Low boost after upgrade, don't know why

[turbo3.8monza]

I just installed a JMB fender well intake from the W body store on my dads 98 regal GS. It sound sweet as hell but he's only making about 6 pounds of boost now and he already installed a smaller pulley on the blower it made about 11.5 psi with horrible 98 air box. Does the computer need to learn that the motor is now getting more air if so do I drive it around for awhile or reset the computer. Helpful info when I installed the new intake I also changed the fuel filter (which was orginal or changed at the dealer in the 2 years before my dad bought it) and I changed the vacuum line from the top of the blower housing to the bypass valve. I know its not giving a false reading because I can smoke the crap out him in my 91 lumina Z34 with a 5 speed and when he had the stock box it was dead even.

 

[1QikTurboI4]

You might have a bit of KR going on, Pm Murphinator he's a Gs guru

 

[murphinator]

I just installed a JMB fender well intake from the W body store on my dads 98 regal GS. It sound sweet as hell but he's only making about 6 pounds of boost now and he already installed a smaller pulley on the blower it made about 11.5 psi with horrible 98 air box. Does the computer need to learn that the motor is now getting more air if so do I drive it around for awhile or reset the computer. Helpful info when I installed the new intake I also changed the fuel filter (which was orginal or changed at the dealer in the 2 years before my dad bought it) and I changed the vacuum line from the top of the blower housing to the bypass valve. I know its not giving a false reading because I can smoke the crap out him in my 91 lumina Z34 with a 5 speed and when he had the stock box it was dead even.

what size pulley did you put on it ?

what is in place for exhaust mods ?

it is not uncommon to put on a smaller pulley and make the car slower if there arent enough exhaust mods in place to support the pulley size

basically it will knock and retard the timing to try to save the pistons.

Many a piston has been chipped by throwing a 3.4 or 3.5 pulley on a car with stock manifolds and exhaust still in place

an intake exhaust ,tune car will crack 13's on the stock pulley


so a z34 is beating it now and it didnt before ?

it sounds like in your case it is dumping boost , first check that vacuum line you said you had your hands on - it could be self inflicted , did it start dumping boost that day ?

I havent messed with it but you can probably disconnect the boost bypass solenoid and get full boost - you should be able to disable the bypass function and see full boost i just forget if you unplug the sol , or plug the vac line to make it happen

you could also adjust the placement of the boost bypass valve to increase or decrease its sensitivity , it is adjustable

boost #s on these cars are decieving since restricted exhaust flow will cause boost stacking either through poor flowing components or from knock retard and torque management combining for sooo much timing being pulled that valve timing doesnt empty the blower quickly enough and it stacks

2 3.5 pulley cars one sees 13psi and one sees 10.5 psi the one seeing 10.5 psi will be faster 9 times out of 10

 

[turbo3.8monza]

the pulley size is 3.4"

the exhaust is stock for now, planing on using 1 5/8" primary headers, no cat, and maybe hooker muffler on a 3" system

my Z34 hung with the buick neck and neck, it wouldn't beat it due the lack of low end torque the buick jumped out quick but if he messed up or lost traction he couldn't catch back up. I haven't done any other work to my Z34 since then

I don't know if it has been doing this for awhile or not, I don't drive alot being its my dads and he always keeps the gauge on the range not the boost

how do you adjust the soleniod

if this problem is due to the restrictive exhaust it will make it eaiser to talk him into it since he doesn't want to be beaten by natural breathing lumina and I'm about to drop in a cammed, high comp. LQ1 in it

 

[murphinator]

the pulley size is 3.4"

the exhaust is stock for now, planing on using 1 5/8" primary headers, no cat, and maybe hooker muffler on a 3" system

my Z34 hung with the buick neck and neck, it wouldn't beat it due the lack of low end torque the buick jumped out quick but if he messed up or lost traction he couldn't catch back up. I haven't done any other work to my Z34 since then

I don't know if it has been doing this for awhile or not, I don't drive alot being its my dads and he always keeps the gauge on the range not the boost

how do you adjust the soleniod

if this problem is due to the restrictive exhaust it will make it eaiser to talk him into it since he doesn't want to be beaten by natural breathing lumina and I'm about to drop in a cammed, high comp. LQ1 in it

a 3.4 pulley with stock manis , downpipe with u bend , and single crush bent catback is a recipe for disaster - no exagerration

that car has to be knocking badly , if you know anybody with a scanner do a couple WOT passes and log KR

as for adjusting the position of the bbv the mounting bracket is slotted , just loosen the bolts and slide it a bit , 10mm I think is what they are

 

[turbo3.8monza]

He has been driving around on the 3.4" pulley for a couple of years with no problems, I guess the uber restrictive air box was his saving grace. It hasn't been knocking or pinging before or after I installed the new intake, but I can defiantly see how stock exhaust is a problem. I almost had him talked into headers and permanent "test" pipe (of course with the O2 simulator) but the biggest thing to him on the exhaust is noise he doesn't want it loud a little rumble is ok but nothing like a loud mouth system. Any recommendations on a quiet muffler with a good deep tone. Of course we will do computer work at that point

 

[murphinator]

He has been driving around on the 3.4" pulley for a couple of years with no problems, I guess the uber restrictive air box was his saving grace. It hasn't been knocking or pinging before or after I installed the new intake, but I can defiantly see how stock exhaust is a problem. I almost had him talked into headers and permanent "test" pipe (of course with the O2 simulator) but the biggest thing to him on the exhaust is noise he doesn't want it loud a little rumble is ok but nothing like a loud mouth system. Any recommendations on a quiet muffler with a good deep tone. Of course we will do computer work at that point

thats the million dollar question right there ^ headers with magnaflow res and dynomax muffler is supposed to be pretty quiet

or headers , magnaflow res and stock gtp dual catback to be quiet for sure but you will need a pair of slp fascia inserts , and a second exhaust hanger to go duals.

there is also a slp template to get the cutouts right for the inserts , they are almost impossible to find now but I have one I rent out if you need it

 

[WildGS]

I would keep looking into the boost solenoid or some other vacuum lines. Also if you unplug the boost solenoid it will limit you to about 5psi of boost.

when the car is running at idle that valve should be open (level pointing up/down) when you blip on the throttle the lever should try and close and go almost all the way to the stop. If you are not hitting the stop you have a problem.

 

[turbo3.8monza]

thanks for the ideas I've watching the youtibe videos with GS's and GTP's in them to find a quiet one that sounds pretty good, judas priest there nasty sounding ones on there (not the good nasty, nasty that makes you want to puke). I'm still thinking about different setups, the old man is dead set on super sleeper, he wasn't to keen on the intake noise at first. but thanks again and I'll post when i figure something out