Corvair Center Forum : Corvair Center Phorum
Posted by: clockman.mulcahy ()
Date: February 03, 2018 06:24AM
I have just finished a 63 turbo car that has a later larger turbo. can i get suggestions on timing? the book said that 24 degree advance but when i stuff the throttle it stumbles. do you think that i need to advance the timing?
Posted by: irfgt ()
Date: February 03, 2018 07:05AM
Try it and see what happens. I it spark knocks then back off the timing.
Posted by: jjohnsonjo ()
Date: February 03, 2018 09:15AM
I'd say more likely carb issues. I run an A/R unit the static is at 18. That means as soon as I stand on it the vacuum is gone and its at 18 and heading down as the boost builds.
65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo
Posted by: kmart356 ()
Date: February 03, 2018 09:58AM
For reference... these are factory specs with timing curves with factory Retard
'62 Spyder cpe - '63 Monza convertible
Posted by: JimBrandberg ()
Date: February 04, 2018 06:55AM
I think the thing to be most concerned about with timing is how much will be the maximum advance, with all the engine and road noise at high RPMs and speed detonation might be hard to hear. 24 degrees is a fair amount to start out with.
Posted by: 63turbo ()
Date: February 04, 2018 08:01AM
I've experimented with turbo timing a lot, as have others... I can vouch for the fact that the stock turbo timing leaves a lot to be desired! The only part of the timing that is kind of close to right is right before the boost retard hits, and even that isn't really right. Much of what "feels" like turbo lag
is actually the overly retarded timing... the car doesn't start to really accelerate until the way too late distributor advance kicks in. I think you would do a lot better using a 95 distributor using vacuum advance/boost retard can. For an even more aggressive mechanical based timing approach, get ahold of kmart356! Real world problems with the stock curve: the engine runs way too hot when cruising at freeway speeds, because it doesn't have enough timing.
If you advance the timing enough to make that right, then the engine is hard to start because it is way too much timing.... 10 to 12 is a lot more like it for starting. If your distributor timing starts at 10 at 500 rpm and ends at
28 to 30 at 3000 rpm (lot closer to correct!) but no vacuum advance, then the car still runs way too hot at light loads and is very doggy because it still doesn't have enough timing.... round and round it goes. It was because of issues like that and others that I bagged the mechanical based approach.
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Posted by: gnvair ()
Date: February 04, 2018 08:26AM
Every combo is different so you have to experiment with it.
I prefer programmable ignitions and locking out all of the mechanical advance mechanism.
I can make changes right from my seat and do not have to deal with inconsistent boost retard mechanisms.
If you want to get the most out of your combo, I strongly advise into some kind of programmable system. The learning curve is super easy.