problem with timing
problem with timing Here is a link to the thread thought I would post here as well since this is turning into more of an engine prob than dyno.
https://ls1tech.com/forums/dynamometer-results-comparisons/393377-low-numbers-dynojet.html
Went to the dyno last night and am a little dissapointed in my numbers. (See attatchment). Car made a max of 358/ 349 hp/tq. Mods are in the sig below. We were tuning with HP tuners.
The heads are bone stock except for some 918 springs, on stock block. For some reason the car did not like anything over 19 deg of timing. We tried 21 and got knock and the air fuel was around 13-1 (Not sure if it can be read clearly from the graph) I am running BP 92 in the tank as well.
It was around 70 deg F in the dynoshop and we had a big fan blowing in front of my car so I don't think that was the problem. ELE is 1100 ft. This was a dynojet as well.
When we were done he showed me countless other dynos where cars with cams like mine without things like LS6 intakes were making the same power as me. Some were cam only cars and there were making more power. Hell even a stock graph was comparable to mine.
I know heads would help but why does this thing dyno so low in the first place?
Any advice, comments? TIA
https://ls1tech.com/forums/dynamometer-results-comparisons/393377-low-numbers-dynojet.html
Went to the dyno last night and am a little dissapointed in my numbers. (See attatchment). Car made a max of 358/ 349 hp/tq. Mods are in the sig below. We were tuning with HP tuners.
The heads are bone stock except for some 918 springs, on stock block. For some reason the car did not like anything over 19 deg of timing. We tried 21 and got knock and the air fuel was around 13-1 (Not sure if it can be read clearly from the graph) I am running BP 92 in the tank as well.
It was around 70 deg F in the dynoshop and we had a big fan blowing in front of my car so I don't think that was the problem. ELE is 1100 ft. This was a dynojet as well.
When we were done he showed me countless other dynos where cars with cams like mine without things like LS6 intakes were making the same power as me. Some were cam only cars and there were making more power. Hell even a stock graph was comparable to mine.
I know heads would help but why does this thing dyno so low in the first place?
Any advice, comments? TIA
TECH Enthusiast
Joined: Mar 2003
Posts: 618
Likes: 0
From: San Diego
What was your injector duty cycle at? Did you try backing off your A/F ratio a bit? I'd push it back down to 12.8 and see how it does. Is 13.1 what you are commanding? (using the PE table). Check your fuel pressure at load, maybe its dropping when you hit the throttle, causing you to run lean and have to back the timing off. When is the last time you changed the fuel filter?
Something is wrong with your tune somewhere. I am just about at 12:1 compression and I run 21-22 degrees of timing. Not saying you should run max timing, just whatever timing is good for your heads. Which being stock should be around 26-27*
Something is wrong with your tune somewhere. I am just about at 12:1 compression and I run 21-22 degrees of timing. Not saying you should run max timing, just whatever timing is good for your heads. Which being stock should be around 26-27*
Originally Posted by Bombguy99z28
What was your injector duty cycle at? Did you try backing off your A/F ratio a bit? I'd push it back down to 12.8 and see how it does. Is 13.1 what you are commanding? (using the PE table). Check your fuel pressure at load, maybe its dropping when you hit the throttle, causing you to run lean and have to back the timing off. When is the last time you changed the fuel filter?
Something is wrong with your tune somewhere. I am just about at 12:1 compression and I run 21-22 degrees of timing. Not saying you should run max timing, just whatever timing is good for your heads. Which being stock should be around 26-27*
Something is wrong with your tune somewhere. I am just about at 12:1 compression and I run 21-22 degrees of timing. Not saying you should run max timing, just whatever timing is good for your heads. Which being stock should be around 26-27*
I asked my tuning guy and he said injector duty cycle was fine AF was actually 12.8 which was what we commanded. We logged fuel pressure just in case the wideband wasn't accurate and it showed 56 or so all the way through.
As soon as midterms are over (this weekend) I am going to pull the plugs and check them. Then do a leakdown test.
Fri afternoon we are going to put it back on the dyno with race gas and see if there is a possibility of false knock making it show KR when it might not be. If so desensitize them some.
This look like a good plan of attack? What about the MSD wires, should I put the stockers on?
TECH Enthusiast
Joined: Mar 2003
Posts: 618
Likes: 0
From: San Diego
naw, you'd know if a wire wasn't giving spark, but I guess it wouldn't hurt just to be safe. The numbers are a tad lower than would be expected, however within the margin of possibility for cam only. I'd be more worried about the timing and what is causing the need to pull so much. Try backing it down to 12.5 maybe, just to make sure it isn't A/F ratio.
Ok went back to the dyno with some 115 octane. Commanded 26* timing and still got some false knock, pretty sure the knock sensors are picking up some valve train noise. So we shut off the knock sensors and ran it again with 26* and we gained exactly 7 horsepower by adding 6 degrees. There was no audiable knock for sure. Something is not clicking with what I have for some reason.
Mods are once again in the sig so this combo is nothing out of the ordinary. Lots of guys are running 27* and making 20 hp/tq more than me. WHY?
Are TTII wheels heavy enough to kill hp?
Could it be a cam problem? Ground wrong? Lots of people run this thing?
Leakdown test? Motor has around 80 thousand on it and 6 thousand of it with cam headers and stuff. Is it wore out. It does pull very strong on the street and carries very good oil pressure and doesn't smoke.
Induction servcie/ tune up?
Help me out guys? Sorry for being a pain in the *** and asking so many Q's
Mods are once again in the sig so this combo is nothing out of the ordinary. Lots of guys are running 27* and making 20 hp/tq more than me. WHY?
