Blew the motor - pics to come
05-13-2010, 09:43 AM
#132
4th Gear Member
Join Date: Aug 2006
Location: LA
Posts: 1,201
That of course would be the smart way to go.....but the folks that I know that build....build for one reason only....to move up to the next race level (dragstrip only) and actually blowing up stuff, is fully expected and anticipated.
Last edited by forensicsteve; 05-13-2010 at 09:46 AM.
05-13-2010, 09:43 AM
#133
4th Gear Member
Join Date: Jan 2005
Location: Florida
Posts: 1,190
yes colder weather will give you a little more boost and power it's not so much of a difference that you can overcome with a little tuning. I've tuned my last two cars myself and being a novice I still had the cars tuned perfect at all boost and weather conditions, it just takes time.
I don't think there's needs to be a warning unless they're purposely giving you a crap tune which no company would purposely do.
Last edited by candymanjl; 05-13-2010 at 09:51 AM.
05-13-2010, 12:05 PM
#135
5th Gear Member
Join Date: Feb 2007
Location: Hawaii
Posts: 2,211
so if the pressure is set at say 300 psi on a stock pump, and you have the BAP set for 30%...it can only output say 420 psi.
what if you have the car tuned so that it requires at least 450 psi of fuel rail pressure to have sufficient flow for the injectors?
I'm still confused as to why his BAP was set to 30%. It should have been maxed out and left alone. I'm not ***** nilly assigning blame. He went lean and blew the motor. All fingers point directly at the BAP IMO. The cold was just a contributing factor in this case.what if you have the car tuned so that it requires at least 450 psi of fuel rail pressure to have sufficient flow for the injectors?
the PCM doesn't know the fuel pressure can't support a full throttle excursion.
so when the RPM is up there, and the injectors are cycling to meet the full throttle demand, the timing is way advanced to make power, that 420 psi BAP setting isn't providing enough fuel for the injectors.
so when the RPM is up there, and the injectors are cycling to meet the full throttle demand, the timing is way advanced to make power, that 420 psi BAP setting isn't providing enough fuel for the injectors.
the PCM has some failsafes to keep from damaging the motor (knock sensor)...but usually you get into these areas so quickly that the PCM can't adapt in time.
same principle almost as when people over-rev their motors. sometimes the components can't handle the speed...sometimes the fueling just isn't there to support that RPM
the the blower is still pushing the same amount of air but with less fuel now...so that makes you lean. the cylinder walls and piston crown get superheated from the lean condition and then it's just a matter of waiting for the piston or the cylinder walls to failsame principle almost as when people over-rev their motors. sometimes the components can't handle the speed...sometimes the fueling just isn't there to support that RPM
it's called an IAT sensor and a proper tune, then you're good from -30 degrees to 130 degrees
yes colder weather will give you a little more boost and power it's not so much of a difference that you can overcome with a little tuning. I've tuned my last two cars myself and being a novice I still had the cars tuned perfect at all boost and weather conditions, it just takes time.
I don't think there's needs to be a warning unless they're purposely giving you a crap tune which no company would purposely do.
yes colder weather will give you a little more boost and power it's not so much of a difference that you can overcome with a little tuning. I've tuned my last two cars myself and being a novice I still had the cars tuned perfect at all boost and weather conditions, it just takes time.
I don't think there's needs to be a warning unless they're purposely giving you a crap tune which no company would purposely do.
then when the cold comes along, the density change is enough to push past the safe boundries of tuning. motor goes pop. the IAT can only do so much to protect the motor
05-13-2010, 12:44 PM
#136
6th Gear Member
Join Date: Nov 2007
Location: Montaner
Posts: 6,193
Regarding the last statement about destruction being anticipated. Bragging rights over how fast your car is kind of lose their luster when the fact is your driving a ticking time bomb around.
05-13-2010, 12:59 PM
#137
4th Gear Member
Join Date: Aug 2006
Location: LA
Posts: 1,201
Building a car to go into the 9s for the private individual (as opposed to a vendor/speed shop) is very expensive and you do have to be able to walk away from the project like it never happened. I am not sure how much I have spent....must be at least 60-70K. Car is on its 3rd build.
Not destruction but sooner or later, this or that will fail. You have to budget for modding and also for fixing/replacing.
It's not a ticking time bomb at all because if it was being driven around town (not street legal anymore), it would be driven under regular driving conditions and not stressed. At the dragstrip, it better had not be a time bomb either...lol, but the machine is stressed to the max and stuff happens. Safety 1, Fun 2, ET 3. It was at 22 lbs boost with last build and 25-27 lbs boost expected with this build.
Not destruction but sooner or later, this or that will fail. You have to budget for modding and also for fixing/replacing.
It's not a ticking time bomb at all because if it was being driven around town (not street legal anymore), it would be driven under regular driving conditions and not stressed. At the dragstrip, it better had not be a time bomb either...lol, but the machine is stressed to the max and stuff happens. Safety 1, Fun 2, ET 3. It was at 22 lbs boost with last build and 25-27 lbs boost expected with this build.
Last edited by forensicsteve; 05-13-2010 at 01:08 PM.
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