Overspinning the SC
#1
Supporting Maxima.org Member
Thread Starter
iTrader: (7)
Join Date: Oct 2000
Location: Puyallup WA
Posts: 7,938
Overspinning the SC
Just got my new SC in - it's a V2 SC Trim.
Max RPM is 53,000
WIth the raised Rev-Limiter and a 6.25 Crank, that puts me at 56445.99 RPM on the impellar.
How dangerous is this?
IanS
Max RPM is 53,000
WIth the raised Rev-Limiter and a 6.25 Crank, that puts me at 56445.99 RPM on the impellar.
How dangerous is this?
IanS
#2
Probably not too dangerous. I remember a long time ago when Matt got the really small pulley, he said that they told him it would be alright to overspin the blower for short periods of time, like a drag race. But he shouldn't spend extended time in the high RPM range overspinning the blower for a long time.
That's how I remembered it. I researched this for a while when I wanted a 2.87 pulley.
That's how I remembered it. I researched this for a while when I wanted a 2.87 pulley.
#3
Originally Posted by iansw
Just got my new SC in - it's a V2 SC Trim.
Max RPM is 53,000
WIth the raised Rev-Limiter and a 6.25 Crank, that puts me at 56445.99 RPM on the impellar.
How dangerous is this?
IanS
Max RPM is 53,000
WIth the raised Rev-Limiter and a 6.25 Crank, that puts me at 56445.99 RPM on the impellar.
How dangerous is this?
IanS
#4
Supporting Maxima.org Member
Thread Starter
iTrader: (7)
Join Date: Oct 2000
Location: Puyallup WA
Posts: 7,938
6.25" diameter crank pulley diameter.
One of the factors you need to know to input for calculating impellar speed.
http://www.vortechsuperchargers.com/...pspeedv-2.html
One of the factors you need to know to input for calculating impellar speed.
http://www.vortechsuperchargers.com/...pspeedv-2.html
#7
Originally Posted by IceY2K1
What I don't get is that they say it's good for 20psi, yet you can't get more then 13-14psi before you're spinning it too fast.
That would be 13-14 psi measured at the manifold after losses through the intake piping. At the blower outlet it will be more, 20 psi if you believe Vortech.
#8
Yikes! I figured .5psi drop from the filter and maybe 1-1.5psi from a CAI, but that leaves 5+psi just from the X-over pipe and TB?
Also, has anyone tapped the X-over pipe for a boost signal?
Also, has anyone tapped the X-over pipe for a boost signal?
Originally Posted by Stephen Max
That would be 13-14 psi measured at the manifold after losses through the intake piping. At the blower outlet it will be more, 20 psi if you believe Vortech.
#9
Originally Posted by iansw
6.25" diameter crank pulley diameter.
One of the factors you need to know to input for calculating impellar speed.
http://www.vortechsuperchargers.com/...pspeedv-2.html
One of the factors you need to know to input for calculating impellar speed.
http://www.vortechsuperchargers.com/...pspeedv-2.html
#12
Originally Posted by IceY2K1
Yikes! I figured .5psi drop from the filter and maybe 1-1.5psi from a CAI, but that leaves 5+psi just from the X-over pipe and TB?
Also, has anyone tapped the X-over pipe for a boost signal?
Also, has anyone tapped the X-over pipe for a boost signal?
I drilled and tapped a test port in my blower outlet back in September, I need to hook a gauge up to it and do some tests, too.
#15
Originally Posted by max'n out
You guys are missing the big thing...it's not the boost measured at the t.b. you gotta worry about killing the blower.
#17
Supporting Maxima.org Member
Thread Starter
iTrader: (7)
Join Date: Oct 2000
Location: Puyallup WA
Posts: 7,938
Hit 12PSI once or twice, usually I'm hitting 11PSI. Then again, I'm still getting used to where the new redline is and usually shift well before it. So I think once I get my shifting down, 12PSI will be pretty normal.
Haven't Dyno Tuned yet (since I just got it all together and properly working last week).
But the blower seems to be taking the abuse without much issue. However- since I only drive on the weekends (I live and work in Downtown Seattle) - and it's been a short amount of time - I can't say much at all about overspinning it - except that it doesn't go KABOOM instantly when you go over the "limit" for RPM's on the blower.
Haven't Dyno Tuned yet (since I just got it all together and properly working last week).
But the blower seems to be taking the abuse without much issue. However- since I only drive on the weekends (I live and work in Downtown Seattle) - and it's been a short amount of time - I can't say much at all about overspinning it - except that it doesn't go KABOOM instantly when you go over the "limit" for RPM's on the blower.
#18
Originally Posted by ejj
I'm going to use one of the blowers test port this weekend or later this week to see...
#19
Originally Posted by ejj
BTW - I never did this. The smallest barbed hose fitting that Home Depot sold was a 1/4". IIRC the fittings in the blower outlet are 1/8", and I never bothered hunting for the correct fitting elsewhere.
I did. I never saw boost pressures above what I normally see inside the intake manifold, i.e. 10-11 psi, even after I disabled the bov so that it wouldn't release air when I closed the throttle after revving. I'm somewhat mystified about this. How does Vortech come up with that 20 psi number?
#20
Originally Posted by Stephen Max
I did. I never saw boost pressures above what I normally see inside the intake manifold, i.e. 10-11 psi, even after I disabled the bov so that it wouldn't release air when I closed the throttle after revving. I'm somewhat mystified about this. How does Vortech come up with that 20 psi number?
