Hey guys/gals. New one here. I'm considering trading in my 2001 Stratus R/T Coupe for a tC when they become available.

I'm wondering if anyone knows if the TRD Supercharger will have a rev-limiter much like the GM-Chevy Impala SS does, that limits rev's to 3K rpm's if the vehicle is sitting still (either in Park or Neutral.) Also, do we have any word as to whether the supercharger will come with a bypass or blow-off valve?

Thanks, and if this has been asked before I apologize - I just joined about 5 minutes ago and need a few nights to catch up. Thanks.

Jeff
www.jeffreystephen.com

 

superchargers don't use BOV... the reason is that you need a BOV for a turbocharger is that the momentum of the turbo keeps compressing intake air... think of it as units of air, the pump is supplying the perfect amount to make the desired pressure at 6000rpm, then you hit the clutch and shift to a lower gear and the engine is now turning 3000rpm which means it needs 1/2 the air supply, but the turbo has that momentum and it is still pumping the same amount of air... so now you would have twice the pressure... this would be bad... so the BOV relieves the pressure back down to a preset maximum so that you don't blow the engine up...

a supercharger on the other hand is "bolted" (really belted) to the engine... so as the engine drops in rpm during a shift, so does the amount of air the "pump" (supercharger) is perfectly matched to the needs of the engine...

make sense??

as far as a rev limiter, this is the first I have heard of a "park" rev limiter... I guess this is just a safety feature to keep you from dumping the clutch??

 

I know plenty of people with centrifugal-style stuperchargers who still use wastegates - especially in high-boost applications. I know a number of Stratus owners with the Ripp mods blower and a BOV on it.

It probably all depends on how much boost the blower puts out.

Yeah the GM motors have a rev-limiter on it, which greatly dumbs down the performance "feeling" of those cars. So I hope Toyota/TRD doesn't do the same. Guess I'll just have to wait and see.

 

why would u want to rev your engine up in park or neutral anyway? u have the need to destroy your pistons rings even faster?
there is good reason for that 3k rev limit...keeps stupid people from wrecking their motor.....

 

okay, so your talking 35psi of boost... your also talking about a complete "do-it-yourself" setup... not a bolt on setup to any vehicle... we are talking about a street driven car, not a 1/4miler... you have to understand that it works like supply and demand - a supercharger is belted to the engine and pumps a corresponding amount of air based on the engine speed - a turbocharger, due to inertia, is always playing catch up, at first it isn't making much boost because exhaust pressures are low, as you rev your engine you get more turbo spool up and more pressure is being built, but then you shift and your demand for volume of air goes down, but the turbon is still pumping so the pressure will spike... on a supercharger it drops speed with the engine so the pumping is dialed into the demand...

 

I understand what you're saying. I just wasn't sure if it applied to all applications.

Scionxb04, I've been revving the motor of my 01 Strat at red lights and parking lots for 3 years now, and the thing hasn't seen a shop since the day I bought it.

A little tap on the accelerator every now and then isn't going to drastically affect the life/performance of an engine. Let's be realistic.

 

ask any mechanic and they will tell u free revving a motor is bad for rings..would u people learn something and read before posting stupid ____

 

and u...look at any vortech supercharger kit and it will have a bov....even the cheap ones have a bosch bov....
http://www.vortechsuperchargers.com/...9-00civic.html here are the kits for my civic....notice the bov

 

You know that if a cop hears you rev the engin you can get in big trouble because its basicly saying you want to race. And we all know thats illegal. You dont want your car taken away for revving do you? I dunno, IMO, it's kinda ___ to sit there and rev anyways.

 

i would also bet any amount of money if i compression tested his motor it wouldnt even be close to where it should be....not that any normal driver would ever notice a slow decrease in compression unless it was a sharp dropoff in compression....

