Camaro XV

[mikels]

Originally Posted by PTAddict

It really is an amazing accomplishment making this kind of HP, pump gas, thermal management, and totally drivable. Crazy good. All on a production block and oiling system, as well.

Does the E67 ECU have any advantages over the E38 for this kind of application? Also interesting to note that you're running hybrid MAF/Speed Density - SD tuning on those ECUs is a PITA, at least with HP tuners, and I've found no discernable advantage in normally aspirated performance applications (the GM crate motor ECUs all run MAF-only as well). But it may well be that, at this HP level, that extra bit of fine transient control is important?

E67 is needed for supercharged applications if wanting to maintain the same level of control as OEM. There are 3 MAP sensors (BARO, SC inlet and Manifold) as well as 2 IAT sensors (IAT1 in MAF sensor, IAT2 in manifold after intercoolers) and SC bypass valve control. E38 lacks the I/O capability to run this many sensors and have this level of control on forced induction applications.

MAF sensor allows more precise air measurement as well - when you think about it, speed density calibration is calculating the mass air flow from MAP, displacement and RPM to determine engine operation. Better to measure actual mass flow and redundantly calculate for better control.

Goal all along as we've refined these 7.0L SC engines has been not just power, but driveability, controllability and practicality (OEM part usage where possible for servicing, pump gas). Mark typically autocross's in 1st gear - not many 900+hp engines (well, none that I can think of) have driveability that allows this sort of operation.

We know there are changes that can be made to make more power, but what's the point if you give up the refinement and control? I think Charlie stated he got ~23-24 mpg in Mayhem on PowerTour this year (and I'm sure it wasn't because he 'babied' the car)- all while generating 880hp/815tq. On pump gas.

Anyone who can drive a stick could drive Hellfire - it is truly that easy to drive. Idles @ 750 rpm, pulls from any gear from idle speeds and never carries on in any way. Just be careful when your right foot gets heavy!

I'm a huge forced induction fan - and love turbocharging. But there is no way I can put together a turbo engine that has the same level of refinement and immediate response that we have with this positive displacement SC engine for same power level.

It's great fun making power (and can never have too much - although we are close.... Nah - just need more traction!) - but the fun stops if the package is unreliable, cantankerous to live with or requires unobtainium fuel, etc.

Dave

[Stielow]

Originally Posted by mikels

E67 is needed for supercharged applications if wanting to maintain the same level of control as OEM. There are 3 MAP sensors (BARO, SC inlet and Manifold) as well as 2 IAT sensors (IAT1 in MAF sensor, IAT2 in manifold after intercoolers) and SC bypass valve control. E38 lacks the I/O capability to run this many sensors and have this level of control on forced induction applications.

MAF sensor allows more precise air measurement as well - when you think about it, mass air calibration is calculating the mass air flow from MAP, displacement and RPM to determine engine operation. Better to measure actual mass flow and redundantly calculate for better control.

Goal all along as we've refined these 7.0L SC engines has been not just power, but driveability, controllability and practicality (OEM part usage where possible for servicing, pump gas). Mark typically autocross's in 1st gear - not many 900+hp engines (well, none that I can think of) have driveability that allows this sort of operation.

We know there are changes that can be made to make more power, but what's the point if you give up the refinement and control? I think Charlie stated he got ~23-24 mpg in Mayhem on PowerTour this year (and I'm sure it wasn't because he 'babied' the car)- all while generating 880hp/815tq. On pump gas.

Anyone who can drive a stick could drive Hellfire - it is truly that easy to drive. Idles @ 750 rpm, pulls from any gear from idle speeds and never carries on in any way. Just be careful when your right foot gets heavy!

I'm a huge forced induction fan - and love turbocharging. But there is no way I can put together a turbo engine that has the same level of refinement and immediate response that we have with this positive displacement SC engine for same power level.

It's great fun making power (and can never have too much - although we are close.... Nah - just need more traction!) - but the fun stops if the package is unreliable, cantankerous to live with or requires unobtainium fuel, etc.

Dave

Professor Mikels has spoken. I don't even mess with it any more I just do what Dave says and it works and hauls a$$....

[PTAddict]

Originally Posted by mikels

MAF sensor allows more precise air measurement as well - when you think about it, mass air calibration is calculating the mass air flow from MAP, displacement and RPM to determine engine operation. Better to measure actual mass flow and redundantly calculate for better control.
Dave

Thanks again for the detailed response and willingness to share. Those additional E67 sensor inputs make sense - similar actually to what I see with the late model Mustang GT500 tunes we've done, although the Mustangs are messier because of the "torque demand" throttling strategy.

I completely agree with all you said, but I think you might have meant to say that Speed Density calibration is calculating mass air flow from MAP/RPM/displacement? I'd completely agree that a properly calibrated MAF sensor is not only precise, but also provides compensation/insurance against all kinds of other variables that affect air mass (intake manifold heat, intake valve temp, spark variation due to knock retard, etc).

[camcojb]

Originally Posted by formula88

Here's a video from the final road course session (about 1/3 into it).

It gets really wild about two minutes in .

Some really sweet driving by all and a great perspective on how hard these guys track their cars.

Thanks for the video Gordon.

[mikels]

Originally Posted by PTAddict

Thanks again for the detailed response and willingness to share. Those additional E67 sensor inputs make sense - similar actually to what I see with the late model Mustang GT500 tunes we've done, although the Mustangs are messier because of the "torque demand" throttling strategy.

I completely agree with all you said, but I think you might have meant to say that Speed Density calibration is calculating mass air flow from MAP/RPM/displacement? I'd completely agree that a properly calibrated MAF sensor is not only precise, but also provides compensation/insurance against all kinds of other variables that affect air mass (intake manifold heat, intake valve temp, spark variation due to knock retard, etc).

Thanks for catch - corrected my faux pas!

I think most OEM's are using similar strategies for forced induction - it allows much better 'picture' of engine operation and more hooks for control.

OEM software and calibrations calculate injector tip temperature, intake valve temp and many, many other parameters that impact engine operation - all this results in more precise control (and closer operation to the edge while maintaining safe operation).

Dave

[Stielow]

Originally Posted by Lous69

Mark,

My favorite part of the day Saturday was when I was watching you make a pass on the Autocross. When you finished your run and idled by, a nice gentleman next to me nudged me and said "That's my son". I said "You are Mark's Dad? You must be very proud. He's an engineer's engineer and one heck of a nice guy who doesn't let all of his success go to his head."

As a proud father myself, I could see how proud he was in his eyes and maybe even a little emotional crackle in his voice.

That was a very cool moment.

Lou

Lou

Thanks for sharing the story. I'm glad my Dad was there.

Mark

[GregWeld]

Originally Posted by Stielow

Professor Mikels has spoken. I don't even mess with it any more I just do what Dave says and it works and hauls a$$....

Sadly I was unable to confirm.... LMAO

[formula88]

Originally Posted by camcojb

Thanks for the video Gordon.

Anytime buddy. You helped make it possible

[camcojb]

Originally Posted by formula88

Anytime buddy. You helped make it possible

Yeah, I guess I did, huh??!!!

[Ns RS]

Originally Posted by GregWeld

Sadly I was unable to confirm.... LMAO

I was the driver in that Viper and I can confirm, that thing did haul a$$ but the driver looked slow at first all crunched up against the wheel. boy was I wrong