Would my car like a SC, or is it better for Turbo
Joined: Apr 2005
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From: South Florida!
Would my car like a SC, or is it better for Turbo
I have a 5AT G35 coupe and Hell bent on boost.
I like the vortech kit, but rattles scare me after having blown HFC and the injen SES exhaust, i dont want any rattles.
So i'm really looking at a turbonetics single turbo.
Now, If I did go with a Vortech and raise my idle (im pre 2004.5 so it would be easy) Do I have to open of an exhaust to get the best preformence?
Strup Headers, 2.5 Test Pipe APS, Stillen Catback
With that set up, should I just go with a TN kit and get a really conservative tune?
I like the vortech kit, but rattles scare me after having blown HFC and the injen SES exhaust, i dont want any rattles.
So i'm really looking at a turbonetics single turbo.
Now, If I did go with a Vortech and raise my idle (im pre 2004.5 so it would be easy) Do I have to open of an exhaust to get the best preformence?
Strup Headers, 2.5 Test Pipe APS, Stillen Catback
With that set up, should I just go with a TN kit and get a really conservative tune?
it all depends on how much money u want to blow.
Turbo will cost u more than SC but if u have the money why not go with turbo. Also turbo will most likely hurt your engine more in the long run vs sc but probably feel a lot more tq (pushing u into your seat) and pw.
The only reason why I went with sc was bc i'm in CA but FL has no smog restriction so more pw to u. If u raise your idle to 1000 there will is no rattle wat so ever. U might have to tighten the belt or pulley once in awhile but nothing too big. The more breathing mods u have the more pw but also u will see less boost bc theres not as much backpressure. I have almost every NA mod except cams and I cant tell if it really does help.
Turbo will cost u more than SC but if u have the money why not go with turbo. Also turbo will most likely hurt your engine more in the long run vs sc but probably feel a lot more tq (pushing u into your seat) and pw.
The only reason why I went with sc was bc i'm in CA but FL has no smog restriction so more pw to u. If u raise your idle to 1000 there will is no rattle wat so ever. U might have to tighten the belt or pulley once in awhile but nothing too big. The more breathing mods u have the more pw but also u will see less boost bc theres not as much backpressure. I have almost every NA mod except cams and I cant tell if it really does help.
Last edited by Mr_pharmD; Feb 25, 2007 at 01:43 PM.
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From: AZ
listen to this video and see if you hear any rattles with the vortech kit during the first 4-5 seconds:
Bear in mind the camera is RIGHT next to the blower so of course it's gonna sound pretty loud in comparison to everything else
all you gotta do is raise the idle to 900-1000 rpms like you said
upgrading the pulley to the 3.12 will help kill rattling noises too
TN single turbo is a decent kit as well. The TN and vortech are very different kits from each other with very different powerbands. I'd only recommend the vortech if you're going to push it and get a 3.12 or 2.87 pulley. Otherwise get the TN kit
Bear in mind the camera is RIGHT next to the blower so of course it's gonna sound pretty loud in comparison to everything else
all you gotta do is raise the idle to 900-1000 rpms like you said
upgrading the pulley to the 3.12 will help kill rattling noises too
TN single turbo is a decent kit as well. The TN and vortech are very different kits from each other with very different powerbands. I'd only recommend the vortech if you're going to push it and get a 3.12 or 2.87 pulley. Otherwise get the TN kit
Last edited by sentry65; Feb 25, 2007 at 02:44 PM.
Joined: Apr 2005
Posts: 3,705
Likes: 7
From: South Florida!
Well what your getting from your vortech is exactly what I'm looking to get for HP numbers... Something above 400HP.
I like the greddy kit, but I don't know if I have the will power to hold out... incase I do upgrade my engine internals and tranny at sometime... but if I just got a vortech with a shorter pullie i could just be done with it and not worry...
I like the greddy kit, but I don't know if I have the will power to hold out... incase I do upgrade my engine internals and tranny at sometime... but if I just got a vortech with a shorter pullie i could just be done with it and not worry...
i dunno from what ive seen and read.. turbo and stock internals in the same sentence is just scary. So i would say how much of a risk you're willing to take.. since FI and stock internals is automatically a risk anyways. Lately ive been reading more of ppl blowing their engines with the ST than with any other kit.. especially with the overboost issues.. but im sure sentry can give more insight on this since he visits the FI forum more than me
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From: AZ
well everyone has their theory why the ST's blow a lot of engines and some may disagree with me, but I think there's a few things at work that cause it to happen.
I think running high amounts of torque at low-ish rpms is really pretty bad on the engine.
