Zytek Engines P1 vs P2

[Aslak Vind]

Without knowing anything, I would suspect a lack of cash from Creation...?

[JAG]

Originally Posted by chewymonster

Don't see how that is possible. As mentioned before direct injection can add about 20 horsepower, but the other power gains can only come with more RPM and the restrictors take care of that. In road cars variable valve timing can add extra horsepower but I don't think it's as effective on a high rev engine. Don't think it's allowed for prototype engines either.

It can't be that simple as WRC cars have gained 40bhp+ using the same restrictors and similar revs, due to gradual improvements. This is using a production block with far more design restrictions than P1 where, if you so wished, you could have a clean sheet design each year.

[JAG]

Originally Posted by davehenrie

Both Judd and AER have stated they are investigating direct injection, but my guess is they don't have the funding necessary to complete the R&D. Whenever there is a statement about DI, they mention a partner. So if one of the Judd customers stepped up and provided the cash(not likely in these financial times) we'd probably see other DI engines.
dh

Porsche used more resources to develop DI than the original engine according to a Racecar Engineering article.

I wouldn't be surprised if the AER Mazda has DI in it's 2011 P1 configuration, as all resources will now be focused on this engine, same goes for Judd if they wish to remain competitive.

[SebringMG]

Depends how much Mazda commit to a motorsport development programme, until this season i have not been particularly convinced they are putting the required cash and development behind the P programme.....lets hope Dyson can apply pressure for further development.

A major manufacturer probably could raise power each season, given the same restrictor, 20bhp sounds a bit much to me though maybe nearer 10-15 at the most though. Problem is that outside Audi, Porsche and Pug nobody has the cash to improve their engine.

[JAG]

There's also the Mazda France backed Pescarolo's and RML Lola.

[geeteeone]

There's a lot you can do with engine mapping to try to mitigate the effects of the air restrictors. I'd imagine that is even more the case when you have a turbocharged engine, such as in the WRC.

It never ceases to amaze me how much power is extracted from these air restricted engines, compared to a few years ago. Todays GT1 cars are running much smaller air restrictors than back in the original GT1 days (McLarens, Panoz, CLKs, etc) but they really aren't that far behind on power now. I keep having to remind myself that they are essentially what used to be GT2.

[knighty]

good morning peeps, I have been reading the comments here with interest and thought I'd write a few points of note

Its quite an open fact, even stated by Zytek themselves that the 4.0 V8 is a running circa 620bhp in 2007, I'd imagine that will raise to about 630 in its 4.5 litre format, the torque is very low, hence they are exploiting hybrids to assist, the reason you use a Zytek engine instead of say a Judd is its lower weight, its certainly the better engine for the ALMS.......but seems a bit stretched for the faster European races.

WRC engines are running circa 350bhp, but nobody ever realises this is with over 600NM of torque, this is principally achieved by running very high compression rations (circa 12-13:1) but with very sophisticated detonation sensing and control equipment and software, also the last time I was dabbling with one theWRC engines are NOT boost limited, just restrictor limited, hence they run LOTS of boost

To myknowledge the Judd AIM engine is a conventional port fuelled engine, not DI......I think (TBC) the latest AER LMP2 mazda engine is DI.

Whe Audi adopted DI on the R8 they stated no appreciable power gain but got an extra lap at leMans......but things have moved on since then......the Porsche LMP2 DI engine made 5% more than its port fuelled brother, but they stated to race engine magazine the benefits are not just power related, they state better combustion control, better traction control, lower fuel in oil, better fuel economy.

hope that helps

[davehenrie]

Originally Posted by knighty

hope that helps

Sure does, thank you!

[skycafe]

Better combustion control then means you can exploit timing agressively will still maintaining an acceptable risk on the detonation front, right?

Does DI offer anything specifically related to a benifit on a restricted engine?

[davehenrie]

Originally Posted by skycafe

Better combustion control then means you can exploit timing agressively will still maintaining an acceptable risk on the detonation front, right?

Does DI offer anything specifically related to a benifit on a restricted engine?

In an article about last year's new Judd DB engine, Judd talked about how the Porsche engine can rev several hundred rpm higher than the XV675 before shifting. Not max rpm mind you, but the hp/torque did not fall off as soon as it did with his engine. The whole purpose of the DB engine was to extend his power curve enough so drivers could also wait that little bit longer before shifting. The DB though, seems to have had a rough year reliability wise though.

However, I don't know if the DFI engine was used in Europe last year. I know that when the Horag Porsche was offered for Rent this season the add listed specs for the older engine.

[cmk]

It was not, as far as I know. Certainly not by Essex or Horag, and I'm pretty sure VM did not have one either - it was not publicized at all if they did. Given the early ending to the LMS and the late date Dyson got theirs, I have to figure that they did not.

[knighty]

Originally Posted by skycafe

Better combustion control then means you can exploit timing agressively will still maintaining an acceptable risk on the detonation front, right?

Does DI offer anything specifically related to a benifit on a restricted engine?

correct - its pretty much standard practice on most road and some high level race engines.......it allows you to run just close to the edge of detonation, just to squeeze out that last bit of power in a safe and non destructive manner. This was a major factor in the success of the GM Katech GT1 engines. as the 2 valve heads are very prone to detonation.

