it's possible , fuel upgrades , head job , correct exhaust , cold air input , good slightly larger intercooler with lil press drop , hi po spark , stuff like that.

 

Errrr.... no. A centifugal supercharger is still a belt driven SC just like a roots or screw type SC. There is no lag associated with any SC.

Turbo lag occurs because the exhaust has isn't getting past the impeller fins quick enough to get the compressor to spin at full speed.

When you have a supercharger there is no exhaust impeller, instead the compressor fin is directly connected to the accessory drive belts. The supercharger will always 100% absolutely spin at a speed that is directly proportional to the engine's RPM's no matter what type of SC you have.

 

ZING!

(but he is right)

One thing to note is that in a low-boost application such as the xb a small turbo will probably feel more powerful than a supercharger. You will have minimal turbo lag, and full boost will come on much earlier than the supercharger which by nature will produce full boost at max RPM, and lower boost at lower rpm. The supercharger is more linear but the turbo creates peak torque at lower RPM which often is faster. Look at accleration times between turbo cars and supercharged cars with the same rated HP, you will see that in most cases the turbo cars accelerate faster.

 

you are incorrect.

do some more reading.

a centrifugal supercharger is a dynamic blower (much like a water pump) and there is lag associated with this design as it is not a positive displacement type sc.. in other words, the air is not forced through the turbine, like a roots or twin screw.

The biggest drawback of the centrifugal supercharger is it's inability to make high levels of boost at low engine rpms. Typically, a centrifugal supercharger will make it's maximum (quoted) boost at the engine's redline rpm and nearly nothing at 1500-2000 engine rpm.

taken from http://www.superchargersonline.com/content.asp?ID=21

 

superchargers 101
http://www.superchargersonline.com/content.asp?id=15

 

But what you are describing is not lag. Turbo lag occurs when the turbo has not completly spooled up. This occurs in large turbos because it takes a ton of exhaust gas to spool a large turbo. Lets take an MKIV Supra for example (single large turbo and lots of other mods). When this car leaves the light at a drag strip it launches on ONLY the power the motor is making. The turbo may not completely spool up until the middle of 2nd gear or the beginning of 3rd gear. This is why you can have a 1000 HP Supra run 11's at over 160 MPH all day long. The turbo just isn't spooling quick enough.

This is the reason why many heavily modded MKIV's are twin turbo. The turbos are placed usually inline with a smaller turbo in front. This way the car is still getting some boost to speed it up toward the begining of the track before the 2nd much larger turbo can take over.

What you are describing with the supercharger is inherent to ANY Supercharger... but it is NOT lag. It is how the supercharger works. It can NEVER (unlike a turbo) spin faster that what it is proportionate ot the motor. The turbo can keep spinning because once the exhaust gas stops moving it isn't stoping the turbo from still spooling (which is why a blow off valve is necessary... it is still bosting between shifts). The supercharger on the other gand is directly connected to the motor, when the revs of the motor drop, so does the speed at which the supercharger is spinning. This is also why most SCers don't have a blowoff valve, only a bypass valve so the motor isn't unnecessarly boosing at low RPM and when you are going light on the throttle.

I may be a car salesman... but I am one of the few who knows what they are talking about. I spent quite a few years in the forced induction world (started with a 91 Eagle Talon TSi AWD then moved on to a 98 Buick Regal GS... yes, the Buick was supercharged via an Eaton M90 roots type SC) then to an 87 Firebird Formula with a supercharged 383 stroker (Vortech). I have done years of research and have first hand knowlege with forced induction.

 

i apologize for using the word lag. how about DELAY.
you assumed i meant turbo lag, i meant a lag in time.

i am also aware of forced induction, and we'll probably fight this til death.. fact is, twin screw SC's produce better boost numbers at lower RPM's simply by design,.. they're positive displacement, not dynamic..

(a water pump vs a hydraulic pump)

 

florenscion is correct... the reason that superchargers are only making max boost at max rpm is because there is no blow off valve to regulate the pressure DOWN to the desired set point... so yes you could just swap pulleys and over run the supercharger for the same effect... you could then have say 7psi at 2500rpm all the way up to 6000rpm...

centrifugals are the quietest and therefore more streetable, this is why they have such popularity... and the smaller bodies help them fit under snug hoods...

aftercoolers (also incorrectly called intercoolers) should be used when ever the final compression temps break the fuel's self ignition line... for standard grade fuel I think this is like 5500deg F... so if you have 7psi boost with an 8:1 compression ratio, then you have no need... but ANY boost on a 12:1 will put you into the danger zone because the fuel is already getting close to that point on average temp days...

regardless of how much aftercooling or boost or compression... the xB/xA engine still suffers from rod failures, so more fuel/boost/compression will just blow the engine... this is an economy engine...

