I have the 2.4L LD9 in my Z24. with the GMPP MP45 SC kit.
I just installed a 2.5" pulley, and only gained 2psi... I was seeing 5 - 5.5psi with the stock pulley. I was under the impression that this Pulley should get me up near 9-10psi. I know other guys have gotten close to that on the MP45. and the Pulleys dont get much smaller than this.
So what gives? any idea what could be going on here?
I noticed only a slight performance increase with the pulley.... no dyno or track times... just driving around.. has a lil more umph but nothing that would knock your socks off.
I am also not noticing much different in IAT with this pulley either.... I was getting pretty consistant 70-80 before... 100 if really in boost for a long time.... now i am still seeing maybe 80-85 normally... and havent gotten on it enough to know where it goes under extended periods of boost.
Granted it is like 50 degrees out.... but still.... guys were telling me that they were getting 10psi and IAT's of 200+ with a 2.5"
So what is wrong here..... something doesnt seem to be working right...
mines the same way, I gave up on trying to figure it out.
2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |
it's just smaller pulley! You should be happy with an extra 2 psi
did you think a smaller pulley was gonna turn it into a porsche or something?
*sigh* Heres my take on you people with putting pulleys on and bitching about the gain not being crazy.
All cars are different, you may have the same head and bottom end the motor came with but no 2 motors are the exact same. I'm running the 2.6", a fully built motor with all the headwork you can want and am seeing 6psi instantly and at 5k 7psi until it shifts at 7k.
Your profile says you have a crapapart i mean mantapart head so if that is on, your increasing the air flow but decreasing boost which is a good thing actually, now if you had a stock head and was seeing very low boost with just the s/c, meth and 2.5" then i'd look into changing the boost actuator below the charger. This may or may not change the boost level though. Your belt may be slipping as well, just for a half ass test, get someone to rev your car up all the way and look at the belt and see if you can see movement in it jumping around at all. I have never had this problem but i know some people have.
Also if your running that POS windshield washer fluid, throw that walmart crap away and get some real meth with distilled water in there and see how she runs. I tried washer fluid and actually felt the car just die like i wasn't even spraying meth because even the -30 stuff is very low in meth.
As far as i know theres not a official "put this pulley on and you will see XXpsi" thread or manual so don't believe what everyone says because thats there application, not yours even though the mods may be the same. Hell one guy on here seen 13psi on the m45 and i'm only seeing 7psi but no offense but i would dirt on that 13psi in a heartbeat because i have the proper mods to have low boost but good power.
not to thread but i am putting in a fully built motor. including having the head port and polished and the supercharger port and polished by steigmier . will this mean i will see lower boost numbers. just so i dont post when my car is done being built.
http://www.cardomain.com/ride/2623318
If someone says they seen 13 psi from a M45
1. There lying
2. There guage is not working right
Ya and if you have a ported head it will be a lower boost number but it will be flowing better. kinda like differant size straws in your drink.
maybe you can buy after market bearings wich will let the m45 run higher rpm's but I doubt it.
I am still running the stock head and exhaust manifold..... So it isnt the "higher flow" that is preventing the boost.
I wanted to install my pulley before the head and header so that i could see the PSI drop from the higher flowing engine.
Apart from my intake, and 2.5" exhaust... my car should flow the same as anyone elses right now.... I was getting 4.5-5psi before the exhaust, then i was getting 5-5.5psi after the exhaust (yeah i know strange that PSI would increase with a better flowing exhaust)
I had been waiting for a better exhaust before doing the pulley..... so now i have the exhaust, so i slapped on the pulley... and was expecting to see in the range or 9ish at least... as that seems to be what alot of people told me they were seeing on a 2.5"
and EVERYONE warned me of the horrible IAT's associated with the 2.5" pulley... and for my recent testing i ran plain old blue washer fluid... (was afraid to turn meth-injection off for fear of heat issues) but wanted to see how bad the temps got. and as i mentioned, even running crappy blue water i was still seeing very normal temeratures. So this again makes me wonder what is going on. Most people were telling me i was crazy to go with a 2.5" pulley... it would bee too much pressure, i would be too much heat...
But so far everything seems very mild. if it was JUST low PSI i would just blow it off as "higher flow = less psi" but as subtle as everything has been with this 2.5" pulley i dont understand why anyone would go any larger than this.
