Pennock's Fiero Forum
  Technical Discussion & Questions
  So why not a superturbo ?

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
So why not a superturbo ? by Tweeder
Started on: 10-01-2013 11:33 AM
Replies: 22 (449 views)
Last post by: Tweeder on 10-03-2013 03:33 PM
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-01-2013 11:33 AM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was reading the diesel power mag at work today and they have an article in there about Banks did a super/ turbo motor in a rig. It used a whipple twin screw that was fed by a turbo. I know people on here say the turbo boost will be restricted due to the supercharger. It does make sense, but why are they as well as others they reference able to do it and not us? Is it because it's a diesel?

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged
PFF
System Bot
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-01-2013 11:40 AM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
Heres a different article on it.

http://m.trucktrend.com/kra...eak_truck/index.html

A quick google showed others.
IP: Logged
IROCTAFIERO
Member
Posts: 791
From: Montgomery, Al USA
Registered: May 2005


Feedback score:    (6)
Leave feedback

Rate this member

Report this Post10-01-2013 01:11 PM Click Here to See the Profile for IROCTAFIEROSend a Private Message to IROCTAFIEROEdit/Delete MessageReply w/QuoteDirect Link to This Post
It can be done, it just isnt for a reason.
cost, complexity, heat, etc

Someone had a Series 1 3800 that was twincharged. They claimed it made plenty of power but they had lots of issues with tuning, etc.

A well-planned turbo setup is your best bet if you want a wild Fiero.

IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post10-01-2013 02:15 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's certainly doable. And it's a lot easier to do on a larger displacement engine like that, where you're going to make a lot more power on less boost. On smaller engines that people put in Fieros, it's a waste of time and money, because tuning it is a pain, and it's not cheap or easy to fit.
IP: Logged
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-01-2013 03:17 PM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
Why would tuning be any worse? I wouldn't mind as I have a turbo sitting on the shelf.

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged
Fiero84Freak
Member
Posts: 4787
From: AR
Registered: Feb 2002


Feedback score: N/A
Leave feedback





Total ratings: 66
Rate this member

Report this Post10-01-2013 03:31 PM Click Here to See the Profile for Fiero84FreakClick Here to Email Fiero84FreakSend a Private Message to Fiero84FreakEdit/Delete MessageReply w/QuoteDirect Link to This Post
You have a much larger tuning "window" with something that big. You don't necessarily have to be incredibly precise on tuning to make power and potentially some corners can be cut or you can make a large amount of power gains, while still losing some potential gains and it not being a very big deal.

With a standard gasoline lower-duty engine like in most every car the tuning window is very small and typically dependent on very specific factors. By dependent, I mean that usually if you say have to push more fuel to a certain amount you have to have very specific supporting modifications for a very specific tunable range. Hence why these and others factors usually combine to make something like this be not only difficult but also potentially cost ineffective. The other thing to consider is one can make very strong power gains on just one specific application - turbocharger-specific or supercharger-specific. Tuning thus becomes focused on reaching a specific power value, and then advancing from there if such is desired to another window of tune-ability.
IP: Logged
fieroguru
Member
Posts: 11660
From: Champaign, IL
Registered: Aug 2003


Feedback score:    (45)
Leave feedback





Total ratings: 257
Rate this member

Report this Post10-01-2013 03:40 PM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
Detroit Diesel had an entire line of engines that were twin charged as OEM equipment... The twin charged concept has merits depending on the application.
IP: Logged
thesameguy
Member
Posts: 1536
From: California
Registered: Dec 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-01-2013 06:10 PM Click Here to See the Profile for thesameguyClick Here to Email thesameguySend a Private Message to thesameguyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure the size of the engine is that important... historically it's the rev range (or lack thereof) that makes twincharging desirable... the bigger the rev range, the more desirable it is. VW has a production twincharged 1.4l, and has for many years, for example. High redline combined with relatively modest power goals and high responsiveness is about the ideal scenario for twincharging...
IP: Logged
darkhorizon
Member
Posts: 12232
From: Flint Michigan
Registered: Jan 2006


Feedback score: (1)
Leave feedback





Total ratings: 450
Rate this member

Report this Post10-01-2013 06:24 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Tweeder:

Why would tuning be any worse? I wouldn't mind as I have a turbo sitting on the shelf.



