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BFB Samba Member
Joined: November 03, 2014 Posts: 1696
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Posted: Thu Sep 23, 2021 4:40 pm Post subject: boost timing question |
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I was curious if anyone retarded timing at low boost more than needed, trying to spike exhaust, and if that spools the turbo any sooner / better?
or would you lose power enough that it'd be counter productive ?
I was looking at timing maps on google and saw one where at WOT it had about 28° , at about 5lbs of boost it dropped to about 15° , at 10lbs timing was back up to 18° .
maybe it was a screw up, maybe it was intentional, I dunno? but I thought if it was intentional maybe that was why and that might just be a cool idea. or maybe it's an old idea I was just unaware of... _________________ Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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buguy Samba Member
Joined: November 17, 2003 Posts: 4915 Location: Port Orange, FL
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Posted: Thu Sep 23, 2021 5:04 pm Post subject: Re: boost timing question |
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I've heard retarded timing helps spool. I never have tested it, but it doesn't feel any different to me. I went to much lower timing to fight off detonation, and i can't tell. I'm headed back to the dyno, and will see what i can see. |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Thu Sep 23, 2021 7:24 pm Post subject: Re: boost timing question |
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buguy wrote: |
I've heard retarded timing helps spool. I never have tested it, but it doesn't feel any different to me. I went to much lower timing to fight off detonation, and i can't tell. I'm headed back to the dyno, and will see what i can see. |
I know you run megasquirt but do you have a knock sensor on your engine. |
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buguy Samba Member
Joined: November 17, 2003 Posts: 4915 Location: Port Orange, FL
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Posted: Fri Sep 24, 2021 12:29 am Post subject: Re: boost timing question |
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No i don't. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12635 Location: Western Canada
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Posted: Fri Sep 24, 2021 5:44 am Post subject: Re: boost timing question |
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richardcraineum wrote: |
I was curious if anyone retarded timing at low boost more than needed, trying to spike exhaust, and if that spools the turbo any sooner / better?
or would you lose power enough that it'd be counter productive ?
I was looking at timing maps on google and saw one where at WOT it had about 28° , at about 5lbs of boost it dropped to about 15° , at 10lbs timing was back up to 18° .
maybe it was a screw up, maybe it was intentional, I dunno? but I thought if it was intentional maybe that was why and that might just be a cool idea. or maybe it's an old idea I was just unaware of... |
Yes. Just based on some experimenting I did 30 years ago with a seat of the pants dyno, I was backing down total timing to try and find a value that gave less detonation and reached a point where suddenly the boost gauge shot up and things got crazy.
My conclusion was that with the timing late enough part of the fuel burn was now happening in the exhaust manifold and the turbine housing. I didn't think the turbine would take that very long without either melting the vanes off or over speeding and exploding so I backed out of that range quickly! I suppose it would help spool up a turbo that was too small for the job but I personally would want to limit it to a second or two at the most. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Fri Sep 24, 2021 6:12 am Post subject: Re: boost timing question |
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Oprn. What you have just described is what rally cars have as antilag where raw fuel is sent to the turbine where it is burnt to keep the turbine wheel moving, hence reducing lag, it does destroy the turbine after a time. |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Fri Sep 24, 2021 6:14 am Post subject: Re: boost timing question |
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I think you should get one and tune your engine with it. |
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kangaboy Samba Member
Joined: August 28, 2010 Posts: 1062 Location: St. Louis, Mo
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Posted: Fri Sep 24, 2021 6:37 am Post subject: Re: boost timing question |
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Bad bug wrote: |
I think you should get one and tune your engine with it. |
After looking into this a few weeks ago and doing a little bit of research, the aircooled VW motor is less than an ideal candidate to put a knock sensor on. Seems its very hard to distinguish knock and normal operating sounds. _________________ -74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Fri Sep 24, 2021 6:42 am Post subject: Re: boost timing question |
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kangaboy wrote: |
Bad bug wrote: |
I think you should get one and tune your engine with it. |
After looking into this a few weeks ago and doing a little bit of research, the aircooled VW motor is less than an ideal candidate to put a knock sensor on. Seems its very hard to distinguish knock and normal operating sounds. |
I think you are wrong. There is a guy on the shoptalk forum by the name of wally that had knock sensor on his t4 turbo engine also jake raby uses knock sensors on his engines when he is tuning them.
