412 BHP...THAT WILL DO NICELY......

[nigeninja]

Night night dyno

[Iconic Ride]

Not really a dyno inquiry as such, but...........

"This allows us to run the injectors sequentially rather than batched..."

This is yet another mention of injector fuel management that I've not been able to mentally process, so I'll once more ask "the dummy question of the day." What, precisely, does this mean? Thanks.

[lotushiast]

Hello Dave,

what typ of camshaft do you use on the intake side?

104 or 107?

Do you use larger valves?

I will do the same to my engine bur with a GT3582R Turbo.

Go the route with seqential injektion and individual cylinder trim via 4 egt probes.

This is the best thread in the last time!

Kindest Regards Harald!!

[Vulcan Grey]

Not really a dyno inquiry as such, but...........

"This allows us to run the injectors sequentially rather than batched..."

This is yet another mention of injector fuel management that I've not been able to mentally process, so I'll once more ask "the dummy question of the day." What, precisely, does this mean? Thanks.

John,

The Esprit uses a bank system that consists of pairs of spark (2 coils for 4 plugs, 1&4 and 2&3) and paired injectors (same pairing 1&4 and 2&3).

So both 1&4 or 2&3 get spark and fuel at the same time every time as their pair. It is called a wasted spark system.

Since the 4 cyl (and the V8) use a flat crank, that means that for instance 1&4 pistons go up at the same time, one in compression and the other in exhaust. The spark on both, saves money on coil packs and circuitry. Same reason pretty much with the injectors.

The V8 is the same, just with 4 coil packs, still wasted spark.

Sequential systems have more coils (one on each cylinder) and more control over fuel injectors by putting them on separate circuits.

[karmavore]

Humm.... I never thought about it but is the wasted fuel being injected at during the exhaust stroke responsible for increased burbling and backfiring?

[Iconic Ride]

As always, thanks again, Travis. As it happens, one of my vehicles actually has "dedicated" coils for each cylinder, but I never imagined that other arrangements produced the "wasted spark" phenomenon. Quite interesting.

[Günter]

@John: in addition to Travis post -see the individual fuel injection as the more precise and effective way if it comes to emission an fuel consumption for every single cylinder.

As on most 'really modern' systems you will have a computer controlled 'multiple injection' of fuel spray in very smal time scales on every single cylinder [just in time with the real injection cycle of the cylinder], that helps on the ignition and combustion process ..but needs resources in the 'engine brain'-box ... and it was over the finance plan in the time the 918 was engineered.

@Lucas: mention that 'unused' fuel can build up an 'overlay' on the inlet port/on the closed inlet valve. But if you think about the smal time point both valve are open during the cycle, it could be possible that some of the fuel vaporates again on the heated head alloy and could get into the exhaust port unburned. But I would more or less say that the overfueling an ignition cut/gear-cut on tuned race engines cause that fuel gets into the exhaust system, and is fired in the hot exhaust parts(catalyst for example) !?

Edited May 9, 2011 by Günter

[CHANGES]

from John......Not really a dyno inquiry as such, but...........

"This allows us to run the injectors sequentially rather than batched..

This is yet another mention of injector fuel management that I've not been able to mentally process, so I'll once more ask "the dummy question of the day." What,

precisely, does this mean? Thanks.

Not a problem John, This is a question about tuning of the engine not how it is measured.....

What this refers to is the way the standard injectors function, and the sequential system we have fitted.....

The crank sensor on your engine tells the ECU when the engine is at TDC. it then fires the injector to fuel the cylinder.

This happens every time the engine is at TDC but it only requires it when the inlet valves are opening....

The ECU does not have the facility to recognise this so fires the injectors even when the valves are closed

Sequential injection only fires the injectors when the inlet valves are opening , no other time during the engine cycle

It is able to do this buy the use of what is best described as a sensor distributor which rotates in time with the cams not the crank.

The advantages of this system are more on control ability , than power advantage , it will not make the engine produce much more in the way of BHP but it will enable it to do its job smoother and more efficiently with large injectors ...... This being an important point in my particular project. ( smooth power )

Hope this helps make it a bit clearer ...

oooh Travis beat me to it.... you guys don't half type quick..

