Timing v.s. boost...
Thread Starter
Staging Lane
Joined: Jun 2002
Posts: 62
Likes: 0
From: Layton, UT
Timing v.s. boost... I've got a question about the lifespan of my motor. I've got a turbotech kit with a T66.
My goal is, and has always been, 450 RWHP. Right now I managed that with 5.5 psi and a tune by yours truly with LS1 edit. I have 24 degree's of timing at WOT.
If I back the timing down to 18 degree's I need 7 psi to make my 450 RWHP.
Which way would be the least detrimental to engine life? Assuming all other things are equal (driving habits, track time, etc...).
My goal is, and has always been, 450 RWHP. Right now I managed that with 5.5 psi and a tune by yours truly with LS1 edit. I have 24 degree's of timing at WOT.
If I back the timing down to 18 degree's I need 7 psi to make my 450 RWHP.
Which way would be the least detrimental to engine life? Assuming all other things are equal (driving habits, track time, etc...).
Staging Lane
Joined: Dec 2001
Posts: 82
Likes: 0
From: Haulin Asstro in MN
Re: Timing v.s. boost... I would say they would be fairly equal. There is reasons for both. Higher boost equal higher intake temps. Higher timing means more pressure on piston before TDC. I personally would got for 7PSI and less timing
Just my .02 cents
Just my .02 cents
FormerVendor
Joined: Dec 2001
Posts: 2,444
Likes: 2
From: WWW.SPEEDINC.COM
Re: Timing v.s. boost... Have you actually tried it both ways or are you just guesstimating?
I think it would make more power with 18 degrees of timing and 7psi than 24 degrees of timing and 5.5 psi due to the efficiency of the combustion chamber (alot of timing is not needed).
I think it would make more power with 18 degrees of timing and 7psi than 24 degrees of timing and 5.5 psi due to the efficiency of the combustion chamber (alot of timing is not needed).
Re: Timing v.s. boost... I have always heard it is safer... and better to run more boost, less timing..
I do know that i could tell a difference in spool up times when my timing was lower... i got boost noticeable sooner with less timing due to the hotter exhaust gases.
I do know that i could tell a difference in spool up times when my timing was lower... i got boost noticeable sooner with less timing due to the hotter exhaust gases.
Re: Timing v.s. boost... oh and my reasoning on the boost vs. timing... both timing and boost create cylinder pressure but a # or two of boost will make more than 6 degrees of timing and be farther away from the detonation threshold than the other way around.... anyone agree??
Re: Timing v.s. boost... can you tell me about your set up? stock compresion? pump gas? can you run this set up when it is hot out? intercooled?
this is a good topic, how sure are you about the 6deg=2psi
this is a good topic, how sure are you about the 6deg=2psi
Thread Starter
Staging Lane
Joined: Jun 2002
Posts: 62
Likes: 0
From: Layton, UT
Re: Timing v.s. boost... I haven't tried messing with the timing too much yet. I kinda picked the numbers out of the air for the 2nd half of the question.
Stock compression, 91 octane gas (******' Utah, I swear to GOD), I run 3 psi on the 91 and go to 5.5 with a mix of 91 and 100 in the tank. I've only had the kit installed for about 2 weeks, but no problems as of yet.
Hehe, I got the excat opposite suggestion on that "other" board. Keep em' coming. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Stock compression, 91 octane gas (******' Utah, I swear to GOD), I run 3 psi on the 91 and go to 5.5 with a mix of 91 and 100 in the tank. I've only had the kit installed for about 2 weeks, but no problems as of yet.
Hehe, I got the excat opposite suggestion on that "other" board. Keep em' coming. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Trending Topics
Re: Timing v.s. boost... </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">this is a good topic, how sure are you about the 6deg=2psi </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">oh no..sorry for the misinterpretation... i didn't mean that 6deg=2psi... i meant that in my experiences.. adding two psi or so helped out more than having 6 degrees more timing...and seemed to be safer as far as hot days in traffic, etc.
