Smaller Displacement = Higher popssible Horsepower?
05-08-2007, 01:42 AM
#79
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Originally Posted by Driftomagnifico
The 944's problem isn't it's stroke or bore it's simply keeping the engine lubricated and cool, and getting air in and out.
Nissan's KA24DE engine has a rod length of 165mm with a 96mm stroke, the piston is relatively lighter being that it is 89mm in diameter, but it has MUCH higher piston speeds compared to the 944. They routinely rev out to 7000 RPM on stock rods and bearings. I've seen as high as 7500 RPM but that is dancing on thin ice. To add fuel to the fire they have huge bearing surfaces and 4cw cranks.
The main issue I've seen with the 944 is that the engine simply does not make top end power with the 8v head setup. Reducing the displacement will only shift the same amount of airflow upwards, as noted before, and you will run into the exact same problems as the 2.5L at a lower RPM. The 8v head's design is so archaic that it's just going to flat out choke at elevated flow levels.
The 16v head on the other hand... would be much better suited at higher RPMs. However, getting the 2.5L running gear up to the task of sustaining 9000 - 9500 RPM is very costly.
Nissan's KA24DE engine has a rod length of 165mm with a 96mm stroke, the piston is relatively lighter being that it is 89mm in diameter, but it has MUCH higher piston speeds compared to the 944. They routinely rev out to 7000 RPM on stock rods and bearings. I've seen as high as 7500 RPM but that is dancing on thin ice. To add fuel to the fire they have huge bearing surfaces and 4cw cranks.
The main issue I've seen with the 944 is that the engine simply does not make top end power with the 8v head setup. Reducing the displacement will only shift the same amount of airflow upwards, as noted before, and you will run into the exact same problems as the 2.5L at a lower RPM. The 8v head's design is so archaic that it's just going to flat out choke at elevated flow levels.
The 16v head on the other hand... would be much better suited at higher RPMs. However, getting the 2.5L running gear up to the task of sustaining 9000 - 9500 RPM is very costly.
This is not totally true as the 8 V head can be made to breathe and has superior T/Q to the 16v , It is all a case of where do you wanna go if a 10 K rpm engine then yes the 16 v is superior as you have better top end T/q and BHP. Destroking has the advantage of reducing the pumping loses at high rpm due in part to the lower piston speed but at the cost of T/Q and your T/Q spread , the higher rpm engine will be less reliable and require more frequent
refreshenings of engine internals , It's all about horses for courses.
05-08-2007, 01:52 AM
#80
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Originally Posted by Driftomagnifico
No matter how big of a throttle you run you won't have the response that ITB's will because of their proximity to the valve. That being said, there are hundreds of cars running ITB's on the streets, and they are high compression N/A engines with generally lower inertia components (think Honda). They drive like any other car when tuned properly.
So my answer is no.
So my answer is no.
On a single butterfly setup the response will be very difficult to regulate and will be on /off in nature. A bigger plenum and throttle body will also promote this effect and make it worse, but will produce more topend power and T/Q,
The ITB by design will have a better throttle response with less of an on/off effect , but will ultimately produce less power than a big single /big plenum setup,
But is much more drivable ...
05-08-2007, 01:57 AM
#81
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Originally Posted by Driftomagnifico
seen a K20 engine put down 314whp on pump gas naturally aspirated.
I have heard such stories too , would love to see it personally
However if they got 1500hp out of 1.5L F1 cars all those years ago then surely we can get a safe 700hp out of 3.0L ?
F1 is off the chart, it would be hard to compare a production engine to the ones used in F1 and the special brew fuels is where most of the power was being made
05-08-2007, 02:10 AM
#82
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Originally Posted by A.Wayne
This is not totally true as the 8 V head can be made to breathe and has superior T/Q to the 16v
The 16v on the other hand suffers from have huge port flow so naturally the torque at the lower end is going to be a bit trashy. It at least has quench pads which can be tapered down to get a bit more midrange torque (Toyota found this out on the 1ZZFE engine - See SAE Papers) among other tricks.
05-08-2007, 02:19 AM
#83
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Originally Posted by A.Wayne
On a single butterfly setup the response will be very difficult to regulate and will be on /off in nature.
The ITB by design will have a better throttle response with less of an on/off effect , but will ultimately produce less power than a big single /big plenum setup,
But is much more drivable ...
The ITB by design will have a better throttle response with less of an on/off effect , but will ultimately produce less power than a big single /big plenum setup,
But is much more drivable ...
A 3.0L engine with a 80mm throttle body supports ~800 CFM giving 266 CFM / L
The 1.6L engine is a stock Honda B16A2 running a MAP system and internals about half the weight of a 944's. It also has much higher compression and a quick ratio gearbox. By all accords this should make the car unbearable to drive.
The reason why it's not hard to drive? Tip-in tuning. You can cut the ignition timing and reduce engine torque and feed timing back in to smooth out the response.
