Festival of Speed at Cal Speedway /Auto Club Speedway April 20 2018 - 928s running?
05-11-2018, 11:09 AM
#121
Drifting
Wait a second here...
I'm carefully eyeballing the rods, and the shank of MA's rod connects to the small-end at its 4 o'clock and 8 o'clock positions, whereas MK's rod, its shank connects to the small-end at the outside of its 3 o'clock and 9 o'clock positions, MUCH WIDER!
Clearly then, they are different rods where MK's is much wider at the shank where it connects to the small end versus MA's rod.
I'm carefully eyeballing the rods, and the shank of MA's rod connects to the small-end at its 4 o'clock and 8 o'clock positions, whereas MK's rod, its shank connects to the small-end at the outside of its 3 o'clock and 9 o'clock positions, MUCH WIDER!
Clearly then, they are different rods where MK's is much wider at the shank where it connects to the small end versus MA's rod.
05-11-2018, 12:22 PM
#122
Banned
The other problem here is that I am fairly certain that the 928 world is a total stranger to high horsepower builds and by that I mean anything over 500HP. I have many cars that make well over 500HP; the Camaro in my signature on 12:1 compression and stock internals makes 1000HP and I have ran it that way on the street for 20,000 problem free miles with just oil changes.
My 997TT with heads, cams, punched out to 3.8, Tial Xona 3076 Turbos is expected to put down 800AWHP in its sleep.
Common thread with these is good engine management. When Carl and I discussed the build for the Devore car, he speced Electromotive ECU right from the get go. When I went to visit Joe Fan last year to see the 928 in question, he told me the car was running its stock computer.
I cannot conceive how one could make a build of this caliber using the ancient ECU that tells you very little of what's happening. If this car had something like AEM Infinity or an Electromotive ECU like it should have, we could all sit down and look at the logs and probably tell what happened in excruciating detail.
Is running a motor like that without aftermarket hardware the fault of the engine builder? Yes, to a degree.
The problem lies with the low horsepower levels achieved in the 928 world and the relative lack of sophistication with engine management. For every Todd motor, there are 20 other people with a strap on Eaton blower making 400whp and thinking they are making big power.
Head over to the 911 side of the equation; when a 911 turbo project is conceived that's going to make big power, the first thing they do is unchain it from the factory ECU and work from there.
So here we have a 928 "race car" that's making as much power as a stock 911 turbo with a tune, and yet it's a highly stressed build that's running 1980s era engine management. It's really puzzling.
My 997TT with heads, cams, punched out to 3.8, Tial Xona 3076 Turbos is expected to put down 800AWHP in its sleep.
Common thread with these is good engine management. When Carl and I discussed the build for the Devore car, he speced Electromotive ECU right from the get go. When I went to visit Joe Fan last year to see the 928 in question, he told me the car was running its stock computer.
I cannot conceive how one could make a build of this caliber using the ancient ECU that tells you very little of what's happening. If this car had something like AEM Infinity or an Electromotive ECU like it should have, we could all sit down and look at the logs and probably tell what happened in excruciating detail.
Is running a motor like that without aftermarket hardware the fault of the engine builder? Yes, to a degree.
The problem lies with the low horsepower levels achieved in the 928 world and the relative lack of sophistication with engine management. For every Todd motor, there are 20 other people with a strap on Eaton blower making 400whp and thinking they are making big power.
Head over to the 911 side of the equation; when a 911 turbo project is conceived that's going to make big power, the first thing they do is unchain it from the factory ECU and work from there.
So here we have a 928 "race car" that's making as much power as a stock 911 turbo with a tune, and yet it's a highly stressed build that's running 1980s era engine management. It's really puzzling.
05-11-2018, 12:31 PM
#123
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Most of the reason that Mark and Joseph's racers are using 20 year old engine management is that they're 20 year old race cars. When we get the new Zombie motor buttoned up I'll strap a NUC to the firewall along with the ST2 and we'll datalog everything. But that capability didn't exist in 1998, or 2003, which is the last time the Zombie was substantially updated.
05-11-2018, 12:41 PM
#124
Admittedly I'm running a motec m48 pro which is still sold but old technology. It is light years ahead of factory. I will have to jump ahead going forward to a new ecu. Not happy about it but it is what it is.
05-11-2018, 12:42 PM
#125
Banned
Rob, I get it, but there are still people in the 928 world that are considering building or are building strokers with the stock computer. It's almost as if it's not thought of at all.
05-11-2018, 01:12 PM
#126
Administrator - "Tyson"
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When it comes to ECU's, money is almost no object for Todd and he's spent the last 10+ years research them, and his top pick is AEM Infinity. Even with how well his car is running with Autronic, he sees a major advantage to starting over and re-wiring the car.
05-11-2018, 01:30 PM
#127
Banned
AEM Infinity is the best, IMHO. On Devore, I went with Electromotive because that's what Carl uses and the engine builder needs to be comfortable with the engine management system.
When I build my own, I use AEM. The motor I built for my turbo targa is a 3.3 of late 1970s vintage, yet it is twin plug, EFI, twin scroll turbo, AEM Infinity, makes over 600HP and is as modern as any new engine out there short of a DFI motor. It's 10 years older than most 928 motors out there but you wouldn't know it.
You could never make that kind of power on the stock CIS or even later motronic even though the hardware of the bottom end would be almost identical.
When I build my own, I use AEM. The motor I built for my turbo targa is a 3.3 of late 1970s vintage, yet it is twin plug, EFI, twin scroll turbo, AEM Infinity, makes over 600HP and is as modern as any new engine out there short of a DFI motor. It's 10 years older than most 928 motors out there but you wouldn't know it.
You could never make that kind of power on the stock CIS or even later motronic even though the hardware of the bottom end would be almost identical.
05-11-2018, 01:32 PM
#128
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Greg built a 612 chp stroker for Andy G's GTS with ITBs that used a Link G4 Extreme for engine management a couple years back, so he has experience with more modern ECUs. Runs pretty well, though they ruined it by connecting it to a Rogerbox, whose pudding internals soak up too much power. 
Note the oil scavenging from the heads, I don't remember what rpm this was.
Note the oil scavenging from the heads, I don't remember what rpm this was.
05-11-2018, 01:34 PM
#129
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05-11-2018, 01:39 PM
#130
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Well sure, the 5-speed already shifted because he got to WOT quicker. Duh!
05-11-2018, 02:15 PM
#131
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Thread Starter
as far as calculating HP, ive never said anything about calculating HP based on the factors you mention. (sound and blurry pictures) what i said, was that compression ratio provides a certain HP gain, if it is due to that alone. those calculators are known and are pretty accurate. +/-10%. fine for discussion.
when Greg says that mark is hitting a rev limiter of 7800rpm, and i say that i have video proof of a redline being hit at 6800rpm, and comparative RPM sound of another 928 engine at 6600rpm verified on the dyno.. why is it so hard o believe you can calculate RPM based on that data?
05-11-2018, 02:19 PM
#132
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Thread Starter
edit: in looking at the pictures again, (the 3 pistons) it seems the rod ends are much higher up in the piston vs the JE piston type in my car..... is that the advantage? so yes, in "engine speak) it seems pretty different. not as much as stock to the JE, but still visually different. if it is 50hp for that mod , vs the aftermarket piston, what is the gain for this mod alone vs a stock piston??? i only gained 50hp with the stroker, by the same logic, i could have gained this with strictly a piston design alone? im only asking as i DONT know.
by the way, you never addressed your mistake in saying that mark and joes engine are using the same rods as me. (or what was in their engine originally) .. clearly you can see the difference. they are a "country mile" different (in rod speak).
05-11-2018, 02:23 PM
#133
followed by 
05-11-2018, 02:41 PM
#134
Rennlist Member
Thread Starter
Milder cams will not raise the static compression ratio since that's a measrement of the the volume of the cylinder at BDC, and the remaining volume with the piston at TDC. It will not change over the life of the engine all else being equal.
However, the dynamic compression ratio is calculated at the moment the intake valve finally closes on the compression stroke. By this time, the piston is well past BDC and has risen in the bore decreasing available cylinder volume thus lowering the engine's effective compression ratio.
Therefore, a big race cam whose aim is high-RPM horsepower, will hang the intake valve open as long as possible to get fuel into the cylinders in the short amount of time available.
Because of that, the race engine's effective compression ratio is much lower than its static compression ratio.
I say all this because MK's engine is running stock street cams with a static compression ratio of 11:1. This implies his engine's effectice compression ratio is much higher than MA's and Joseph's engines due to the intake valve closing much earlier for good, torque-ier street-driving manners.
Yet, by his own admission, MK states he's been running 91 octane for 10+ years and he has had ZERO problems, a simply remarkable feat.
One can reasonably conclude then, since MK did not blow his engine while running 91 octane street gas on his 11:1 static cr engine, which also has a HIGHER effective compression ratio due to his street cams, that MA with his race engine with its lower effective compression ratio and race gas mixture, MA's engine did NOT blow due to fuel type used.
All else being equal, MA's engine was safer compression-wise as well as fuel-type used versus. MK.
Sterling, please tell us where MK is wrong about the operation of vario cams and their effect on power production throughout the power band.
It is my opinion that he's 100% correct in his assessment.
