Me too!!!
Timing Effects On Power Output
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Timing Effects On Power Output
I just had my car tuned again. It was tuned with 17 degrees of timing on topend, but it was very hot and the car pulled out 8 degrees of timing because of high IAT's which resulted in 9 degrees of advance. I have meth, but my IAT sensor does not pick up the meth spray since it is in the MAF. I made 620rwhp with all that timing pulled, and I was wondering if anyone had an educated guess as to haw much power I left on the table. I would also like to hear some suggestions as to how to fix the problem. Thanks in advance for the answers.
Burning Brakes
Joined: Mar 2005
Posts: 822
Likes: 1
From: Henderson Texas
There are 2 ways you can go about fixing your problem.
1. the way I did it was to cut the wires from the maf where the iat is integrated and splice in an IAT sensor from a gto (I just had this laying around is why I used it) and placed the new sensor after the meth and after the maf...last in line basically.
1st maf 2nd meth injection 3rd IAT sensor.
After that I went into hptuners and went to the IAT/Timing table and changed the values to not pull any timing until I hit around 104 degrees and then pulling 7-10 or so from there up just in case the meth ever stops working it pulls alot of timing for you for safety.
2. the other way to do it is not putting the sensor in and just adjusting the tables to not remove timing up to a certain temp. and hope that the meth works all the time.
Call me if you need any help. 903-705-2886
1. the way I did it was to cut the wires from the maf where the iat is integrated and splice in an IAT sensor from a gto (I just had this laying around is why I used it) and placed the new sensor after the meth and after the maf...last in line basically.
1st maf 2nd meth injection 3rd IAT sensor.
After that I went into hptuners and went to the IAT/Timing table and changed the values to not pull any timing until I hit around 104 degrees and then pulling 7-10 or so from there up just in case the meth ever stops working it pulls alot of timing for you for safety.
2. the other way to do it is not putting the sensor in and just adjusting the tables to not remove timing up to a certain temp. and hope that the meth works all the time.
Call me if you need any help. 903-705-2886
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
There are 2 ways you can go about fixing your problem.
1. the way I did it was to cut the wires from the maf where the iat is integrated and splice in an IAT sensor from a gto (I just had this laying around is why I used it) and placed the new sensor after the meth and after the maf...last in line basically.
1st maf 2nd meth injection 3rd IAT sensor.
After that I went into hptuners and went to the IAT/Timing table and changed the values to not pull any timing until I hit around 104 degrees and then pulling 7-10 or so from there up just in case the meth ever stops working it pulls alot of timing for you for safety.
2. the other way to do it is not putting the sensor in and just adjusting the tables to not remove timing up to a certain temp. and hope that the meth works all the time.
Call me if you need any help. 903-705-2886
1. the way I did it was to cut the wires from the maf where the iat is integrated and splice in an IAT sensor from a gto (I just had this laying around is why I used it) and placed the new sensor after the meth and after the maf...last in line basically.
1st maf 2nd meth injection 3rd IAT sensor.
After that I went into hptuners and went to the IAT/Timing table and changed the values to not pull any timing until I hit around 104 degrees and then pulling 7-10 or so from there up just in case the meth ever stops working it pulls alot of timing for you for safety.
2. the other way to do it is not putting the sensor in and just adjusting the tables to not remove timing up to a certain temp. and hope that the meth works all the time.
Call me if you need any help. 903-705-2886
Premium Supporting Vendor
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From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
One thing to be careful of is to watch your actual timing if you relocate your IAT sensor after the nozzles. It can raise timing from the cooler IAT's if you did not adjust that in your IAT tables, resulting in more timing than you desired.
If you are using the alky as a fuel requirement, have it pull a lot of timing out above 100 degrees. With proper working alky, IAT's will stay 10-20 degrees below ambient.
If you are using the alky as a fuel requirement, have it pull a lot of timing out above 100 degrees. With proper working alky, IAT's will stay 10-20 degrees below ambient.
Burning Brakes
Joined: Mar 2005
Posts: 822
Likes: 1
From: Henderson Texas
I feel like you are probably only leaving about 40hp on the table...who knows maybe more. You should be able to feel the difference though if you were to run as much timing as your commanding.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Im guessing at the answer to my own question, but using some horsepower calculators they tend to say 10hp for every 2 degrees of timing. So 40hp seems logical, but since this is a forced induction motor I was hoping it was closer to 80hp. I really wanted to see 700rwhp from this combo. It was about 100 degrees in the dyno area when I made my pulls, and the last two were back to back when it made 620.
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Former Vendor
Joined: Jun 2002
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From: Bridgewater Ma
What I would be scared about is that the car is tuned for 9 degree's of timing.So,what will happen when it gets full timing on the street with the cooler air? Could be ugly.When meth is used I shut down the timing retard on the dyno to get an accurate tune,then put the IAT retard back in after.This is because on the dyno the MAF gets heat soaked.
Safety Car
Joined: May 2002
Posts: 3,615
Likes: 2
From: waterloo ontario
St. Jude Donor '08
Bro-you need to do this:
This will insure you don't pull timing with the meth-then go inot HPT and look at the IAT table-go and double those #'s. this way if the meth fails you will pull more than enough timing.
I'm working on a plate that will bolt in between the the TB and the intake and will come with a IAT sensor-all you need to do is cut 2 wires and your done.
FWIW-my car picks up about 50rwhp for every 2 degrees
This will insure you don't pull timing with the meth-then go inot HPT and look at the IAT table-go and double those #'s. this way if the meth fails you will pull more than enough timing.
I'm working on a plate that will bolt in between the the TB and the intake and will come with a IAT sensor-all you need to do is cut 2 wires and your done.