05-08-2007, 02:28 AM
#84
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No one is going to argue 8v vs 16v , horse for courses. if the power level desired is below 600 whp the 8 V will easily support this. Not sure what you mean by absurd boost levels , 450 whp @1.3 bar is not excessive , when you have to maintain that for 2-6 hrs..
While the jap engines are very efficient as street engines , they have not been able to translate this performance to the track , as there T/Q to Hp spread is not as favourable as their european counterpart. You should really be comparing a 944 T to a 1985 toyota supra, which was a poor design .....
While the jap engines are very efficient as street engines , they have not been able to translate this performance to the track , as there T/Q to Hp spread is not as favourable as their european counterpart. You should really be comparing a 944 T to a 1985 toyota supra, which was a poor design .....
05-08-2007, 02:34 AM
#85
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Originally Posted by Driftomagnifico
I've driven a 1.6L engine with a 60mm throttle body on it. That's roughly 460 CFM worth of airflow giving 287 CFM / L
A 3.0L engine with a 80mm throttle body supports ~800 CFM giving 266 CFM / L
The 1.6L engine is a stock Honda B16A2 running a MAP system and internals about half the weight of a 944's. It also has much higher compression and a quick ratio gearbox. By all accords this should make the car unbearable to drive.
The reason why it's not hard to drive? Tip-in tuning. You can cut the ignition timing and reduce engine torque and feed timing back in to smooth out the response.
A 3.0L engine with a 80mm throttle body supports ~800 CFM giving 266 CFM / L
The 1.6L engine is a stock Honda B16A2 running a MAP system and internals about half the weight of a 944's. It also has much higher compression and a quick ratio gearbox. By all accords this should make the car unbearable to drive.
The reason why it's not hard to drive? Tip-in tuning. You can cut the ignition timing and reduce engine torque and feed timing back in to smooth out the response.
Yes , But this does not change the physics involved now does it ..
if done correctly mechanics and the mapping all is well ....
would still love to see 315 whp on 93 pump gas out of a K20
05-08-2007, 02:55 AM
#86
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Originally Posted by A.Wayne
I have heard such stories too , would love to see it personally
Here is a stock internal K20 engine.
362whp K-Series - NATURALLY ASPIRATED
This is what a modern 4-cyl engine can do with alot of RnD behind it.
05-08-2007, 03:05 AM
#87
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Originally Posted by A.Wayne
While the jap engines are very efficient as street engines , they have not been able to translate this performance to the track , as there T/Q to Hp spread is not as favourable as their european counterpart. You should really be comparing a 944 T to a 1985 toyota supra, which was a poor design .....
05-08-2007, 03:08 AM
#88
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Originally Posted by A.Wayne
Yes , But this does not change the physics involved now does it ..
if done correctly mechanics and the mapping all is well ....
would still love to see 315 whp on 93 pump gas out of a K20
if done correctly mechanics and the mapping all is well ....
would still love to see 315 whp on 93 pump gas out of a K20
1. It's not that big of a deal.
2. If you can't get the car to run smoothly then you need to learn how to modulate the damn throttle.
3. You can do alot via tuning to dampen any ill-effect. Nevermind the dampening a 6L plenum does to overall response.
05-08-2007, 01:43 PM
#89
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Originally Posted by Driftomagnifico
Why not a 89' Skyline GT-R? It has a similar displacement at a little under 2600cc and yet makes power from 3000 RPM to 8200 RPM factory stock. It also dominated just about every form of racing it was entered in from 1989 to 2003. You know of any other "un-favourable" engines that ran for 14 years at the top of their class?
Not sure what you are talking about , i have never seen a gt-r win anything , other
than the village olympics. I have done many rb 26 over the years and it has it's own special issues" to win in every form of racing LOL, i tell you what get any of your little buddies gt-r done anyway you want , pull a 2.07 sec lap at sebring for 5 laps straight and you would be as fast as a N/A porsche , and you are running boost .
Skyline dominate every from of racing LOL
05-08-2007, 02:19 PM
#90
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Originally Posted by A.Wayne
Not sure what you are talking about , i have never seen a gt-r win anything , other
than the village olympics. I have done many rb 26 over the years and it has it's own special issues" to win in every form of racing LOL, i tell you what get any of your little buddies gt-r done anyway you want , pull a 2.07 sec lap at sebring for 5 laps straight and you would be as fast as a N/A porsche , and you are running boost .
Skyline dominate every from of racing LOL
than the village olympics. I have done many rb 26 over the years and it has it's own special issues" to win in every form of racing LOL, i tell you what get any of your little buddies gt-r done anyway you want , pull a 2.07 sec lap at sebring for 5 laps straight and you would be as fast as a N/A porsche , and you are running boost .
Skyline dominate every from of racing LOL
Better check your history there buddy because you're completely wrong. http://en.wikipedia.org/wiki/Skyline_gtr Skyline's were giving Porsche 904's a run for their money back in the '60s. They've had plenty of success, and certainly more than your average sports car.