 

this is an antisurge valve, that is its technical name and it isn't in place to prevent damage, it is there to stop noise... I understand your desire to understand the S/C setup, but you need to research first... here's the technical scoop... based on the downstream location of most throttle plates, the supercharger is still producing the boost when you let off the throttle, because the engine is still spinning at the high rpm - (the "gas pedal" controls the air throttle plate) - but say you are still in gear and the engine is spinning at 6000rpm... well the s/c is still pumping based on the desired pressure at 6000, but the throttle plate is constricting what can get by, the throttle plate sees high pressures on the upstream side and negative (vacuum) pressure on the downstream side, but the s/c keeps packing the air until it reaches its pumping maximum and literally the air starts popping back out the intake - this is quite noisy, but it isn't hurting anything... we're talking low pressures... and the pistons will never see this pressure, even if you floor it again after letting off, because you have a few inches at high pressure and a few more inches of intake at low pressure, not to mention a evacuated cylinder just trying to suck more air in... we are also talking about a very small amount of air to be "blown off"... so you will not hear this device doing its job, everybody loves the turbo BOV, but that isn't gonna happen here...

when a t/c is releasing the pressure it is because of the momentum of the impeller continuing to pump enough air to make desired boost at peak rpm, but when you shift down the next gear the engine is gonna need only half the air that the impeller is pushing, so until the impeller slows down it needs to dump quite a bit of air... so the BOV on a t/c is extremely audible, and definitely on high boost applications, but only when it is vented to atmosphere... (otherwise it might be into the exhaust) an alternative bypass valve might allow exhaust air to bypass the exhaust side impeller, which will help the impeller get down to the proper speed MUCH faster...

if you'd like to read a really good source on this info, I recommend picking up a copy of either BOOST
or SUPERCHARGED

sometimes I oversimplify... but my comprehension is there, feel free to ask questions, but more imporantly - walk away with understanding of what I am talking about... I have a degree in mechanical engineering and I have been working on engines and electronics for as long as I can remember... but I am not an expert, I'll be the first to say that... but I am extremely well read... I've spent a whole lot more time tinkering with aircooled engines, but watercooled engines are okay...

the real issue is here, now with quotes of 55 hp, I would put this at 5psi of boost... 215hp needs a limited slip differential... anyone fitted one for the Camry transmissions...

 

MAXFLOW AIR BYPASS VALVES Flows 320 CFM @ 8 PSI
...their superchargers are centrifugal.....please go read...stop wasting my time
MAXFLOW AIR BYPASS VALVES Flows 320 CFM @ 8 PSI
Compact design is ideal for import applications and tight engine compartments
Includes gasket for installation (steel and aluminum mounting flanges available separately from Vortech)
Two bolt mounting pattern will retrofit to standard HKS/Greddy style mounting pads
u can also use these with turbo's which ive seen many people do
u can also use one from hks or greddy in its place which ive also seen done on the vortech kits...this gave them the ability to adjust boost....

non-centrifugal like the one on my 1,800hp alcohol injected drag boat....doesnt require any type of boost controll because its directly belt driven and runs at the exact same rpm as the motor...unlike the vortech ones which takes time to slow down...this is how vortech keeps the boost up between shifts....the non-centrifugal jackson racing one which is roots type spins with the motor has drop in psi between swifts when the rpm's drop...
ive driven civic's with both centrifugal and non-centrifugal...dont need no degree...have real world building experience
<img src=http://www.nipponpower.com/images/vortech04.jpg> <blow off valve

 

i thought u are here to ask questions. then u refuse to accept the answer/truth???
if u already know the answer, why would u ask people here???

why would u want to do that kind of stuff? whats your point?


are you trying to be a street racer? since u always revving the motor at red lights?

 

you do realize that this is COMPLETELY FALSE... there is not a single supercharger that runs on a clutch type system that I have ever run across, it is impossible to function the way you are talking about.... superchargers of all kinds spin in perfect sync with the engine, there might be small amounts of belt slippage on a super high boost application, but you are completely 100% incorrect on this one... sorry

it kinda messes up the point of your post... not sure what the flowrate of a anti-surge valve has to do with the amount of air that will need to be dumped... I'm not saying that I'm not sure about the facts, I am saying that I am not sure what your point is...

 

Wow what a FLAMING. guys new to the board, you could be a little nicer dont you think?

 

some of the guys arent really new, but what a crazy disagreement.

