Put the 2.7" pulley on, and only getting 5psi????? - Boost Forum

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Put the 2.7" pulley on, and only getting 5psi?????
Sunday, June 26, 2005 1:46 PM
Well last night i put my 2.7" pulley on the car and it only goes up to about 5psi and right when i am about to shift at like 5200 rpm it goes almost to 5.5psi (about 5.25 to be more exact)... shouldnt i be getting atleast 6psi? and i was testing it when it was fairly cold out side ( 9 degrees F )
but even though its only showing that much psi i do know it pulls harder then before.




Re: Put the 2.7" pulley on, and only getting 5psi?????
Sunday, June 26, 2005 1:49 PM
what is the stock size pulley again? 2.8?






Re: Put the 2.7" pulley on, and only getting 5psi?????
Sunday, June 26, 2005 1:51 PM
^ That is correct 2.8



Car is for Sale!Supercharger kit is for sale!
Re: Put the 2.7" pulley on, and only getting 5psi?????
Sunday, June 26, 2005 1:52 PM
yea stock is 2.8" and it goes 4-5psi (mostly just 4.5psi but some times 5) and with the new one i am always getting 5psi... but not much more so i am getting some more but people say they are getting 6psi with the 2.7"




Re: Put the 2.7
Sunday, June 26, 2005 5:22 PM
ive hit 6.2psi on the stock pully without the alcohol.. guess everybodys setup will see different results
i imagine there are alot of factors that play in that also, temp/ humidity/ altitude + other car mods





Re: Put the 2.7
Sunday, June 26, 2005 5:25 PM
Damn you people and your forced induction! I shake my fist at you!.......I have no life


I apologize for all that, it just came out.



Re: Put the 2.7
Sunday, June 26, 2005 6:01 PM
why are you shifting at 5200 ???

redline is 6450







Re: Put the 2.7
Sunday, June 26, 2005 7:34 PM
I know its higher... and i was just shifting at that last night.. but even when i went up to red line it doesn't even make 6psi

bluzr2 - man i wish i could hit that on a stock pulley only mods i have is 4-2-1 header and 2.5" exhaust from header back and the s/c... And i know if you have a more free flowing engine you see less boost but more power... but i don't think the header+exhaust would do any thing for free flowing... But i am sure Calgary's altitude of 3350 feet (1,049m) doesn't help any as well.




Re: Put the 2.7
Sunday, June 26, 2005 8:06 PM
With the 2.7" pulley and the 62mm throttle body, I've seen 8psi right at the top of a gear, before shifting. Most days/nights it's 6-7psi.




Re: Put the 2.7
Sunday, June 26, 2005 8:07 PM
With a header on i was hitting 8psi, since i removed it i have only hit 6psi. I had a 2.3 TB before and after the header. I still have to install the 2.4" pulley, but that will happen at the same time as some other mods.


Re: Put the 2.7
Sunday, June 26, 2005 10:33 PM
what this sucks... why am i only hitting 5psi and some people are hitting like 7 and 8psi... in about 2 weeks im going to saskatoon which is a lot lower altitude so i guess ill see if that has any thing to do with it...




Re: Put the 2.7
Sunday, June 26, 2005 11:36 PM
some might actually be your header , more so the way it is designed , the extreme bends and pipe routings are very restrictive


the stans/isuzu header has alot straighter piping


also there is a reason rsm likes pacesetters over the others , the header is alot straighter and less restrictive







Re: Put the 2.7
Monday, June 27, 2005 3:24 AM
ive got the 2.6 pullyboys, Q.C., and at 3K i see 6psi, top of the gear i see 7.5-8 psi,

i still need alcholl and a TB

chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: Put the 2.7
Monday, June 27, 2005 6:33 AM

I thought I was the only seeing low boost numbers. I have the 2.6 pulley and the only time I see 6.5 - 7 is when I jump on it from a stop. 1st gear will go 6.5 - 7 then 2-3-4 the most I see is 5.5. It doesn't matter if it's 15*F or 95*F outside.

I wish I could measure CFM to see if I'm flowing more than with the 2.8 pulley... Another thing to consider is a free flowing system will create less back pressure and show lower psi numbers while flowing more cfm.

And then again maybe my boost gauge is just screwed...





