My draw through turbo

With Turbo and Super charging you can create massive horsepower with vw motors.

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madmike
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Re: My draw through turbo

Post by madmike » Sat Jun 30, 2018 5:19 am

Good old sidedraft :roll: it's ether good for idling & WOT but not good for cruising :lol:

advinnie
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Re: My draw through turbo

Post by advinnie » Sat Jun 30, 2018 6:01 am

Ha ha ha I do understand stand that but I can't understand why my issue is only at 2609-2900 rpm?

advinnie
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Re: My draw through turbo

Post by advinnie » Sat Jun 30, 2018 7:28 am

It wasn't the plugs it was the timing.
But the cleaned plugs in and same old problem. Then dropped the ignition timing down two degrees are the problem rpm range and all seems good

madmike
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Re: My draw through turbo

Post by madmike » Sun Jul 01, 2018 5:22 am

glad you got it sorted :wink: :lol:

advinnie
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Re: My draw through turbo

Post by advinnie » Sun Jul 01, 2018 5:38 am

Yes I can most definitely say that retarding the timing by 2 degrees between 2600 & 2900 has solved it . I was running 27 degrees @ 2600 & 30 degrees @2900 now @ 25 @ 2600 & 28 degrees @ 2900

advinnie
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Re: My draw through turbo

Post by advinnie » Sun Jul 01, 2018 5:41 am

Yes I can most definitely say that retarding the timing by 2 degrees between 2600 & 2900 has solved it . I was running 27 degrees @ 2600 & 30 degrees @2900 now @ 25 @ 2600 & 28 degrees @ 2900. This is at 101Kpa, my cruise timing is 8 degrees my advanced

advinnie
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Re: My draw through turbo

Post by advinnie » Wed Jul 04, 2018 2:03 pm

Hi all, I've got to asj a question. Over the last few days I've been re writing my ignition map and the old girl is running better than ever. Now my crusing manifold pressure is around -6 psi /60Kpa but some how and I don't know how this happened in my over run bins of -8 and -10 psi/46&32 Kpa bins my ignition timing had set it's self to TDC (0 degrees) any way the result of this is amazing it truly is, the sound coming from the exhaust on over run is great although I now have no engine breaking at all, but can anyone see any issues with this?

advinnie
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Re: My draw through turbo

Post by advinnie » Thu Jul 05, 2018 2:25 am

Let's talk about timing 😁
Know I've been told by a Porsche turning garage just down the road to me that to set idle timing to give maximum torque when the pedal is first pushed you do the following.
Warm engine and slowly advance the ignition timing till you get the highest manifold pressure. Now at 13 degrees BTDC I have a manifold reading of 73Kpa, at 18 degrees BTDC I have 70Kpa and at 25 degrees BTDC at idle (1000 rpm) I get my highest reading of 67Kpa. But seriously running 25 degrees BTDC at idle this can't be right can it?

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petew
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Re: My draw through turbo

Post by petew » Fri Jul 06, 2018 2:44 am

Paging Mario and Piledriver.

It might be fine as long as your head temps aren't too high. What AFRs do you have at idle? I think the standard ACVW idle timing is something around 12-15deg.

advinnie
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Re: My draw through turbo

Post by advinnie » Fri Jul 06, 2018 3:53 am

Running that timing advance at idle kind off works.
I've always had a very lean condition at idle if 18:1 but as soon as I come of off idle my A/F ratio goes to 13.8:1.
Anyway what I've found with idle timing set at 25 degrees BTDC is that the amount of torque the engine produces when you open the throttle from a stand still is amazing. The rear end of the bug goes to the floor and the nose lifts up high but at 1400-1500 rpm I get engine knock with 25 degrees BTDC so have had to lower it down to 19 degrees BTDC to get rid of the knock but in doing that I now have 25 at idle dropping down to 19 at 1400 rpm then advancing again back up to the 31 degrees BTDC at 3200rpm the issue with this is that when accelerating from idle I have great torque at first then torque reduces and the nose of the bug drops and the high torque I get at the beginning just off of idle doesn't come back till the timming starts to advance again. Hope this makes sense?

All so I'm really not happy, I have been running windscreen wash in my water injection system and it's been great been running 10 psi without any issues and I could do a 10psi pull from 65mph to 100mph in fourth (so a long time at 10psi) without detonation but I've just replaced the windscreen wash fluid for a 50/50 methanol/water mix ( 50/50 by weight NOT volume) and now am getting slight detonation at only 153Kpa/ 7.8 psi boost. I have not changed the ignition timing nor anything else just replaced the windscreen wash (28% methanol, 5% perfume, 2% colouring and 65% water) with the 50/50 mix of methanol/water.

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petew
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Re: My draw through turbo

Post by petew » Fri Jul 06, 2018 4:44 am

Just googled it... 7.5-10 degrees BTDC. That's the stock setting with a dizzy. I wish I hadmy tune file with me but from memory I set mine at 10deg. I reckon it would depend on your cam too. Maybe with a really lumpy cam you'd want a slightly higher idle and more advance. My idle is set at around 900rpm.

advinnie
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Re: My draw through turbo

Post by advinnie » Fri Jul 06, 2018 6:01 am

My idle is at 900-1000rpm and timing now at 17 degrees BTDC. This allows me to have the the butterfly screw/idle screw turned in by 3/4 turns from fully closed. The more idle advance I run the more I can close the butterflys

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kangaboy
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Re: My draw through turbo

Post by kangaboy » Fri Jul 06, 2018 9:20 am

advinnie wrote:
Fri Jul 06, 2018 6:01 am
My idle is at 900-1000rpm and timing now at 17 degrees BTDC. This allows me to have the the butterfly screw/idle screw turned in by 3/4 turns from fully closed. The more idle advance I run the more I can close the butterflys
Mine is something close to this as well. My idle settles around 1100RPM though. I like having the higher idle to help a little with the oil pressure. I'll get some numbers and update with kpa and actual ignition timing to compare though.
'74 Standard- 1776T, MS3X3
'76 Westy- Stock 2.0L L-Jet

advinnie
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Re: My draw through turbo

Post by advinnie » Fri Jul 06, 2018 9:49 am

Cheers mate. If I could figure out how to down size a photo on the phone I would post one of my ignition map.
My oil pressure sits a 7-9 psi at 900 ish rpm once my engine is up to temperature and that's with 15w50 oil witch I'm going to swap back to 15w40 witch also has the same idle pressure but a much better pressure across the rpm range.
With the 15w40 oil I get 42 psi at 4000rpm and it doesn't rise any more with more rpm where as with the 15w50 in seeing 58 psi at 5300rpm witch is to much

advinnie
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Re: My draw through turbo

Post by advinnie » Fri Jul 06, 2018 11:40 am

Well I've sorted the detonation issue out. I was continuously getting detonation kicking in at 7 psi boost above 3000rpm with a timing of 24 degrees BTDC after I've changed to a 50/50 mix of methanol/water. I had to reduce the timing down to only 15 degrees BTDC to get rid of it. Any way after a lot of f#@king around I noticed I had some how pulled the boost reference line of the fuel regulator so the fuel pressure/ flow to the carb was not increasing 😡 anyway as soon as I reconnected the boost line all detonation went away and can now run 10 psi again. Just goes to proves that a draw through set-up DOSE NEED a boost sensitive fuel regulator to keep the fuel bowl full 🙄

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