928 engines......a close look at some well known ones
06-11-2013, 07:42 PM
#16
Three Wheelin'
Mike:
Please read what I wrote, again.
Nascar engine builders don't use chassis dynos. Those engines are developed and the horsepower output is measured on an engine dyno....like 99.9% of professional engine builders use.
Nascar (themselves) may bring a calibrated dyno to one facility to test all of the car, at the same time.....they might even own a dyno, which retains the same calibration and then take it to different places.....but they are using this as a "reference tool" to class the cars.....not an absolute measuring device.
You might be able to trust your results from the same dyno that you use over and over again (I do this, too)....right up to the point where they have it worked on or re-calibrated, but comparing your results to a result that Louis Ott got is useless. These RWHP dyno shops have no "standard" to calibrate their dyno. People's ego's tend for them to want their engine to be more powerful, therefore, dyno shops that "inflate" results get more business and more repeat business. This is what causes "inflated horsepower" results.
Hell, change your tire pressures up and down 30 pounds and compare the results....on the same day. Put a set of really sticky rear tires on and compare the results.
Can't do that on an engine dyno.
Do you seriously think that Carl is making 900rwhp, yet can't pull 5th gear?
That's my point. Comparing results that can be "altered" by a setting or by how much air you have in your tires is futile....at best.
Please read what I wrote, again.
Nascar engine builders don't use chassis dynos. Those engines are developed and the horsepower output is measured on an engine dyno....like 99.9% of professional engine builders use.
Nascar (themselves) may bring a calibrated dyno to one facility to test all of the car, at the same time.....they might even own a dyno, which retains the same calibration and then take it to different places.....but they are using this as a "reference tool" to class the cars.....not an absolute measuring device.
You might be able to trust your results from the same dyno that you use over and over again (I do this, too)....right up to the point where they have it worked on or re-calibrated, but comparing your results to a result that Louis Ott got is useless. These RWHP dyno shops have no "standard" to calibrate their dyno. People's ego's tend for them to want their engine to be more powerful, therefore, dyno shops that "inflate" results get more business and more repeat business. This is what causes "inflated horsepower" results.
Hell, change your tire pressures up and down 30 pounds and compare the results....on the same day. Put a set of really sticky rear tires on and compare the results.
Can't do that on an engine dyno.
Do you seriously think that Carl is making 900rwhp, yet can't pull 5th gear?
That's my point. Comparing results that can be "altered" by a setting or by how much air you have in your tires is futile....at best.
Aside from NASA, my own other reason is I have a skilled EFI tuner that uses one.
When we were tuning my car, after the work was done we made a full power pull for the official bragging number and I was joking about holding the shop cooling fan in front of the airbox. I can't imagine either of us fudging it in any way, that would be unthinkable even though it's trivial.
I do however wonder about the real motivation for a struggling dyno guy to keep the customers happy and ensure others use him.
Atlanta had a school cheating scandal where teachers changed answers to inflate test scores. There were parents that knew this and actually angled to get their kid with those teachers!
06-11-2013, 11:17 PM
#17
Former Sponsor
You're right about the non-reliability of chassis dynos. Sorry if it came across as a rebuttal. I only bring it up because it's amusing to me that I now consider them my yardstick.
Aside from NASA, my own other reason is I have a skilled EFI tuner that uses one.
When we were tuning my car, after the work was done we made a full power pull for the official bragging number and I was joking about holding the shop cooling fan in front of the airbox. I can't imagine either of us fudging it in any way, that would be unthinkable even though it's trivial.
I do however wonder about the real motivation for a struggling dyno guy to keep the customers happy and ensure others use him.
Atlanta had a school cheating scandal where teachers changed answers to inflate test scores. There were parents that knew this and actually angled to get their kid with those teachers!
Aside from NASA, my own other reason is I have a skilled EFI tuner that uses one.
When we were tuning my car, after the work was done we made a full power pull for the official bragging number and I was joking about holding the shop cooling fan in front of the airbox. I can't imagine either of us fudging it in any way, that would be unthinkable even though it's trivial.
I do however wonder about the real motivation for a struggling dyno guy to keep the customers happy and ensure others use him.
Atlanta had a school cheating scandal where teachers changed answers to inflate test scores. There were parents that knew this and actually angled to get their kid with those teachers!