"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
Re: Put the 2.7
Monday, June 27, 2005 7:47 AM
did you check for any leaks in the system???? are you sure your boost gauge is accurate????



Re: Put the 2.7
Monday, June 27, 2005 11:50 AM
Yea i was talking to some one here who has this kit on his Cavy... and he said its more then likely just my boost gauge... they aren't 100% accurate... unless you pay like $400 for one its not going to be perfectly accurate which makes sense... cuz people said they have been getting psi numbers from 5psi all the way to 9psi with the 2.7" pulley so i guess its different for each car and boost gauge.



Re: Put the 2.7
Tuesday, June 28, 2005 5:31 PM
Freebs- Just a question...when u took off ur stock pulley and put the new one on...did you take the supercharger off the motor or were u able to do it without taking the s/c off??? Thanks



Car is for Sale!Supercharger kit is for sale!
Re: Put the 2.7
Tuesday, June 28, 2005 6:32 PM
TaetschZ24 wrote:ive got the 2.6 pullyboys, Q.C., and at 3K i see 6psi, top of the gear i see 7.5-8 psi,

i still need alcholl and a TB

chris


Where did you get a 2.6 pulley and what belt size.



Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
Re: Put the 2.7
Tuesday, June 28, 2005 6:32 PM
TaetschZ24 wrote:ive got the 2.6 pullyboys, Q.C., and at 3K i see 6psi, top of the gear i see 7.5-8 psi,

i still need alcholl and a TB

chris


Where did you get a 2.6 pulley and what belt size.

Thanks.



Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
Re: Put the 2.7
Tuesday, June 28, 2005 7:31 PM
listening......


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Re: Put the 2.7
Tuesday, June 28, 2005 8:26 PM
Bobby wrote:Freebs- Just a question...when u took off ur stock pulley and put the new one on...did you take the supercharger off the motor or were u able to do it without taking the s/c off??? Thanks


Removal of the S/C is not necessary. Depending on the type of puller you use, you may have to remove your coolant overflow bottle.






Re: Put the 2.7
Wednesday, June 29, 2005 1:06 PM
Yep all i did was drain my coolant tank and took it out and put on the Pulley puller i had.... It is the puller meant for the M-90 or GTP supercharger... pulls the stock pulley off nicely... but get the hub removal plate too because to put the new hub on you have to heat it up ( i heated till it glowed) and it goes on very very easy, then quickly slid it on to the s/c shaft and once it touches the shaft you have about 2 seconds litterly till it cools enough and is stuck there... now if you put it on not enough or too far you need to pull it off and do it again but you need the hub removal plate to do this since the hub is a lot smaller then the pulleys and the pulley puller is just too big.


Supercharged 2.4L
Re: Put the 2.7
Thursday, June 30, 2005 9:19 AM
"more then likely just my boost gauge... they aren't 100% accurate... unless you pay like $400 for one its not going to be perfectly accurate which makes sense... "

i have a regular boost guage on the pillar plus i have the areoforce interceptor that reads the boost directly from the computer.. if you dont have one id highly reccomend one just to keep an eye on the KR if nothing else. plus youcan watch the IAT to see how well the alcohol injection is working



Re: Put the 2.7
Friday, July 01, 2005 2:27 AM
i got my Q.C pulley form parts for your car. its for a grand prix GTP, so there is one extra rib, ( i really dont care, function over form. )

i dident need to grind the snout down to use it. and it was a pretty easy swap.

i replaced my idler pulley with a bearing that replaces the hub and bearing asmbly. ( ill post latter with a part # for the bearing , it beats paying GM 210 for teh asmbly.) Its a little biger than stock diamiter so the stock belt dosent slip ( the part # off the gattor back belt that GM gave with the kit is for a 10 ply belt, cut it in half with a shears)
im happy with the performence, though reading my plugs id say its running leaner than befor and i should get a FPR.

it has a notesable amount of tourqe now.

chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: Put the 2.7
Friday, July 01, 2005 10:22 AM
Pulley boys is making some pulleys with thr 4rib on the quick change pulleys you just have to ask them about it... probably wont be till they are done looking at my pulley though that they have.


bluzr2 - yea i have a knock gauge that i am going to be using mainly to know when to have the alcohol spray and such...


Supercharged 2.4L
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