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TECH Regular
Joined: Apr 2002
Posts: 462
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From: ...
Re: Timing v.s. boost... Timeing like compression ratio are maxed out mostly on NA cars to squeeze out the last 10hp or so. Compared to boost they are nothing. Droping 1.3 points of compression and running 2psi of boost should result in the same hp, however with that setup I can run 3 times more boost pressure so at 7psi I would make the same hp as 10.1:1 at 5psi, yet I could run up to 18psi on 93octane now instead of just 5psi. Same thing with timeing, lower timing and lose 10hp but gain 50hp with 2 extra psi of boost and yes boost is easier on the motor then timeing, so go for the boost. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
TECH Resident
Joined: Jan 2002
Posts: 956
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From: Phoenix, AZ
Re: Timing v.s. boost... What is the lowest advance we'd want to run on our cars? I've been struggling with the same thoughts . . . I can run 5psi on 91 with pretty well full timing, but I'm thinking 7psi with reduced timing is better. I have no proof to back this up however. I'd just like to know what the lowest ignition I can run is . . . and another question . . . in LS1-Edit in the spark advance tables, which rows correspond to WOT? A buddy of mine says that around .6 and up is WOT. Any other thoughts on that?
- Dug
- Dug
Moderator
Joined: Nov 2001
Posts: 3,048
Likes: 12
From: Raleigh, NC
RiceEater, I'm with u.
2 PSI boost is a lot more power than 2 degrees of timing. No... I can't say how much.
Perhaps a shop that has time on their hands to test those things can answer that question.
That being said, I've heard too LITTLE timing can adversely affect more than just power... that too little can ALSO create detonation. Is that a crazy idea? What happens when timing is reduced to too little?
2 PSI boost is a lot more power than 2 degrees of timing. No... I can't say how much.
Perhaps a shop that has time on their hands to test those things can answer that question.
That being said, I've heard too LITTLE timing can adversely affect more than just power... that too little can ALSO create detonation. Is that a crazy idea? What happens when timing is reduced to too little?
TECH Resident
Joined: Aug 2003
Posts: 948
Likes: 0
From: orlando, florida
When I was at stock compression my car would ping if i ran less then 14* timing, There for yes i do believe to little timing will cause detonation. I think if your runing stock compression once you try pushing more then 9psi of boost your timing is gonna be getting so low that you,d gain power from lower boost/more timing. But generally if the car is setup right you'll gain more from 2psi of boost and less timing as long as you keep a resonable amount of timing in it.
I have always run my turbo cars with lower timing and high boost. Its easier to control detonation with the boost controller then LT1/LS1 edit or other programming methods.
Jose
Jose
TECH Apprentice
Joined: Jan 2004
Posts: 337
Likes: 0
From: Frisco TX (Dallas Area)
In my experience 1 degree of timing = about 2- hp, while 1 psi of boost can = about 5+ hp. Now the downside: more boost psi = inlet temp increase, so there's a point of deminishing return. If you are IC/AC, then jump the boost because that's a lot more potential and the IC can DELETE THE HEAT! If you aren't, use the timing advance to get your hp. About 6 psi on a non-IC setup is the best (rough) compromise. So if you can get the hp you want at 6-7 psi, that's the way to go. I would suggest that you go to 20-23 degrees of timing, then up the boost until you see KR, then back the timing down until the KR is gone. Hey, this is my HO and comes from 3800 Roots SC work. This takes some balancing work, but seems to give the best area under the curve. The old GN Buick axiom at the track was to use higher octane gas and up the boost at the same timing. That seemed to work best.
Sum it up, go the most boost with the most timing with 0 KR, that's the sweet spot. HTH
edit: Ha Ha, can't spell!
Sum it up, go the most boost with the most timing with 0 KR, that's the sweet spot. HTH
edit: Ha Ha, can't spell!
Last edited by TeeKay; Jun 4, 2004 at 06:41 PM.
