Boost Levels

[chuck93sc]

what levels are you guys running at wot?just curious to see if there's an average.i don't believe the factory boost guage is very accurate.

[Randee of the Redwoods]

BUT, my vote for 10-11 pounds is based on the performance AFTER several modifications.

[92bird]

Good survey, but there are too many variables. Such as modifications, altitude, model year, and weather. For example, I live in Denver, CO which is just over 1 mile above sea-level, and when my car was stock I pushed only 10psi, wot, 5,500 rpm's. When I went to Tulsa for the SCCoSW meet, I made about 14 psi at 5,500 rpm.

So there is a lot that can change!

Jeramie

[chuck93sc]

yes jeramie i understand the large amount of variables possible(mainly mods,altitude,and especially pulley size but i figured if there were enough responses it would average out.one thing i'd like to know is what are you 15# guys doin' to show that much boost?thanks for all your replies,chuck

[Jason Marsh]

My 15# of boost came after installing a 95 blower with a 10% pulley. It was at 12-13# with the 10% pulley on the 93 blower.

[95SCBird]

After puting a 10% pully on mine on the stock gauge it is pigged at 15 before the pully it was at 12

[MarcinR]

My 95 did 13 lbs stock....After the ZR intake and raised top mod I gained about 1.5 lbs of boost....A 5% pulley brought me up to 16 lbs of boost. Will know for sure after my new Auto Meter boost gauge goes in since the stocker is not too accurate.....

[cheezhd]

RPM's are the biggest variable in my book! I am almost completely stock, Bored out because I warped the heads and drug a connecting rod into the combustion chamber. I push 12 psi at about 5,000 rpm's.

JIM=---'90 35th Anniversary SC

[Brian Voigt]

I am running the Autometer Boost gauge, along with the stock (dont ask me why I have both, stock didnt work, and replacement and autometer came in mail at same time.. ohwell).

Ok, so I am running both, the autometer seems to show about 1-2 lb higher than the stock at WOT. There is still one thing that I have yet to check.. I am just running a Vacuum T, so that both work. I dont know if this effects the performance because there is 2 lines that the air is filling, so wouldnt the boost/vac show a little less "intense" because there is twice the volume of air to push around? One of you smart guyz can theorize on that. I was thinking I would un "T" it and run one at a time and get accurate readings.. maybe a fun weekend project if anyone is interested in the results. I know they are off, but fairly close at all readings, maybe off by 1-2 lbs most of the time but no more.

[Randee of the Redwoods]

T fitting wouldn't make any difference. It just air from the manifold adapter. That's a steady flow of fresh air always being replenished. The pressure just shoves it up the tube to the gauge. That tiny tube and fitting in no way even scratch the surface on the amount of air in that ic tube. I know how you're thinking but it won't apply here. Vacuum, MAYBE. But under boost(or anything above 0) I'm almost positive that the T doesn't matter.

[Brian Voigt]

Yeah, I never really thought it was basically an unlimited air supply, I just thought that it was from the base of the hose, and from there, the T fit would add about a third of volume.. but yeah, that makes sense... I'll pay a little more attention to the boost differences and report soon.

[XR7 Dave]

I found that my Autometer gauge reads within 1 lb of the stock gauge. I have also found that where you measure the pressure tells a whole other story. I have found that when temperatures are high, the manifold will actually read higher than the outlet of the SC and vice versa when the air is cool and the intercooler is not heat soaked. I actually have three boost gauges.

[Tommie boy]

Now that the nights have gotten cooler I have been pushing more boost. I maxed out the gauge the other night so I am guessing I am running 15+ on the cold nights. I have hit the 15 psi mark before but this went a little beyond 15 the other night. I have a complety stock 95 auto except for the removed air silencer. I guess its time for exhaust before the head gaskets blow again.

[Stryford]

i don't know how accurate my stock gauge is, but the most i've seen in my bone stock '94 SC's boost gauge is about 12 pounds.

[jim Demmitt]

Got special S ported blower with extra porting roator pitch a little diferaint this is with only 10% overdrive. has instaint boost to max psi. but everything has to work together or your lost in the dark

[Jay Miller]

I have a 95 SC and I top put at 15.2 PSI the only Mod I have is a K&N. I thought the more boost you have might just mean you have more back pressure. What do you think

[Vic W]

I am getting 10-11 with a K&N and free flow exhaust.
Prior to that it gently pegged 15.

[Jimmy 2Coupes]

Vic, what year is your SC?