Are TTII wheels heavy enough to kill hp?
Could it be a cam problem? Ground wrong? Lots of people run this thing?
Leakdown test? Motor has around 80 thousand on it and 6 thousand of it with cam headers and stuff. Is it wore out. It does pull very strong on the street and carries very good oil pressure and doesn't smoke.
Induction servcie/ tune up?
Help me out guys? Sorry for being a pain in the *** and asking so many Q's
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Verdad Gallardo On my first dyno pull, my a/f was at 13.5, but I had 0 knock still, timing was around 28-30 I believe. I'd say your knock sensor is messing up if it shows some, hence why your timing is low.
Yes but on the last two runs we ran it with the knock sensors turned off and then commanded 26* and it still didn't make any more than like 6 hp.
Hp shouldn't come that hard with that much more timing.
That is why I went there with race gas to see if I had any false knock and also to know for sure I could command as much timing as most other cars with stock heads and this cam gets.
But again with the knock sensors off I don't know why it won't make any more power
Hp shouldn't come that hard with that much more timing.
That is why I went there with race gas to see if I had any false knock and also to know for sure I could command as much timing as most other cars with stock heads and this cam gets.
But again with the knock sensors off I don't know why it won't make any more power
Going to have a leakdown test done but if it comes back a little off would this have anything to do with the timing and low hp issue.
I just don't see how some guys can just throw in this cam on their bone stock motor with basically no bolt ons, make 380+ hp and run like 28* and everthing is fine.
thanks for any responses.
I just don't see how some guys can just throw in this cam on their bone stock motor with basically no bolt ons, make 380+ hp and run like 28* and everthing is fine.
thanks for any responses.
Did a top engine clean and then got the leakdown test done and everything was perfect. All cylinders were between 0 and 1% and number 3 was 2%. So this thing is practically new. All tests were done at 100psi as well.
So what to do? I know the bottom end is good so do I pull the 224/224- 563/112 cam and put in something larger or do I put on a nice set of heads like TEA's LS1 stage 1.
Input is greatly appreciated. I just think 358/449 for this car with the mods is fairly low. And I think the inability to run large amounts of timing like everyone else contribuites to it.
So what to do? I know the bottom end is good so do I pull the 224/224- 563/112 cam and put in something larger or do I put on a nice set of heads like TEA's LS1 stage 1.
Input is greatly appreciated. I just think 358/449 for this car with the mods is fairly low. And I think the inability to run large amounts of timing like everyone else contribuites to it.
Originally Posted by 954RR
Ok went back to the dyno with some 115 octane.
Go back with 92 octane and 28* timing with the KR disabled and see how it does.
I questioned that. It is because of the motor does not have the compression to efficiently burn that much octane, right? I think commanded 6* more WOT and it yeilded 6-7 hp making the total like 168, which I guess for my mods and such would be right on par? Not sure on that one though.
I just ran the 115 too make sure that the KR I was getting was indeed false so I didn't hurt anything.
I just ran the 115 too make sure that the KR I was getting was indeed false so I didn't hurt anything.
https://ls1tech.com/forums/showthread.php?t=393377
from the graph it looks like 5800
torque is nice though like 350 from 3000-5000 before it starts to fall off
if this truely is all this thing is going to make with this cam, then I may begin looking at a bit bigger cam to use with some nice heads on my quest for over 400hp. It just does not look like I will get there with this cam even if I did have heads.
from the graph it looks like 5800
torque is nice though like 350 from 3000-5000 before it starts to fall off
if this truely is all this thing is going to make with this cam, then I may begin looking at a bit bigger cam to use with some nice heads on my quest for over 400hp. It just does not look like I will get there with this cam even if I did have heads.
Originally Posted by 954RR
https://ls1tech.com/forums/showthread.php?t=393377
from the graph it looks like 5800
torque is nice though like 350 from 3000-5000 before it starts to fall off
if this truely is all this thing is going to make with this cam, then I may begin looking at a bit bigger cam to use with some nice heads on my quest for over 400hp. It just does not look like I will get there with this cam even if I did have heads.
from the graph it looks like 5800
torque is nice though like 350 from 3000-5000 before it starts to fall off
if this truely is all this thing is going to make with this cam, then I may begin looking at a bit bigger cam to use with some nice heads on my quest for over 400hp. It just does not look like I will get there with this cam even if I did have heads.
Straight line performance installed it. I bought the car with the cam already installed, but I did call the shop and they said there was no way that I could be off they said they just lined up the dots. Anyways wouldn't it just not run right over all if it was a tooth off or something?
Here is a short run down of the last few numbers row by row
RPM HP Torque A/F
5400 345.4 335.9 12.7
5500 345.5 335.9 12.7
5600 350.4 328.7 12.7
5700 354.5 326.6 12.7
5800 356.7 323.0 12.7
5900 353.7 314.8 12.6
6000 352.2 308.3 12.6
6100 348.7 300.2 12.5
6200 351.1 297.4 12.5
Here is a short run down of the last few numbers row by row
RPM HP Torque A/F
5400 345.4 335.9 12.7
5500 345.5 335.9 12.7
5600 350.4 328.7 12.7
5700 354.5 326.6 12.7
5800 356.7 323.0 12.7
5900 353.7 314.8 12.6
6000 352.2 308.3 12.6
6100 348.7 300.2 12.5
6200 351.1 297.4 12.5
Originally Posted by 954RR
Straight line performance installed it. I bought the car with the cam already installed, but I did call the shop and they said there was no way that I could be off they said they just lined up the dots. Anyways wouldn't it just not run right over all if it was a tooth off or something?