FWIW-my car picks up about 50rwhp for every 2 degrees
Drifting
Joined: Mar 2006
Posts: 1,872
Likes: 7
From: Richmond VA
Hmm, just about the same thing. Finished mine last week. Can't say that it made much difference on the track, but it should be safer if I ever tune with the meth. It is still slow in this heat/humidity.
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
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From: http://www.mphparts.com 800-364-1975
What I would be scared about is that the car is tuned for 9 degree's of timing.So,what will happen when it gets full timing on the street with the cooler air? Could be ugly.When meth is used I shut down the timing retard on the dyno to get an accurate tune,then put the IAT retard back in after.This is because on the dyno the MAF gets heat soaked.
Who knows how much power was left on the table. Could be a bunch (50hp), could be a little (10hp). Every configuration is different. Mine stopped making more power after 15 degrees of timing on 15psi of boost. Adding timing only made it more prone to predetonation and didn't make more power.
How much boost are you making? To make 620rwhp on only 9 degrees of timing I'd guess 12-15psi?
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Fully agree with Slowhawk.
Who knows how much power was left on the table. Could be a bunch (50hp), could be a little (10hp). Every configuration is different. Mine stopped making more power after 15 degrees of timing on 15psi of boost. Adding timing only made it more prone to predetonation and didn't make more power.
How much boost are you making? To make 620rwhp on only 9 degrees of timing I'd guess 12-15psi?
Who knows how much power was left on the table. Could be a bunch (50hp), could be a little (10hp). Every configuration is different. Mine stopped making more power after 15 degrees of timing on 15psi of boost. Adding timing only made it more prone to predetonation and didn't make more power.
How much boost are you making? To make 620rwhp on only 9 degrees of timing I'd guess 12-15psi?
Melting Slicks
Joined: Nov 2004
Posts: 2,715
Likes: 0
From: Tinker till it blows... then back it off a notch, maybe!!
St. Jude Donor '08
Bro-you need to do this:
This will insure you don't pull timing with the meth-then go inot HPT and look at the IAT table-go and double those #'s. this way if the meth fails you will pull more than enough timing.
I'm working on a plate that will bolt in between the the TB and the intake and will come with a IAT sensor-all you need to do is cut 2 wires and your done.
FWIW-my car picks up about 50rwhp for every 2 degrees
This will insure you don't pull timing with the meth-then go inot HPT and look at the IAT table-go and double those #'s. this way if the meth fails you will pull more than enough timing.
I'm working on a plate that will bolt in between the the TB and the intake and will come with a IAT sensor-all you need to do is cut 2 wires and your done.
FWIW-my car picks up about 50rwhp for every 2 degrees
Has the meth ever failed? What afr's are you running with the 2 nozzles at full tilt?
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
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From: http://www.mphparts.com 800-364-1975
I am making 15lbs at 6900, but I make peak power at about 6200 which is about 13lbs. I think what is happening is by the time I hit 15lbs the IAT's are up and I'm pulling so much timing that the power starts to drop off. It doesn't just fal on it's face, but it does start to taper off.
Assuming nothing is out of whack, you should be closer to/over 700rwhp with 15psi of boost on a 346. It sounds like you are leaving a ton of power on the table.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
It's a forged 347. Unported 317 heads milled to 71cc (just cleaned up), D1SC with A&A Intercooler, 222/228 567/567 113lsa cam. I thought it should be closer to 700 as well, but its been a challenge to get the bugs worked out. It started off with belt slip limiting me to 11lbs of boost and 575rwhp, but has slowly gotten better with tuning and belt adjustments. The compression according to my calculations is about 9 to 1. I used Diamond 8.6cc dish pistons, but dont remember the out of deck height. I also used stock gm gaskets.
Last edited by redcycle13; Jun 12, 2007 at 11:59 AM.
Instructor
Joined: Jun 2007
Posts: 186
Likes: 0
From: Kansas City MO
Bro-you need to do this:
This will insure you don't pull timing with the meth-then go inot HPT and look at the IAT table-go and double those #'s. this way if the meth fails you will pull more than enough timing.
I'm working on a plate that will bolt in between the the TB and the intake and will come with a IAT sensor-all you need to do is cut 2 wires and your done.
FWIW-my car picks up about 50rwhp for every 2 degrees
This will insure you don't pull timing with the meth-then go inot HPT and look at the IAT table-go and double those #'s. this way if the meth fails you will pull more than enough timing.
I'm working on a plate that will bolt in between the the TB and the intake and will come with a IAT sensor-all you need to do is cut 2 wires and your done.
FWIW-my car picks up about 50rwhp for every 2 degrees
Former Vendor
Joined: Jun 2002
Posts: 2,045
Likes: 3
From: Bridgewater Ma
Never had one fail. Last year we got an expensive 427ci blower car tuned last minute which we ran the meth full tilt to make up for the serious lack of fuel.Made 4 track passes the next day and the car ran mint at 11.5-1 A/F. So,we trusted a $25k+ motor on it.
Melting Slicks
Joined: Nov 2004
Posts: 2,715
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From: Tinker till it blows... then back it off a notch, maybe!!
St. Jude Donor '08
The ECS/Alky control kit is the best hands down Never had one fail. Last year we got an expensive 427ci blower car tuned last minute which we ran the meth full tilt to make up for the serious lack of fuel.Made 4 track passes the next day and the car ran mint at 11.5-1 A/F. So,we trusted a $25k+ motor on it.
Never had one fail. Last year we got an expensive 427ci blower car tuned last minute which we ran the meth full tilt to make up for the serious lack of fuel.Made 4 track passes the next day and the car ran mint at 11.5-1 A/F. So,we trusted a $25k+ motor on it.I am referring to setups where meth is a MUST to keep afr's in check