[MotorMouth]

Ok, here's the deal on the vacuum line mod. After some testing with my G-Tech, scan tool and a peak and hold boost gauge:

THIS DOSE NOT WORK!

Further more, anyone with this line dissconnected PLEASE HOOK IT BACK UP! I did some testing and found no gains in boost but I did find what could be a potentially big issue. With the line dissconnected I found that if you hit the rev limmiter there is a 15+ psi boost spike that occurs in the intake. Now with the computer backing off fuel at the rev limmiter this could be a potentially damage the motor. Also, at not time did I see the boost climb above 12 to 12.5 psi up to red line.

With the line connected the computer uses the solonoid to back the boost off to make the hit of the rev limmiter more soft and not as hard on the engine.

Again, I found no gains in boost or hp. Just writing this to save everyone the headache of possibly damaging the motor in a missed shift or red line bounce.

 

[John]

What were you watching the boost with a scan tool or a boost gauge at the intake? by boost gauge shows 14.5 at 6000 rpm if you use a scan tool its getting its signal from the sc soleniod which is not recieving any boost reading because its signal line is plugged. and what did you test the horsepower with?

 

[JPK]

Interesting.

Navymitch is gonna have his car dynoed with and without the mod done this afternoon, I think.

Can anyone elaborate on MotorMouth's findings?

 

[MotorMouth]

What were you watching the boost with a scan tool or a boost gauge at the intake?

Both...

by boost gauge shows 14.5 at 6000 rpm

What type of gauge are you using? If you are using anything anolog they are not very accurate. Especially the Auto-meter ones that read 30 in/hg to 30 psi. I am using a very accurate digital boost gauge.

if you use a scan tool its getting its signal from the sc soleniod which is not recieving any boost reading because its signal line is plugged

Incorrect. All the solonoid is there for is to be modulated by the computer for boost adjustments. The boost or manifold pressure is measured by the MAP sensor on the passanger side intake of the motor.

and what did you test the horsepower with?

G-Tech pro. Using an estimated weight of 3250 with me in the car and 1/2 tank of fuel.

 

[Vita]

Using an estimated weight of 3250 with me in the car and 1/2 tank of fuel.

you must be a big guy, the car itself weighs 2933 or so

 

[BlackLine]

2880 weighted it at my dads work accurate to 10 pounds

 

[Sp00ner]

Interesting...

This sounds pretty interesting, I haven't tried this yet, not sure I was going to even before reading this. This guy sounds like he did the most thorough testing of anyone so far, is there any counter evidence to this? Something concrete, someone with test data, maybe a Saturn/GM Tech, anything???

 

[John]

if what you said is true why does the boost drop to 6 psi when you unplug the solenoid? and my analog gauge shows exactly 12 psi when hooked, the same thing as my tech 2. so why would it be wrong all of a sudden when i change the boost level?

 

[MotorMouth]

you must be a big guy, the car itself weighs 2933 or so

Sorry that was supposed to be a 1 not a 2. I weigh 235. I was roughing the weigh estimate.

 

[MotorMouth]

if what you said is true why does the boost drop to 6 psi when you unplug the solenoid?

If you are refering to unpluging the electrical conector, unpluging it opens the solonoid and allows pressure to flow freely to the actuator valve.

As for the gauge, don't know what to tell you. I have tried 4 different configurations in regards to blocking the boost signal to the solonoid and the actuator valve and have not seen any changes in boost leveles. Even after 25 test runs.

 

[John]

well we will see after a dyno i guess, navy is supposed to be dynoing his today

 

[Sp00ner]

Gotta agree

Maybe I shouldn't talk too much, but I just can't see why Saturn would leave such a simple, easy modification completely untapped. I know there is some speculation about durability and such, but maybe that talk it truth. Not everything that makes that car go faster without immediate engine damage is not always a good thing. Hell, look at NOS, you can just stick a hose into your intake, turn on the bottle, and BAM... Instant extra power... You could just stick an O2 tank in the trunk and run a line into the intake and get more power, but neither of them are good for the life of your car!

 

[haunter]

Maybe I shouldn't talk too much, but I just can't see why Saturn would leave such a simple, easy modification completely untapped.

they have to guarentee the engine wont go bam for over 100,000 miles

DSM's can run alot more boost than stock, GTP's can, SRT-4's can

its the way it goes, overengineer for extreme safety

 

[MotorMouth]

I know there is some speculation about durability and such,

Now don't get me wrong on this. I am not saying that the motor can not take any more power.

The motor is engineered VERY stout. Powder forged rods, forged crank, oil cooled piston, yada yada yada...

My reason for making the post in the first place was to warn of potentally dangerous boost spikes at redline or in missing a shift caused by dissabling the ECM's control over the boost solonoid by taking away the boost signal. Also, what I have tested as a no gain in performance from dissabling the solonoid as well.

 

[BlackLine]

i wonder where navy is at, he had an 5:30 appointment, I WANT NUMBERS!!

 

[Redline 1]

I also waiting to hear something.

 

[redlin-er]

Somebody go look for him on the side of the road.......

 

[Sp00ner]

they have to guarentee the engine wont go bam for over 100,000 miles

DSM's can run alot more boost than stock, GTP's can, SRT-4's can

its the way it goes, overengineer for extreme safety

Well, if that's the case you're indicating that the GM engineers determined that leaving the boost wide open to redline would in fact decrease the durability of the engine. At least that's what it sounds like. If it does decrease the durability of the engine, then that is bad for the engine. Like I've said before, I don't have alot of exp. with Super/turbocharged engines, but it seems to me if the engineers could squeeze an extra 15hp out of the engine they would have. When you are already as close as a Redline is to an SRT-4, why would you not open that puppy up? Unless opening that sucker up will beat the engine to a pulp over 70,000 miles. Lets face it, people expect cars to last like a million miles now.

 

[JPK]

Lets face it, people expect cars to last like a million miles now.

Anyone who plays the "tuner game" should know better though.

If you buy a new honda civic, do proper maintneance and keep it stock, then yes, it should last. But if you take that car and turbocharge it, raise the redline and run NOS, then of course it's not gonna last as long.

 

[goofyguy]

not true. they build a 500hp motor turn it down to 200hp and in that way it can in no way hurt itself due from abuse.