. Porting the stock heads works very well, they are a great place to start with out buying another set of castings. You can deck them down to 66-68 and up the compression while porting them, also run a thinner head gasket to get the compression higher with the stock 317 heads. Or you could find a set of LS6 heads, 243, or the new equivalent, i think 799 is the new casting number. These have a 65 cc chamber and are also a great place to start porting, you can leave the chamber be or deck them a little more. You can run stock head gasket or a thinner one to tweak in your compression. You can find a set of 5.3l heads as well, these have a 862 casting with a 61cc chamber. You can have these ported and have the deck just cleaned up if they are used, but I'm not sure i would deck them any amount over clean up. All the stock casting are a great place to start and each has its usefulness in getting you where you need to be for compression. If you have the money i always recommend running a trick flow head. They are aftermarket castings that produce better flow numbers and have a better design for making hp and reducing detonation. The 225 head comes in a 65 or 71 cc chamber and can be tweaked from there. As far as who ports the heads, don't go to your local shop and have the guy with a die grinder port them, go to a reputable LS porter that can run a tried and true cnc porting program on them. Guys like WCCH, patriot and TEA are all well know. I always recommend TEA, as they seem to get higher flow numbers using a smaller valve and always seem to be on top or close to for hp output on guys set ups. There are all sorts of guys on here running all the heads i just said, to give you an idea: Stroked out ss, Chase and I are running the trick flow heads, Krambo's monster is running ls6 heads ported by TEA i think, zippys 408 is running a 5.3 head, and its to hard to list all the guys running a ported a 317 head. Every head is a good choice as long as it matches your set up and goals. Here is a quick idea of what you could expect for compression ish. Stock compression on GM head gasket 10.04 ish Deck stock heads to 68 cc with gm gasket 10.5 ish decked stock heads with .040 cometic gasket 10.78 ish LS6 head with gm gasket 10.87 ish ls6 head with .040 gasket 11.18 ish 5.3l head with gm gasket 11.43 ish 5.3l head with .040 head gasket 11.77 ish Like was said before get the marine injectors you probably are close to needing them already. Your cam isn't going to require a real high stall, a 3000-3200 with good flowing heads should be all you need. If its really a weekend truck and you want to push it harder, go a little bigger with the cam, 226-228 intake duration ish and a 3600-3800 stall. If your serious about upgrading to a set of heads, and chasing more power you may want to buy a slightly larger injector now, something that will flow into the 52 pound range with our fuel pressure. When buying injectors, make sure they are not drilled out stock ones and your tuner has the correct info on them Edited December 26, 2011 by shadowsniper3006 (see edit history) Quote Link to comment Share on other sites More sharing options...
holdenhunt Posted December 26, 2011 Author Report Share Posted December 26, 2011 Well i have plenty of options to consider now! Thanks for the help im sure it wont be the last time I need to ask. Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted December 26, 2011 Report Share Posted December 26, 2011 ask away, I'm sure the other guys here are looking for technical questions and would love a little paper racing as well. Quote Link to comment Share on other sites More sharing options...
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