Boost limits of the SC
06-20-2005, 12:10 AM
#1
The Stig
Thread Starter
Boost limits of the SC
I'm pretty new to forced induction cars. I found this site:
http://www.gadgetonline.com/super.htm
I read about the boost limits of SC's, especially the "modified roots" type.
It says on the site that a modified roots type has a limit of about 13psi, where the pressure in the manifold would exceed the pressure in the SC housing causing a backflow.
I know that the SS has an Eaton roots type SC, but does anyone know if this could be a problem for potential upgrades?
http://www.gadgetonline.com/super.htm
I read about the boost limits of SC's, especially the "modified roots" type.
It says on the site that a modified roots type has a limit of about 13psi, where the pressure in the manifold would exceed the pressure in the SC housing causing a backflow.
I know that the SS has an Eaton roots type SC, but does anyone know if this could be a problem for potential upgrades?
10-08-2005, 10:46 AM
#11
New Member
Join Date: 10-07-05
Location: Winnipeg
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
Okay the supercharger is limited by RPM, not boost level.....we are running 15 psi and over 300 whp on a M-62 on the Tiburons........If you guys are hitting 10 psi with only 220 whp you need to open your engine up....headers, bigger exhaust, re-profiled cams and head porting....there is no reason you cannot tune over 300 whp out of the M-62, NextGeneration Motorsports has had 3 years of tuning with a Auquacooled M-62 and has acheived 340 whp with more to come................the limiting factor of this supercharger is what RPM it loses efficiency, I know for a fact it can pump enough air mass to support over 300 whp...........if your PSI is going up too high for low HP numbers your motor is plugged up and needs to be opened up
10-08-2005, 04:19 PM
#12
The Stig
Thread Starter
Originally Posted by Maximus
Okay the supercharger is limited by RPM, not boost level.....we are running 15 psi and over 300 whp on a M-62 on the Tiburons........If you guys are hitting 10 psi with only 220 whp you need to open your engine up....headers, bigger exhaust, re-profiled cams and head porting....there is no reason you cannot tune over 300 whp out of the M-62, NextGeneration Motorsports has had 3 years of tuning with a Auquacooled M-62 and has acheived 340 whp with more to come................the limiting factor of this supercharger is what RPM it loses efficiency, I know for a fact it can pump enough air mass to support over 300 whp...........if your PSI is going up too high for low HP numbers your motor is plugged up and needs to be opened up
10-08-2005, 06:33 PM
#13
New Member
Join Date: 10-07-05
Location: Winnipeg
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
well on the Tib V-6 we do see a loss of boost from any mod like that, but even though the boost number is lower the HP goes up.......The supercharged Tiburons have really responded well to head porting/bigger valves and cam shafts.....If you weren't aware we run re-grinds on the facory cam, it is done by Crower for a very good price.........On anaturally aspirated V-6 we gain 28 whp alone from cam re-grinds and alot more on a boosted car.....The Tiburon V-6 has very good flowing heads, comparable to a Honda B-18 CFM wise......Yet we still see pretty substantial gains from head porting on Supercharged cars....
A good setup for the Cobalt would be
Aggresively ported heads
bigger valves
re-grind factory cams( $300.00 from Crower approx)
Long tube headers
2 3/4 " single exhaust
a Pulley to spin the SC to the RPM we Tibs run
and ECU tuned to run these parts without CELs
I am not too familiar with the Cobalt and its ECU system and limitations, as well I dont know your fuel sytem either, but these items have worked extremely well on the Tiburon with the same supercharger.........we have M-62 supercharged Tibs running low 12's with a 50 shot of juice with a 117 mph trap....you have a smaller engine but it has a pretty good airpump sitting on top......The key seems to be finding HP in all the details, but head porting and cams are absolutely huge on a supercharged car.....60-70 whp once your at higher boost
A good setup for the Cobalt would be
Aggresively ported heads
bigger valves
re-grind factory cams( $300.00 from Crower approx)
Long tube headers
2 3/4 " single exhaust
a Pulley to spin the SC to the RPM we Tibs run
and ECU tuned to run these parts without CELs
I am not too familiar with the Cobalt and its ECU system and limitations, as well I dont know your fuel sytem either, but these items have worked extremely well on the Tiburon with the same supercharger.........we have M-62 supercharged Tibs running low 12's with a 50 shot of juice with a 117 mph trap....you have a smaller engine but it has a pretty good airpump sitting on top......The key seems to be finding HP in all the details, but head porting and cams are absolutely huge on a supercharged car.....60-70 whp once your at higher boost
10-08-2005, 06:38 PM
#14
The Stig
Thread Starter
Originally Posted by Maximus
well on the Tib V-6 we do see a loss of boost from any mod like that, but even though the boost number is lower the HP goes up.......The supercharged Tiburons have really responded well to head porting/bigger valves and cam shafts.....If you weren't aware we run re-grinds on the facory cam, it is done by Crower for a very good price.........On anaturally aspirated V-6 we gain 28 whp alone from cam re-grinds and alot more on a boosted car.....The Tiburon V-6 has very good flowing heads, comparable to a Honda B-18 CFM wise......Yet we still see pretty substantial gains from head porting on Supercharged cars....