I think its safe to say that DI offers gains to any engine, restricted or not.......there are two different ways of doing it known as stratified or homogeneous, stratified means a vertical injector close to the spark plug which runs the engine VERY lean.......or Homogeneous which is a more horizontal injector position and gives a more uniform spread of the fuel spray......all motorsport systems are a homogeneous/horizontal layout.........stratified is more for raod cars that drive around low/mid rpms

hope that makes sense

[HORNDAWG]

Originally Posted by knighty

correct - its pretty much standard practice on most road and some high level race engines.......it allows you to run just close to the edge of detonation, just to squeeze out that last bit of power in a safe and non destructive manner. This was a major factor in the success of the GM Katech GT1 engines. as the 2 valve heads are very prone to detonation.

I think its safe to say that DI offers gains to any engine, restricted or not.......there are two different ways of doing it known as stratified or homogeneous, stratified means a vertical injector close to the spark plug which runs the engine VERY lean.......or Homogeneous which is a more horizontal injector position and gives a more uniform spread of the fuel spray......all motorsport systems are a homogeneous/horizontal layout.........stratified is more for raod cars that drive around low/mid rpms

hope that makes sense

So, theoretically, the best combustion configuration is a Hemi with homogeneous injection? Per se.


L.P.

[Aslak Vind]

However, I don't know if the DFI engine was used in Europe last year. I know that when the Horag Porsche was offered for Rent this season the add listed specs for the older engine.

It was not.

[davehenrie]

Originally Posted by Aslak Vind

It was not.

What about this season at LM? Will the DFI engine be made available or are they stuck with the previous version?
dh

[Aslak Vind]

I am told, that both cars will be updated to full 2009 specs, including the DI lump.

[skycafe]

Originally Posted by knighty

correct - its pretty much standard practice on most road and some high level race engines.......it allows you to run just close to the edge of detonation, just to squeeze out that last bit of power in a safe and non destructive manner. This was a major factor in the success of the GM Katech GT1 engines. as the 2 valve heads are very prone to detonation.

I think its safe to say that DI offers gains to any engine, restricted or not.......there are two different ways of doing it known as stratified or homogeneous, stratified means a vertical injector close to the spark plug which runs the engine VERY lean.......or Homogeneous which is a more horizontal injector position and gives a more uniform spread of the fuel spray......all motorsport systems are a homogeneous/horizontal layout.........stratified is more for raod cars that drive around low/mid rpms

hope that makes sense

Indeed it does make sense.

Question, with a restrictor and DI, is an advantage seen in that you are moving more air into chamber because it does not contain fuel, thus increase in air volume?

I know from reading a Racecar Engineering a few years ago on the Elan engine, they were having issues as they approached choke point. I guess at that point the air is very disturbed and you have volume compremise, so does DI enhance the volume that wee bit more, maintaining tuneability and driveability at peak level? Or is it only control enhancement against the detonation threshold that is occuring that offers the power enhancements?

[knighty]

Originally Posted by skycafe

Indeed it does make sense.

Question, with a restrictor and DI, is an advantage seen in that you are moving more air into chamber because it does not contain fuel, thus increase in air volume?

I know from reading a Racecar Engineering a few years ago on the Elan engine, they were having issues as they approached choke point. I guess at that point the air is very disturbed and you have volume compremise, so does DI enhance the volume that wee bit more, maintaining tuneability and driveability at peak level? Or is it only control enhancement against the detonation threshold that is occuring that offers the power enhancements?

My feeling is tha amount of fuel in the air is minimal, so no great gain in volumetric efficiency.

DI does not enhance the volumetric efficiency of an engine.......I'm pretty sure the power increase comes via a greater increase in cylinder pressure........a cylinder pressure trace is oftern termed a bell-curve, as it rises and drops quite abruptly, in the shape of a bell........all you have to do is increase the area under that curve via making the bell wider or taller, or both........more area under the cylinder pressure curve = more power........also with a DI system bear in mind you are now injecting fuel independent of what the valves are doing.......so you can then exploit things like pre and post injection to ensure a complete/increased burn of the main charge........you just cant do that on a port fuelled injected (PFI) engine, as the valves will be shut!

Just to clarify, the Corvette GT1 is a conventional PFI engine, I was only referring to it because its renowned for having a very complex but effective Bosch detonation sensing system.......its not DI......sorry for any confusion

[Aslak Vind]

Strange, I remember Corvette talking about their 2008 LM engine, as being a DI engine?

[skycafe]

Ok, cool. As I was driving to work I was thinking about this and it dawned on me that downstream of the restrictor you already have the disturbed and limited mixture.

So, with direct injection you can fling in the fuel independent of the air flow from the valves and you can totally control the mixture for engine load, rpm, etc, totally indepedent of what air flow is doing. You by pass the physical limitations of the air flow (I do understand that you have to maintain favorable mixtures in the chamber, but you have far more control in exploiting those mixtures).

Fascinating stuff! Thanks for your time with this, I look forward to your posts and I end up gaining knowledge each time. You have a gift for teaching.

Robert

[knighty]

Originally Posted by Aslak Vind

Strange, I remember Corvette talking about their 2008 LM engine, as being a DI engine?

skycafe - glad to be of service!

Aslak Vind - you could well be correct........since about 2006 GM have had DI on production engines, so it wouldnt surprise me that the GT1 has already been using it........man thats a great engine, shame it will never be seen in an LMP1 car, I desperatley wanted that to happen.

[Aslak Vind]

I think Jan mentioned it some time ago, making the Vette go longer on each stint compared with the DBR9.

[Ted bennett]

Would DI have a cooling effect on the compressed charge that port injection would not, leading to a small volumetric efficiency gain ?

[chewymonster]

Corvettes don't have DI, so I don't think the GT1 Corvettes have it either, but then again that engine is not very similar to the ZR6 engine.

[Bob Riebe]

Do any direct injection engines have variable spray pattern nozzel?