Many ST guys get a boost controller and tune the boost to come on as early as possible. That's all great - I mean bragging that you have full boost at 3000 rpms seems pretty neat, but it's bad news on the stock block IMO. I know many people run that way just fine. In a drag race, you're at 3000 rpms for like not even a second, but daily driving where you want to stab the throttle to build up boost while at low rpms, that's when that might happen.
Think of it this way, if you're driving at 40mph and another car that's driving 80mph rear ends you, it'll dent your rear bumper more than if you were driving at 70mph. It does have something to do with the inertia of how fast the engine internals are already moving
You're asking the engine to do 8+psi, over 50% more air pressure than can naturally get into the engine, and the engine isn't spinning very fast to get it out. People who run nitrous try to not spray real early for two reasons - because of possible puddling, and also because it's dramatically harder pushing so much power through an engine that's not spinning very fast to pass the air out the exhaust. A lot of nitrous guys these days are starting to use progressive controllers not only because it's easier on the engine, but it's also easier to not lose traction when the nitrous kicks in
Having boost come on really early makes you more prone to overboost. Look at the really high whp cars like what GTM has been building lately. You could have a turbo kit doing 8 psi, and have the same kit doing 14 psi. Because the kit is the same, you know the kit has the potential to build boost early in the exact same way, but setting it to come on ASAP isn't always the best.
With the higher boost tunes, the better shops tune the boost controller to delay the boost so it comes on later in the powerband to prevent overboost from happening. Running higher boost means there's that much less time for the wastegate to react and open. If you set the boost controller to let boost come on ASAP with a 20 psi tune and you get some overboost, it's going to be a lot of extra boost - like 3 or 4 psi or maybe more. If you're not running a good engine management, or never set up parameters how to deal with extra boost, you're going to run lean on top of pushing higher psi than normal through the engine
Another thing is, the rpms with the greatest amount of torque is the rpm range that has the greatest cylinder pressure and is the most prone to possible detonation which can be fatal.
High rpms are stressful on the engine too, but in a more predictable mechanical way. If you have 350tq at 4500 rpms and 350 tq at 6600 rpms, the cylinder pressure isn't different between those two rpms, but that amount torque is happening more frequent at 6600 rpms than 4500 rpms and it builds up heat faster. So if you can just manage the heat at high rpms, IMO that's going to be safer than running 50-100 more tq in the midrange as far as impact stress on the rods/pistons.
Anyway, that was a major reason I chose the vortech, because despite its higher parasitic loss being a SC, it seems to naturally deliver boost as the engine IMO is able to deal with it as it spins faster. That and some of the other various reason that have been talked about to death.
If you look at the people who have damaged their engines with the vortech, it seems like it was mostly from high rpm use or running too lean creating more heat to the point that piston ringlands were chipped off. That's a lot different from the sheer breaking force of running a lot of torque and snapping rods like what turbos usually do. I haven't heard of many vortech cars actually breaking rods - I'm sure they're out there, and would REALLY like to know who they are and talk with them, but no one ever seems to be able to come up with any names...and I've been around on the forums awhile now (mainly my350z.com)
Out on the street, people usually are more likely to floor the gas at mid rpms than take it all the way up to redline. So even though the vortech is pushing out lots of power at redline, because you're most likely to only redline it once or twice in a row out on the street, you're not doing it as often like you might floor it at mid rpms - in which case the turbo will give you more kick, and more engine stress
The vortech absolutely will never overboost because it doesn't generate excess boost that goes out a wastegate. What it makes, is what you get.
As far as parasitic losses, I've done calculations from two different sources, one from Sport Compact Car's article on how to calculate parasitic losses, and another from Corky Bell's Supercharged book. On my 450+whp vortech car, according to those sources, the parasitic hp loss is around 15 crank hp at 4000 rpms and just under 40 crank hp at redline. Most vortech setups aren't as high as mine so a 400whp setup would probably be more like 12 hp at 4000 rpms and 30 hp at redline
Turbos also deliver so much power so quick all at once that the shock of it can also be harmful to the rods vs the boost coming on in a more gradual way. Then there's the heat issue where turbos run dramatically higher temps under the hood than a supercharger would ever dream of
The TT kits tend to start boost earlier in the powerband than ST kits, but when the TT's kick in, they don't kick in quite as hard as the ST. The ST actually come in with more torque a lot of times than the same whp TT setup. It has to do with compressor efficiencies etc.
That said, I still think turbos are fine on the stock block as long as you're not shooting for over 400tq and plan to abuse the engine by running it beyond redline a lot, or pushing lots of boost at too low of an rpm. Run a good engine management, get a good tune, use quality high octane gas, some basic cooling mods never hurt, and don't go nuts with a boost controller trying to get the turbos to spool earlier than they normally would with a spring
...but like I said, there's many who disagree with me and some people have run turbos on their stock engine car for over 50k miles
I think running high amounts of torque at low-ish rpms is really pretty bad on the engine.