 

Ok, i'm gonna have to stick up for this guy in the thread. Reving your engine doesn't do ____. If you sit their and bounce it off the rev limiter, then yeah, but thats obviously not what hes doing. A simple rev isnt going to effect your piston rings . Why do u think people would rev it up and then drop the clutch when racing if it really effected the motor. Seriously guys...

 

good to see someone put one of the "i know everything" brats to shame.

 

i used to run one....you have no idea what your talking about.....after i shut my car off i could hear it wind down....and i could adjust boost from within the car....something u cant do with normal supercharger without changing the pulley...
read this... http://www.sandsautomotive.com/whipp...son-chart.html notice how it says Centrifugal superchargers have lag....cause they spool up like a turbo....quit wasting my time educating u people...

when i drove my neigbors civic with jackson racing supercharger it wouldnt hit full boost till redline...the boost would rise with rpm....the vortech supercharger i had would hit full boost around 3,000rpm and hold that boost till redline...nothing like a normal supercharger.....more like a turbo...even sounded like a turbo spooling and i got the whooosh between shifts.....

type of supercharger your talking about looks like this..roots type.. <img src=http://www.jacksonracing.com/Graphics/Products/Large/989-300_1.jpg>
vortech's look like this..Centrifugal type... <img src=http://www.vortechsuperchargers.com/images/s-trim_cw_cvd_sat.gif>

roots type spin 2-3 revolutions to one revolution of the crank.....means at 8,000rpm the jackson racing would spin 16,000 to 24,000rpm(depending on pulley used)
vortech superchargers spin over 50,000rpm
they work nothing alike....and i have 0 boost when idling...the jackson racing supercharger roots type always made boost...even idling...he had the internal bypass valve removed....and his car was still slow....roots type suck....we both had the same car...2k civic si with b16a2....reason why i smoked him...roots type have a adiabatic efficiency of 40-60%...centrifugal superchargers have a 60-78% adiabatic efficiency

 

seriously, read a book... I understand what you are saying, but I think you are missing the point... a roots type blower is most efficient at lower rpms, sure it makes boost right off the line, it loses its efficiency as the rpms climb... centrifugals are a completely different beast, they have an efficiency range which is in the 10s of thousands, so most people set them up to make approximate the most boost where torque and hp are peaking... but you will see a basically linear increase in boost as you climb the rpm range... this is the simplicity of a centrifugal...

BUT you can easily put a different pulley on it and get the same setup to make peak boost much lower in the rpm range and then you MUST use a BOV to release this pressure... then you'll have a flat boost level above the point where you have designed it to do so... most people don't set it up this way, because it takes energy to compress that air and the BOV is just letting that pressurized air go away for free... I don't have my books with me, but later on today I will calculate what the energy losses are, but I would venture to guess that the losses will exceed the hp gain... if not, it will be close enough to not justify the extra plumbing... pumping that air up to high pressure would be the same as towing a parachute, but if you engine is using the air you have "paid" to compress then you are more efficient...

a BOV is not a necessary part of a correctly designed supercharger, with a turbo charger that makes any significant pressure it is a necessary evil... UNLESS you are dealing with a constant rpm application - like water pumps, gas compressors, etc...

as far as what you were hearing wind down, I'm not sure what to tell you... the centrifugal is a direct drive system... I would like to see the clutch mechanism that you are saying this setup would require, it would wear out, so there will be replacement items available... it is new to me...

http://www.sandsautomotive.com/whipp...-compared.html
on this page, from your same site, it explains that centrifugals are fixed ratio, call them and ask if they have some clutch system it theirs, but I'm at a loss to tell you what that noise you were hearing was, but I am saying that it was NOT the supercharger "winding down" like a turbo... of course this is based on their not being a clutch installed on the unit...

do you know what adiabatic efficiency means?? just curious... I have a thermodynamics book that takes about a chapter to explain it... I didn't learn from Car&Driver...

and if all roots blowers suck, then I guess this is why the only type of supercharger you see on Top Fuel Dragsters...??? 6000hp isn't testament to their abilities??