Is there a relationship between IAT, EGT and detonation?
Is there a relationship between IAT, EGT and detonation? I was thinking if there is a relationship between those three. I'm asking because Im getting a D-1SC very soon and i want to setup the car for road course racing without blowing up my motor due to high IAT or high EGT which could cause detonation from what i understand soo far. I was wondering if i need to watch my IAT or EGT or both of them after 20min of hard driving. What do u think guys?
TECH Apprentice
Joined: Apr 2002
Posts: 308
Likes: 0
From: Austin, TX
Originally Posted by NoGo
Just keep your knock sensors and get an onboard a/f meter.
A good scanner like EFI-Live is a good place to start. It will log most of what you need.
Originally Posted by QuickSilver2002
EGT will give you some indication of A/F, but it is not that intresting on a supercharged car. Turbos are where EGT is more important.
A good scanner like EFI-Live is a good place to start. It will log most of what you need.
A good scanner like EFI-Live is a good place to start. It will log most of what you need.
TECH Apprentice
Joined: Apr 2002
Posts: 308
Likes: 0
From: Austin, TX
Originally Posted by LSs1Power
I have EFI V5 Live and it gives me the IAT, but i wanted to know if there is a relationship between IAT and Detonation. I heard that detonation could be caused by high IAT even if u have enough fuel and the car is tuned right. That is why i wanted to confirm this piece of information. At what temp (IAT) do i have to start worrying about detonation if there is a relationship between the two? Im going to get a really good wideband A/F ratio gauge from this site http://www.plxdevices.com/products.htm
The relationship is there but there is no magic formula (like x IAT = detonation). You will just have to learn what your particular setup likes and dislikes. Detonation thresholds depend on so many things that you just have to experiment under different conditions (weather, fuel, load, boost) The knock sensors help out quite a bit here. You can monitor KR with EFI-Live and you should be able to see where it starts to see lite pre ignition. You then have to add more fuel, back down the timing, lower the boost, improve the intercooling, run better fuel, or simply back off the throttle. Think of it as a balancing act. Some people run leaner a/f with less timing, while others will run rich a/f with more timing. It's all about trying to controlling heat and pressure in the combustion chamber (IAT is just one factor in that equation).
Sounds like i need to have my laptop in my view when im on the road course then. Its going to be intresting driving and monitring the screen LOL. Anyone know when better intercoolers are needed? For example if the weather out side is 90F and the IAT started at 110F and after 20min of hard driving it went up to 170F.... Is this good or bad and when do we know that we need a better intercooler?
Thanks for the useful info.
Thanks for the useful info.
There is no specific IAT that is going to cause detonation. There are alot of factors to consider.
1) How sensitive is your car to detonation
2) Gas Quality / Octane
3) Boost Level
4) Intercooler Efficiency
5) Load on Engine
You don't have to drive and monitor your screen. Put a good conservitive tune in the thing (a/f around 11:1 ON THE STREET, timing in the low 20's) run an octane booster (or race gas) and you will be fine.
The biggest thing you should be worrying about when deciding to road race a FI is getting your fuel system up to spec. Ensure that you have the proper size fuel rails, pump, and injectors. More RR cars kill #7 because of improper fuel damping, too small rails, or injectors.
Additionally, if you are going to run a usual supercharger kit, you are going to have to either run an air/oil separator on the crankcase vent system or diconnect it entirely. The high RPM's coming into the corners will cause your motor to burp all kind of oil into your inlet hat of the supercharger. The extra oil getting into the motor could cause it to ping like crazy.
Good Luck
1) How sensitive is your car to detonation
2) Gas Quality / Octane
3) Boost Level
4) Intercooler Efficiency
5) Load on Engine
You don't have to drive and monitor your screen. Put a good conservitive tune in the thing (a/f around 11:1 ON THE STREET, timing in the low 20's) run an octane booster (or race gas) and you will be fine.
The biggest thing you should be worrying about when deciding to road race a FI is getting your fuel system up to spec. Ensure that you have the proper size fuel rails, pump, and injectors. More RR cars kill #7 because of improper fuel damping, too small rails, or injectors.
Additionally, if you are going to run a usual supercharger kit, you are going to have to either run an air/oil separator on the crankcase vent system or diconnect it entirely. The high RPM's coming into the corners will cause your motor to burp all kind of oil into your inlet hat of the supercharger. The extra oil getting into the motor could cause it to ping like crazy.
Good Luck
Trending Topics
Originally Posted by NoGo
1) How sensitive is your car to detonation
2) Gas Quality / Octane
3) Boost Level
4) Intercooler Efficiency
5) Load on Engine
Additionally, if you are going to run a usual supercharger kit, you are going to have to either run an air/oil separator on the crankcase vent system or diconnect it entirely. The high RPM's coming into the corners will cause your motor to burp all kind of oil into your inlet hat of the supercharger. The extra oil getting into the motor could cause it to ping like crazy.
Good Luck
2) Gas Quality / Octane
3) Boost Level
4) Intercooler Efficiency
5) Load on Engine
Additionally, if you are going to run a usual supercharger kit, you are going to have to either run an air/oil separator on the crankcase vent system or diconnect it entirely. The high RPM's coming into the corners will cause your motor to burp all kind of oil into your inlet hat of the supercharger. The extra oil getting into the motor could cause it to ping like crazy.
Good Luck
1) How can i tell? It never detonated until now.
2) 94 Sunoco Gas
3) 8 psi on stock engine, thinking of 10psi on 104 octane.
4) Im really not sure how efficient the twin intercoolers are? Do u know?
5) How can i measure the load on the engine? I have seen in EFI live something aboit load, but what numbers i should be looking for?
Do u kow if i need to run an air/oil separator on the crankcase on a procharged car since the oiling is externally?
Thanks for the info guys
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo TECH Apprentice
Joined: Apr 2002
Posts: 308
Likes: 0
From: Austin, TX
you are going to have to either run an air/oil separator on the crankcase vent system or diconnect it entirely
Originally Posted by QuickSilver2002
Yep, this caused me major problems. I had to disconnect it and vent to atmosphere. Going to the ls6 style PCV will help in the corners... but you still have vapor issues to deal with from blowby.
Which SC do u have?
Firstly, valve springs: I had one let go my first year of RR. I was lucky and nothing else got damged (the spring bound when it broke), but I learned an important lesson. If you are going to spin the snot out of your stock car ensure that your valvetrain is up to the task.
If you are going to be running 10psi on the D1 on a road coarse then you really need to consider a spring belt tensioner for your blower. The belt heat/expansion/wear that occurs while road racing can cause your blower to start slipping once everything gets warmed up.
I'm not a big fan of the ATI setup for the F-bods. The intercooler setup does not allow for much 'intercooling'. If you are considering RR you may want to address this point. Either add some additional ducting, clear a path for the air, etc...
You can't tell how sensitive your car is to detonation until you get the blower hooked up.
Again, I would just get a good tune in the car. Park the a/f around 11:1 and set the timing conservative. If you are really worried about detonation, they have gizmos that plug into your KR. When the knock sensor pick up KR a light lights up on your dash.
Good Luck
If you are going to be running 10psi on the D1 on a road coarse then you really need to consider a spring belt tensioner for your blower. The belt heat/expansion/wear that occurs while road racing can cause your blower to start slipping once everything gets warmed up.
I'm not a big fan of the ATI setup for the F-bods. The intercooler setup does not allow for much 'intercooling'. If you are considering RR you may want to address this point. Either add some additional ducting, clear a path for the air, etc...
You can't tell how sensitive your car is to detonation until you get the blower hooked up.
Again, I would just get a good tune in the car. Park the a/f around 11:1 and set the timing conservative. If you are really worried about detonation, they have gizmos that plug into your KR. When the knock sensor pick up KR a light lights up on your dash.
Good Luck
TECH Apprentice
Joined: Apr 2002
Posts: 308
Likes: 0
From: Austin, TX
If you are really worried about detonation, they have gizmos that plug into your KR. When the knock sensor pick up KR a light lights up on your dash.
Originally Posted by NoGo
Firstly, valve springs: I had one let go my first year of RR. I was lucky and nothing else got damged (the spring bound when it broke), but I learned an important lesson. If you are going to spin the snot out of your stock car ensure that your valvetrain is up to the task.
If you are going to be running 10psi on the D1 on a road coarse then you really need to consider a spring belt tensioner for your blower. The belt heat/expansion/wear that occurs while road racing can cause your blower to start slipping once everything gets warmed up.
I'm not a big fan of the ATI setup for the F-bods. The intercooler setup does not allow for much 'intercooling'. If you are considering RR you may want to address this point. Either add some additional ducting, clear a path for the air, etc...
Good Luck
If you are going to be running 10psi on the D1 on a road coarse then you really need to consider a spring belt tensioner for your blower. The belt heat/expansion/wear that occurs while road racing can cause your blower to start slipping once everything gets warmed up.
I'm not a big fan of the ATI setup for the F-bods. The intercooler setup does not allow for much 'intercooling'. If you are considering RR you may want to address this point. Either add some additional ducting, clear a path for the air, etc...
Good Luck
Great advice from Kevin, I would absolutely do valve springs.
You might want to also look into some of the nitrous threads discussing LS1 Edit tuning for high IAT readings... you could have the pcm pull a lot of tuning when it gets too hot...
You might want to also look into some of the nitrous threads discussing LS1 Edit tuning for high IAT readings... you could have the pcm pull a lot of tuning when it gets too hot...
air, boost, car, dangerous, detonating, detonation, efi, egt, egts, iat, intake, live, measuring, preigniting, reasons, relationship, scanner, supercharger, temperature