Just to close the 993 engine had them. Kangaboy in your re-search did they say where they put the knock sensor? |
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kangaboy Samba Member
Joined: August 28, 2010 Posts: 1062 Location: St. Louis, Mo
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Posted: Fri Sep 24, 2021 7:37 am Post subject: Re: boost timing question |
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Bad bug wrote: |
kangaboy wrote: |
Bad bug wrote: |
I think you should get one and tune your engine with it. |
After looking into this a few weeks ago and doing a little bit of research, the aircooled VW motor is less than an ideal candidate to put a knock sensor on. Seems its very hard to distinguish knock and normal operating sounds. |
I think you are wrong. There is a guy on the shoptalk forum by the name of wally that had knock sensor on his t4 turbo engine also jake raby uses knock sensors on his engines when he is tuning them.
Just to close the 993 engine had them. Kangaboy in your re-search did they say where they put the knock sensor? |
Hydraulic lifter may play a roll in the examples you've provided. I didn't say it was impossible in my response, I said less than Ideal. _________________ -74 Standard - "CaliBug" 2084T, MS3X w/FI and Crank Fire
-76 Westy - "Gandalf"
-18 GTI SE
skills@eurocarsplus wrote: |
that fucking thing looks like it drove through a J.C. Whitney catalogue and hit everything on the way out |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Fri Sep 24, 2021 1:57 pm Post subject: Re: boost timing question |
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kangaboy wrote: |
Bad bug wrote: |
kangaboy wrote: |
Bad bug wrote: |
I think you should get one and tune your engine with it. |
After looking into this a few weeks ago and doing a little bit of research, the aircooled VW motor is less than an ideal candidate to put a knock sensor on. Seems its very hard to distinguish knock and normal operating sounds. |
I think you are wrong. There is a guy on the shoptalk forum by the name of wally that had knock sensor on his t4 turbo engine also jake raby uses knock sensors on his engines when he is tuning them.
Just to close the 993 engine had them. Kangaboy in your re-search did they say where they put the knock sensor? |
Hydraulic lifter may play a roll in the examples you've provided. I didn't say it was impossible in my response, I said less than Ideal. |
The engine that jake raby and wally are running are all solid pattern camshaft. |
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buguy Samba Member
Joined: November 17, 2003 Posts: 4915 Location: Port Orange, FL
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Posted: Fri Sep 24, 2021 2:53 pm Post subject: Re: boost timing question |
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I have heard of people having them work and some that say the engine was too noisy and didn't read well. Personally, it's no secret when mine has knock. You can hear it down the street! |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Fri Sep 24, 2021 5:08 pm Post subject: Re: boost timing question |
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If you have a noisy valve train it will have a little problem in working correctly but as i have always told friends here that they should pay attention to setting up their cars properly. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12635 Location: Western Canada
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Posted: Sat Sep 25, 2021 5:09 am Post subject: Re: boost timing question |
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Bad bug wrote: |
If you have a noisy valve train it will have a little problem in working correctly but as i have always told friends here that they should pay attention to setting up their cars properly. |
And how exactly would that be in relation to a knock sensor? Not being a smart a$$ here, I want to know as a knock sensor is in my plans. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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buguy Samba Member
Joined: November 17, 2003 Posts: 4915 Location: Port Orange, FL
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Posted: Sat Sep 25, 2021 6:39 am Post subject: Re: boost timing question |
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I used a web cam and aluminum push rods in my engine, and when i take the belt off the engine is dead quiet. The one foot of 3" down pipe however, not so much!