A good setup for the Cobalt would be
Aggresively ported heads
bigger valves
re-grind factory cams( $300.00 from Crower approx)
Long tube headers
2 3/4 " single exhaust
a Pulley to spin the SC to the RPM we Tibs run
and ECU tuned to run these parts without CELs
I am not too familiar with the Cobalt and its ECU system and limitations, as well I dont know your fuel sytem either, but these items have worked extremely well on the Tiburon with the same supercharger.........we have M-62 supercharged Tibs running low 12's with a 50 shot of juice with a 117 mph trap....you have a smaller engine but it has a pretty good airpump sitting on top......The key seems to be finding HP in all the details, but head porting and cams are absolutely huge on a supercharged car.....60-70 whp once your at higher boost
A good setup for the Cobalt would be
Aggresively ported heads
bigger valves
re-grind factory cams( $300.00 from Crower approx)
Long tube headers
2 3/4 " single exhaust
a Pulley to spin the SC to the RPM we Tibs run
and ECU tuned to run these parts without CELs
I am not too familiar with the Cobalt and its ECU system and limitations, as well I dont know your fuel sytem either, but these items have worked extremely well on the Tiburon with the same supercharger.........we have M-62 supercharged Tibs running low 12's with a 50 shot of juice with a 117 mph trap....you have a smaller engine but it has a pretty good airpump sitting on top......The key seems to be finding HP in all the details, but head porting and cams are absolutely huge on a supercharged car.....60-70 whp once your at higher boost
10-08-2005, 07:16 PM
#15
Senior Member
Join Date: 06-04-05
Location: LongIsland
Posts: 2,040
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Maximus
Okay the supercharger is limited by RPM, not boost level.....we are running 15 psi and over 300 whp on a M-62 on the Tiburons........If you guys are hitting 10 psi with only 220 whp you need to open your engine up....headers, bigger exhaust, re-profiled cams and head porting....there is no reason you cannot tune over 300 whp out of the M-62, NextGeneration Motorsports has had 3 years of tuning with a Auquacooled M-62 and has acheived 340 whp with more to come................the limiting factor of this supercharger is what RPM it loses efficiency, I know for a fact it can pump enough air mass to support over 300 whp...........if your PSI is going up too high for low HP numbers your motor is plugged up and needs to be opened up
I know your trying to be helpfull and all but you got to remember first the tiburons have one a v6 motor, and 2 you have .8 displacment on us so there shouldn't be any wonder why tiburons can hit those numbers on 15 psi from a m-62 intercooled supercharger. And im sure any stock tiburon with 15 psi thrown at it will not hit 300 whp with out a bunch of supporting mods like the ones mentioned in your post. Also I want to see how hard it is for the cobalt to get to 275 hp with out dipping into the motor than will see if 300 is possible cause from reading about the motor itself the top and bottom end really don't have to be touched to hit those numbers on the stock m-62 just a whole lot of tunning and small thing here and there. Any way i think us cobalt owners have to firgure out how to get the stock power to the ground better first before we start worryingtrying to get 300 wheel horse.
10-08-2005, 07:37 PM
#16
Member
Join Date: 09-22-05
Location: S.C.
Posts: 258
Likes: 0
Received 0 Likes
on
0 Posts
Darksun280
I know your trying to be helpfull and all but you got to remember first the tiburons have one a v6 motor, and 2 you have .8 displacment on us so there shouldn't be any wonder why tiburons can hit those numbers on 15 psi from a m-62 intercooled supercharger. And im sure any stock tiburon with 15 psi thrown at it will not hit 300 whp with out a bunch of supporting mods like the ones mentioned in your post. Also I want to see how hard it is for the cobalt to get to 275 hp with out dipping into the motor than will see if 300 is possible cause from reading about the motor itself the top and bottom end really don't have to be touched to hit those numbers on the stock m-62 just a whole lot of tunning and small thing here and there. Any way i think use cobalt owns have to firgure out how to get the stock power to the ground better first before we start worryingtrying to get 300 wheel horse.
I hear ya man.
MOD MONEY- red ss sc lsd recaros
axis mods 18"
IPP carbon fiber hood
psi fi kit
on the way-exhuast,headers,intake
I know your trying to be helpfull and all but you got to remember first the tiburons have one a v6 motor, and 2 you have .8 displacment on us so there shouldn't be any wonder why tiburons can hit those numbers on 15 psi from a m-62 intercooled supercharger. And im sure any stock tiburon with 15 psi thrown at it will not hit 300 whp with out a bunch of supporting mods like the ones mentioned in your post. Also I want to see how hard it is for the cobalt to get to 275 hp with out dipping into the motor than will see if 300 is possible cause from reading about the motor itself the top and bottom end really don't have to be touched to hit those numbers on the stock m-62 just a whole lot of tunning and small thing here and there. Any way i think use cobalt owns have to firgure out how to get the stock power to the ground better first before we start worryingtrying to get 300 wheel horse.
I hear ya man.
MOD MONEY- red ss sc lsd recaros
axis mods 18"
IPP carbon fiber hood
psi fi kit
on the way-exhuast,headers,intake
10-08-2005, 08:25 PM
#17
New Member
Join Date: 10-07-05
Location: Winnipeg
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
okay you may be looking at what I am saying wrong......you do not throw 15 psi at a motor, your supercharger will throw a certain volume of air depending on RPM, the volume of air to make a Tiburon make 5 psi is likely going to make 12 psi on the Cobalt as the Tiburon will be able to eat more air, I realise this..........what iam trying tell you guys is this supercharger has no problem pumping enough airflow to go well over 300 whp, now the volume of air to make 300 whp is going to be nearly identical on any engine 4 or 6 cylender.....lets say the volume is1200 CFM(any number will do) to produce 300 whp......now if you theow 1200 CFM at a Stock Cobalt your going to see the boost levels rise likely to 22 psi, but if you port the heads, add bigger valves and do the mods I described you would see your Ecotec handle the 1200 CFM and boost likely hover around 15 PSI.
Now a roots blower will start losing efficiency at around 15 PSI, the higher the boost levels reach the harder the blower becomes to turn and the less efficient the setup becomes.........which is why bolting on a 20 psi pulley on a stock motor wont do anything but create drag and lose power.....but if you open the car up you can retain that 20 psi pulley but your actual boost will be down to 15 psi and your whole system will work 100x better.
the principles of 4 stroke engines and tuning are universal, all or motor will respond to the same basic mods the same way..........There is alot of experience with the M-62 coming from the Tiburon camp and what applies to our cars will apply to the Cobalt
HP is determined by air volume, PSI is your motor reactions to this airflow, the higher the volume of air you can pump at the lowest possible PSI is ideally the goal of tuning this supercharger.....as if to pump 1200 CFM the blower has to fight 25 PSI of pressure your sytem is going to experience tons of parasitic loss, the 1200 CFM will produce 300 whp whehter its at 12 psi or at 25 PSI as its still the same volume of air, except the car at 25 psi is going to lose another 20 HP trying to force the blower to overcome 25 PSI
turn a supercharger in the free air unattached to your motor, it will turn like nothing with little to no resistance, but that same supercharger attached to your motor at 15 psi is going to take much more NRG to turn..
which is why I am saying you likely have alot of room left on the stock supercharger, its your motors ability to pump air thats the problem, which can be easily solved with some minor engine work....
Now a roots blower will start losing efficiency at around 15 PSI, the higher the boost levels reach the harder the blower becomes to turn and the less efficient the setup becomes.........which is why bolting on a 20 psi pulley on a stock motor wont do anything but create drag and lose power.....but if you open the car up you can retain that 20 psi pulley but your actual boost will be down to 15 psi and your whole system will work 100x better.
the principles of 4 stroke engines and tuning are universal, all or motor will respond to the same basic mods the same way..........There is alot of experience with the M-62 coming from the Tiburon camp and what applies to our cars will apply to the Cobalt
HP is determined by air volume, PSI is your motor reactions to this airflow, the higher the volume of air you can pump at the lowest possible PSI is ideally the goal of tuning this supercharger.....as if to pump 1200 CFM the blower has to fight 25 PSI of pressure your sytem is going to experience tons of parasitic loss, the 1200 CFM will produce 300 whp whehter its at 12 psi or at 25 PSI as its still the same volume of air, except the car at 25 psi is going to lose another 20 HP trying to force the blower to overcome 25 PSI
turn a supercharger in the free air unattached to your motor, it will turn like nothing with little to no resistance, but that same supercharger attached to your motor at 15 psi is going to take much more NRG to turn..
which is why I am saying you likely have alot of room left on the stock supercharger, its your motors ability to pump air thats the problem, which can be easily solved with some minor engine work....
10-08-2005, 08:32 PM
#18
New Member
Join Date: 10-07-05
Location: Winnipeg
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
actualy a bone stock Tib with 5 PSI turbo hits 300 whp, with a Vortech the Tib hits 330 whp at 10 psi, with a Eaton we hit 300 whp at 12 psi.......all this on completely stock engines except supporting fuel mods.........the Tib responds well to boost...........but the volume of air passing thru the the Tib to produce 300 whp is going to be nearly identical to the volume of air required to produce 300 whp on a Cobalt......it how our engines respond to that volume of air, a fre flowing engine like the Tib will take that volume fairly easily without raising boost levels too high...........the Coblat stock will respond with very high boost levels..........which is why cams and heads are so important.................A supercharged engine loves big ports and big cams without huge overlap.....the HP is in airflow trust me
10-09-2005, 02:29 AM
#19
Senior Member
Join Date: 06-04-05
Location: LongIsland
Posts: 2,040
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Maximus
actualy a bone stock Tib with 5 PSI turbo hits 300 whp, with a Vortech the Tib hits 330 whp at 10 psi, with a Eaton we hit 300 whp at 12 psi.......all this on completely stock engines except supporting fuel mods.........the Tib responds well to boost...........but the volume of air passing thru the the Tib to produce 300 whp is going to be nearly identical to the volume of air required to produce 300 whp on a Cobalt......it how our engines respond to that volume of air, a fre flowing engine like the Tib will take that volume fairly easily without raising boost levels too high...........the Coblat stock will respond with very high boost levels..........which is why cams and heads are so important.................A supercharged engine loves big ports and big cams without huge overlap.....the HP is in airflow trust me
10-09-2005, 04:04 AM
#20
New Member
Join Date: 10-07-05
Location: Winnipeg
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
I must apologize some of my figures from the Tib are likely off a little on boost per HP on the turbo setup.............we hit 300 whp with 10 psi Vortech supercharger with headers....the Turbo is better, i think it is actualy 6-7 psi on the turbo....
but before you guys could do some of the mods I suggest, you would have to have the ECU tuned or a piggyback system.....
as I was saying before the Tib has very good flowing heads, yet with porting the supercharged cars gained a whole bunch of power, and i know the Ecotec head will not flow like ours, so I will guarantee head porting will yield big dividends when your running faster blower speeds....head porting may be worth 50 hp......regrind camshafts will also yield big numbers.... I gained 78 whp over stock from NA mods, i cannot see why a supercharged car can't do better...........
The Tiburon comunity is very lucky to have a dedicated skilled tuner, Tim Coni who owns NextGeneration Motorsports.....he has done things with a M-62 others thought would never be possible, and has produced some very high powered SC'd Tiburons, I think his best is 340 whp off a M-62 with the stock intercooler, but now he has developed a new intercooler core section which is improved dramatically over stock......but tests on lower HP cars has produced 30 whp from this new intercooler core, not tested on the higher HP cars yet.....this unit uses a huge resevior which is built to hold ice............also he uses Meth injection at higher boosts to reduce detonation...........Anyways he would be an amazing guy to get working on the Cobalt, He specialises in roots supercharger applications and produces some of the best aftermarket parts available for any car, he is pricey but his quality is absolutely the best.....contact him......He also has extensive experience with Ford SVT products and also is very hooked up with custom electronics..............If anyone can tweak the Cobalt this guy can, he has alot of experience working with roots superchargers.....
but before you guys could do some of the mods I suggest, you would have to have the ECU tuned or a piggyback system.....
as I was saying before the Tib has very good flowing heads, yet with porting the supercharged cars gained a whole bunch of power, and i know the Ecotec head will not flow like ours, so I will guarantee head porting will yield big dividends when your running faster blower speeds....head porting may be worth 50 hp......regrind camshafts will also yield big numbers.... I gained 78 whp over stock from NA mods, i cannot see why a supercharged car can't do better...........
