How little timing can I run and not hurt anything??
#1444186
05/29/13 12:17 PM
05/29/13 12:17 PM
|
Joined: Dec 2006
Posts: 1,178
Indy
FlyFish
OP
super stock
|
OP
super stock
Joined: Dec 2006
Posts: 1,178
Indy
|
I have my small block stroker currently at 25° total timing. I'm wanting the car to slow down another 2 tenths, so I was going to pull the timing down a few more degrees...will this hurt anything? Can I run 20° total timing and not damage anything? I know it will cause more exhaust heat, but is that it?
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: Thumperdart]
#1444188
05/29/13 01:39 PM
05/29/13 01:39 PM
|
Joined: Dec 2006
Posts: 1,178
Indy
FlyFish
OP
super stock
|
OP
super stock
Joined: Dec 2006
Posts: 1,178
Indy
|
I'm just trying to get this thing to run in Sportsman (12.0 bottom dial). I'm real close...just need a little more. This is what I have done so far:
I added as much weight to the car as possible (safely). I removed the secondaries on the carb (now its a 2 barrel), backed the timing off 10 degrees (25° total currently), and I'm short shifting at 5500 RPM (I normally shift at 6500). This combo has slowed the car a little over a second from high 10.7x ET to 11.87 (calculated from my 1000' time on my last 3 pass when I lifted at the 1000' cone and ran 12.05)....I just need to kill a little bit more to get to 12.0 so I don't have to coast the last 320'.
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: FlyFish]
#1444190
05/29/13 01:46 PM
05/29/13 01:46 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
You will be suprized how much timing you would need to pull out to slow it .2.... what rpm do you launch at... lower that and shift 500 less than you are shifting now... I have a mech throttle stop on my dom set at 1/3 open and launch soft and shift real early to go 10.0 
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: MR_P_BODY]
#1444191
05/29/13 02:11 PM
05/29/13 02:11 PM
|
Joined: Dec 2006
Posts: 1,178
Indy
FlyFish
OP
super stock
|
OP
super stock
Joined: Dec 2006
Posts: 1,178
Indy
|
Unfortunately I can't shift any lower RPM, my converter flashes to a little over 5K, so I'm pretty much shifting as soon as I see the tach move (which is about 5500).
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: FlyFish]
#1444192
05/29/13 02:31 PM
05/29/13 02:31 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Put a mech throttle stop on it.. at part throttle the conv flashes/stalls at a lower rpm due to not making the torque like full throttle
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: FlyFish]
#1444193
05/29/13 03:08 PM
05/29/13 03:08 PM
|
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
|
Quote:
I have my small block stroker currently at 25° total timing. I'm wanting the car to slow down another 2 tenths, so I was going to pull the timing down a few more degrees...will this hurt anything? Can I run 20° total timing and not damage anything? I know it will cause more exhaust heat, but is that it?
You are going to melt something , as it is your headers must be cherry red by the end of the pass .
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: MR_P_BODY]
#1444194
05/29/13 03:12 PM
05/29/13 03:12 PM
|
Joined: Dec 2006
Posts: 1,178
Indy
FlyFish
OP
super stock
|
OP
super stock
Joined: Dec 2006
Posts: 1,178
Indy
|
So should I turn my timing back up to 35° (or close to it)?
67 Barracuda street car, 408, e85, 1.38 60', 6.44 @105.9 in the 1/8 mile, 10.19 @130.5 in the 1/4...so far....
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: FlyFish]
#1444197
05/29/13 03:24 PM
05/29/13 03:24 PM
|
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
|
Quote:
Quote:
Ever researched the "ET genie" ?
Yeah, but I'm not dropping 500 bucks to go slower. I just want it slower for a few races.
Can you run the class in your daily driver ? 
What have you done to SAFELY ADD weight ? Adding weight is the best way to do it , can you swap steel you added for LEAD ???
I think the $500 will be cheaper than the potential damage you are going to do ....
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: JohnRR]
#1444198
05/29/13 03:38 PM
05/29/13 03:38 PM
|
Joined: Jan 2003
Posts: 19,372
Las Vegas
Al_Alguire
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 19,372
Las Vegas
|
As already pointed out the only potential damage will likely be the exhaust vavels. Well it will also run a bit hotter normally with that much out of it.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: wyoming]
#1444201
05/29/13 04:56 PM
05/29/13 04:56 PM
|
Joined: Jun 2006
Posts: 5,163
CT
GTX MATT
master
|
master
Joined: Jun 2006
Posts: 5,163
CT
|
Forced induction cars run 15-20 degrees, but that is with the aid of electronics and only when necessary  My forced induction job runs as little as 10 degrees at certain rpm/load conditions and exhaust temps don't pass 1100 degrees. That being said it isn't 10 degrees throughout the rpm range, and that is only under full load/boost conditions.
Last edited by GTX MATT; 05/29/13 05:01 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: GTX MATT]
#1444202
05/29/13 05:52 PM
05/29/13 05:52 PM
|
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
|
Quote:
Forced induction cars run 15-20 degrees, but that is with the aid of electronics and only when necessary
My forced induction job runs as little as 10 degrees at certain rpm/load conditions and exhaust temps don't pass 1100 degrees. That being said it isn't 10 degrees throughout the rpm range, and that is only under full load/boost conditions.
I didn't know that , but how does that help with a car not running forced induction and a timing computer ? He doesn't want to pony up the 5 bills for the ET thingamabob , I don't think he is going to pony up for forced induction so he can roll back the timing more ....
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: GTX MATT]
#1444204
05/29/13 06:03 PM
05/29/13 06:03 PM
|
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
I Win
|
I Win
Joined: Jan 2003
Posts: 75,043
U.S.S.A.
|
Quote:
To be more specific I should have said they run as little as 15-20 from the factory, because at certain points they will be in a normal 34+ range.
But still exhaust temps are reasonable, they should remain reasonable in an NA application, although my car also runs around 11-11.5:1 AFR under said conditions. I'm just playing devil's advocate. 
Ever break in a cam with the timing at only 20-25 degrees ??? You won't get half way thru the break in before the radistor is boiling over ...
|
|
|
Re: How little timing can I run and not hurt anything??
[Re: JohnRR]
#1444205
05/29/13 06:22 PM
05/29/13 06:22 PM
|
Joined: Jun 2006
Posts: 5,163
CT
GTX MATT
master
|
master
Joined: Jun 2006
Posts: 5,163
CT
|
Quote:
Quote:
To be more specific I should have said they run as little as 15-20 from the factory, because at certain points they will be in a normal 34+ range.
But still exhaust temps are reasonable, they should remain reasonable in an NA application, although my car also runs around 11-11.5:1 AFR under said conditions. I'm just playing devil's advocate.
Ever break in a cam with the timing at only 20-25 degrees ??? You won't get half way thru the break in before the radistor is boiling over ...
I wouldn't try to operate the engine at speed for extended periods of time with the timing retarded because it would surely overheat, but for a track car for 12 seconds at a time I think he will get away with it, just lock the timing out OR run vacuum advance on manifold vacuum to prevent overheating at idle.
At WOT my forced induction car sees the timing curve below, the car has been operated at WOT for in excess of 12 seconds many times without exhaust temperatures surpassing 1100 degrees.
I know that his car is not forced induction, and he SHOULD better explore other ways to limit his power, BUT
RPM Total timing
800 8.13
1200 13.05
1600 13.05
2000 12
2400 11.29
2800 9.89
3200 9.54
3600 9.54
4000 11.29
4400 12
4800 13.75
5200 16.21
5600 16.57
6000 19.03
6400 20.43
6800 23.25
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
|
|
|
|
|
