LS2 402 Way Low Dyno Numbers. Help Please!
04-16-2006, 01:30 PM
#61
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Could you possibly post an idle log as well as a wot log? I think others could help better if they had something to diagnose.
I gotta think that you are having things going on that the logs will show.
Perry
I gotta think that you are having things going on that the logs will show.
Perry
04-16-2006, 10:55 PM
#62
I will get that posted up tomorrow. I did get a chance to look at one of GTODoug's scans and saw 1 thing that struck me as different from my logs.
At full throttle I am only hitting the .76 g/cyl cells on the spark table. Doug is up over 1.00. What would cause me not to hit the higher cells?
At full throttle I am only hitting the .76 g/cyl cells on the spark table. Doug is up over 1.00. What would cause me not to hit the higher cells?
04-17-2006, 09:49 AM
#63
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get rid of the freaking stock injectors and get some 36's at least. the stockers are not going to support the power potential that that motor is going to make, so why even try and tune it with them in it??
04-17-2006, 11:22 AM
#64
yea why the hell do you have stock injectors, in my little cammed 350 lt1 i had to put at the very least 30# and those were at 85% with only 374rwhp.....why cheap out on the injectors, big part of power = fuel
do you have a fuel pump either?
do you have a fuel pump either?
04-17-2006, 12:38 PM
#66
Nope and since so many of you have been kind enough to break my ***** about the stock injectors, I went ahead and charged some damn 42# from SPDC just now. The good news is that the credit card statement wont come for another month so I have about 24 days before I have to hear any bitching about it.
Now, what are the thoughts about the .76 g/cyl cells being the highest that I am hitting? The HPT guys are telling me that .76 is normal range at WOT across the 4K +RPMs. GTODoug is hitting cells up over 1.00 in the spark table scans. I am wondering if I should be also.
Tony, would you happen to have an HPT tune that I could look at or some scans from a comparable setup? I am really trying to avoid the leakdown test if you hadn't noticed.
Now, what are the thoughts about the .76 g/cyl cells being the highest that I am hitting? The HPT guys are telling me that .76 is normal range at WOT across the 4K +RPMs. GTODoug is hitting cells up over 1.00 in the spark table scans. I am wondering if I should be also.
Tony, would you happen to have an HPT tune that I could look at or some scans from a comparable setup? I am really trying to avoid the leakdown test if you hadn't noticed.
04-17-2006, 05:57 PM
#67
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Good job on the injectors. For reference, I was hitting 98% duty cycle on 28.8 lb injectors...346 cam only! My roomate hit 116% with his heads/cam 346.
Stock injectors are only good for MAYBE 380 whp.
Also, I know this sounds stupid, but you may wanna take a look into your exhaust setup. I know that wouldn't rob 100 hp, but I'm sure you're cutting yourself short with the y-piped configuration.
You are using the low octane timing table for your tuning, right? I know these are obvious questions, but we all overlook stuff from time to time.
.76 g/cyl does seam a bit low, imho, but you gotta realize that in speed density mode, the MAP sensor is the only thing telling the computer what's going on...so what happens when two differently sized motors are both seeing the same MAP pressure? Does that mean they have the same airflow? No, not at all. Is you're friend with the 402 also running in SD mode?
And lastly, don't pay any attention to your O2 sensors during high throttle. Narrowband O2's are designed to operate between 14.0:1 and 15.0:1 for the most part. It's a 1 volt range they have to work with, and it is confined to very close to the stoichiometric ratio. A wideband is the only way to really know your AFR.
It's not that the narrowbands are just a little off... their signals are MEANINGLESS below about 14.0:1.
Stock injectors are only good for MAYBE 380 whp.
Also, I know this sounds stupid, but you may wanna take a look into your exhaust setup. I know that wouldn't rob 100 hp, but I'm sure you're cutting yourself short with the y-piped configuration.
You are using the low octane timing table for your tuning, right? I know these are obvious questions, but we all overlook stuff from time to time.
.76 g/cyl does seam a bit low, imho, but you gotta realize that in speed density mode, the MAP sensor is the only thing telling the computer what's going on...so what happens when two differently sized motors are both seeing the same MAP pressure? Does that mean they have the same airflow? No, not at all. Is you're friend with the 402 also running in SD mode?
And lastly, don't pay any attention to your O2 sensors during high throttle. Narrowband O2's are designed to operate between 14.0:1 and 15.0:1 for the most part. It's a 1 volt range they have to work with, and it is confined to very close to the stoichiometric ratio. A wideband is the only way to really know your AFR.
It's not that the narrowbands are just a little off... their signals are MEANINGLESS below about 14.0:1.
04-18-2006, 12:54 AM
#68
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Hahaha.....
Tony tell me if you concure...
You DID fix your problem the first time, your cam WAS off (I agree it looks dead on right now)
However by fixing your first problem you have found the weak link in your set up, you are down on power because you are starving your motor for fuel...
stock injectors are not able to stand up to most big H/C cars, But that is only the first part, changing your injectors are a start and you will find more power till probably 5500 rpms now, But I bet it falls on its face after that...
You need a fuel pump as well, that stocker is not going to push enough fuel to power #42's on a 402 with a BIG cam ... That WILL be your next problem... I would fix this before it effects you,
Right now you are playing with fire(literally), you are making WOT runs while your detonation is starting at 4000 rpms...
Give her the fuel she is asking for before you are buying a new shortblock....again...
Tony tell me if you concure...
You DID fix your problem the first time, your cam WAS off (I agree it looks dead on right now)
However by fixing your first problem you have found the weak link in your set up, you are down on power because you are starving your motor for fuel...
stock injectors are not able to stand up to most big H/C cars, But that is only the first part, changing your injectors are a start and you will find more power till probably 5500 rpms now, But I bet it falls on its face after that...
You need a fuel pump as well, that stocker is not going to push enough fuel to power #42's on a 402 with a BIG cam ... That WILL be your next problem... I would fix this before it effects you,
Right now you are playing with fire(literally), you are making WOT runs while your detonation is starting at 4000 rpms...
Give her the fuel she is asking for before you are buying a new shortblock....again...
04-18-2006, 07:49 AM
#69
Originally Posted by KingWalrus
Good job on the injectors. For reference, I was hitting 98% duty cycle on 28.8 lb injectors...346 cam only! My roomate hit 116% with his heads/cam 346.
Stock injectors are only good for MAYBE 380 whp.
Also, I know this sounds stupid, but you may wanna take a look into your exhaust setup. I know that wouldn't rob 100 hp, but I'm sure you're cutting yourself short with the y-piped configuration.
You are using the low octane timing table for your tuning, right? I know these are obvious questions, but we all overlook stuff from time to time.
.76 g/cyl does seam a bit low, imho, but you gotta realize that in speed density mode, the MAP sensor is the only thing telling the computer what's going on...so what happens when two differently sized motors are both seeing the same MAP pressure? Does that mean they have the same airflow? No, not at all. Is you're friend with the 402 also running in SD mode?
And lastly, don't pay any attention to your O2 sensors during high throttle. Narrowband O2's are designed to operate between 14.0:1 and 15.0:1 for the most part. It's a 1 volt range they have to work with, and it is confined to very close to the stoichiometric ratio. A wideband is the only way to really know your AFR.
It's not that the narrowbands are just a little off... their signals are MEANINGLESS below about 14.0:1.
Stock injectors are only good for MAYBE 380 whp.
Also, I know this sounds stupid, but you may wanna take a look into your exhaust setup. I know that wouldn't rob 100 hp, but I'm sure you're cutting yourself short with the y-piped configuration.
You are using the low octane timing table for your tuning, right? I know these are obvious questions, but we all overlook stuff from time to time.
.76 g/cyl does seam a bit low, imho, but you gotta realize that in speed density mode, the MAP sensor is the only thing telling the computer what's going on...so what happens when two differently sized motors are both seeing the same MAP pressure? Does that mean they have the same airflow? No, not at all. Is you're friend with the 402 also running in SD mode?
And lastly, don't pay any attention to your O2 sensors during high throttle. Narrowband O2's are designed to operate between 14.0:1 and 15.0:1 for the most part. It's a 1 volt range they have to work with, and it is confined to very close to the stoichiometric ratio. A wideband is the only way to really know your AFR.
It's not that the narrowbands are just a little off... their signals are MEANINGLESS below about 14.0:1.
After putting in the new timing values, I was hitting cells in the .84 range. I am not sure that I understand what you are talking about w/ regards to the MAP pressures in differently sized motors. GTODoug's motor is a 408 so it should be comparable if that is what you are refering to. I think that he was running with the MAF on the scan that I looked at. Please keep in mind that I wasn't physically there to see it. He is someone that I met through the forums and he e-mailed the scan for me to look at.
I am currently working on the wideband situation. I have a buddy that has the innovative (not the one with the gage, the one with the scanner thing) and I may just buy a sensor and use his scanner. Unfortunately, I did not buy the EIO version of HPT
04-18-2006, 07:53 AM
#70
I am curious if the heads having been milled .045 would effect the alignment of the LS6 intake. Should I have the same .045 shaved of the bottom of the intake? Is there even enough "meat" on the LS6 intake to mill .045 from the bottom?
04-18-2006, 09:03 AM
#71
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FYI, my high compression 408 is in the .92-1.0 g/cyl range at WOT.
don't hesitate putting in the 42's. that will not introduce a variable, it will ELIMINATE a variable. instead of replacing you pump, you could probably get by with a hot-wire kit for $50-75 or whatever they cost. it will provide more voltage to the stock pump.
don't hesitate putting in the 42's. that will not introduce a variable, it will ELIMINATE a variable. instead of replacing you pump, you could probably get by with a hot-wire kit for $50-75 or whatever they cost. it will provide more voltage to the stock pump.
04-18-2006, 09:08 AM
#72
Originally Posted by 383ss
FYI, my high compression 408 is in the .92-1.0 g/cyl range at WOT.
don't hesitate putting in the 42's. that will not introduce a variable, it will ELIMINATE a variable. instead of replacing you pump, you could probably get by with a hot-wire kit for $50-75 or whatever they cost. it will provide more voltage to the stock pump.
don't hesitate putting in the 42's. that will not introduce a variable, it will ELIMINATE a variable. instead of replacing you pump, you could probably get by with a hot-wire kit for $50-75 or whatever they cost. it will provide more voltage to the stock pump.
04-18-2006, 07:56 PM
#74
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Guys,
I am at a loss. Why would injectors make such low numbers in the low rpm range? While I was breaking in my new SLP402 with AFR 225 heads, I used my stock LS6 injectors and kept things below 4500rpm. I made no less tire shredding torque up to my 4500 redline than I have now using 36# injectors.
Chuck
I am at a loss. Why would injectors make such low numbers in the low rpm range? While I was breaking in my new SLP402 with AFR 225 heads, I used my stock LS6 injectors and kept things below 4500rpm. I made no less tire shredding torque up to my 4500 redline than I have now using 36# injectors.
Chuck
04-18-2006, 09:31 PM
#75
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Originally Posted by Chuck Harmon
Guys,
I am at a loss. Why would injectors make such low numbers in the low rpm range? While I was breaking in my new SLP402 with AFR 225 heads, I used my stock LS6 injectors and kept things below 4500rpm. I made no less tire shredding torque up to my 4500 redline than I have now using 36# injectors.
Chuck
I am at a loss. Why would injectors make such low numbers in the low rpm range? While I was breaking in my new SLP402 with AFR 225 heads, I used my stock LS6 injectors and kept things below 4500rpm. I made no less tire shredding torque up to my 4500 redline than I have now using 36# injectors.
Chuck
04-19-2006, 12:00 AM
#77
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Originally Posted by Chuck Harmon
Guys,
I am at a loss. Why would injectors make such low numbers in the low rpm range? While I was breaking in my new SLP402 with AFR 225 heads, I used my stock LS6 injectors and kept things below 4500rpm. I made no less tire shredding torque up to my 4500 redline than I have now using 36# injectors.
Chuck
I am at a loss. Why would injectors make such low numbers in the low rpm range? While I was breaking in my new SLP402 with AFR 225 heads, I used my stock LS6 injectors and kept things below 4500rpm. I made no less tire shredding torque up to my 4500 redline than I have now using 36# injectors.
Chuck
No he said his power down low is much better, but he is detonating his *** off above 4000 rpms...
04-19-2006, 12:45 AM
#78
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I agree with the whole getting bigger,better,injectors theory.Im just curious as to why hasn't anyone commented on his possible vacuum leak.IIRC,a vacuum leak is when a motor pulls in air from somewhere its isnt supposed and can't take it into account when trying to calculate the proper A/F ratio resulting in a lean condition.Right?Resulting in the detonation he may be hearing above 4k.Shouldn't the detonation show up on the plugs in the cylinders thats its happening?Plus if its in certain cylinders and not in all,wouldnt that help him narrow it down as far as where to look at for the possible leak?I usaully dont chime in on posts like these considering that I know nothing compared to you guys.I was just reading along and was waiting for the vacuum leak possibility to be addressed when I got to the last post and my mouth dropped open.sorry if any info I present here is wrong.........
04-19-2006, 01:47 AM
#79
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Carlos-I am running the car in open loop SD. I am also using the 1bar upgrade as well. The graph I sent you has no maf on the car at that time. I am posting a scan from a pull on the dyno yesterday:
There are some other things that could affect it as well like a/f ratio, altitude, etc.
I would imagine you'd run out of fuel as well by 4K. I have my FMS 42's seeing a peak of 75% duty cycle. Keep us updated, if you need a base table for the FMS 42's shoot me an email.
Dougie
There are some other things that could affect it as well like a/f ratio, altitude, etc.
I would imagine you'd run out of fuel as well by 4K. I have my FMS 42's seeing a peak of 75% duty cycle. Keep us updated, if you need a base table for the FMS 42's shoot me an email.
Dougie