Retarding Timing on Blower Motor
Moderator: John_Heard
Retarding Timing on Blower Motor
Hello All! I have a question to pose, but first I just wanted to state that I really enjoy this site. I find my way on to a lot of them, but rarely post unless they are top notch and this one really is. Ok, enough of that!
My buddy and I are putting together a blown sbc for my altered and we are in need of some advise on the timing.
Here are a few specs:
377 with 7:1 (static) compression
8-71 blower pushing 16 lbs of boost
Hilborn 4 port mechanical injection
MSD pro billet dist with rev limiter (8k) and boost retard
powerglide tranny shifting at 7500
powered by C12
I have spoke to a few guys and they tell me since I will be locking out my distributor to start with the advance at 28* and slowly advance it to max of 32* . Some guys tell me I do not need to run boost retarded ignition others do. I just do not know what is best. It would seem that performance may suffer without retarding it. My compression is low enough that I don't feel knock is a concern (should be under 15:1 dynamic). If I do use the MSD retard then do I set it to where it retards it 1* for every pound of boost or more and what do you think I should lock my timing at? Thanks,T
My buddy and I are putting together a blown sbc for my altered and we are in need of some advise on the timing.
Here are a few specs:
377 with 7:1 (static) compression
8-71 blower pushing 16 lbs of boost
Hilborn 4 port mechanical injection
MSD pro billet dist with rev limiter (8k) and boost retard
powerglide tranny shifting at 7500
powered by C12
I have spoke to a few guys and they tell me since I will be locking out my distributor to start with the advance at 28* and slowly advance it to max of 32* . Some guys tell me I do not need to run boost retarded ignition others do. I just do not know what is best. It would seem that performance may suffer without retarding it. My compression is low enough that I don't feel knock is a concern (should be under 15:1 dynamic). If I do use the MSD retard then do I set it to where it retards it 1* for every pound of boost or more and what do you think I should lock my timing at? Thanks,T
- Moparious Maximus
- Posts: 125
- Joined: Mon Oct 05, 2009 6:05 pm
- Location: Iowa
Re: Retarding Timing on Blower Motor
If you know what you are doing and keep an eye on your tuneup, you wont need a timing retard. If you want to run it like a regular bracket car and never check the plugs and be 100% safe all the time, yea its probably a good idea.
IMO, there are 2 factors. Do you trust yourself tuning it? ..... How well will you take it if it does hurt itself?.
IMO, there are 2 factors. Do you trust yourself tuning it? ..... How well will you take it if it does hurt itself?.
'63 Plymouth, Straight axle, Leaf springs, Drum brakes, 31x10.5wx15 Rears 3215lbs
Best time to date 7.99 @ 170 mph
572" Wedge 8-71 @ 28% OD, ALKY, Glide, Dana
http://www.youtube.com/watch?v=vq-xzFWHtFk
http://www.youtube.com/watch?v=JfyZSw59R_o
Best time to date 7.99 @ 170 mph
572" Wedge 8-71 @ 28% OD, ALKY, Glide, Dana
http://www.youtube.com/watch?v=vq-xzFWHtFk
http://www.youtube.com/watch?v=JfyZSw59R_o
Re: Retarding Timing on Blower Motor
On my own I would be concerned, but my buddy built promod engines for Reher-Morrison but he's never fooled with blowers before. I'm just trying to kinda get a baseline from some of you that have been down this road before. Oh and I would be
deeply sick if we fouled it up! LOL!
deeply sick if we fouled it up! LOL!
Re: Retarding Timing on Blower Motor
I've been running a 427 bbc - 8:1 static w/671 making 8 lbs of boost, spinning to around 6500 - dcr of about 11:1 - I ran 32 to 34 degrees total advance on a locked out Unilite distributor with no boost retard - 112 fuel on the track. Of course, I drive mine on the street as well as making the occasional pass down the qtr, so I'm probably not as harsh on mine as you'll be on yours.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline
http://www.marsh-racing.com/harrys_camaro-1.htm
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline
http://www.marsh-racing.com/harrys_camaro-1.htm
Re: Retarding Timing on Blower Motor
Thanks for the reply! It really helps hearing what others are doing.
Re: Retarding Timing on Blower Motor
I have a 32 Bantam Altered with a 406 SBC, 8-71 blower, Enderle Bird Injector, 10.5:1 static. Right now I am running about 16 # boost and the distributor is locked at 30 degrees. I do not run a retard. So far, running alcohol, I haven't experienced any detonation damage. I do keep it happy by running a little bigger nozzle than needed, giving up a little on the top end. I understand about not wanting to do any damage. I fund everything out of my own wallet also!
32 Bantam Altered
SBC, 8-71 Blower, Injected, Alcohol
I intend to live forever... so far... so good
SBC, 8-71 Blower, Injected, Alcohol
I intend to live forever... so far... so good
Re: Retarding Timing on Blower Motor
Mean looking Bantam! Looks like most guys aren't fooling with the retard. I'm thinking I will probably skip it myself.
Re: Retarding Timing on Blower Motor
Some fellas on another board seem to think because my cam has 114 lsa that I will run into detonation problems with C12. If so it seems the easy fix would be C16. Thoughts?
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