I had chromoly push rods 10-12 years ago in my draw through engine and it was much noisier.
Also i think real forged pistons would add quite a bit of rattle to an engine. Just because of the difference in tolerance. |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Sat Sep 25, 2021 10:26 am Post subject: Re: boost timing question |
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oprn wrote: |
Bad bug wrote: |
If you have a noisy valve train it will have a little problem in working correctly but as i have always told friends here that they should pay attention to setting up their cars properly. |
And how exactly would that be in relation to a knock sensor? Not being a smart a$$ here, I want to know as a knock sensor is in my plans. |
Well correct rocker arm geometry it will be good also to ensure that the side play on the rockers are set correctly.
For natural aspirated engines running steel pushrods zero lash would contribute to a reduction of noise on the valve train.
Try of cam being used would add to a noisy valve train so selection of cam is important. |
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Bad bug Samba Member
Joined: March 11, 2006 Posts: 1119 Location: Jamaica
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Posted: Sat Sep 25, 2021 10:30 am Post subject: Re: boost timing question |
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buguy wrote: |
I used a web cam and aluminum push rods in my engine, and when i take the belt off the engine is dead quiet. The one foot of 3" down pipe however, not so much!
I had chromoly push rods 10-12 years ago in my draw through engine and it was much noisier.
Also i think real forged pistons would add quite a bit of rattle to an engine. Just because of the difference in tolerance. |
Ok. I will be running a web86b in my engine. I chose this cam because of what i read here of it being less noisy than other cams and it also producing torque and power. My aim for my engine is to make good torque so it will be a joy to drive daily. |
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Ohio Tom Samba Member
Joined: February 09, 2006 Posts: 1657 Location: Marshallville Ohio
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Posted: Sat Sep 25, 2021 11:56 am Post subject: Re: boost timing question |
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It is true that leaving the timing at 24deg under no/light boost will help to spool in applications where Lag is a problem.
My 2332 drag motor. Big cam, Big T3/4 (Chinese) turbo with worn housing. Big plenum intake setup.
Yeah, it has really bad lag.. I mean really bad.. Un-kay..
Not really a problem for a drag car. I sit on the line against the rev-limiter building boost long before the light turns green...
I normally just run it locked at 24deg.
I tried programming it to be 32 off boost, and 24 on boost (switch activated).
It was actually slower to build boost. Defiantly slowed down the spooling.
Went back to locked at 24deg.
No need for anything but WOT settings on a Drag car anyways.
Granted, this is an extreem application.
A milder cam, smaller intake, better turbo; won't have near the issue with Lag and will likely not matter enough to notice timing changes.
Anti-Lag is for Ralley cars and over size turbos. They are on/off the gas every few seconds. A 0.01sec improvement in spooling is worth the effort to them. |
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buguy Samba Member
Joined: November 17, 2003 Posts: 4915 Location: Port Orange, FL
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Posted: Sat Sep 25, 2021 2:50 pm Post subject: Re: boost timing question |
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Bad bug wrote: |
buguy wrote: |
I used a web cam and aluminum push rods in my engine, and when i take the belt off the engine is dead quiet. The one foot of 3" down pipe however, not so much!
I had chromoly push rods 10-12 years ago in my draw through engine and it was much noisier.
Also i think real forged pistons would add quite a bit of rattle to an engine. Just because of the difference in tolerance. |
Ok. I will be running a web86b in my engine. I chose this cam because of what i read here of it being less noisy than other cams and it also producing torque and power. My aim for my engine is to make good torque so it will be a joy to drive daily. |
I run a Web 163. That along with a small turbo and it boosts instantly pretty much everywhere. I do have launch control and hooked up rolling anti-lag last weekend. Never used launch control yet (stock trans gears), but i did try the rolling anti-lag. Didn't hold it long enough to build any boost. Like i said though, mine boosts instantly so it really was just for fun. I may try to get a video of the rolling anti-lag tonight. |
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