LS1GTO Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
2,691 Posts
Discussion Starter #1
I was driving home today and had the Predator plugged in. While I was thinking about the readings I thought it might be interesting if everyone with a predator or other scan tool reported their findings.

The first thing I wanted was the MAP readings at WOT. We all know that more air flow is better and the MAP reading should tell us if the filter & intake tube is restrictive. The higher the reading the less restrictive the air flow. We could get interesting results if we all use the same parameters - in this case the same rpm - and list the equipment we're using.

Maybe know one is interested but I'm going to give this a shot.

CONDITION:
On the highway in 6 gear @ 2k rpm, punch it and note the MAP reading.

14.5 for me using the stock air box and filter with Speed Inc intake tube.
 

·
Captain Thread Killer returns
Joined
·
21,898 Posts
mlc said:
I was driving home today and had the Predator plugged in. While I was thinking about the readings I thought it might be interesting if everyone with a predator or other scan tool reported their findings.

The first thing I wanted was the MAP readings at WOT. We all know that more air flow is better and the MAP reading should tell us if the filter & intake tube is restrictive. The higher the reading the less restrictive the air flow. We could get interesting results if we all use the same parameters - in this case the same rpm - and list the equipment we're using.

Maybe know one is interested but I'm going to give this a shot.

CONDITION:
On the highway in 6 gear @ 2k rpm, punch it and note the MAP reading.

14.5 for me using the stock air box and filter with Speed Inc intake tube.
Sounds like a great idea....I sometimes ride around with my predator plugged in and wonder how my readings compare to others......I will do this tomorrow hopefully
 

·
I hack cars.
Joined
·
8,111 Posts
I would recommend using MAF readings rather than MAP for a few reasons. One being its MUCH more precise at WOT and it also has an easy correlation to air flow in G/Sec.
 

·
Registered
Joined
·
2,691 Posts
Discussion Starter #4
MAF would be more sensitive to RPM than MAP, IMO. there would be a direct correlation of air flow to rpm, where as air pressure would only vary at a percent of the change in rpm.

But anyway.. We could do both.
 

·
Mod Hungry... Empty Wallet
Joined
·
2,137 Posts
Guess you don't need or want A4 readings? Or maybe you do for comparison?
 

·
Registered
Joined
·
42 Posts
The really big issue for these cars is inlet air temp.Have been intrigued by the mods made by the Predator and had a lengthy conversation with Diablo today.Here is the deal.They do not modify the speed fan cutoff so the fans cut out either at 30mph or a calculation made by the PCM based upon ac settings and other parameters.This is good because the fans Kicking in early lower both the ECT and IAT Thus,although they are on most of the time at idle they do go off at speed, as the PCM over rides temp control SO I would suggest sticking with the Predator on&off settings .

Now here is the deal on temps versus ignition advance curve.If you feel the car being sluggish or sorta flat with high outside temps, read on. Per Diablo, they do not alter the retard formula controlled by the PCM based uppon temps.At 86 degrees F as measured by the IAT sensor ,total advance is retarded 1 degree,at 95 degrees 3 degree advance reduction,113 degrees,4 degree advance reduction,and 1 degree retard for every 9 degree increase in IAT over that up to a total retard of 11 degrees

Thats a potential loss of almost one third of total advance.Remember these are factory settings and are not altered by Predator .Predator does alter total advance and the curve by not retard curve so as to prevent the KR from kicking on.

Today it was 94 degrees F. AT idle my IAT was 141 degrees.Driving around town at 30 or 40 mph it never dropped lower than 134 degrees.Thus if I hit the go pedal at any of these times my advance was 6 or 7 degrees retarded making the car feel a little down on power.On the open road I drove 12 miles at 60 to 70 MPH and the IAT never dropped lower than 104 degrees or 10 degrees higher than outside temp.Retard still of 4 degrees.......this is a power killer ,Im running stock intake and do not feel any available CAI add on will do any better without external ducting to get away from heat soak under the hood..folks heat is the enemy and the ls1,ls6 are fussy when it comes to heat
 

·
Go Tigers!
Joined
·
2,455 Posts
scheer said:
The really big issue for these cars is inlet air temp.Have been intrigued by the mods made by the Predator and had a lengthy conversation with Diablo today.Here is the deal.They do not modify the speed fan cutoff so the fans cut out either at 30mph or a calculation made by the PCM based upon ac settings and other parameters.This is good because the fans Kicking in early lower both the ECT and IAT Thus,although they are on most of the time at idle they do go off at speed, as the PCM over rides temp control SO I would suggest sticking with the Predator on&off settings .

Now here is the deal on temps versus ignition advance curve.If you feel the car being sluggish or sorta flat with high outside temps, read on. Per Diablo, they do not alter the retard formula controlled by the PCM based uppon temps.At 86 degrees F as measured by the IAT sensor ,total advance is retarded 1 degree,at 95 degrees 3 degree advance reduction,113 degrees,4 degree advance reduction,and 1 degree retard for every 9 degree increase in IAT over that up to a total retard of 11 degrees

Thats a potential loss of almost one third of total advance.Remember these are factory settings and are not altered by Predator .Predator does alter total advance and the curve by not retard curve so as to prevent the KR from kicking on.

Today it was 94 degrees F. AT idle my IAT was 141 degrees.Driving around town at 30 or 40 mph it never dropped lower than 134 degrees.Thus if I hit the go pedal at any of these times my advance was 6 or 7 degrees retarded making the car feel a little down on power.On the open road I drove 12 miles at 60 to 70 MPH and the IAT never dropped lower than 104 degrees or 10 degrees higher than outside temp.Retard still of 4 degrees.......this is a power killer ,Im running stock intake and do not feel any available CAI add on will do any better without external ducting to get away from heat soak under the hood..folks heat is the enemy and the ls1,ls6 are fussy when it comes to heat
Thanks for this post, it explains a lot. So the predator does not allow retard
past a certain point vs the stock setting? Am I reading that right?
 

·
GTOholic
Joined
·
1,504 Posts
Scheer's comments are consistant with my own findings. That's why I switched BACK to the stock box from the Speed Inc. High Flow Induction kit.

I'll try to get Dad's laptop tomorrow. I'm going to the dragstrip anyway, so I should be able to get lots of WOT data.
 

·
Registered
Joined
·
42 Posts
Yellow Jacket M6 said:
Thanks for this post, it explains a lot. So the predator does not allow retard
past a certain point vs the stock setting? Am I reading that right?
thats correct,but the amount of retard is significant ,also did not post but water temp effects up to a retard of an additional 1 degree at 230 degrees f.However when its below zero f ,additional advance of up to 8 gegrees can be added to help cold weather starts.This is controlled by the ect sensor
 

·
Mod Hungry... Empty Wallet
Joined
·
2,137 Posts
scheer said:
thats correct,but the amount of retard is significant ,also did not post but water temp effects up to a retard of an additional 1 degree at 230 degrees f.However when its below zero f ,additional advance of up to 8 gegrees can be added to help cold weather starts.This is controlled by the ect sensor
Would this mean that a functional hood, that brings air in and takes it out (thinking *maybe* PFYC), would help eliminate heat soak by removing internal heat?
 

·
Registered
Joined
·
2,691 Posts
Discussion Starter #11
scheer said:
The really big issue for these cars is inlet air temp.Have been intrigued by the mods made by the Predator and had a lengthy conversation with Diablo today.Here is the deal.They do not modify the speed fan cutoff so the fans cut out either at 30mph or a calculation made by the PCM based upon ac settings and other parameters.This is good because the fans Kicking in early lower both the ECT and IAT Thus,although they are on most of the time at idle they do go off at speed, as the PCM over rides temp control SO I would suggest sticking with the Predator on&off settings .

Now here is the deal on temps versus ignition advance curve.If you feel the car being sluggish or sorta flat with high outside temps, read on. Per Diablo, they do not alter the retard formula controlled by the PCM based uppon temps.At 86 degrees F as measured by the IAT sensor ,total advance is retarded 1 degree,at 95 degrees 3 degree advance reduction,113 degrees,4 degree advance reduction,and 1 degree retard for every 9 degree increase in IAT over that up to a total retard of 11 degrees

Thats a potential loss of almost one third of total advance.Remember these are factory settings and are not altered by Predator .Predator does alter total advance and the curve by not retard curve so as to prevent the KR from kicking on.

Today it was 94 degrees F. AT idle my IAT was 141 degrees.Driving around town at 30 or 40 mph it never dropped lower than 134 degrees.Thus if I hit the go pedal at any of these times my advance was 6 or 7 degrees retarded making the car feel a little down on power.On the open road I drove 12 miles at 60 to 70 MPH and the IAT never dropped lower than 104 degrees or 10 degrees higher than outside temp.Retard still of 4 degrees.......this is a power killer ,Im running stock intake and do not feel any available CAI add on will do any better without external ducting to get away from heat soak under the hood..folks heat is the enemy and the ls1,ls6 are fussy when it comes to heat
I'll be reading this a few time to get it straight. :banghead:
I don't know why your IAT is so high though. Mine is running only a few degrees above ambient.

I agree the temp kills but I still would like MAP readings.
 

·
Registered
Joined
·
2,691 Posts
Discussion Starter #12
Huntress said:
Guess you don't need or want A4 readings? Or maybe you do for comparison?
I would but how can you keep the auto from kicking down a gear?
 

·
Registered
Joined
·
42 Posts
mlc said:
I'll be reading this a few time to get it straight. :banghead:
I don't know why your IAT is so high though. Mine is running only a few degrees above ambient.

I agree the temp kills but I still would like MAP readings.
Sorry,no way IS your slow speed IAT NEAR AMBIENT with temps over 80 degrees. IAT temps are deadly as they cause big time pre ignition or knock
and thats why the PCM starts to retard at a quick rate and thats why predator does not alter the rate of retard.....what type induction do you have?The only CIA that looks appealing to me is the one to be released by Lingenfelter soon.
 

·
DAAAT'S RIGHT
Joined
·
1,650 Posts
scheer said:
The really big issue for these cars is inlet air temp.Have been intrigued by the mods made by the Predator and had a lengthy conversation with Diablo today.Here is the deal.They do not modify the speed fan cutoff so the fans cut out either at 30mph or a calculation made by the PCM based upon ac settings and other parameters.This is good because the fans Kicking in early lower both the ECT and IAT Thus,although they are on most of the time at idle they do go off at speed, as the PCM over rides temp control SO I would suggest sticking with the Predator on&off settings .

Now here is the deal on temps versus ignition advance curve.If you feel the car being sluggish or sorta flat with high outside temps, read on. Per Diablo, they do not alter the retard formula controlled by the PCM based uppon temps.At 86 degrees F as measured by the IAT sensor ,total advance is retarded 1 degree,at 95 degrees 3 degree advance reduction,113 degrees,4 degree advance reduction,and 1 degree retard for every 9 degree increase in IAT over that up to a total retard of 11 degrees

Thats a potential loss of almost one third of total advance.Remember these are factory settings and are not altered by Predator .Predator does alter total advance and the curve by not retard curve so as to prevent the KR from kicking on.

Today it was 94 degrees F. AT idle my IAT was 141 degrees.Driving around town at 30 or 40 mph it never dropped lower than 134 degrees.Thus if I hit the go pedal at any of these times my advance was 6 or 7 degrees retarded making the car feel a little down on power.On the open road I drove 12 miles at 60 to 70 MPH and the IAT never dropped lower than 104 degrees or 10 degrees higher than outside temp.Retard still of 4 degrees.......this is a power killer ,Im running stock intake and do not feel any available CAI add on will do any better without external ducting to get away from heat soak under the hood..folks heat is the enemy and the ls1,ls6 are fussy when it comes to heat
This needs it's own thread.

So is there anything that the Predator can do to help this, or is it strictly an induction problem?
 

·
Registered
Joined
·
42 Posts
JayStew said:
This needs it's own thread.

So is there anything that the Predator can do to help this, or is it strictly an induction problem?
Predator is on the money and makes all the right adjustments.This is an induction problem and probably will only be corrected with a hood type intake port direct to the MAF like the Vette.Just my view but getting rid of the heat will impact performance more than most mods.
 

·
DAAAT'S RIGHT
Joined
·
1,650 Posts
Ok, driving down the interstate. Air temp about 90 deg. According to the Predator IAT was 100-102 deg. At 2k rpm in 6th I floored it, MAP 14.6, MAF 11.5-12.0

I am all stock air box and tube.
 

·
Registered
Joined
·
2,691 Posts
Discussion Starter #17
scheer said:
Sorry,no way IS your slow speed IAT NEAR AMBIENT with temps over 80 degrees. IAT temps are deadly as they cause big time pre ignition or knock
and thats why the PCM starts to retard at a quick rate and thats why predator does not alter the rate of retard.....what type induction do you have?The only CIA that looks appealing to me is the one to be released by Lingenfelter soon.
Friday I left work with the predator on. the car was cold but by the time I got on the highway it was warmed up. Except for a short stop at one light I kept moving. The IAT never got above 84 for the 30 minutes of drive time on the highway. The outside temp was ~78.

BUT, after coming out of the grocery store the IAT was ~140 and no matter how long I drove, moving forward, the IAT would not get below 113.

I'm not making these number up.

It seems that once the intake gets hot it wont cool down.
 

·
May I quote you on that?
Joined
·
22,046 Posts
I've found after heatsoaking to 140, it takes several miles at freeway speed to get it back anywhere near ambient. City driving it never really cools down. We need some thin, high performance metallized insulation to wrap the snorkel and airbox.
 

·
Registered
Joined
·
2,691 Posts
Discussion Starter #19
mistermike said:
I've found after heatsoaking to 140, it takes several miles at freeway speed to get it back anywhere near ambient. City driving it never really cools down. We need some thin, high performance metallized insulation to wrap the snorkel and airbox.
I saw the perfect stuff but it was a while ago and I don't remember where I saw it. I'm stopping THD tonight on the way to golf to look for it.

...it? plyable(sp?), self adhesive, aluminum backed, 1/8 inch insolation for home heat duct.
 
1 - 19 of 19 Posts
Top