Kaboom!

[quote name='Old Splatterhand' date='Jun 7 2005, 12:39 AM']maybe i'm misunderstanding something, but let's start it simple:



at 0,8 bar the T51 flows a certain number.

are you sure this certain number equates 260 fwhp? i feel that this base number is too low to start with. i can't back that up with experience though.


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Allways remember that a naturally aspirated rotary engine can only produce a reasonably fixed amount of power in it's present ported form(As does any engine),if it is side ported it will be X amoun of hpt,and bridged will be another and so on.

Anyone who has built a13b with extend port running naturally aspirated will know that a bridgeport will make more power because of the longer duration of intake timing.

A good extend port 13b will run around 200-220hp at the flywheel in Naturally aspirated from.A good bridgeport will run around 250-280hp flywheel,and a peripheral port around 280-330 depending on the size port and throttle bodies.

These above figures are approximate,but close to actual from my experience, and apply to naturally aspirated engines wtih appropriate ancillaries.

If we say that an engine is running at 1.2bar boost above atmospheric then take into account the fact that the incoming air will heated by the turbo the air molecules will be somewhat further spaced apart than ambient air temperature so this means less volume of oxygen in the incoming charge.Also there are slight losses through an intercooler in boost pressure,but if boost is measured after the intercooler then that is irrelevant.

The point is that at 1.2 bar boost you are aproximately,taking into account the losses, putting twice the volume of air through the engine that an atmospheric engine could cope with,with the porting it is running.

So doing the sums that would mean that a 13b extend port that was running naturally aspirated with around 220hp at the flywheel would run around 440hp flywheel at 1.2 bar.

A naturally aspirated bridge port running 250-280hp could run 500-560hp flywheel at 1.2bar.And a Peripheral port running 280-330hp naturally aspirated could run 560-660-hp flywheel at 1.2 bar boost.



At the end of the day an engine is a pump,and it can only pump fixed maximum volumes of air at whatever boost level you have it and at with certain porting.



Hope this makes things a little clearer as to why some dyno figures at somewhat spurious to say the least.You may have a turbo that is said to flow Xlbs of air at a certain boost level,but if you are trying to force it into a hole that cannot take all of that air then it does not matter,the engine and port type then becomes the determining factor,and the turbo starts to heat the air more due to the compressor meeting a wall of back pressure (Relatively speaking).

Regards

Carl

cjr

A good answer to this would be bill turning up to the Japshow at Pod next weekend. We can then see and report back to the forum what a fuel injected westfeild can do. I KNOW that this car is light and SHOULD have power. We all have issues with our cars last event I went to I sheared my intake comp going down the strip. Atleast let some people see what is being worked on then we can either agree with every thing that gets said or disagree. Sitting in the background a spouting this that and the other is fine. Then again it don't half get on every ones ****!! Show what you have then pass comment..

bill shurvinton

[quote name='cjr' date='Jun 7 2005, 01:54 PM']A good answer to this would be bill turning up to the Japshow at Pod next weekend. We can then see and report back to the forum what a fuel injected westfeild can do. I KNOW that this car is light and SHOULD have power. We all have issues with our cars last event I went to I sheared my intake comp going down the strip. Atleast let some people see what is being worked on then we can either agree with every thing that gets said or disagree. Sitting in the background a spouting this that and the other is fine. Then again it don't half get on every ones ****!! Show what you have then pass comment..


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Doing a 1/4 mile in a car designed for handling and fast lap times hardly proves a thing. I am trying to explain one of the most basic laws governing operation of internal combusion engines. You can't grasp it, then please ignore me and that way we all stay happy.



The fact that you are quoting HP to 4 significant figures in your signature would tend to suggest that the language of mathematics is not one you are totally fluent in. So possibly blind faith in what the tuner tells you is the right approach. You are happy with the numbers you have and want to believe them.



I am trained to get to the truth behind headline numbers. The truth is often harsh and something one doesn't want to hear. That does not make it wrong.



Bill



BTW its 'doesn't half'

DAT.rota

As a quiet member of this web site I do not understand why certain people continue to shoot figures down with scientific b#$@ instead helping people with constructive tips when the owner of the vehicle stated that at the track he had issues with intercooler pipes blowing off at reasonable boost pressure this in turn would lower your terminal speed when you cross the line but we have the same arguments hear in australia! we the rotary community are a minority group stop dividing the group and help each other to stamp the engine in the motorsport world as a dominant and reliable engine not something that has to be rebuilt all the time! it is actually great to see all the hints and tips from engine builders on this web site! sorry for the speel but all this arguing drives me crazy WORK TOGETHER PEOPLE

BNA_ELLIS

Went dyno yesterday but not good news.

Found my front secondary injector lifts about 4-5 mm under boost and all the mixture come spraying out right next to the hotside of the turbo.

Only went up to 6,000 rpm because of this and obviously stopped all actvity once it was spotted.

Car will make lots of power.

Below is a comparison of previous dyno two weeks ago at reworx at 1.2 bar

& yesterday's at gforce at 1.35 bar.

The comparison is only up to to 6,000rpm due to the injector problem.

reworx 4k 110 4.5k 170 5k 250 5.5k 370 6k 430 6.5k 490 7k 535 7.5k 550

gforce 4k 150 4.5k 205 5k 315 5.5k 450 6k 485 ? ? ? ?

The above is flywheel horsepower.

It looks to me like the two different dyno at 1.2 bar will read very close to the same amount of power output.

Dyno part 3 in a few weeks time.

bill shurvinton

[quote name='DAT.rota' date='Jun 18 2005, 02:30 AM']As a quiet member of this web site I do not understand why certain people continue to shoot figures down with scientific b#$@ instead helping people with constructive tips when the owner of the vehicle stated that at the track he had issues with intercooler pipes blowing off at reasonable boost pressure this in turn would lower your terminal speed when you cross the line but we have the same arguments hear in australia! we the rotary community are a minority group stop dividing the group and help each other to stamp the engine in the motorsport world as a dominant and reliable engine not something that has to be rebuilt all the time! it is actually great to see all the hints and tips from engine builders on this web site! sorry for the speel but all this arguing drives me crazy WORK TOGETHER PEOPLE


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Quite simple. As an Engineer (in fact a chartered engineer) I do not b#$@. I do however try and make sure that important issues get discussed. I never said that Brian's car would not make a very respectable HP once full boost was available and it had been properly tuned. I said that I did not believe the dyno. And I still don't. He does however have the capability to produce a genuine 500HP at 6000RPM, and well over 600 by 9000.