You should start your own project thread
*Update* turbotype4
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jonas_linder
- Posts: 1587
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Tony Z
- Posts: 1244
- Joined: Wed Aug 30, 2000 12:01 am
Hey Jonas...
I notice your drawings have #1 and 2 cylinders merging and 3&4 merging at the turbo...
Dual inlet turbo for better responce and then you seem to loose the pulsation effect. Merge 1&3 and 2&4 together to get even pulasing going thru the turbine... even better responce and effiency. Try to get the exhaust pipes as close to equal length as possible (but still short)
I notice your drawings have #1 and 2 cylinders merging and 3&4 merging at the turbo...
Dual inlet turbo for better responce and then you seem to loose the pulsation effect. Merge 1&3 and 2&4 together to get even pulasing going thru the turbine... even better responce and effiency. Try to get the exhaust pipes as close to equal length as possible (but still short)
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Piledriver
- Moderator
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- Joined: Sat Feb 16, 2002 12:01 am
There is much doubt in my mind the "pulsation effect" is a feature.
I read thru a fellows PhD thesis while back, basically about turbocharger characteristics. and he got significantly BETTER low>high midrange turbine efficiency, and was only down 2% at the very upper end, with an intentionally "worst case" 5 liter chamber "log" manifold.
Apparently the pulses aren't as efficient at pushing the turbine around as smooth flow of the ~same energy. They blow through.
I think I still have that...
I read thru a fellows PhD thesis while back, basically about turbocharger characteristics. and he got significantly BETTER low>high midrange turbine efficiency, and was only down 2% at the very upper end, with an intentionally "worst case" 5 liter chamber "log" manifold.
Apparently the pulses aren't as efficient at pushing the turbine around as smooth flow of the ~same energy. They blow through.
I think I still have that...
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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Tony Z
- Posts: 1244
- Joined: Wed Aug 30, 2000 12:01 am
There are two things in my mind that push the pulastion idea....
1) not really to do with pulsation, but having two cyliders exhaust within 180deg of each other into a shared exh pipe is going to create unnecessary back pressure for the second cylinder to overcome.
2) every Marine engine (medium speed) that I have ever worked on has a exhaust system that relies on a pulsation effect. Anything from an inline 6 to a V16 has some sort of seperation of the exhausts. These things are also built for a slight fuel saving effect. OK, the really big slow speed engines rely on a constant volume effect, where all the cylinders spill into a huge chamber, which then feeds the turbos with a constant pressure of exhaust gas. Remember, sound is energy and if you can harness the energy relesed when the exh valve opens, you will win slightly.
This is something that I prefer to debate face to face, but pull out any book on theory of engine design, especially for industrial and marine applications and they talk about the pulsation effect. I dont think its so prominent in automotive applications due to space, design and the variable rev range we deal with, plus we have huge amounts of heat compared to a diesel engine, so that also counts in our favour. That said, maybe the pulsation effect may be worth 1/10 sec down the 1/4 mile, but if Jonas is building the exh from scratch, it makes no sense to discard this (proven) thoery when all thats required is moving two pipes 3cm each...
{edit, spelling}
1) not really to do with pulsation, but having two cyliders exhaust within 180deg of each other into a shared exh pipe is going to create unnecessary back pressure for the second cylinder to overcome.
2) every Marine engine (medium speed) that I have ever worked on has a exhaust system that relies on a pulsation effect. Anything from an inline 6 to a V16 has some sort of seperation of the exhausts. These things are also built for a slight fuel saving effect. OK, the really big slow speed engines rely on a constant volume effect, where all the cylinders spill into a huge chamber, which then feeds the turbos with a constant pressure of exhaust gas. Remember, sound is energy and if you can harness the energy relesed when the exh valve opens, you will win slightly.
This is something that I prefer to debate face to face, but pull out any book on theory of engine design, especially for industrial and marine applications and they talk about the pulsation effect. I dont think its so prominent in automotive applications due to space, design and the variable rev range we deal with, plus we have huge amounts of heat compared to a diesel engine, so that also counts in our favour. That said, maybe the pulsation effect may be worth 1/10 sec down the 1/4 mile, but if Jonas is building the exh from scratch, it makes no sense to discard this (proven) thoery when all thats required is moving two pipes 3cm each...
