Vortech or Stillen...Help me...
Registered User
Joined: May 2003
Posts: 1
Likes: 0
From: Seattle, WA
With ANY forced induction application, the less exhaust restriction you have the more power the engine will produce. You want the largest primaries available. Whoever said headers and hi-flow cats will reduce power doesn't have any clue to what they are talking about, especially with FI!!!
Thread Starter
Registered User
Joined: Jun 2004
Posts: 36
Likes: 0
From: Los angeles
I was told by 3 different people at Stillen that you should have a somewhat restrictive exhaust system on the vehicle for the supercharger to build up boost, otherwise the vehicle just spits it all out and loses it.
They recommended a exhaust system and that was it. No headers or cats or test pipes. with their Stage 4 kit coming kit, they said it will work with their headers as well.
They recommended a exhaust system and that was it. No headers or cats or test pipes. with their Stage 4 kit coming kit, they said it will work with their headers as well.
Originally posted by Dan Ferraro
With ANY forced induction application, the less exhaust restriction you have the more power the engine will produce. You want the largest primaries available. Whoever said headers and hi-flow cats will reduce power doesn't have any clue to what they are talking about, especially with FI!!!
With ANY forced induction application, the less exhaust restriction you have the more power the engine will produce. You want the largest primaries available. Whoever said headers and hi-flow cats will reduce power doesn't have any clue to what they are talking about, especially with FI!!!
Registered User
Joined: Feb 2004
Posts: 1,041
Likes: 0
From: columbia md.
[QUOTE]Originally posted by 2003z
I'm sorry, but you are wrong. I gained 20hp by replacing my test pipes with stock cats, and my fuel flow richened. Its due to their system not sensing full boost with a less restrictive system, and thusly not properly enriching the fuel. [/QUOS
Something not quite right here. To attempt to achieve the designed Volumetric Efficiency of an I.C Engine you must fill the cylinders to their max capacity (A/F mixture assuming timing and injector pulse etc. are correct for the loading conditions.)Any restriction to exhaust flow which prevents this filling will prevent the Engine from achieving its V.E for the conditions of the engine loading.
Also during the intake stroke the exhaust valve is closed allowing the boost pressure to build up. Why would the system not sense full boost. Bad valves? Comments would be appreciated. Thanks
I'm sorry, but you are wrong. I gained 20hp by replacing my test pipes with stock cats, and my fuel flow richened. Its due to their system not sensing full boost with a less restrictive system, and thusly not properly enriching the fuel. [/QUOS
Something not quite right here. To attempt to achieve the designed Volumetric Efficiency of an I.C Engine you must fill the cylinders to their max capacity (A/F mixture assuming timing and injector pulse etc. are correct for the loading conditions.)Any restriction to exhaust flow which prevents this filling will prevent the Engine from achieving its V.E for the conditions of the engine loading.
Also during the intake stroke the exhaust valve is closed allowing the boost pressure to build up. Why would the system not sense full boost. Bad valves? Comments would be appreciated. Thanks
Registered User
Joined: May 2004
Posts: 100
Likes: 0
From: Mesa, Az
Exhaust Restriction
More exhaust restriction is never a good thing for FI or NA but FI has two related issues that can affect the potential benefit.
One was already alluded to and that being that the A/F must always be correct.
The second is valve overlap. At the top of the exhaust stroke the exhaust valve has not yet fully closed and the intake valve is opening. This is done so that at high speed the gas transfer speed is improved due to its inertia. On FI it is sometimes beneficial to reduce the overlap since with a pressurized mixture more may escape. If overlap isn't reduced the less exhaust restriction and/or higher boost will increase lost through the exhaust valve.
http://www.AzBikeTech.com
One was already alluded to and that being that the A/F must always be correct.
The second is valve overlap. At the top of the exhaust stroke the exhaust valve has not yet fully closed and the intake valve is opening. This is done so that at high speed the gas transfer speed is improved due to its inertia. On FI it is sometimes beneficial to reduce the overlap since with a pressurized mixture more may escape. If overlap isn't reduced the less exhaust restriction and/or higher boost will increase lost through the exhaust valve.
http://www.AzBikeTech.com
Registered User
Joined: Aug 2003
Posts: 96
Likes: 0
From: ca
Re: Exhaust Restriction
Originally posted by Gary Evans
More exhaust restriction is never a good thing for FI or NA but FI has two related issues that can affect the potential benefit.
One was already alluded to and that being that the A/F must always be correct.
The second is valve overlap. At the top of the exhaust stroke the exhaust valve has not yet fully closed and the intake valve is opening. This is done so that at high speed the gas transfer speed is improved due to its inertia. On FI it is sometimes beneficial to reduce the overlap since with a pressurized mixture more may escape. If overlap isn't reduced the less exhaust restriction and/or higher boost will increase lost through the exhaust valve.
http://www.AzBikeTech.com
More exhaust restriction is never a good thing for FI or NA but FI has two related issues that can affect the potential benefit.