However, the dynamic compression ratio is calculated at the moment the intake valve finally closes on the compression stroke. By this time, the piston is well past BDC and has risen in the bore decreasing available cylinder volume thus lowering the engine's effective compression ratio.
Therefore, a big race cam whose aim is high-RPM horsepower, will hang the intake valve open as long as possible to get fuel into the cylinders in the short amount of time available.
Because of that, the race engine's effective compression ratio is much lower than its static compression ratio.
I say all this because MK's engine is running stock street cams with a static compression ratio of 11:1. This implies his engine's effectice compression ratio is much higher than MA's and Joseph's engines due to the intake valve closing much earlier for good, torque-ier street-driving manners.
Yet, by his own admission, MK states he's been running 91 octane for 10+ years and he has had ZERO problems, a simply remarkable feat.
One can reasonably conclude then, since MK did not blow his engine while running 91 octane street gas on his 11:1 static cr engine, which also has a HIGHER effective compression ratio due to his street cams, that MA with his race engine with its lower effective compression ratio and race gas mixture, MA's engine did NOT blow due to fuel type used.
All else being equal, MA's engine was safer compression-wise as well as fuel-type used versus. MK.
Sterling, please tell us where MK is wrong about the operation of vario cams and their effect on power production throughout the power band.
It is my opinion that he's 100% correct in his assessment.
The other problem here is that I am fairly certain that the 928 world is a total stranger to high horsepower builds and by that I mean anything over 500HP. I have many cars that make well over 500HP; the Camaro in my signature on 12:1 compression and stock internals makes 1000HP and I have ran it that way on the street for 20,000 problem free miles with just oil changes.
My 997TT with heads, cams, punched out to 3.8, Tial Xona 3076 Turbos is expected to put down 800AWHP in its sleep.
Common thread with these is good engine management. When Carl and I discussed the build for the Devore car, he speced Electromotive ECU right from the get go. When I went to visit Joe Fan last year to see the 928 in question, he told me the car was running its stock computer.
I cannot conceive how one could make a build of this caliber using the ancient ECU that tells you very little of what's happening. If this car had something like AEM Infinity or an Electromotive ECU like it should have, we could all sit down and look at the logs and probably tell what happened in excruciating detail.
Is running a motor like that without aftermarket hardware the fault of the engine builder? Yes, to a degree.
The problem lies with the low horsepower levels achieved in the 928 world and the relative lack of sophistication with engine management. For every Todd motor, there are 20 other people with a strap on Eaton blower making 400whp and thinking they are making big power.
Head over to the 911 side of the equation; when a 911 turbo project is conceived that's going to make big power, the first thing they do is unchain it from the factory ECU and work from there.
So here we have a 928 "race car" that's making as much power as a stock 911 turbo with a tune, and yet it's a highly stressed build that's running 1980s era engine management. It's really puzzling.
My 997TT with heads, cams, punched out to 3.8, Tial Xona 3076 Turbos is expected to put down 800AWHP in its sleep.
Common thread with these is good engine management. When Carl and I discussed the build for the Devore car, he speced Electromotive ECU right from the get go. When I went to visit Joe Fan last year to see the 928 in question, he told me the car was running its stock computer.
I cannot conceive how one could make a build of this caliber using the ancient ECU that tells you very little of what's happening. If this car had something like AEM Infinity or an Electromotive ECU like it should have, we could all sit down and look at the logs and probably tell what happened in excruciating detail.
Is running a motor like that without aftermarket hardware the fault of the engine builder? Yes, to a degree.
The problem lies with the low horsepower levels achieved in the 928 world and the relative lack of sophistication with engine management. For every Todd motor, there are 20 other people with a strap on Eaton blower making 400whp and thinking they are making big power.
Head over to the 911 side of the equation; when a 911 turbo project is conceived that's going to make big power, the first thing they do is unchain it from the factory ECU and work from there.
So here we have a 928 "race car" that's making as much power as a stock 911 turbo with a tune, and yet it's a highly stressed build that's running 1980s era engine management. It's really puzzling.
05-11-2018, 02:48 PM
#135
Rennlist Member
Thread Starter
For those in the know, there is really no torque vs gearing pandora's box. Its HP-seconds. Since HP is the engine's capacity to accelerate (a car at any speed) , the slush box if it can apply HP between shifts better or take less time to make a shift, then it will conserve potential rear wheel HP. Comparing a same rear wheel hp auto vs manual, this characteristic will be the determinant factor. (hint: the torque multiplication of the slush box, allows for greater utilization of available HP. yes, this creates more rear wheel forces, regardless of engine torque levels)
Last edited by mark kibort; 05-11-2018 at 04:42 PM.
