calling Mark Adams
Discussion
Hi Mark.
been thinking recently, I was dismissing the injector idea on the 4.5 on the basis that it sprays onto the butterlfy .. but I see that you also regularly advise fitting different injectors to the RV8 cars too .. so on that basis there's obviously more to this than meets the eye ..
without giving away all your secrets, what's the idea behind the injector changes?
Joo :-)
been thinking recently, I was dismissing the injector idea on the 4.5 on the basis that it sprays onto the butterlfy .. but I see that you also regularly advise fitting different injectors to the RV8 cars too .. so on that basis there's obviously more to this than meets the eye ..
without giving away all your secrets, what's the idea behind the injector changes?
Joo :-)
Joo, I believe what he was on about was that by using an injector with a finer-droplet and dispersal pattern, more surface is covered in a single pulse which increases the air density via the cooling effect, which leads to a cooler and more dense intake.... resulting in a power-increase.... which makes technical sense...
Also, most injectors begin to sacrifice efficiency once they exceed about 70% of their design rating (due to increasing pulse lengths). Again, also, the injectors are designed to deliver best atomization at the designed pressure, and either raising or lowering the pressure will adversely affect this...
As far as Bosch is concerned, their pintle style injectors give the best atomization and widest spray pattern of any injector. Which model Mark specifically is using, I have no idea... if Bosch at all???
But if we all share our data and work together... maybe we can all get that magical 420bhp out of our cerbies...
Also, most injectors begin to sacrifice efficiency once they exceed about 70% of their design rating (due to increasing pulse lengths). Again, also, the injectors are designed to deliver best atomization at the designed pressure, and either raising or lowering the pressure will adversely affect this...
As far as Bosch is concerned, their pintle style injectors give the best atomization and widest spray pattern of any injector. Which model Mark specifically is using, I have no idea... if Bosch at all???
But if we all share our data and work together... maybe we can all get that magical 420bhp out of our cerbies...
From things I've looked at on Imprezas, I think Phoenix has something there...
From my very little understanding of the RV8 TVRs, I don't think the standard Lucas injectors have a particularly good (ie fine & wide) spray pattern.
And since they run in batches of 4, there is little "recovery" time between cycles, so they are rarely working at their absolute best.
I'll get to know a little more when I get around to fitting the VEMS ECU in the Griff in the summer...
From my very little understanding of the RV8 TVRs, I don't think the standard Lucas injectors have a particularly good (ie fine & wide) spray pattern.
And since they run in batches of 4, there is little "recovery" time between cycles, so they are rarely working at their absolute best.
I'll get to know a little more when I get around to fitting the VEMS ECU in the Griff in the summer...
There is one thing about 'too much' atomization... When you consider that at 6000 RPM the intake valves are opening 50 times a second - leaving only about .010 secs to provide the necessary fuel... With such a brief intake valve open time you may feel that having a fuel injector that delivers a wide highly atomized pattern into the intake would be ideal to ensure a homogenous mixture - but this is not necessarily the case.
At low RPMs highly atomized fuel has enough time to pass by the intake valve and create a homogenous mixture but as the RPMs increase problems will start to develop. In an engine running at high RPMs there is limited time for the fuel to reach the combustion chamber. This is compounded by the fact that often there is residual exhaust pressure present when the intake valve is opened (moreso in the AJPV8's O/C cam timing). The residual exhaust pressure tends to blow the lighter drops of atomized fuel back into the intake, which tends to adhere and condense to the intake walls. This presents a few problems. Fuel "puddling" in the intake increases drag thereby reducing airflow, large quantities of highly atomized fuel can displace air in the ports, and if the "puddled" fuel does reach the combustion chamber it will cause air/fuel ratio variances between cylinders. All in all, there can be detrimental side effects which can cause some severe £££ damage....
With the Lucas type injectors, the disc is heavier and thus might not be as responsive as the Bosch pindle type, but the disc types do have advantages, for one thing, they're able to run at 90% without any damaging consequences and the 'squirt pattern' is generally less complex as far as dynamics are concerned.... you have to remember, ££££ are invested by some manufacturers designing intake manifolds/injector positioning/throttle-bodies etc., it would cost a lot of man-hours, multiple designs of intake manifolds and countless engine-failures to get it spot on...
I personally from my limited understanding would accept the professional arguement, dont mess with it unless its been proven to not lead to damage... but if someone has it figured out from abc to xyz... then its all good... but would you be willing to make such a change to a high performance engine without fully understanding the ramifications or without a warranty?... just my opinion... based on general technical data available freely...
At low RPMs highly atomized fuel has enough time to pass by the intake valve and create a homogenous mixture but as the RPMs increase problems will start to develop. In an engine running at high RPMs there is limited time for the fuel to reach the combustion chamber. This is compounded by the fact that often there is residual exhaust pressure present when the intake valve is opened (moreso in the AJPV8's O/C cam timing). The residual exhaust pressure tends to blow the lighter drops of atomized fuel back into the intake, which tends to adhere and condense to the intake walls. This presents a few problems. Fuel "puddling" in the intake increases drag thereby reducing airflow, large quantities of highly atomized fuel can displace air in the ports, and if the "puddled" fuel does reach the combustion chamber it will cause air/fuel ratio variances between cylinders. All in all, there can be detrimental side effects which can cause some severe £££ damage....
With the Lucas type injectors, the disc is heavier and thus might not be as responsive as the Bosch pindle type, but the disc types do have advantages, for one thing, they're able to run at 90% without any damaging consequences and the 'squirt pattern' is generally less complex as far as dynamics are concerned.... you have to remember, ££££ are invested by some manufacturers designing intake manifolds/injector positioning/throttle-bodies etc., it would cost a lot of man-hours, multiple designs of intake manifolds and countless engine-failures to get it spot on...
I personally from my limited understanding would accept the professional arguement, dont mess with it unless its been proven to not lead to damage... but if someone has it figured out from abc to xyz... then its all good... but would you be willing to make such a change to a high performance engine without fully understanding the ramifications or without a warranty?... just my opinion... based on general technical data available freely...
This was the result of a few mods on my 450SE, the injectors as well as offering more power and total smoothness of the engine the pick up from low revs in high gears is very good.I was/ am pleased.
www.pistonheads.co.uk/gassing/topic.asp?f=12&h=&t=120656
www.pistonheads.co.uk/gassing/topic.asp?f=12&h=&t=120656
[quote=PHØENIX]
Ps I hope you will let us know if any side-effects are noted....
[/quote]
You guys will be the second to know after Austec.
:
Got the before chart, picking after up in a couple of weeks, when car in for more works. (Not engine)It was late at night, as these sessions always are.
Ps I hope you will let us know if any side-effects are noted....
[/quote] You guys will be the second to know after Austec.
: Got the before chart, picking after up in a couple of weeks, when car in for more works. (Not engine)It was late at night, as these sessions always are.
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