Its not.

There is some speculation that it helps to introduce a supercharger bypass as the turbo flow overcomes SC flow to increase the blower/turbo efficiency lambda. Under 500whp I doubt you would need to be concerned with this. The physics of twin charging is very forgiving and easy to calculate... That being the math shows favorable efficiency on both the turbo and the blower if you have a moderate to large sized turbo.
IP: Logged
darkhorizon
Member
Posts: 12232
From: Flint Michigan
Registered: Jan 2006


Feedback score: (1)
Leave feedback





Total ratings: 450
Rate this member

Report this Post10-01-2013 06:26 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonEdit/Delete MessageReply w/QuoteDirect Link to This Post

darkhorizon

12232 posts
Member since Jan 2006
 
quote
Originally posted by Tweeder:

Why would tuning be any worse? I wouldn't mind as I have a turbo sitting on the shelf.



Its not.

There is some speculation that it helps to introduce a supercharger bypass as the turbo flow overcomes SC flow to increase the blower/turbo efficiency lambda. Under 500whp I doubt you would need to be concerned with this. The physics of twin charging is very forgiving and easy to calculate... That being the math shows favorable efficiency on both the turbo and the blower if you have a moderate to large sized turbo.
IP: Logged
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-02-2013 11:19 AM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was reading that in dealing with the heat issue of being twin charged, someone had suggested but no answer, lowering the boost at the supercharger from the stock 3.8 to a 4.0 and use a larger turbo. The theory is that there's less heat generated from 4 psi vs 8 psi.
Here's the link

http://www.theturboforums.c...fcab72ad8dfa934b73bc
------------------
86 SE Convertible 3800sc 4t65e HD.

[This message has been edited by Tweeder (edited 10-02-2013).]

IP: Logged
PFF
System Bot
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-02-2013 04:04 PM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
Why would people bleed the supercharger boost off after a certain psi to let the turbo take over?

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged
Justinbart
Member
Posts: 3259
From: Flint, MI
Registered: Sep 2009


Feedback score: N/A
Leave feedback





Total ratings: 119
Rate this member

Report this Post10-02-2013 05:21 PM Click Here to See the Profile for JustinbartSend a Private Message to JustinbartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Tweeder:

Why would people bleed the supercharger boost off after a certain psi to let the turbo take over?



It's not about pressure it's about flow and efficiency ranges.

------------------
Turbo 3800 E85 F23 5spd spec5
11.17@132.6

IP: Logged
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-02-2013 05:27 PM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Justinbart:


It's not about pressure it's about flow and efficiency ranges.



So they bleed off the boost to allow the supercharger to spin more freely to reduce the amount of drag thus allowing more air in from the turbo?

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-02-2013 05:37 PM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
Here's a write up from someone that did a gtp.

http://www.scvt.net/index.p...ncharge-project.138/

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged
darkhorizon
Member
Posts: 12232
From: Flint Michigan
Registered: Jan 2006


Feedback score: (1)
Leave feedback





Total ratings: 450
Rate this member

Report this Post10-02-2013 09:50 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Tweeder:

Here's a write up from someone that did a gtp.

http://www.scvt.net/index.p...ncharge-project.138/



Ehhh.. He is pretty far off base for the most part.

The eaton blower doesnt "make boost" Its just a blower that doesnt let air back out of where it just put it... it makes compression inside of the lower intake manifold... so if there is no pressure to make, aka its 15psi above and below the blower, you effectively have zero load on the blower. The bigger pulley is just an idea that underdriving the blower may gain you a half a horsepower due to less rotating mass.
IP: Logged
Spiders1
Member
Posts: 178
From: Fredericksburg VA USA
Registered: Jul 2013


Feedback score: (4)
Leave feedback

Rate this member

Report this Post10-02-2013 10:47 PM Click Here to See the Profile for Spiders1Click Here to Email Spiders1Send a Private Message to Spiders1Edit/Delete MessageReply w/QuoteDirect Link to This Post
Eventually the turbo will be held back by the supercharger. It becomes a parasitic at high rpm.
IP: Logged
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-03-2013 01:07 AM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spiders1:

Eventually the turbo will be held back by the supercharger. It becomes a parasitic at high rpm.