There used to be a joke of a Porsche Performance shop over in Arizona....they are the ones that originally got my attention with their dyno results....and made me start thinking about things logically. The numbers that they claimed were always really high....but if you "dug" deeper....their "stock" numbers were way off, too. They would magically make 50 more hp, at the rear wheels (stock) than the Porsche factory rated the engines at the flywheel. There were some worthless dyno results, there!
Randy Aase said it best, I think...this was several years ago, BTW.
"I've never actually had an air cooled 930 engine that made 600hp, on my dyno.....even after the customer insists on the "hero run" with crazy boost.....which they all insist on. The one thing that has always amazed me, is that they somehow all make over 700hp, once they leave here."
06-11-2013, 11:39 PM
#18
Rennlist Member
Jim,
It was 599hp, and the true heartbreak was that he didn't break 600 because he left the A/C on (didn't really use it much uphere in the PacNW and forgot to turn it off in the Texas heat
)
It was 599hp, and the true heartbreak was that he didn't break 600 because he left the A/C on (didn't really use it much uphere in the PacNW and forgot to turn it off in the Texas heat
)
06-12-2013, 12:07 AM
#19
Addict
Rennlist Member
Rennlist Member
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
06-12-2013, 12:21 PM
#20
Rennlist Member
Ya, but doesn't the AC turn itself off when your on WOT or near atmospheric manifold pressure?
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
06-12-2013, 02:20 PM
#21
Former Sponsor
I based my calculations off of 5 speed 928's with 15% loss for drivetrain.
Lets start with the smallest engine of the bunch, my 1981 4.5L L jet motor (9-1 CR) with early Euro S cams, and custom ported heads. MSDS headers into Y pipe 3.5" exhaust. 311 crank HP 335ftlbs. This equates to 69 HP per liter and 74 ftlbs per liter. My BMEP at peak torque is 184.37psi and BMEP at peak power is 159psi.
Next up is a 4.7L Euro S LH engine with full race exhaust (same as mine) but running a full L jet intake-injection. 10.4 CR. It made 327hp-350ftlbs. Nearly identical to mine as 69.6 HP/L and 74.5 ftlb/L. Its peak torque BMEP is 183.9psi and peak power of 159.7psi...
Moving on to 32V 928's
Mark Kiborts stroker, 6.4L with full race exhaust same as ours. A full 437hp and 480ftlbs!!! 68.3 HP/L and 75ftlbs/L Almost the same as both 16V engines....since the 32V head flows quite a bit better than the euro S, the intake must be the big restriction. BMEP at peak torque is 185.6psi and BMEP at peak power is 161.24 psi....very similar to the 16V euro engines.....
All three of these engines are quite mild, with stock or near stock cams and no high end parts. SO lets take a look at some more custom 928 engines!
Dennis "screamer" 5.0L Still very stock, just with custom ground cams. 441hp and 425 ftlbs.....VERY impressive results for still using stock valve sizes and stock intake! 88.2HP/L and 85ftlbs/L. BMEP at torque peak is 212psi and BMEP at peak HP is 192.75psi.....very impressive results when you consider a modern NASCAR engine is 226psi at torque peak and 211psi and HP peak....
Louie Ott's 6.4L stroker with custom ITB intakes, around 11-1 CR. I believe he has Devek custom cams as well. 685HP and 607ftlbs....WOW..... 106.9HP/L more impressive 94.8 ftlbs/L BMEP at torque peak is an amazingly high 234psi!!!! BMEP at HP peak is still high at 218.9psi... Louie's peak torque BMEP is near world class "engine master build challenge" for pushrod style engines. The winner of that competition tends to have peak torque BMEP of around 245psi!!!!! Or just 28ftlbs more than Louies engine.
Lastly we have Mike Simards 7.0L monster....full custom, super light parts to allow for 7500+ rpm, larger ITB intake than Louie (I think louie is 52mm Simard is 54mm). 752HP and 590ftlbs. The ability to turn more RPM helps make 107.4HP/L and 84.3 ftlbs/L. BMEP at peak torque is 208psi and only 188psi at Peak HP. The larger ITB's seem to drop off a bit of torque, but his engine is slightly lower CR at 10.5-1.
