So when i get on my car the boost will drop down from 18 to round 5 b/w 6000 rpms. Any idea why? Would it be the tune? Mods include 2.7 with 60's I,H,E

 

Belt Slippage

 

that would make sense i guess. ill have to check into it. thanks

 

do you have a smaller belt or an aftermarket tensioner? I'm not sure on whether or not the GM smaller belt is good for 2.7 and lower

 

i've got the stage 2 belt. i believe thats good up to 2.6 but may be wrong. oh well just gives me a reason to get the intense supercharger spacer. should take out some of the slack

 

so what are my options to fix this belt slipping problem.

 

cobalt addiction adjustable belt tensioner, i have to get this cuz i can feel my belt slipping sometimes when i take off, i have 2.7 also

 

k do you also have the stage 2 belt?

 

2.7 stage 2 belt 60# injectors, all that stuff, i feel the car jerk sometimes when i get on it in 2nd gear i know it's the belt slipping so i gotta get the tensioner, i would recommend the same for you, i dont drop to anywhere near 5 lbs of boost tho...

i dont drop in boost at all, they say that at 6000 rpm without the boost bypass mod on, then u shold drop to stock 12.5 lbs of boost because of the solenoid, but i dont know y it would drop to 5... does it stay at 5 for long or what?

 

just b/w 6000-7000 rpms. otherwise im right round 18. i want to get this problem fixed cause you can deffentaly feel it stop pulling as much.

 

have u tryed the boost bypass mod yet? it's in the how-to section, u should try that and see if it's your boost solenoids droppin the extra boost and if it works then when u race or whatever u can just do the mod.

 

idk. im not a bid fan of the boost bypass mod. just doesnt seem right to me. but idk maybe ill try it.

 

u might as well, it could just be your solenoid letting go of the extra boost, if not than it could just be belt slippage, and it may be something else, i'm not sure sorry bro.

 

thanks ill give it a shot. cant hurt to try. gotta eliminate things.

 

troubleshoot and eliminate!

 

If its the boost bypass soleniod, it will limit any boost at any rpm, and it would only drop it to 12 psi, not 5. Also, he has a custom tune, if they know what they are doing while tuning, the boost limit should be reset to above what he normally sees so he doesn't have issues. I would have to say belt slip, I have seen it happen with a 2.8 pulley, so I don't doubt it on a 2.7 or smaller.

 

yea but to 5 lbs? thats some really bad slippage, and if it does come down to that then the tensioner is needed, i have belt slippage but see no drop in boost. i also hit 7200 redline without the bypass mod on and still see no drop in boost like you and others say, so every car is different.

just throwin him some ideas.

theres another cobalt around here with a 2.7 that sees no slippage on a stock tensioner so yah know... all different for some reason.

 

There shouldn't be a drop in boost for anything other than the stock tune. Even stage 1 raises the boost bypass limit, to 18 psi I think, not sure on that number though. Its up there, I ran a 2.8 on stock stage 1 tune and never needed the boost bypass. I have disabled it before just for drivability, it makes the car smoother in the mid-range part throttle driving situations.

Like you said, easiest way is to disable the boost soleniod and see what happens, if it still drops it is belt-related, if not, then you need another bypass solenoid (I have one) or a better tune.

 

well i need to go see my tuning guy soon anyways. (got unholy ideas with my nitrous setup) ill have to talk to him about it. ill try the boost mod for ***** and giggles although i dont have much faith in it. otherwise ill check for belt slippage. thanks guys for the good info.

 

doesnt intense or someone of the like offer a boost solenoid kit? i remember hearing about it somewhere, if it is your solenoid u can purchase the kit. i'll find more info for u.

 

It if is belt slip the intense spacer will work too. I get no slip, but it does make my injen a little off connecting to the TB. There are a lot of possible causes though.

 

if its a belt slip issue then ill fix it over the winter. im going to be getting the intense spacer anyways. im switching to a post blower setup for my nitrous.

 

Where is the nozzle now? Just wondering, as I am having plates made to add the nozzle either under the blower or behind the TB, haven't decided yet. What shot are you running?

 

right now its mounted inside the cai. bout 6 inches away from the blower. some people claim that the fuel will eat up the insides. im not 100% about the truth there. im not sure what the coating is. i feel that your fine spraying before. after all the 8-71 blower and its specify nitrous kit are on top. im sure the coating is different though. gonna do some more research before i do anything for sure. im running a 35 shot on the street for the most part with the occasion 50 shot. i love it. talk about fun. but i havent been spraying do to the fact of the boost problem. need to fix that first.

 

Ok, I have the same setup then. I am running a 50 wet shot, punched into the transistion hose right before the TB. I plan to move it mainly to hide the nozzle, but I will be sure to let everyone know the effects on the rotor coating when I do take the blower off in the near future. I have had it this way for about 3 months, used maybe 50-60 lbs of nitrous so far.