I wonder at what HP that would be?

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post10-03-2013 09:19 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spiders1:

Eventually the turbo will be held back by the supercharger. It becomes a parasitic at high rpm.


Not necessarily true. It depends on several variables, and in any case where it is true, the blower is already a hindrance to performance at that RPM by itself, as it would be a restriction to air flow regardless of whether there's a turbo before the blower or not.

As long as the blower can flow enough CFM to fill the needs of the engine's displacement at any given RPM, it will not be a restriction or parasitic, regardless of whether it is compressing air. It will simply plateau and stop adding power. Turbochargers are also afflicted with compressive limits, and if the cold side is unable to flow enough air to meet the needs of an engine at a given RPM, will also become a restriction at that RPM.
IP: Logged
Spiders1
Member
Posts: 178
From: Fredericksburg VA USA
Registered: Jul 2013


Feedback score: (4)
Leave feedback

Rate this member

Report this Post10-03-2013 12:16 PM Click Here to See the Profile for Spiders1Click Here to Email Spiders1Send a Private Message to Spiders1Edit/Delete MessageReply w/QuoteDirect Link to This Post
Even a tiny turbo like the ones on a stock Eclipse or an Audi can hit about 25 to 30lbs of boost before they become
inefficient. The same is not true for a supercharger either roots or centrifugal. I have heard of a 650 hp Lotus Elise
that is twin charged. It's on YouTube.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post10-03-2013 02:45 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spiders1:
Even a tiny turbo like the ones on a stock Eclipse or an Audi can hit about 25 to 30lbs of boost before they become
inefficient. The same is not true for a supercharger either roots or centrifugal. I have heard of a 650 hp Lotus Elise
that is twin charged. It's on YouTube.


PSI is irrelevant in terms of flow. 600 PSI or 10 PSI at 300 CFM is still only flowing at 300 CFM. If you're only capable flowing 300 CFM at any RPM where the engine needs more than that to remain efficient and make power, you're a restriction. For an engine to continue making power at higher RPMs, you need to be able to flow enough air into and out of the cylinder, for it to make that power (along with the fuel and spark requirements). The only thing adding PSI via boost does, is increase the pressure inside the cylinder, so that you make more power than you would at a lower cylinder pressure.
IP: Logged
PFF
System Bot
darkhorizon
Member
Posts: 12232
From: Flint Michigan
Registered: Jan 2006


Feedback score: (1)
Leave feedback





Total ratings: 450
Rate this member

Report this Post10-03-2013 02:59 PM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Spiders1:

Eventually the turbo will be held back by the supercharger. It becomes a parasitic at high rpm.


Completely wrong. The blower works on pressure ratio, and as long as there is none, there is no blower. Its "parasitic" only in the form of rotating mass.

 
quote
As long as the blower can flow enough CFM to fill the needs of the engine's displacement at any given RPM, it will not be a restriction or parasitic, regardless of whether it is compressing air. It will simply plateau and stop adding power. Turbochargers are also afflicted with compressive limits, and if the cold side is unable to flow enough air to meet the needs of an engine at a given RPM, will also become a restriction at that RPM.


Wrong again. This is true of a dual compressor setup, but not this one. The blower "displacement" scales directly with the pressure coming into the turbo.. so technically at 14psi of boost, the blower has an effective displacement of an "m180" blower instead of a "m90".

IP: Logged
Tweeder
Member
Posts: 1025
From: Kitimat, BC, Canada
Registered: Aug 2012


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-03-2013 03:33 PM Click Here to See the Profile for TweederSend a Private Message to TweederEdit/Delete MessageReply w/QuoteDirect Link to This Post
When charging the supercharger with air from the turbo, you allow the super to work less harder in a sence claiming the loss in HP robbed from parasitic loss due to the belt.

------------------
86 SE Convertible 3800sc 4t65e HD.

IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock