Fueling & Injection - tuning for a cam

I'll be getting cam soon but i was also planning on getting bigger injectors. If i have a tune setup for stock injectors how hard would it be to adjust it for 42 lb injectors? I'm buying from comp cams because one of my friends can get me his employee discount, can they send a tune for my cam at my elevation?

Also, down the road i plan on getting 4.11's how hard would it be to tune for that?
Thank you for your time.

How big a cam are you going with? Unless the cam is huge and your getting heads, you will never need 42lb injectors.

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the cam will be around 224 but i will be spraying nitrous in it. I maxed out the stock injectors with a 100 dry shot and stock motor. I want to eventually go with 150 shot but i'll need more injector for the cam and the nitrous.

How big a cam are you going with? Unless the cam is huge and your getting heads, you will never need 42lb injectors.

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+1 42 lb are probably too big and yes you can go too big on injectors. Your best bet is to get a true dyno tune and see where your injectors are at. Then use math to figure the best injectors for you.

You will need a custom tune, especially considering the dry shot of nitrous. Many reputable tuners can send you a mail order tune to get you close, but there's nothing like having it tuned on the road and on the dyno.

well with stock internals and 100 dry shot the injectors were 98% maxed out. so i figure i go with 42 lb injectors to have room to grow. For the mail order tunes, who would be the best and what exactly do you need to do? Also can they send a tune with elevation factored in?

I wouldn't go 150 on a dry shot. Dry shots always go lean for a brief second when you hit it. The more you throw at it, the leaner it goes. I wouldn't bet my engine on the PCM keeping up with the nitrous. Wet may be more expensive, but it's safer.

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well with stock internals and 100 dry shot the injectors were 98% maxed out. so i figure i go with 42 lb injectors to have room to grow. For the mail order tunes, who would be the best and what exactly do you need to do? Also can they send a tune with elevation factored in?
Im sorry man but getting a tune on the dyno is alot better than a mail order tune there is to many varables that could be diffrent from one car to another . so i would def spend the extra money and get it done right the first time!!

yes, get it tuned right!

Since most dyno tunes are only WOT tunes, make sure you get a comprehensive street tune also. If you only get the typical WOT dyno tune, you've got nothing.

Wouldnt the SVO 30 lb injectors be better? In the September 2004 issue of GMHIGH TECH it shows Futral and 2 or so others running them in there cars. I think myself I am going to run 30 SVO Ford injectors as soon as I get my FAST 90. I think 42 would be to much. When Ford rated the 30 lb it was with there fuel presure which uis I beleive 35lb to 40lb of fuel presure and with the LS1 run 60lb they would go on up to around 34 to 36lb. Good Luck

thanks for all the responses, the trouble is there is no one in town to tune my car the right way. There are a few shops with dynos but i dont trust them on tuning an LS1. So i would have to tow my car 8 hours away to get it tuned right but even then it'll be at a diff elevation.

I wouldn't go 150 on a dry shot. Dry shots always go lean for a brief second when you hit it. The more you throw at it, the leaner it goes. I wouldn't bet my engine on the PCM keeping up with the nitrous. Wet may be more expensive, but it's safer.

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IF they are going lean then your nozzle needs to be physically re-aimed at the MAF period. This is basic dry N20 tuning, nothing advanced here...


and the rest of you guys stop telling him that 42s are too big. 42s are easy to tune even if he didn't need an injector that large, not to mention, that if he is spraying 125-150dry and plans on making any furhter engine mods that he NEEDS those sized injectors.....

i've never tuned anything before, how hard would it be to tune for the new cam and for the new injectors?

No way to answer that for ya...

thanks well i'll have some help but hopefully i can get everything in order once its all put together.

+1 42 lb are probably too big and yes you can go too big on injectors. Your best bet is to get a true dyno tune and see where your injectors are at. Then use math to figure the best injectors for you.


60lb injectors would not be too big. There is no reason not to go with a large injector. Way too many of my customers go with small "cheaper" injectors just to upgrade later.