Clearly the 32V intake is a restriction......imagine what Dennis engine could do with an ITB....a properly sized ITB on a 5.0L could make 530hp and 474ftlbs if it performed similar to Louies......however Louis spins his up to 6350rpm at peak power....with peak torque around 5100rpm.... Simard makes peak power past 7000...maybe 7200!!!
So what does all of this mean...I dunno, its slow at work and calculating all this ate up some time!!!!
Lets start with the smallest engine of the bunch, my 1981 4.5L L jet motor (9-1 CR) with early Euro S cams, and custom ported heads. MSDS headers into Y pipe 3.5" exhaust. 311 crank HP 335ftlbs. This equates to 69 HP per liter and 74 ftlbs per liter. My BMEP at peak torque is 184.37psi and BMEP at peak power is 159psi.
Next up is a 4.7L Euro S LH engine with full race exhaust (same as mine) but running a full L jet intake-injection. 10.4 CR. It made 327hp-350ftlbs. Nearly identical to mine as 69.6 HP/L and 74.5 ftlb/L. Its peak torque BMEP is 183.9psi and peak power of 159.7psi...
Moving on to 32V 928's
Mark Kiborts stroker, 6.4L with full race exhaust same as ours. A full 437hp and 480ftlbs!!! 68.3 HP/L and 75ftlbs/L Almost the same as both 16V engines....since the 32V head flows quite a bit better than the euro S, the intake must be the big restriction. BMEP at peak torque is 185.6psi and BMEP at peak power is 161.24 psi....very similar to the 16V euro engines.....
All three of these engines are quite mild, with stock or near stock cams and no high end parts. SO lets take a look at some more custom 928 engines!
Dennis "screamer" 5.0L Still very stock, just with custom ground cams. 441hp and 425 ftlbs.....VERY impressive results for still using stock valve sizes and stock intake! 88.2HP/L and 85ftlbs/L. BMEP at torque peak is 212psi and BMEP at peak HP is 192.75psi.....very impressive results when you consider a modern NASCAR engine is 226psi at torque peak and 211psi and HP peak....
Louie Ott's 6.4L stroker with custom ITB intakes, around 11-1 CR. I believe he has Devek custom cams as well. 685HP and 607ftlbs....WOW..... 106.9HP/L more impressive 94.8 ftlbs/L BMEP at torque peak is an amazingly high 234psi!!!! BMEP at HP peak is still high at 218.9psi... Louie's peak torque BMEP is near world class "engine master build challenge" for pushrod style engines. The winner of that competition tends to have peak torque BMEP of around 245psi!!!!! Or just 28ftlbs more than Louies engine.
Lastly we have Mike Simards 7.0L monster....full custom, super light parts to allow for 7500+ rpm, larger ITB intake than Louie (I think louie is 52mm Simard is 54mm). 752HP and 590ftlbs. The ability to turn more RPM helps make 107.4HP/L and 84.3 ftlbs/L. BMEP at peak torque is 208psi and only 188psi at Peak HP. The larger ITB's seem to drop off a bit of torque, but his engine is slightly lower CR at 10.5-1.
Clearly the 32V intake is a restriction......imagine what Dennis engine could do with an ITB....a properly sized ITB on a 5.0L could make 530hp and 474ftlbs if it performed similar to Louies......however Louis spins his up to 6350rpm at peak power....with peak torque around 5100rpm.... Simard makes peak power past 7000...maybe 7200!!!
So what does all of this mean...I dunno, its slow at work and calculating all this ate up some time!!!!
The automatics are like "jet boats". They "soak up" about 20% when you are making in the 300 horsepower range. After 400hp, the power they "absorb" goes up dramatically. After 500 horsepower, the amount they "absorb" gets crazy.
Andy's engine made 605 hp on a DTS engine dyno. I did not run this vehicle on a RWHP dyno....there was no point. However I believe that Andy has done that.
Maybe Andy can post those results.
Andy?
06-12-2013, 07:08 PM
#22
Drifting
Our old Dynojet is now being used at Miller Motorsports Park for NASA Competition. They weigh the cars then measure them all on the same dyno for class specification so nobody has an unfair advantage. Regardless of how accurate the dyno is, everybody has to play by that dyno. For that it serves as an exact performance standpoint, everyone is equal performance and weight wise regardless of the value of the numbers. Yes, you may be able to fudge it a bit by tire pressure and how tightly it's tied down but that's why there are certified operators.
Wheel dynos have their use and it certainly is easier to tune a serious performance car on a dyno than it is on the street.
Even engine dynos cause racing and driveability problems once the engine is installed in the car. The dynamics are different and very hard to duplicate on an engine dyno. Integrated Engineering is right across our back alley and they have an engine dyno to develop and test their engine components. They sponsor a salt racer that runs almost 900 hp on the engine dyno and requires almost a complete retune to actually be able to put that power down on the salt.
Wheel dynos have their use and it certainly is easier to tune a serious performance car on a dyno than it is on the street.
Even engine dynos cause racing and driveability problems once the engine is installed in the car. The dynamics are different and very hard to duplicate on an engine dyno. Integrated Engineering is right across our back alley and they have an engine dyno to develop and test their engine components. They sponsor a salt racer that runs almost 900 hp on the engine dyno and requires almost a complete retune to actually be able to put that power down on the salt.
06-12-2013, 07:11 PM
#23
Race Director
Thread Starter
I would love to see the engine dyno data from Andy's engine....I recall 608hp..so 605 for sure.....
So lets take a look at Andy's (pure guesses at this point)
605 actual crank HP....so lets say 514whp with 15% loss or 544whp with 10%.....
I'd guess Andy's engine hit peak HP around 6300....about the same as Louie.... So that makes 504ftlbs at 6300 rpm.....damm impressive.... So peak power BMEP is almost 195psi.....
So lets take a look at Andy's (pure guesses at this point)
605 actual crank HP....so lets say 514whp with 15% loss or 544whp with 10%.....
I'd guess Andy's engine hit peak HP around 6300....about the same as Louie.... So that makes 504ftlbs at 6300 rpm.....damm impressive.... So peak power BMEP is almost 195psi.....
06-12-2013, 07:25 PM
#24
Former Sponsor
I would love to see the engine dyno data from Andy's engine....I recall 608hp..so 605 for sure.....
So lets take a look at Andy's (pure guesses at this point)
605 actual crank HP....so lets say 514whp with 15% loss or 544whp with 10%.....
I'd guess Andy's engine hit peak HP around 6300....about the same as Louie.... So that makes 504ftlbs at 6300 rpm.....damm impressive.... So peak power BMEP is almost 195psi.....
So lets take a look at Andy's (pure guesses at this point)
605 actual crank HP....so lets say 514whp with 15% loss or 544whp with 10%.....
I'd guess Andy's engine hit peak HP around 6300....about the same as Louie.... So that makes 504ftlbs at 6300 rpm.....damm impressive.... So peak power BMEP is almost 195psi.....
The really beautiful part was that it made over 450 ft lbs from 3,600 to 7,000 rpms. It made over 500 ft lbs. from 5200 to 6300.
Works pretty good, in front of an automatic.....
06-12-2013, 07:33 PM
#25
Three Wheelin'
Unless it's going in a drag car, pure horsepower isn't all that important. What is important is a big fat torque curve in the usable rpm area. In the old Can-Am days that's why the cars had short & tall intake stacks- really widened the torque curve.
06-12-2013, 07:34 PM
#26
Race Director
Thread Starter
Found the data.............. Andy quoted a dynojet pull of 525whp-438 torque and a mustang pull of 498whp-same torque.....
609 actual hp at 6800rpm.....WOW, but look at the peak torque of 511ftlbs at 5800rpm....damn peak torque bmep of 197.6.... How about MORE than 600 hp from 6300-7000.....damm average torque of 476 ftlbs from 3000-7000 and HP of 457!!!!! That is SICK... Hmm in my racer...shift at 7000 drop to 5250....never under 500HP-torque......
609 actual hp at 6800rpm.....WOW, but look at the peak torque of 511ftlbs at 5800rpm....damn peak torque bmep of 197.6.... How about MORE than 600 hp from 6300-7000.....damm average torque of 476 ftlbs from 3000-7000 and HP of 457!!!!! That is SICK... Hmm in my racer...shift at 7000 drop to 5250....never under 500HP-torque......
06-12-2013, 10:21 PM
#27
Former Sponsor
Found the data.............. Andy quoted a dynojet pull of 525whp-438 torque and a mustang pull of 498whp-same torque.....