Edited May 9, 2011 by CHANGES

[CHANGES]

From Harald

what typ of camshaft do you use on the intake side?

104 or 107?

Do you use larger valves?

I re-timed both the exhaust and inlet to 104. using vernier pulleys , i used verniers to make sure timing was spot on regardless of head skimming and gasket thickness....

I retained all the original SE Valve sizes, with the HC head....

Edited May 9, 2011 by CHANGES

[Iconic Ride]

"...the wasted fuel being injected at during the exhaust stroke..." (Lucas)

"...the individual fuel injection as the more precise and effective way if it comes to emission an fuel consumption..." (Gunter)

"Hope this helps make it a bit clearer ..." (Dave)

Yes............and not necessarily. Am I to understand that saving construction costs (on stock engines) by allocating a cylinder-to-coil ratio of 2 to 1 means using twice as much fuel per crank revolution? What have I missed here?

Edited May 10, 2011 by Iconic Ride

[lotus4s]

John,

The short answer is no. The ECM controls the amount of fuel injected and only injects half of the amount of fuel needed for a full charge on each crank revolution into the intake but that fuel charge only goes into the cylinder with every two crank revolutions on the intake stroke. Clear as mud?

Common sense might lead one to think that some efficiency might be lost with that system but I have no idea if that's the case. I guess it could serve to keep the intake valves a little cooler during combustion but who knows....

Edited May 10, 2011 by lotus4s

[CHANGES]

The reason the batch system was used on stock engine is as was previously stated , manufacturing cost.......There are some efficiency gains with the sequential system purely on the quality of the fuel charge,

On the compression stroke when the valves are closed the injected fuel is to all intensive purposes in fired into static air, as it has no where to go it attaches to the valve and port wall and forms tiny beads of fuel instead of mist..... when the valve opens the rush of induction air turn the beads back into a mist along with the second injection of fuel. however the mist is not as fine as initially from the injector , leading to a slightly less efficient burn......evident in the fact that the HC level is higher on this type of system..... With the sequential system the single charge does not have this problem and the system can be tuned for more accurate fueling , creating a smoother running engine with lower HC level....This all happens so quick it is difficult to comprehend, but is just one of those many little improvements that when packaged together make such a difference.......

I

[Iconic Ride]

Thank you, Jim. Thank you, Dave. The two of you have actually managed to clear this up for me.

[bosbon_be]

Well the first page holds the injector size at 800's and he mentioned ditching the secondary injectors so my guess is 4 800cc mains and no secondaries.....

I've read that when using secondaries it can give more HP's, I know it is easier without them, but if you want the optimum...

The advantage of putting the outer injector way upstream is that power is often gained from the cooling effect of the fuel, plus a better mixing of the fuel and air on the way to the engine is achieved. On a 200bhp engine we have typically seen an 8bhp power gain.

Dave Walker from Emerald's web site: http://www.emeraldm3d.com/em_how.html

Edited May 11, 2011 by bosbon_be

[CHANGES]

From Peter.....I've read that when using secondaries it can give more HP's, I know it is easier without them, but if you want the optimum...

The advantage of putting the outer injector way upstream is that power is often gained from the cooling effect of the fuel, plus a better mixing of the fuel and air on the

way to the engine is achieved. On a 200bhp engine we have typically seen an 8bhp power gain.

There are several schools of thought on this particular area. Each one is more tailor fitted to a specific application , or to meet a requirement.....

It is correct gains can be made by putting secondary's further up the induction, but only in a certain power band , it requires a constant fast moving turbulent air flow to be effective...

If the air flow is to low or interrupted the the fuel particles will drop out of suspension and have a detrimental effect..

This is why on our Esprit's they only function at higher RPM and full throttle ..

However it must always be considered why secondary's are used in the first place....

The usual reason is the primary's are not large enough to sustain the higher rpm......but have to be that size maintain the correct fueling at low rpm.....This can be for a number of reasons . The type, and resistance of the injector (limiting its performance ability ) or the ECU's ability to control them......or both....

There are so many different designs for engine induction , you could write volumes just on the variations and applications of such......each has its place.....