Many ST guys get a boost controller and tune the boost to come on as early as possible. That's all great - I mean bragging that you have full boost at 3000 rpms seems pretty neat, but it's bad news on the stock block IMO. I know many people run that way just fine. In a drag race, you're at 3000 rpms for like not even a second, but daily driving where you want to stab the throttle to build up boost while at low rpms, that's when that might happen.
Think of it this way, if you're driving at 40mph and another car that's driving 80mph rear ends you, it'll dent your rear bumper more than if you were driving at 70mph. It does have something to do with the inertia of how fast the engine internals are already moving
You're asking the engine to do 8+psi, over 50% more air pressure than can naturally get into the engine, and the engine isn't spinning very fast to get it out. People who run nitrous try to not spray real early for two reasons - because of possible puddling, and also because it's dramatically harder pushing so much power through an engine that's not spinning very fast to pass the air out the exhaust. A lot of nitrous guys these days are starting to use progressive controllers not only because it's easier on the engine, but it's also easier to not lose traction when the nitrous kicks in
Having boost come on really early makes you more prone to overboost. Look at the really high whp cars like what GTM has been building lately. You could have a turbo kit doing 8 psi, and have the same kit doing 14 psi. Because the kit is the same, you know the kit has the potential to build boost early in the exact same way, but setting it to come on ASAP isn't always the best.
With the higher boost tunes, the better shops tune the boost controller to delay the boost so it comes on later in the powerband to prevent overboost from happening. Running higher boost means there's that much less time for the wastegate to react and open. If you set the boost controller to let boost come on ASAP with a 20 psi tune and you get some overboost, it's going to be a lot of extra boost - like 3 or 4 psi or maybe more. If you're not running a good engine management, or never set up parameters how to deal with extra boost, you're going to run lean on top of pushing higher psi than normal through the engine
Another thing is, the rpms with the greatest amount of torque is the rpm range that has the greatest cylinder pressure and is the most prone to possible detonation which can be fatal.
High rpms are stressful on the engine too, but in a more predictable mechanical way. If you have 350tq at 4500 rpms and 350 tq at 6600 rpms, the cylinder pressure isn't different between those two rpms, but that amount torque is happening more frequent at 6600 rpms than 4500 rpms and it builds up heat faster. So if you can just manage the heat at high rpms, IMO that's going to be safer than running 50-100 more tq in the midrange as far as impact stress on the rods/pistons.
Anyway, that was a major reason I chose the vortech, because despite its higher parasitic loss being a SC, it seems to naturally deliver boost as the engine IMO is able to deal with it as it spins faster. That and some of the other various reason that have been talked about to death.
If you look at the people who have damaged their engines with the vortech, it seems like it was mostly from high rpm use or running too lean creating more heat to the point that piston ringlands were chipped off. That's a lot different from the sheer breaking force of running a lot of torque and snapping rods like what turbos usually do. I haven't heard of many vortech cars actually breaking rods - I'm sure they're out there, and would REALLY like to know who they are and talk with them, but no one ever seems to be able to come up with any names...and I've been around on the forums awhile now (mainly my350z.com)
Out on the street, people usually are more likely to floor the gas at mid rpms than take it all the way up to redline. So even though the vortech is pushing out lots of power at redline, because you're most likely to only redline it once or twice in a row out on the street, you're not doing it as often like you might floor it at mid rpms - in which case the turbo will give you more kick, and more engine stress
The vortech absolutely will never overboost because it doesn't generate excess boost that goes out a wastegate. What it makes, is what you get.
As far as parasitic losses, I've done calculations from two different sources, one from Sport Compact Car's article on how to calculate parasitic losses, and another from Corky Bell's Supercharged book. On my 450+whp vortech car, according to those sources, the parasitic hp loss is around 15 crank hp at 4000 rpms and just under 40 crank hp at redline. Most vortech setups aren't as high as mine so a 400whp setup would probably be more like 12 hp at 4000 rpms and 30 hp at redline
Turbos also deliver so much power so quick all at once that the shock of it can also be harmful to the rods vs the boost coming on in a more gradual way. Then there's the heat issue where turbos run dramatically higher temps under the hood than a supercharger would ever dream of
The TT kits tend to start boost earlier in the powerband than ST kits, but when the TT's kick in, they don't kick in quite as hard as the ST. The ST actually come in with more torque a lot of times than the same whp TT setup. It has to do with compressor efficiencies etc.