{edit, spelling}
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Piledriver
- Moderator
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- Joined: Sat Feb 16, 2002 12:01 am
I thought it was a "proven' theory too until I saw considerable cold, hard data VERY clearly showing otherwise... on a high-speed gasoline engine.
(IIRC Saab 16v was the test engine)
(IIRC Saab 16v was the test engine)
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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Twystd1
- Posts: 323
- Joined: Sat Nov 13, 2004 8:42 pm
I am with Pile on this...
I read the same articles and it was backed up with dyno data. I have also brought this up at another subscription BBS where the best and brightest of engine builders in the US hang out. (IMHO) (Don't ask)
We were ALL taken back with the data that was available from several OEM tests as well as several thesis on this subject written by college engineering students.
It took me a couple of days to find this stuff via google last year.
I was as surprised as you. I B too tired to give ya synopsis of why... Go search it up. The data is available as public knowledge.
CAVEAT: Over 6500 - 7500 RPMs, dependent upon the engine configuration. The log style was somewhat less effective. But still within 8% of a merged manifold.
The log style was MORE effective under 5K RPMs on most of the configurations tested.
All engines and their specific configurations are different. Bottom line... Only a dyno and lap times will tell the real truth about ANY configuration.
Clayton
I read the same articles and it was backed up with dyno data. I have also brought this up at another subscription BBS where the best and brightest of engine builders in the US hang out. (IMHO) (Don't ask)
We were ALL taken back with the data that was available from several OEM tests as well as several thesis on this subject written by college engineering students.
It took me a couple of days to find this stuff via google last year.
I was as surprised as you. I B too tired to give ya synopsis of why... Go search it up. The data is available as public knowledge.
CAVEAT: Over 6500 - 7500 RPMs, dependent upon the engine configuration. The log style was somewhat less effective. But still within 8% of a merged manifold.
The log style was MORE effective under 5K RPMs on most of the configurations tested.
All engines and their specific configurations are different. Bottom line... Only a dyno and lap times will tell the real truth about ANY configuration.
Clayton
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Piledriver
- Moderator
- Posts: 22879
- Joined: Sat Feb 16, 2002 12:01 am
I have been thinking about an optimized "log"...
There are more efficient was of getting gasses in and out smoothly than the typical log setup used in those tests...
(A stock T1/T4 muffler is a rather poor example, but that's something like the idea...)
Look at your average (decent) intake plenum for instance. Bell mouths. Even runner lengths... Smooth exit flow. Minimal turbulence... Maybe some anti-reversion going on. Possibly swirl to conserve energy...
I'm thinking of tracking down a big SS rice muffler shell or 2 to play with.
(1 on each side, w/6" slash cut ex runners projecting into the chambers, works from a packaging standpoint)
It's possible (even probable) that the very good volume>surface area of a large "expansion chamber" might be keeping the heat in the gasses better, explaining at least SOME of what is seen.
(converting velocity to pressure)
Coated SS is about as good as it gets insulation wise, at least amongst things that won't melt.
Is this thread officially hijacked yet ?
There are more efficient was of getting gasses in and out smoothly than the typical log setup used in those tests...
(A stock T1/T4 muffler is a rather poor example, but that's something like the idea...)
Look at your average (decent) intake plenum for instance. Bell mouths. Even runner lengths... Smooth exit flow. Minimal turbulence... Maybe some anti-reversion going on. Possibly swirl to conserve energy...
I'm thinking of tracking down a big SS rice muffler shell or 2 to play with.
(1 on each side, w/6" slash cut ex runners projecting into the chambers, works from a packaging standpoint)
It's possible (even probable) that the very good volume>surface area of a large "expansion chamber" might be keeping the heat in the gasses better, explaining at least SOME of what is seen.
(converting velocity to pressure)
Coated SS is about as good as it gets insulation wise, at least amongst things that won't melt.
Is this thread officially hijacked yet ?