I am going to go back and try to find my conversations with other people about how 2.5" is too much... and i am crazy to go that small....
well ill be picking up the 2.5" in a few weeks, i will keep you ladies posted. i know what you need to do to run 2.4 and 2.5" pulley........effectively
jesterz413 wrote:not to thread but i am putting in a fully built motor. including having the head port and polished and the supercharger port and polished by steigmier . will this mean i will see lower boost numbers. just so i dont post when my car is done being built.
Yes.. the better things flow, the less PSI you will see. psi = pressure, and pressure is the resistance to flow...
what is most important is "mass" or "volume"... pressure is relative. You want to move as much air as possible in a set amount of time.
pressure is really more a measure of IN-EFFICIENCY.... higher pressure indicates that the air that was TRYING to be moved didnt all move...
pressure is like "traffic" everyone is trying to go home... but the road is only so wide. so everything backs up...
it is just harder to meansure and report the volume of air, which is really the important part. How much air actually makes it "home" in a given time.
pressure is "congestion" how many cars are backed up on the road.... but as long as you make it home in time for dinner... it doesnt matter if you were the only one on the road or smooshed in between 3000 others.
a wider freeway will move ALOT more cars int he same amount of time.... "porting" anyting is like "adding a lane". will lessen the congestion... but will maintain or increase the volume.
And everyone told me something was wrong with my set up when I was only getting 7.5 PSI with a 2.4" pulley. Apparently now everyone agrees with exactly what I said.
No to engines or S/Cs for that matter will perform the exact same. The first engine my S/C was on would see 7.5 PSI with the stock pulley, the second was only getting 5.5 PSI.
Mine, stock pulley was only 3 PSI.
I get 7.5ish on the 2.6", 180,000 mile engine.
2001 Olds Alero (LD9)
650 whp / 543 ft-lb
@turboalero
My built engine with stock pulley is only netting me 3psi.
Seriously I think your belt might be slipping. Don't hold me to that just saying it might be something to look into. What is the brand and part number of the belt you are running.
FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!
Hey Ken other then maybe a belt slipping and running crappy washer fluid. It sounds like your right where you should be at.
i normally run a mix of -30 washer fluid and a bottle of Heet. So far havent seen a need for anything more... with the cold weather here, i have had relatively low IAT... so didnt see a need to dump in the good stuff.... yet.
Today i managed to get on it for awhile... got IAT up towards 150 after a while.... this is with the meth on, and just shooting the blue crap.
So seeing that... i may get back to the heet and -30 stuff... see how much difference that makes.
or possibly could be your air intake! might want to re-design that maybe or try a different filter.
would increasing the voltage to your map sensor help?
just going out on a limb here... wouldnt hurt to try though eh?
12.33 @ 111.67 mph [Oct 2009]
Dyno'd on 08/02/09 - Mustang Dyno:
327.6 WHP 333.6 WTQ [10.1 AFR]
I don't understand why you guys dont just run Meth and Water?
Why all the hassle and second guessing with Washer fluid
exactly, you guys try to cut corners since washer fluid is cheaper, it pays to play ladies. pay it or sell your car.
Wade Jarvis wrote:My built engine with stock pulley is only netting me 3psi.
Seriously I think your belt might be slipping. Don't hold me to that just saying it might be something to look into. What is the brand and part number of the belt you are running.
It is the stock belt... not sure if it was changed with the SC install... i bought the car already boosted...
but it is the belt that came on the car. still looks ok... but it is old. I know I have put 80k miles on it myself...
so i am probably due for a new one.
what is a good belt? should i go smaller? is there a high friction belt? or any type of belt dressing to increase friction?
I am tempted to pour in some good meth juice and try out the 2.3" pulley.... see what that is like.
BOOSTED / JMdecals.com! wrote:exactly, you guys try to cut corners since washer fluid is cheaper, it pays to play ladies. pay it or sell your car.
I dont waste good stuff in cleveland winters... firstly it is SO cold here that rarely do the IAT's get above 80.... and secondly as crappy as the roads are, i rarely even hit my 3psi meth threshold.
So seems silly to pour in the good stuff just so it can evaporate, or i can burn it up trying to spin my way up the driveway.
When summer hits, and i can drive like i like to, and the heat becomes a factor, i will start running the good stuff too.
but for now it is just a waste of my money.
do you run race fuel when you go shopping??
well i have a cobalt daily and a sunfire, the sunfire only comes out on weekends so yes, yes i do.