That said, I still think turbos are fine on the stock block as long as you're not shooting for over 400tq and plan to abuse the engine by running it beyond redline a lot, or pushing lots of boost at too low of an rpm. Run a good engine management, get a good tune, use quality high octane gas, some basic cooling mods never hurt, and don't go nuts with a boost controller trying to get the turbos to spool earlier than they normally would with a spring
...but like I said, there's many who disagree with me and some people have run turbos on their stock engine car for over 50k miles
Last edited by sentry65; Mar 2, 2007 at 01:46 PM.
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From: AZ
Yeah see if you can check one out in person if possible. It isn't for everyone. Some people have bought a vortech, and 3 weeks later sold it for a TT kit because they were so unhappy with the stock out of the box power. IMO the stock vortech kit with the stock tune sucks. I mean, it's obviously pretty safe, but if you want FI, you want to feel some sort of oomph out of the the engine, so I'm always telling people to get the 3.12 pulley and a custom tune.
I've debated with hardcore turbo guys left and right and think turbos are a great way for FI, but on a stock engine I'm a little more concerned about running such high boost so early in the powerband. IMO if you're going to build the block up anyway, sure get a turbo kit and go nuts with the early torque/boost because the engine can handle it just fine. But still, the vortech's track record on the stock block in comparison to the stock block with turbos speaks for itself, but there's always exceptions
The biggest oxymoron I came across was when I started a thread on my350z.com about 50-70mph times in top gear tests. Magazines use that as one of their tests all the time. How useful of a benchmark it is, is questionable because who really ever does 50-70mph in 6th gear?
But anyway, I used the car's stopwatch and posted my time back then (don't remember it, and was making less power back then) I was curious what time the turbo guys would run since they have more boost at low rpms, but they usually have either the 3.3 or 3.5 final drive (I have 3.9 on my vortech). No one tried it except alberto with his TN setup (who's time was slower than me and he's even at a lower elevation) because everyone was concerned about putting too much stress on the engine
I was thinking WTF? So now here's a test to show off their low rpm boost that should dominate over my vortech kit's small boost and they don't want to do it because now they're worried about low rpm/high boost engine stress?
One of the reason's people want turbos is they want to get high amounts of boost early on in the powerband, but then they dismiss that test saying it's worthless because you should obviously downshift to be higher in the powerband and any sort of low rpm test like that is stupid since it doesn't reflect real world accelleration ---->which was a point I've been stressing all along with the vortech where you're never going to race low in the powerband. So why do turbo guys brag so much about having boost come on so early?
BTW, my car did better (or close, it wasn't exactly scientific) than Alberto's car for that test probably because of my 3.9 final drive. I was making around 1.4-2 or so psi between 2000-2800 rpms. Alberto was probalby making 0-4 or 5 psi between 1750-2400 rpms
I've debated with hardcore turbo guys left and right and think turbos are a great way for FI, but on a stock engine I'm a little more concerned about running such high boost so early in the powerband. IMO if you're going to build the block up anyway, sure get a turbo kit and go nuts with the early torque/boost because the engine can handle it just fine. But still, the vortech's track record on the stock block in comparison to the stock block with turbos speaks for itself, but there's always exceptions
The biggest oxymoron I came across was when I started a thread on my350z.com about 50-70mph times in top gear tests. Magazines use that as one of their tests all the time. How useful of a benchmark it is, is questionable because who really ever does 50-70mph in 6th gear?
But anyway, I used the car's stopwatch and posted my time back then (don't remember it, and was making less power back then) I was curious what time the turbo guys would run since they have more boost at low rpms, but they usually have either the 3.3 or 3.5 final drive (I have 3.9 on my vortech). No one tried it except alberto with his TN setup (who's time was slower than me and he's even at a lower elevation) because everyone was concerned about putting too much stress on the engine
I was thinking WTF? So now here's a test to show off their low rpm boost that should dominate over my vortech kit's small boost and they don't want to do it because now they're worried about low rpm/high boost engine stress? One of the reason's people want turbos is they want to get high amounts of boost early on in the powerband, but then they dismiss that test saying it's worthless because you should obviously downshift to be higher in the powerband and any sort of low rpm test like that is stupid since it doesn't reflect real world accelleration ---->which was a point I've been stressing all along with the vortech where you're never going to race low in the powerband. So why do turbo guys brag so much about having boost come on so early?
BTW, my car did better (or close, it wasn't exactly scientific) than Alberto's car for that test probably because of my 3.9 final drive. I was making around 1.4-2 or so psi between 2000-2800 rpms. Alberto was probalby making 0-4 or 5 psi between 1750-2400 rpms
Last edited by sentry65; Mar 5, 2007 at 03:05 PM.
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