[GEORGE ONEILL]

Stuff ya couple big iderhos up them pipes get all the boost ya want never halfta leavem drivway Pappy told me dat

[sctomb]

Damn, some of you guys better start doing exhaust mods before you blow the s... out of your motors.
If you want to keep you head gaskets, you are risking them at 16lbs. That seems like too much backpressure for a good exhaust system. I hope that you guys are doing the exhaust before you are getting pulleys and tops.

Tom

[SCandelous95]

Jay,

i also have a 95 SC with just a k/n, fresh air tubing and a jacobs multispark ig. system. other than that its stock and i easily get 14 psi and more if i push it. maybe it was that year model that did better or maybe the older SC's have more engine wear or something?

[Todd Jelle]

My stock 92SC gets 11.5 when pushed. My 94 SC got 11.5, I added a flowmaster exh., SCPI top, 70 mm TB, MAF from SCPI and MAC fresh air intake and the result is 14 lbs @ 5000rpm. It scares the @#%$ out of me to see that guage go so high. I'd rather see it down around 13lbs. I know I need the headers if not some head porting too! I'm sure I'll then see less boost but more power. BOOST does not mean power!!!

[chuck93sc]

:) :) :) :) :) :) :) :) :) :) :) :) :) :) :) :

[cudaz101]

My 90 SC stock was makin' 12psi when hittin' the high notes, then put the 10% pulley on there and made 14psi, then ~~~~canned the Airbox silencer and put in a Panel K&N and Flowmaster Exh. and she was Blowin' 15+psi,...Some catz think that they should be at 12 or so when everything is right, but mine has ran great with no probs till recently...Still troubleshooting it...I still have that little weak ~~~ origional MAF body in it, and think that this mod will pair up with everything else really well...


LOWFAT-SC

[Les Borda]

Stock 90XR7,prior to K&N panel filter and a home made fresh air intake...11-12lbs boost..after 12-almost 14lbs...no other mods at all.

[90tbirdsc]

My bone stock 90 with 37K pulled a max of 12 until I replaced the Resonator with a stainless magnaflow and it now max's out at between 10 and 11. Running at 16 seems very high and very dangerous.

[chuck93sc]

i can't believe this poll is still going over a year later

is this the longest poll ever?

thanks for the input everyone ,the numbers speak for themselves

[FearThis SC]

My boost levels have fell about 4 to 5 psi after getting exhaust done. I was getting about 14psi before getting the 2½ True Dual Exhaust. Now, I get between 8 to 10psi. If I really hit it hard maybe 11 or 12 psi.

I like my boost range, not to high, but not too low.

BTW: exhaust is my only mod (2½ dual back from factory cats). Headers and high flow cats are next after I finally blow headgaskets.......ekkkk!

Late,
FearThis SC

[Jim Demmitt Jr Blown Gas 90SC]

My boost level will be 18lbs with new blower combo

[BadBlackSC]

Well I have a full custom 3inch exhaust, besides Headers(Ported stock)
After all the MODs I have including the Top-mount IC, with 10% pulley, i tach the boost guage at around 3500-3600rpms. With an 89-93 Pulley it taches the boost guage at around 4100. This is with a Heavily ported 94/95 Blower.
So ummm, big boost!
-Chris

[stephencrist]

Mega boost+lack of fuel=detonation.Detonation+time=$$$

Finally got the 80mm.calibrated to stop the mid-range detonation, but it still does it some under WOT. Increased fuel pressure to the point that it runs a little rich at idle, but still not enough fuel under WOT. I get instantaneous 15#+ and climbs with RPM, but I need to get off my butt & upgrade the dual 2" to 2 1/4"+, long tube headers, Hi-flow cats, and whatever I decide about mufflers. That should get the boost level down some.

Of course, once I get the boost down to a safer level, as a diehard's "rule of thumb", I am compelled to compliment my 80mm. C&L MAFS with a 85mm. throttlebody, 1 1/2" custom raised top, custom lower intake mods., 48# injectors, cam, and a larger custom air tube (by then, the MAC will be too small :) )

Damn, I might wind up right back at 15# +/- anyway. Well the Fel-Pro's have held up this long, you gotta have faith in something I guess. I don't care if it does wind up running at 15# as long as I can rid it of the detonation.

Obviously, I could downgrade the 10% pulley on the '95 blower, but then that would take all of the fun out of it.:D

[chuck93sc]

stephen
get the eec tuner,,,,,,,no more fuel problems

[fred 4 pt 3]

Actually, the 80 mm maf doesn't have enough air signal for a decently modded SC. Get the 90 !!