609 actual hp at 6800rpm.....WOW, but look at the peak torque of 511ftlbs at 5800rpm....damn peak torque bmep of 197.6.... How about MORE than 600 hp from 6300-7000.....damm average torque of 476 ftlbs from 3000-7000 and HP of 457!!!!! That is SICK... Hmm in my racer...shift at 7000 drop to 5250....never under 500HP-torque......
609 actual hp at 6800rpm.....WOW, but look at the peak torque of 511ftlbs at 5800rpm....damn peak torque bmep of 197.6.... How about MORE than 600 hp from 6300-7000.....damm average torque of 476 ftlbs from 3000-7000 and HP of 457!!!!! That is SICK... Hmm in my racer...shift at 7000 drop to 5250....never under 500HP-torque......
We nicknamed it "The Diesel".
This engine is why I realized that I needed to make some lighter cranks and start thinking about additional rpm potential. The camshafts are very mild....it has to idle with an automatic transmission hooked up to it!
06-12-2013, 10:35 PM
#28
Race Director
Thread Starter
You think that would get you out of the corners quicker?
We nicknamed it "The Diesel".
This engine is why I realized that I needed to make some lighter cranks and start thinking about additional rpm potential. The camshafts are very mild....it has to idle with an automatic transmission hooked up to it!
We nicknamed it "The Diesel".
This engine is why I realized that I needed to make some lighter cranks and start thinking about additional rpm potential. The camshafts are very mild....it has to idle with an automatic transmission hooked up to it!
Lighter cranks-assemblies.....with race cams.....I'd guess thats another 100hp easy.... 95HP/L isn't pushing very hard....but almost 80ftlbs/L is quite impressive....
I can't even imagine what a 600whp-2850lb 928 racer would be like....mine seems plenty fast (scary at times) at only 10.75
To max out my class I need between 332whp (on DOT) or 313 on slicks... the next class lower would require me dropping to 256whp....
06-12-2013, 10:58 PM
#29
Former Sponsor
It would JUMP off corners.....until the transmission SNAPPED!!!!
Lighter cranks-assemblies.....with race cams.....I'd guess thats another 100hp easy.... 95HP/L isn't pushing very hard....but almost 80ftlbs/L is quite impressive....
I can't even imagine what a 600whp-2850lb 928 racer would be like....mine seems plenty fast (scary at times) at only 10.75
To max out my class I need between 332whp (on DOT) or 313 on slicks... the next class lower would require me dropping to 256whp....
Lighter cranks-assemblies.....with race cams.....I'd guess thats another 100hp easy.... 95HP/L isn't pushing very hard....but almost 80ftlbs/L is quite impressive....
I can't even imagine what a 600whp-2850lb 928 racer would be like....mine seems plenty fast (scary at times) at only 10.75
To max out my class I need between 332whp (on DOT) or 313 on slicks... the next class lower would require me dropping to 256whp....
The really interesting thing about classing a vehicle using horsepower is that they don't tell you over what rpm range it can make that power. If you could make 332hp over a huge rpm range....that would be ideal.
We are getting ready to build a new engine for Rob Edward's new racecar (Anderson's old racecar.) I think we are going to build a "higher rpm" 5.4 or 5.8 version, with one of my new (now ready for testing) single plenum manifolds....yes, it is now plural.
Should be an interesting motor.....
06-12-2013, 11:01 PM
#30
So you really need about 400 flywheel....and the 'ability" to "flip" a switch to make it slightly lower, when required....
The really interesting thing about classing a vehicle using horsepower is that they don't tell you over what rpm range it can make that power. If you could make 332hp over a huge rpm range....that would be ideal.
We are getting ready to build a new engine for Rob Edward's new racecar (Anderson's old racecar.) I think we are going to build a "higher rpm" 5.4 or 5.8 version, with one of my new (now ready for testing) single plenum manifolds....yes, it is now plural.
Should be an interesting motor.....
The really interesting thing about classing a vehicle using horsepower is that they don't tell you over what rpm range it can make that power. If you could make 332hp over a huge rpm range....that would be ideal.
We are getting ready to build a new engine for Rob Edward's new racecar (Anderson's old racecar.) I think we are going to build a "higher rpm" 5.4 or 5.8 version, with one of my new (now ready for testing) single plenum manifolds....yes, it is now plural.
Should be an interesting motor.....