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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Piledriver
- Moderator
- Posts: 22879
- Joined: Sat Feb 16, 2002 12:01 am
(this following would be very easy to implement in just a low<>high speed mode, just using the cooling plenum pressure on an actuator...)
Last night I had an idea to very simply and ~instantly (few mS)
switch a 4>1 collector-based intake and/or exhaust from 4>1 to tri-y mode and back.
Assuming a little collector magic, it could potentially provide 6 (possibly staggered/overlapping)
Helmholtz tuning peaks all across the engines powerband. (between the 2nd/3rd/4th harmonic)
... and with infinitely variable timing, (using this variable lift rocker technique, or split cam variable lobes for example)
it could be possible to keep both intake and exhaust "on the pipe" at all times.
It would be ... computationally interesting, and probably sound really weird
as the intake and ex switch modes constantly...
Some more details over on Jakes forum, trying do document this one... just in case.
Greg McGee
Last night I had an idea to very simply and ~instantly (few mS)
switch a 4>1 collector-based intake and/or exhaust from 4>1 to tri-y mode and back.
Assuming a little collector magic, it could potentially provide 6 (possibly staggered/overlapping)
Helmholtz tuning peaks all across the engines powerband. (between the 2nd/3rd/4th harmonic)
... and with infinitely variable timing, (using this variable lift rocker technique, or split cam variable lobes for example)
it could be possible to keep both intake and exhaust "on the pipe" at all times.
It would be ... computationally interesting, and probably sound really weird
as the intake and ex switch modes constantly...
Some more details over on Jakes forum, trying do document this one... just in case.
Greg McGee
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
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jonas_linder
- Posts: 1587
- Joined: Sun Sep 08, 2002 12:01 am
I'm aware of the paring of pipes 
that is a 4-1 collector.. I'm not sure if the pictures are not showing it correct Anyway, that is not what I'm going to use.. the tuners in sweden have noticed much better spoolup when the pipes are paired correctly in a twin-entry housing.
And yes.. the pipes will be close to equal length
Thanks for noticing
Pile.. yes that engine is not a 8v pushrod engine.. sure you should look at new technology but you have to pick out the correct facts.
And there is a big difference between single and twin entry turbos.. anyway.. this is not the thread to discuss it
that is a 4-1 collector.. I'm not sure if the pictures are not showing it correct Anyway, that is not what I'm going to use.. the tuners in sweden have noticed much better spoolup when the pipes are paired correctly in a twin-entry housing.And yes.. the pipes will be close to equal length
Thanks for noticing
Pile.. yes that engine is not a 8v pushrod engine.. sure you should look at new technology but you have to pick out the correct facts.
And there is a big difference between single and twin entry turbos.. anyway.. this is not the thread to discuss it
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jonas_linder
- Posts: 1587
- Joined: Sun Sep 08, 2002 12:01 am
A little tip for anyone intressted in twinscroll designed header is to look at Jonas N new header!
Anyway..
Update
I needed a daily driver so I bought my self a fastback from Jonas
I have done a little work to it over the past few months and a friend has helped me to paint the last pieces!
Anyway we were at bugrun last weekend and got very inspired
I got to see a certain satin black fastback with a big-ass turbo type4 (Patte).
Today a friend came by my work and "donated" this
I am so luck having friends like this
Look out for some more work updates in the near feture
Anyway..
Update
I needed a daily driver so I bought my self a fastback from Jonas
I have done a little work to it over the past few months and a friend has helped me to paint the last pieces!
Anyway we were at bugrun last weekend and got very inspired
I got to see a certain satin black fastback with a big-ass turbo type4 (Patte).
Today a friend came by my work and "donated" this
I am so luck having friends like this
Look out for some more work updates in the near feture
but i dont think it will move with your stock 1600cc-
Type 4 Unleashed
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- Joined: Tue Nov 08, 2005 10:43 pm
So you gonna go 10,000 rpm 
Richard
EMW
“Have you ever noticed how some people never
have the money to do it right, but can always
find the money to do it twice ?”
EMW
“Have you ever noticed how some people never
have the money to do it right, but can always
find the money to do it twice ?”