What I have done is look specifically at my fueling requirement to obtain the smooth performance in line with the modifications made......

I decided that the original system had considerable limitations and significant gains could be made by illuminating the secondary's.....

Once the secondary's were removed a better gas flow can be achieved in the inlet manifold right up to the primary's... This can greatly increase the air volume and quality that arrives at the cylinder .

Then by using large high end primary's fired sequentially by new ECU system , we can achieve a massive improvement in power and torque , as apposed to 8 bhp !!!!!

This is however just one more part in the overall design , which all links together to give the final package.... ( smooth 412 )

[drellis]

very well done, for most of us reading on here it is just great to see possible development options and I love the quality look to your engine bay, sorry if thus has been covered but is your gearbox standard?

[CHANGES]

From Drellis...............sorry if thus has been covered but is your gearbox standard?

Actually it was the first question i expected to be asked , but you are the first to ask ..... Answer is it is a new standard box.... i do know the limitations and i do have a spare, and if it goes south the a GTO one is one the cards.....

Edited May 14, 2011 by CHANGES

[karmavore]

I can't believe no one has commented on the estimated drivetrain loss of only ~30HP. That's not bad all all! Thanks for that Dave, Troy.

[CHANGES]

To be continued >>>>>

Edited May 17, 2011 by CHANGES

[MrDangerUS]

Hi Dave,

Nice tutorial! Quite professional and informative. I very much agree with your Total Systems Integration approach-the sum of incremental improvements makes a great difference.

FYI:

I hacked additional 5mm of the diffuser port upper "roof" area (between top bolt holes), opening it up in Z axis direction.

I'm going to mill the spacer accordingly. This should increase the flow at least 20-22cfm.

I will send you the picture of my "Moustache Diverter". This time, it will be the real McCoy welded to the back cover.

IMO, if you want to pursue it, there are certain systems improvements, which will get your engine close to 455-465.

Great job!

Edited May 18, 2011 by MrDangerUS

[CHANGES]

CONTINUED FROM PAGE 6 >>>>>>>>>>>>>>>

I hope this has been of interest and maybe explained a little bit more of what is involved to achieve 400+ .

I think that it would be very difficult to just bolt on and achieve 400+

You will need to work the ingredients as well as adding a few new ones to form the desired out come....

Looking forward to any comments , questions and new ideas

Dave L. ................

Edited May 18, 2011 by CHANGES

[Jonathan]

Nice job

PS love the write up on boost pressure and temperature working against your means - most people just go for more pressure + more pressure wihtout thinking of what they're actually doing.

Great write up - seriously one of the most informed + plain English things I've read on here.

Edited May 18, 2011 by Jonathan

[CHANGES]

Thankyou John and Jonathan for your appreciation of the air flow paper..

I was trying to write it in a way that would not over dramatise the the detail.....and get boring.....not sure what others thought...

John, i like your thinking on the plenum Flow diverter, it has wonderful potential for situations where high flow in the plenum needs managing. especially carb turbo's. I think members will find your pic's of great interest....

Very early on in the thread Lucas , Artie and others were asking about the finer details on how a smooth 412 could be gained out of a 910 engine.. Hopefully this paper has answered a few questions...I do not know what gas flow systems they are employing, but feel it would be very interesting to find out....so if you chaps can give us that info it may answer a few question that may shed new light on why there is the bhp or even whp difference between us..

All of this info will help form a bigger bank of useful data for different stages of tuning on the 910 engine for all members.. .. can't be bad..

[CHANGES]

Hi Buddsy,

I have not driven it yet, but on the dyno there was no lag at all ... this can be seen in the graph...The new ECU has turbo anti lag system built in as well as the flow factors..

Troy from N'hampton motor sport said when he took it on small drive it was very impressive .....no turbo lag was mentioned....

I hope to have it back in 10 days time and will give you a full breakdown on how it drives....both Good and Bad points .... after all , that is what it is all about , Drive-ability...

Edited May 20, 2011 by CHANGES

[mike_sekinger]

Continues to be very impressive.

..... you do not want to deploy anti-lag..... oh no