Shop owners - Tuners - opinions on SC parasitic loss
03-14-2007, 02:02 PM
#41
Originally Posted by booger
WE are strickly talking about parasitic loss . at the same psi on the exact same motor
who here can say they run the same timing maps, same boost, and same A/F at the same elevation, same ambient temp, same dyno, same fuel octane, and same everything else on the car.
I don't know what else to say. We talk about 13 psi SC vs 13 psi turbo and every car is running drasticaly different setups - cams, exhaust, cats/TP, etc. We talk about bone stock out of the box tunes with 8 psi vs 8 psi, and that's not a good comparison because the tunes are apparently too drastically different to think it's within reason to compare
So now you're talking about optimally tuning each type of car. Well a small turbo will always have more area under the curve for the same psi compared to a SC so no contest there. I mean, I agree with you that a turbo is going to be more capable, but I'm thinking if the parasitic loss of the SC was really rearing it's ugly head in a major way, then adding more boost wouldn't be giving people more power. Several people with 2.87 pulleys are getting in the 430-450whp range with 11-12 "psi" yet they were making 390-410whp at 9-10psi with the 3.12 pulley. If the vortech was truely running into the threshold of parasitic loss overcoming power being made, then they wouldn't be making more power. As far as power beyond a 2.87 pulleyed stock blower... I dunno, I'm not willing to go any further.
Maybe you're already at that threshold where more boost is meaningless - obviously with the belt slipping, that's causing it to be meaningless anyway other than more power before it slips
I'm still trying to find people who have blown up rods with a vortech kit though - regardless of power
If I recall the greddy TT's stock tune wasn't all that safe...seem to remember at least a couple blown up engines, but then again, same with the early prochargers
I dunno, I still don't see how worrying about parasitic losses are going to make me or anyone lose sleep at night unless they're shooting for over 500whp on the stock displacement engine
Last edited by sentry65; 03-14-2007 at 02:14 PM.
03-14-2007, 02:09 PM
#42
What ever....I'll stick to the safe side when figuring fuel requirements . That for 600whp you'll need 750whp worth of fuel . And at around 400whp the fuel needs will be about 1/3 less than that [ 500whp worth ] Just to be on the safe side .
03-14-2007, 02:21 PM
#43
as long as the A/F and fuel pressure are good, I don't see how it matters other than worse gas mileage. I guess for someone starting from scratch, they'd just make sure to get larger injectors and a better fuel pump than they normally would think to get. If the fuel system wasn't up to par, there wouldn't be good pressure or A/F
I've never really thought of it in any other way. If my tuner gave me my car with perfect A/F and fuel pressure, I probably wouldn't ask him if my 600whp car has 750whp worth of fuel or not, and if it didn't that he should go back and add more fuel - it's not like he's measuring fuel volume, he's just getting the A/F to be around 11.5 or so
Booger, I kinda wonder why you're sticking with the vortech if you're really worried about the parasitic loss - even now that you have the Dsport belt setup so your belt shouldn't slip anymore. Do you not think you'll be able to make more power beyond the 13psi that you've been slipping at?
I never intended to go above 500whp on a stock block so I've been happy with the vortech. I might someday stroke my engine to 4.24 liters and see how it does with the stock vortech 2.87 blower first before thinking of trying the T-trim and possibly slipping at whatever given power level
I've never really thought of it in any other way. If my tuner gave me my car with perfect A/F and fuel pressure, I probably wouldn't ask him if my 600whp car has 750whp worth of fuel or not, and if it didn't that he should go back and add more fuel - it's not like he's measuring fuel volume, he's just getting the A/F to be around 11.5 or so
Booger, I kinda wonder why you're sticking with the vortech if you're really worried about the parasitic loss - even now that you have the Dsport belt setup so your belt shouldn't slip anymore. Do you not think you'll be able to make more power beyond the 13psi that you've been slipping at?
I never intended to go above 500whp on a stock block so I've been happy with the vortech. I might someday stroke my engine to 4.24 liters and see how it does with the stock vortech 2.87 blower first before thinking of trying the T-trim and possibly slipping at whatever given power level
Last edited by sentry65; 03-14-2007 at 02:30 PM.
03-14-2007, 03:47 PM
#44
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You could two cars that looked like this:
350z 10psi 425rwhp
350z 10psi 455rwhp
Assuming same dyno and conditions, what is the big difference? The 455 rwhp guy is running a smaller pulley, but has better flowing heads and exhaust. Just like an extremely restrictive exhaust (say clogged cats) will show a higher PSI, but lower power
While Corky's statements on doubling power seem to hold pretty true in a world I'm more familiar with (supercharged Lightnings), it depends on many factors.
-Mark
350z 10psi 425rwhp
350z 10psi 455rwhp
Assuming same dyno and conditions, what is the big difference? The 455 rwhp guy is running a smaller pulley, but has better flowing heads and exhaust. Just like an extremely restrictive exhaust (say clogged cats) will show a higher PSI, but lower power
While Corky's statements on doubling power seem to hold pretty true in a world I'm more familiar with (supercharged Lightnings), it depends on many factors.
-Mark
03-14-2007, 04:00 PM
#47
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Originally Posted by sentry65
who care's about boost, did you gain power?
-Mark
03-14-2007, 04:18 PM
#50
Originally Posted by sentry65
I think the BPV is probably most likely at fault. HF cats adds power even when NA and you don't even have cams
I believe so too... The ATI BPV is a serious POS... ATI attempted another BPV, that looks like a cheap plastic tial in black.. I havent seen anyone else with it.. I may be the only one with it...... Because I only see others with the Grey mushroom looking bpv....
03-14-2007, 05:19 PM
#51
Originally Posted by sentry65
as long as the A/F and fuel pressure are good, I don't see how it matters other than worse gas mileage. I guess for someone starting from scratch, they'd just make sure to get larger injectors and a better fuel pump than they normally would think to get. If the fuel system wasn't up to par, there wouldn't be good pressure or A/F
I've never really thought of it in any other way. If my tuner gave me my car with perfect A/F and fuel pressure, I probably wouldn't ask him if my 600whp car has 750whp worth of fuel or not, and if it didn't that he should go back and add more fuel - it's not like he's measuring fuel volume, he's just getting the A/F to be around 11.5 or so
Booger, I kinda wonder why you're sticking with the vortech if you're really worried about the parasitic loss - even now that you have the Dsport belt setup so your belt shouldn't slip anymore. Do you not think you'll be able to make more power beyond the 13psi that you've been slipping at?
I never intended to go above 500whp on a stock block so I've been happy with the vortech. I might someday stroke my engine to 4.24 liters and see how it does with the stock vortech 2.87 blower first before thinking of trying the T-trim and possibly slipping at whatever given power level
I've never really thought of it in any other way. If my tuner gave me my car with perfect A/F and fuel pressure, I probably wouldn't ask him if my 600whp car has 750whp worth of fuel or not, and if it didn't that he should go back and add more fuel - it's not like he's measuring fuel volume, he's just getting the A/F to be around 11.5 or so
Booger, I kinda wonder why you're sticking with the vortech if you're really worried about the parasitic loss - even now that you have the Dsport belt setup so your belt shouldn't slip anymore. Do you not think you'll be able to make more power beyond the 13psi that you've been slipping at?
I never intended to go above 500whp on a stock block so I've been happy with the vortech. I might someday stroke my engine to 4.24 liters and see how it does with the stock vortech 2.87 blower first before thinking of trying the T-trim and possibly slipping at whatever given power level
I dont know about the other guys that have replied [ if they are tuners or owners ] , but Sharif is the only one so far that has replied and he seems to agree with the artical in DSport mag and my thoughts on it .
I bought Derek's cog set up to be able to build boost to redline and to try to get the most out of what I have . Im not worried about trying to have the top whp with a SC . That will never happen with my AT5 . I dont make excuses , or try to dream up reason why my SC isnt making the same whp as a turbo . Nor do I try to make my SC seem like it is better in some areas of the power curve than a turbo . Anyone can come up with graphs and calculations on this and that . Trying to justify something that isnt true or isnt going to happen in real life .
So maybe you can sit back for a while and not dominate a thread and let a few others reply . So we can get some opinions from others
03-14-2007, 05:30 PM
#52
...we obviously disagree on many things then
I think the parasitic loss is what it is, and it increases at a somewhat exponential rate as you push the blower further and further. As long as you're under the area where the SC really starts to fall on its face the parasitic loss isn't a show stopper for making decent power. That's all I've ever thought.
kinda like how the stillen makes perfectly good power up until around 340whp then it just falls on its face after that trying to make more
The parasitic loss I do think will become really severe trying to cross the 500whp mark with a vortech, where adding another lb of boost does hardly anything at all other than raise under hood temps. Otherwise, that's partly why I run 96 octane fuel and water injection despite my power levels - because I know the engine is working harder than what the dyno is showing
btw, how do you take a certain volume of fuel and determine how much hp that fuel is capable of making? I'm sure there's something that'll explain it
I haven't been dabating dyno curves or turbo vs SC in this thread. I've only brought up compressor efficiencies and parasitic loss issues with turbos and SC in regards to turbos because turbos are the only other FI method there is really. Also that Dsport article you keep bringing up has to do with turbo/NA parasitic loss compared to SC parasitic loss so how can someone talk about it without mentioning a turbo?