The Tiburon comunity is very lucky to have a dedicated skilled tuner, Tim Coni who owns NextGeneration Motorsports.....he has done things with a M-62 others thought would never be possible, and has produced some very high powered SC'd Tiburons, I think his best is 340 whp off a M-62 with the stock intercooler, but now he has developed a new intercooler core section which is improved dramatically over stock......but tests on lower HP cars has produced 30 whp from this new intercooler core, not tested on the higher HP cars yet.....this unit uses a huge resevior which is built to hold ice............also he uses Meth injection at higher boosts to reduce detonation...........Anyways he would be an amazing guy to get working on the Cobalt, He specialises in roots supercharger applications and produces some of the best aftermarket parts available for any car, he is pricey but his quality is absolutely the best.....contact him......He also has extensive experience with Ford SVT products and also is very hooked up with custom electronics..............If anyone can tweak the Cobalt this guy can, he has alot of experience working with roots superchargers.....
10-09-2005, 04:49 AM
#21
New Member
Join Date: 12-18-04
Location: Reseda, CA
Posts: 50
Likes: 0
Received 0 Likes
on
0 Posts
I look at it this way -
If the Ecotec is so high and mighty then if a poor Zetec Focus at 2.0L with a smaller M45 Eaton supercharger running about 14psi can make over 200hp with just bolt-ons, no cams, no headwork, then I can see the SS doing alot more with more boost.
300hp is possible with the M62 supercharger and the SS being intercooled from the factory is half the battle won.
You'll most likely need -
Ported Supercharger Housing
Larger Crank Pulley with smaller blower pulley to increase boost to around 14-16psi
Re-Programed ECU or Piggy-back ECU
Corsa or Borla Exhaust
Some sort of Long Tube Header and relocated cat converter
To make it a bit easier you might want to use an GM Racing mildly CNC ported "Street" head and GM Racing cam blanks ground for a supercharged engine.
Like Max said - Supercharged cars react well to mods
And as far as putting the power down, stop going to the strip with plain-ole' street tires!
Add an LSD and read Russ O'Blenes story on how to get traction with a FWD car.
I have a set of drag radials because I'm interested in what my car can do in normal street mode. I have OUTgrown the need to compete in the Stoplight Grand Prix. For those bored souls in other parts of the country in small townships with nothing else to do but run WOT up and down lonely country roads, I don't know what to tell you. All I can tell you is that regular street tires are meaningless at the strip.
http://www.overboost.com/story_intro.asp?id=1319
http://www.overboost.com/story_intro.asp?id=1337
http://www.overboost.com/story_intro.asp?id=1340
If the Ecotec is so high and mighty then if a poor Zetec Focus at 2.0L with a smaller M45 Eaton supercharger running about 14psi can make over 200hp with just bolt-ons, no cams, no headwork, then I can see the SS doing alot more with more boost.
300hp is possible with the M62 supercharger and the SS being intercooled from the factory is half the battle won.
You'll most likely need -
Ported Supercharger Housing
Larger Crank Pulley with smaller blower pulley to increase boost to around 14-16psi
Re-Programed ECU or Piggy-back ECU
Corsa or Borla Exhaust
Some sort of Long Tube Header and relocated cat converter
To make it a bit easier you might want to use an GM Racing mildly CNC ported "Street" head and GM Racing cam blanks ground for a supercharged engine.
Like Max said - Supercharged cars react well to mods
And as far as putting the power down, stop going to the strip with plain-ole' street tires!
Add an LSD and read Russ O'Blenes story on how to get traction with a FWD car.
I have a set of drag radials because I'm interested in what my car can do in normal street mode. I have OUTgrown the need to compete in the Stoplight Grand Prix. For those bored souls in other parts of the country in small townships with nothing else to do but run WOT up and down lonely country roads, I don't know what to tell you. All I can tell you is that regular street tires are meaningless at the strip.
http://www.overboost.com/story_intro.asp?id=1319
http://www.overboost.com/story_intro.asp?id=1337
http://www.overboost.com/story_intro.asp?id=1340
"Finding traction is not a black art like some people think it is," says Russ O'Blenes, a chassis engineer who works for GM Racing and just happens to be one of the brains behind the suspension used by Lisa Kubo and Nelson Hoyos. "
Thread
Thread Starter
Forum
Replies
Last Post
z28addiction
Wanted - What to buy - All categories
0
09-28-2015 12:03 AM