One was already alluded to and that being that the A/F must always be correct.
The second is valve overlap. At the top of the exhaust stroke the exhaust valve has not yet fully closed and the intake valve is opening. This is done so that at high speed the gas transfer speed is improved due to its inertia. On FI it is sometimes beneficial to reduce the overlap since with a pressurized mixture more may escape. If overlap isn't reduced the less exhaust restriction and/or higher boost will increase lost through the exhaust valve.
http://www.AzBikeTech.com
If what you are saying is right then if I remove the headers, cats
and reinstall the factory headers and cats I should get back at
least 20 hp at the wheels. I just wasted 4500.00 cdn and now
have to pay another 600.00 to get back 20 hp.
There should be a warning from stillen about this to people
before they by all the stillen toys for the Z and then find out
their car does not run right.
and reinstall the factory headers and cats I should get back at
least 20 hp at the wheels. I just wasted 4500.00 cdn and now
have to pay another 600.00 to get back 20 hp.
There should be a warning from stillen about this to people
before they by all the stillen toys for the Z and then find out
their car does not run right.
Registered User
Joined: Jun 2004
Posts: 41
Likes: 0
From: Florida
Originally posted by 2003z
if the belt goes out, there will be no boost, but you will be ok. I have the stillen, for about 5000 miles now, 1 dragstrip day and 3 days on the racetrack without problems. I am burning excessive oil, but I don't think its stillen related, since several early vin people have had this problem. I love the stillen and would do it again. its the only mod I feel I got my money's worth out of. I have the stage 3, and I bought it used, so I don't have the warranty. However, due to the fact they offer a warranty, and got their CARB exemption on the 1st try, plus their engineering background and relationship with nissan, I'm not worried about it.
if the belt goes out, there will be no boost, but you will be ok. I have the stillen, for about 5000 miles now, 1 dragstrip day and 3 days on the racetrack without problems. I am burning excessive oil, but I don't think its stillen related, since several early vin people have had this problem. I love the stillen and would do it again. its the only mod I feel I got my money's worth out of. I have the stage 3, and I bought it used, so I don't have the warranty. However, due to the fact they offer a warranty, and got their CARB exemption on the 1st try, plus their engineering background and relationship with nissan, I'm not worried about it.
BURNING OIL MEANS ITS GOING TO BLOW TAKE IT IN TO A TUNER ASAP AND BUILD THAT MOTOR
Registered User
Joined: May 2004
Posts: 100
Likes: 0
From: Mesa, Az
If what you are saying is right then if I remove the headers, cats and reinstall the factory headers and cats I should get back at least 20 hp at the wheels. I just wasted 4500.00 cdn and now have to pay another 600.00 to get back 20 hp.
There should be a warning from stillen about this to people
before they by all the stillen toys for the Z and then find out
their car does not run right.
There should be a warning from stillen about this to people
before they by all the stillen toys for the Z and then find out
their car does not run right.
Originally posted by techz33
BURNING OIL MEANS ITS GOING TO BLOW TAKE IT IN TO A TUNER ASAP AND BUILD THAT MOTOR
BURNING OIL MEANS ITS GOING TO BLOW TAKE IT IN TO A TUNER ASAP AND BUILD THAT MOTOR
Registered User
Joined: Mar 2004
Posts: 38
Likes: 0
From: Seattle, WA
If Stillen is saying THEIR supercharger requires back pressure, and they are also saying THEIR headers will work with THEIR supercharger, then they are also saying THEIR headers are restrictive. 
I have to laugh at this.... That is some very interesting marketing. I'll take note and not follow their cue. LOL
2003z,
just how does their system "sense" boost? And you can not "enrichen the fuel", just the mixture. The mixture is determined by the computer. If you are running too rich or too lean then you would have been better off doing some tuning rather than replacing hiflow exhaust components with the stock components.
It seems like Stillen is trying to cover themselves.
I have to laugh at this.... That is some very interesting marketing. I'll take note and not follow their cue. LOL2003z,
just how does their system "sense" boost? And you can not "enrichen the fuel", just the mixture. The mixture is determined by the computer. If you are running too rich or too lean then you would have been better off doing some tuning rather than replacing hiflow exhaust components with the stock components.
It seems like Stillen is trying to cover themselves.
Registered User
Joined: Jun 2003
Posts: 78
Likes: 0
From: planet earth
[QUOTE]Originally posted by DanF
[B]If Stillen is saying THEIR supercharger requires back pressure, and they are also saying THEIR headers will work with THEIR supercharger, then they are also saying THEIR headers are restrictive. I have to laugh at this.... That is some very interesting marketing. I'll take note and not follow their cue. LOL
ok, lets try this...on a few applications eg the one above and various motors I have seen at my shop, increased exhaust scavenging will cause a decrease in performance. By increasing the exhaust flow out you need to get more in right? A lot of times on positive displacement blowers (roots) you will need to increase blower speed to get back a slight drop in MAP caused by the freely flowing exhaust. However if you have to speed the compressor up too much then you increase the heat generated into the charge.... dillema! Z parts and Gary are good about noting the overlap concerns on boosted cars.. I have seen guys come in with wild cams on t/c cars and by killing some overlap (decreasing scavenging) they run sooo much better. Actually, if you call stillen R&D they will tell you NOT to run headers with their current blower for that very reason.... Do a little research and you will see this is true
[B]If Stillen is saying THEIR supercharger requires back pressure, and they are also saying THEIR headers will work with THEIR supercharger, then they are also saying THEIR headers are restrictive.
I have to laugh at this.... That is some very interesting marketing. I'll take note and not follow their cue. LOLok, lets try this...on a few applications eg the one above and various motors I have seen at my shop, increased exhaust scavenging will cause a decrease in performance. By increasing the exhaust flow out you need to get more in right? A lot of times on positive displacement blowers (roots) you will need to increase blower speed to get back a slight drop in MAP caused by the freely flowing exhaust. However if you have to speed the compressor up too much then you increase the heat generated into the charge.... dillema! Z parts and Gary are good about noting the overlap concerns on boosted cars.. I have seen guys come in with wild cams on t/c cars and by killing some overlap (decreasing scavenging) they run sooo much better. Actually, if you call stillen R&D they will tell you NOT to run headers with their current blower for that very reason.... Do a little research and you will see this is true
Originally posted by DanF
2003z,
just how does their system "sense" boost? And you can not "enrichen the fuel", just the mixture. The mixture is determined by the computer. If you are running too rich or too lean then you would have been better off doing some tuning rather than replacing hiflow exhaust components with the stock components.
It seems like Stillen is trying to cover themselves.
2003z,
just how does their system "sense" boost? And you can not "enrichen the fuel", just the mixture. The mixture is determined by the computer. If you are running too rich or too lean then you would have been better off doing some tuning rather than replacing hiflow exhaust components with the stock components.
It seems like Stillen is trying to cover themselves.
They sense boost by running a vacuum line to their piggyback. I think jawbone summed it up nicely in the above post.
Registered User
Joined: Mar 2004
Posts: 38
Likes: 0
From: Seattle, WA
Interesting... I am anxious to see the results of a local car we have been working on. We did 1 5/8" headers and 2 1/4" exhaust. Cats were replaced with 2 1/2" pipes. He picked up 22 HP to the wheels. Last week an associate installed the Vortech system on the same car. He picked up 105 HP to the wheels. Next the car will be coming back for 1 3/4" primary headers and dual 2 1/2" exhaust. It will be interesting to see if he gains or loses power...
Registered User
Joined: Mar 2004
Posts: 38
Likes: 0
From: Seattle, WA
Interesting... I am anxious to see the results of a local car we have been working on. We did 1 5/8" headers and 2 1/4" exhaust. Cats were replaced with 2 1/2" pipes. He picked up 22 HP to the wheels. Last week an associate installed the Vortech system on the same car. He picked up 105 HP to the wheels. Next the car will be coming back for 1 3/4" primary headers and dual 2 1/2" exhaust. It will be interesting to see if he gains or loses power...
Registered User
Joined: Aug 2003
Posts: 258
Likes: 0
From: Alexandria, Louisiana
Stillen Hood Option
I have plans for the Stage 4 Stillen kit myself because I AIN'T gonna fight my Borla headers again!!
I spoke with some folks @ Stillen last week & they said that they're working on a new style hood due to the complaints around the current version ( & it's "second" lump in the middle ). The swept-back cowl induction look is OK with me but it's that other lump that makes it look like an afterthought. BTW - Stage 4 will not be ready until the end of the year ( or so I'm told ) but it will be considered "off-road" useage only because it is designed to work with test pipes as well. Guess it's nitrous until then!!
I spoke with some folks @ Stillen last week & they said that they're working on a new style hood due to the complaints around the current version ( & it's "second" lump in the middle ). The swept-back cowl induction look is OK with me but it's that other lump that makes it look like an afterthought. BTW - Stage 4 will not be ready until the end of the year ( or so I'm told ) but it will be considered "off-road" useage only because it is designed to work with test pipes as well. Guess it's nitrous until then!!
Thread
Thread Starter
Forum
Replies
Last Post
350Z_Al
Exterior & Interior
133
Oct 29, 2020 07:44 PM
seagrasser
Zs & Gs For Sale
6
Oct 11, 2015 03:27 PM
AbyteZero
Engine, Drivetrain & Forced-Induction (DIY)
3
Sep 22, 2015 09:17 AM