I think the parasitic loss is what it is, and it increases at a somewhat exponential rate as you push the blower further and further. As long as you're under the area where the SC really starts to fall on its face the parasitic loss isn't a show stopper for making decent power. That's all I've ever thought.
kinda like how the stillen makes perfectly good power up until around 340whp then it just falls on its face after that trying to make more
The parasitic loss I do think will become really severe trying to cross the 500whp mark with a vortech, where adding another lb of boost does hardly anything at all other than raise under hood temps. Otherwise, that's partly why I run 96 octane fuel and water injection despite my power levels - because I know the engine is working harder than what the dyno is showing
btw, how do you take a certain volume of fuel and determine how much hp that fuel is capable of making? I'm sure there's something that'll explain it
I haven't been dabating dyno curves or turbo vs SC in this thread. I've only brought up compressor efficiencies and parasitic loss issues with turbos and SC in regards to turbos because turbos are the only other FI method there is really. Also that Dsport article you keep bringing up has to do with turbo/NA parasitic loss compared to SC parasitic loss so how can someone talk about it without mentioning a turbo?
Last edited by sentry65; 03-14-2007 at 05:43 PM.
03-14-2007, 05:48 PM
#56
Originally Posted by sentry65
booger, then put me on your ignore list
I'm here to participate and there's no one else has posted in here anyway during the last couple hours
I'm here to participate and there's no one else has posted in here anyway during the last couple hours
2- Are you a shop owner ?
3- This is my thread , and I asked you to let it rest so you dont try to dominate the thread . You seem not to read anyone elses opinion or dont think anyone elses opinion matters .
4- Read the threads Topic....you are not a pro tuner nor a shop owner , I think that is the only ones I asked a opinion from .
And to add , since you already ruined the thread and no one with an opinion that matters wont reply because of you...Thanks !
Last edited by booger; 03-14-2007 at 05:51 PM.
03-14-2007, 05:48 PM
#57
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Originally Posted by sentry65
...we obviously disagree on many things then
I think the parasitic loss is what it is, and it increases at a somewhat exponential rate as you push the blower further and further. As long as you're under the area where the SC really starts to fall on its face the parasitic loss isn't a show stopper for making decent power. That's all I've ever thought.
kinda like how the stillen makes perfectly good power up until around 340whp then it just falls on its face after that trying to make more
The parasitic loss I do think will become really severe trying to cross the 500whp mark with a vortech, where adding another lb of boost does hardly anything at all other than raise under hood temps. Otherwise, that's partly why I run 96 octane fuel and water injection despite my power levels - because I know the engine is working harder than what the dyno is showing
btw, how do you take a certain volume of fuel and determine how much hp that fuel is capable of making? I'm sure there's something that'll explain it
I think the parasitic loss is what it is, and it increases at a somewhat exponential rate as you push the blower further and further. As long as you're under the area where the SC really starts to fall on its face the parasitic loss isn't a show stopper for making decent power. That's all I've ever thought.
kinda like how the stillen makes perfectly good power up until around 340whp then it just falls on its face after that trying to make more
The parasitic loss I do think will become really severe trying to cross the 500whp mark with a vortech, where adding another lb of boost does hardly anything at all other than raise under hood temps. Otherwise, that's partly why I run 96 octane fuel and water injection despite my power levels - because I know the engine is working harder than what the dyno is showing
btw, how do you take a certain volume of fuel and determine how much hp that fuel is capable of making? I'm sure there's something that'll explain it
-Mark
03-14-2007, 06:19 PM
#59
Regarding belt slippage for those of you who are using the vortech. Have you ever considered getting a larger cog gear for on the back side of the jackshaft? This would great a sort of step up since the cog gear on the back of the jackshaft and the cog on the back of the V2 would no longer have a 1:1 ratio. This would allow you to run a larger pulley on the front of the jackshaft which translates to more surface contact on the pulley.
Just a thought.
Just a thought.
03-14-2007, 06:23 PM
#60
Originally Posted by Quamen
Regarding belt slippage for those of you who are using the vortech. Have you ever considered getting a larger cog gear for on the back side of the jackshaft? This would great a sort of step up since the cog gear on the back of the jackshaft and the cog on the back of the V2 would no longer have a 1:1 ratio. This would allow you to run a larger pulley on the front of the jackshaft which translates to more surface contact on the pulley.
Just a thought.
Just a thought.