 

so because it's quieter, it's more streetable? how'd the ricer civic drivers not get this memo!!!

oh, btw, BOV's don't regulate your boost level.. sorry

 

first off the popularity I was referring to was not to the ricer, this would be like saying which cheese is most popular to poor people... ricers are a class unto themselves, they have no regard to quality, curteousy, decency... anyone who believes that I need to hear their exhaust from a mile away when they are coming home from their minimum wage job at 2am will never show up on the brain radar... I was referring to manufacturer's, kit makers, etc... ya know - educated people...

second, I am positive that you are mistaken about the purpose of a BOV... the BOV has a set pressure and when that pressure is met or exceeded it reduces the intake pressure to the atmosphere... two examples of when a BOV will go off - 1) let off the throttle at a shift point, turbo is still pumping but has no where to go... 2) overall system design has the turbo "coming on" and too much pressure is built up, so instead of an engine failure, you just release the extra pressure...

could you be confusing this with a wastegate?? this device allows the exhaust to bypass the turbo thereby reducing the available exhaust energy to the turbo...

either way, you need to be more cafeful with blanket statements unless you are positive about what you are talking about... if you need some research starting points you can read up on BOV's below...
http://www.pagewise.com/turbocharger-kits.htm
http://www.superstreetonline.com/tec...76/index1.html

 

ok, i was making a joke against ricers...

second, your links to "learn" about BOV's are about as elementary as they get.

a blow off valve DOES NOT regulate system pressure. it only relieves pressure during shifts or off-throttle situations..

a wastegate is what controls system pressure, and coupled with a manual or electronic boost controller, can be done by the driver of the car.

explain how a blowoff valve limits system pressure.... it has 3 ports. input from a pilot line, input from the turbo piping, and outlet to atmosphere..

there are no other connections to the BOV .. and believe me, i know this from first-hand experience.

so, does thepilot tube connected to the BOV somehow limit system pressure? or maybe the BOV just KNOWS what psi you want to run at... hmm..

you dont see tuners under their hood adjusting their bov when they want to up the boost, do you? then why would you get in your head that BOV's have anything to do with boost levels?

yes, you do adjust BOV's, typically by adding more spring pressure, because the bovs are open at idle causing the car to idle rough or even die. . but they don't regulate system pressure.....

oh, and here's a link
http://www.c-speedracing.com/faq/07.php

how's that for a blanket statement?

 

http://www.pagewise.com/turbocharger-kits.htm

i just read this link.. omg what a crock of ____! who wrote this? have they ever WORKED on a turbo'd car?

"the valve in the blow off valve" lol, like it's some huge complex device..

my advice, don't take websites that are spam, seriously...

 

Well you all seem to have gotten into it again.
You are both half right.
In turbo applications a BOV is never used to regulate boost, only to relieve pressure between shifts to eliminate compressor surge and other ill effects of closing the throttle with pressure in the manifold. In a turbo car a wastegate, electronically or mechanically controlled is used to regulate boost.
Now obviously with a belt driven supercharger you can't use a wastegate to regulate boost. SO how do you do it? You could regulate it by installing a clutch in the charger pulley that slips under certain circumstances, which would be tricky. You could also regulate it by using a pressure bleed after the charger and before the intake, kind of like a BOV but it would have to be a solenoid that could cycle incredibly fast as it would be quite tricky to regulate boost pressure in this manner.
Generally superchargers employ no boost pressure regulation and rely on sizing the pulleys so that they make some boost down low and a lot up top. Another option is to install some sort of gearbox into the charger driveline, perhaps with a CVT like cone gear which changes the ratio as RPM increases to keep boost constant, but this would be incredibly complex and expensive.

Have fun battling this one out yall.

 

actually, on a SC, you can control boost by using a recirculate valve. toyota did it on the 4AGZE over 10 years ago....

you recirculate your boost pressure back to the "inlet" side of the SC, thereby keeping boost pressures low. i'm pretty sure this is what the Blitz kit does, to keep such low PSI levels.

 

http://www.toymods.org.au/4A-GZE_Tech.html

 

QUote from your source...

"An electromagnetic clutch is installed on the supercharger, allowing it to freewheel when it is not needed. The clutch is controled by the engine's electronic control unit (ECU). A combination blow-off/bypass valve is provided to route air around the supercharger when the clutch is disengaged or when boost exceeds 8 PSI (nominal). The valve is operated by manifold vacuum/pressure. The ECU has the ability to force the bypass closed via an electronic vacuum cut off solenoid valve."

This is employing two of the methods I mentioned, the only significant difference is that it recirculates the air back into the inlet of the supercharger, just like a recirc valve on many turbo engines. I assume that this is to avoid blowing off already metered air to the atmosphere and messing up the A/F ratio.

 

you are correct.

me and migthens were fighting about turbos.. SC is a totally different animal.

i would imagine the Blitz SC has much more power potential (read up on specs for that SC, it's a Lysholm model 1200, also known as a whipple 1200AX ) than it currently puts out. this SC is capable of pressures well over 1bar, with very efficient (relative to other SC models) temp/hp requirements.

i researched the twin screw sc for oer a month last year.. learned a lot.

 

http://www.automotivearticles.com/Su...Choices_.shtml

good article.. minus the spelling errors of course lol

 

That's OK him (?) and I got into a fight awhile ago, but it shook out OK in the end.
PRetty much andy turbo or supercharger for the xb/a is going to have wayy more potential thatn it can use beause over 6-7 psi the motor will break rods. The 1.5 was designed with economy in mind whihc means lightweight reciprocating components and high compression which do not hold up to boost terribly well.

 

the links are elementary on purpose... I am not saying that the only way a BOV is setup is to regulate pressure, but that is exactly what the device is for... it is to keep the overall system pressure below a certain point... this is its purpose... this is what is called regulation... no you aren't gonna dial it in, but it could work this way.... some car manufacturer are just using an electric pop off valve that keeps system pressure below a certain number and it is also automatically opening under certain throttle situations...

the recirc valve setup that you mention is exactly what setup I was referring to... so I guess I am not following what part of my statements you don't understand... I never said that all systems were setup the same, I am still standing on the fact that BOVs regulate system pressure - having a set maximum pressure which is dumped by any valve is considered regulation...