I'm amazed that there isn't a pressure drop of at least 1 or 2 psi between the blower and manifold.
#21
Originally Posted by ejj
Interesting. Could it be the intake? Vortech's site says the SC flows up to 1000 CFM...IIRC the filters most of us use don't flow that much.
I'm amazed that there isn't a pressure drop of at least 1 or 2 psi between the blower and manifold.
I'm amazed that there isn't a pressure drop of at least 1 or 2 psi between the blower and manifold.
#22
Supporting Maxima.org Member
Thread Starter
iTrader: (7)
Join Date: Oct 2000
Location: Puyallup WA
Posts: 7,938
Originally Posted by Stephen Max
There might have been. But not a 10 or even 5 psi difference. You make a good point about the filter. I need to redo the test with the filter removed.
I've Dynoed without a filter before - no HP difference.
But then again - I had my compressor leaking air, so that may skew results. (But it wasn't leaking 5psi or anything!)
#23
Originally Posted by Stephen Max
There might have been. But not a 10 or even 5 psi difference. You make a good point about the filter. I need to redo the test with the filter removed.
I can't imagine that is costing us 7+psi though...
We should ask Vortech.
#24
Originally Posted by iansw
I've Dynoed without a filter before - no HP difference.
But then again - I had my compressor leaking air, so that may skew results. (But it wasn't leaking 5psi or anything!)
But then again - I had my compressor leaking air, so that may skew results. (But it wasn't leaking 5psi or anything!)
S
#27
Supporting Maxima.org Member
Thread Starter
iTrader: (7)
Join Date: Oct 2000
Location: Puyallup WA
Posts: 7,938
On which part of it? Overspinning the blower or why Vortech says 20PSI?
As for overspinning the blower, I do it all the time - hitting 13PSI now that I'm used to the raised redline. Probalby shouldn't do it tho since I'm lean up top from the A32 MAF. <Never detonated once yet, knock on wood>. Had this blower almost a year now....no issues.
As for the 20PSI - I have no answers for ya.
As for overspinning the blower, I do it all the time - hitting 13PSI now that I'm used to the raised redline. Probalby shouldn't do it tho since I'm lean up top from the A32 MAF. <Never detonated once yet, knock on wood>. Had this blower almost a year now....no issues.
As for the 20PSI - I have no answers for ya.
#28
Originally Posted by IceY2K1
*bump*
Sorry for the old thread, but did we come to a conclusion on this?
Sorry for the old thread, but did we come to a conclusion on this?
I've thought about this a lot, and what I think is that the Vortech blowers are too big for a 3 liter engine, and we operate to the left of the surge limit line at high rpm. Efficiency goes to hell, and boost pressure never reaches what the blowers are capable of achieving if air flow was not impeded.
#31
Originally Posted by Stephen Max
What size pulley and what is your fuel cut rpm?
I was hoping somebody with the know-how could plot out where the VQ30 falls on this map, similar to what somebody did for the VQ35 on the 350z forum...
#33
I've already did this for the VQ30, but I was working on turbo maps also for a BIG post and got lazy. IIRC, just shift them about 500rpm to the left...roughly.
I'll dig this one up and post it tonight.
I'll dig this one up and post it tonight.
Originally Posted by JeffesonM
no blower for me
I was hoping somebody with the know-how could plot out where the VQ30 falls on this map, similar to what somebody did for the VQ35 on the 350z forum...
I was hoping somebody with the know-how could plot out where the VQ30 falls on this map, similar to what somebody did for the VQ35 on the 350z forum...
#34
They have a larger trim SC, however they won't trade/upgrade it with the Maxima smaller SC.
Somebody could buy the larger trim outright and then mod it probably.
Somebody could buy the larger trim outright and then mod it probably.
Originally Posted by chris'smax
By upgrading(via sending it to vortech) the trim on the supercharger wouldn't that solve the overspin problem
#36
s trim to t-trim
I haven't called vortech yet, but you should be able to swap a sc or sq trim blower for the t trim blower which flows more air and has a higher rpm. its the swap I plan on making. Also my friend has a 4.6 liter stang with the t trim and he sees 10psi all the time. he has the vortech aftercooler and a 3.60 I think( i forget- i'll ask ) pulley any ways he wants to trade so thats my plan.
#37
Originally Posted by crewchief264
I haven't called vortech yet, but you should be able to swap a sc or sq trim blower for the t trim blower which flows more air and has a higher rpm. its the swap I plan on making. Also my friend has a 4.6 liter stang with the t trim and he sees 10psi all the time. he has the vortech aftercooler and a 3.60 I think( i forget- i'll ask ) pulley any ways he wants to trade so thats my plan.
#38
i have thought about this also...from what i remember from vortech's press release a few years ago the cost was $800+ for the t-trim impellar upgrade. basically the cost of a new blower.
i guess its just not feasable to drop $800 for whatever gains you would be getting.
i guess its just not feasable to drop $800 for whatever gains you would be getting.
Thread
Thread Starter
Forum
Replies
Last Post
MaximaSpd85
Supercharged/Turbocharged
36
10-07-2010 02:36 PM
streetzlegend
Supercharged/Turbocharged
29
04-04-2010 09:07 PM