I am currently running a 2.7 pulley(17.5psi), CAI, 3" downpipe no cat and 3" all the way out, 42.5lbs injectors, and tuned. I am planing on putting on a nitrous kit soon. But my concern is that i am running to much boost to run nitrous with out replacing any of the enternals. Do you guys think its safe or unsafe ot do this?

 

holy crap whats your altitude there

 

I get 16.2 lbs with my 2.9. i don't think a 2.7 and 42s are safe without some other prcautions.

i would def get 60lb injectors if your going to spray the car

 

I"ll let you know... I"ll be running that with a 2.85 and 42's... full exhaust and airbox mod... its going in in about a week

 

not trying to start anything but aren't you running the CA Stage 4 or 5???

 

2.7 and 42s are perfectly safe. On a wide band my car dips into the low 11's at 7k.

 

Do you think the stock head gasket will hold.

 

I was running stg VI... but demodded .. then stock was too slow... slightly remodded... and I'm building up a motor in the meantime for a nice project come spring time.

 

Ill be running on the stock headgasket for a week or so til my other head gets back from porting and polishing... then I"ll stud and cometic the bitch on the stock motor for now... keep other as a spare until all parts are in and money is ready to go (just in case it does blow up)

 

2.7 and 42# plus nitrous is not a great idea. Just the 2.7 with 42# is going to put you close or at 100% IDC which is bad, plus spray on top of that is going to be real bad. The stock internals should be able to handle it, but it will put you right at the 300 HP limit for the pistons. If you are going to be spraying very often you should consider doing internals to prevent damage further down the line and I would think about getting some 60#.

An AFR of low 11s is not necessarily good because not only is it a bit low, but you are probably just dumping fuel to get a low 11 AFR with 42#.

 

You *ABSOLUTELY* need to be running stock timing. If you have some stage tune it's not a good idea.

This has nothing to do with you injector size because if your running a wet shot they have ZERO to do with it. Fuel is injected via the nitrous kit.

I have run a 50 and 75 shot with a 2.8 and I haven't had any problems and I have some monitoring systems (WBO2), knock light/sensor and HPTuners and Aerotech. I feel it's

 

I am currently running 21-22 deg. of timing. If i run the nitrous, what do you recomend for timing.

 

With my 2.7 iam seeing between 18-19lbs of boost, and i would HIGHLY recomend getting 60lbs hour injectors, my idc with 42.5 at 5k rpms was 122%.

 

Well depends what part of the map your talking. For the most part I run stock 2005 timing.
~15 degree, at the meat of the map.

 

I should also say when I have run a 75 shot on that timing without much issue.

If your going to do 50 you could probably tweak a little, but I dunno if it's worth the risk.

Without nitrous you can run more timing for sure, but with the juice I play it safe.

I would rather run a 50 shot than a 2.5 pulley.

 

Why i stick with the 2.7.

 

I'm personally going back to the stock map (timing) when I use nitrous I also have my "safety" measure... fuel pressure gauge, nitrous pressure gauge, aeroforce, wideband and hp tuners access... but yeah I might drop timing down an extra 2 deg just to be safe with the 75 shot.... should be interesting..

 

Instead of retarding the timing how bout running meth injection with the nitrous injection so you can keep a good amount of timming and not hurt the car. I was talking to snow performance and they said they are experimenting with this concept and said it sould work. The meth will cool the charge enough to add timing rather than retard it with the nitrous.

 

I also have meth injection currently so i might try this and see what happens. This way i don't have to worry bout changing the timing cause i don't have HPT.

 

Nitrous will also cool the charge as well. I would still go back to stock timing tables or real close to them.

 

Well I don't recomend you run nitrous when your IDC's are probably way over 100% as is.

That 2.7 is way too small for the 42lb. injectors without nitrous.

I recomend you install 60lb. or 50lb. injectors, get tuned and then worry about nitrous.

 

2.7 and 42lb. are fine. 2.6 is too small. Ive had my car on a wide band already, at 7k my a/f is in the mid 11's. I have the lucas injectors witch are underrated. A 2.7 pulley is too small for GM 42lbs injectors.....I should be installing the nitrous kit sometime this week. I am going to run the nitrous solo and with the meth and see what happens.

 

Dude, NO NO NO, stop right now.

A/F has nothing to do with why a 2.7 isn't safe. It's fuel injector duty cycle.

I'm not going to argue with you or sit here for an hour explaining why a 2.7 is not safe with 42's.

Read this thread and you will then understand. Stop giving incorrect information.

https://www.cobaltss.net/forums/show...t=stop+madness