Louie928

Thanks John.
I seem to end up using a lot of words to say not as much as I want. I am not 100% sure if the LH/MAF can be tuned for the low RPM reversion flow when using long duration/high lift cams. I've done it using a piggyback so I think the LH with Sharktuning could do it. The concern would be if there was fine enough RPM resolution on the map near idle and up to around 2000 rpm. The other issue with an engine such as mine which responds so quickly to throttle, both up and down, is that the LH may not be fast enough to keep up. Not so much on acceleration because there is the acceleration enrichment table in the Sharktuner. On deceleration, it may not catch it quick enough to settle into a stable idle. The injectors are cut completely off then come back on under about 1700 RPM IIRC. With closed trottle, 1700 RPM to idle RPM happens really quick. My DTA tuning map doesn't cut the injectors off under deceleration so keeps it somewhat alive under decel. That also make a nice light popping and crackle out the exhaust when decelerating. We'll find out when Adam gets his black beastie going using the stock ECU and STed. His car is an auto so will be more forgiving. SC and turbo engines won't be so twitchy with throttle so I doubt there would be a problem with Sharktuned LH/MAF/EZ-K.

John Speake

Certainly everyone is on a learning curve of how the SharkTuner can work with highly modified engines. So far it's doing pretty well. And the base maps are a very sound basis for modification.
Lots of the hard work already done for you :-)

As I have said before, we are more than willing to consider special modifications to the ST for customers' special requirements.

BC

The fact remains that the LH could never have handled what Louie has done with his engine, individual throttle bodies, etc.

Louie928

I'm not so sure about that Brendan. Without the Sharktuner it's for sure the LH wouldn't work. By fitting a MAF to the inlet air stream, it just might work. That's what Adam will determine. There is enough reason to believe it would work to give it a try. It may require John to do some customization of the ST if there is some small thing that needs a tuning fix.

BTW, I got my Cayenne coil plug covers from Sunset Thursday. Those are the parts that were back ordered until late September.

PorKen

Could you add some antireversion features in the airbox to the MAF?

BC

Well, Then I SHOULD have just been patient. I paid about 10 bucks more a piece, but had them 1 week ago or more. No biggie - still need to order the VEMS anyway. Trying to get more feedback on the Coil wiring - thanks for your help on that. The per-cylinder price was great all said and done though. Everything will look so clean now with the wires, distributors, etc gone.

I am going to follow Todd's advice and get spark plugs that let the spark jump where its open to the chamber more, thereby hopefully not needing the Voltage power of a CDI to ignite the mixture plus (possibly) large amounts of water vapor with alcohol. Thats the only drawback to the Cayenne COPS - precludes any CDI use.

Louie928

I doubt it would be a practical thing to do. The ITB intake does the antireversion duty by having the throttle plate close to the valve so the reversion flow can't get out and mess up the flow going to other cylinders, or get back out the intake inlet. Having a really large volume airbox would help, but there is always limited space on a 928. The large volume air box would have the effect of the MAF not responding to instantaneous air mass changes too. The problem is that with big cams the MAF reads a higher voltage than it normally would at idle because air is going both directions across the hot wire. That gets you higher voltage and an overly rich mixture. Using the ST, you lean out the mixture (more negative numbers in the map) at idle and slightly above. The reversion is usually over by around 1700 RPM with the B1 grind cams so MAF output then is dependent on air the engine is using so would be "normal". I don't anticipate that situation on Adam's engine so much because he's using the ITB intake.

Louie928

The one worry I have on the Cayenne coils is whether they have enough inductance to "ring" properly and provide a long enough spark duration. Maybe they use a ferrite core. I'm not a fan of CDI systems unless they are of the multi spark variety like MSD. True, CDI provides a really high energy spark, but it doesn't last long enough to heat up the fuel and ignite it. I've read some information that suggests that the CDI spark plasma pressure can blow the mixture away and not ignite it too. I figured that if these Cayenne coils worked on the turbo engine they should be ok.

Does Todd use surface gap plugs? I tried those 40 yrs ago and gave up on them then. Too cold.
Sort of OT with the coil info....

Your VEMS system looks quite capable and a good price too. The knock sensing appears like they have done it right with the gated listening period. AFAIK, the J&S Electronics, http://www.jandssafeguard.com/, is the only other one that does that. The setup for the VEMS knock sensor looks like quite a task and the statement to not use the knock sensing to tune with is puzzling. You are suppose to tune spark advance by conventional means. Apparently, the knock sense does not retard timing, but how is the knock sense indication output to the user and is it really any good? I missed that part. Even the setup for the fuel injectors is complex with ramp time and such. Where do you get that info you need to set it up? I gave up on trying to understand the WBO2 setup and how it's implemented. In the end, it looked like they were using one of the VEMS fuel injector outputs to drive the sensor heater with all the complex heater temperature controller with PID loop settings left up to the user to figure out. Maybe I missed a crucial part of the write up. That's way more tweaking than I want to get into. It's hard enough to get the engine to run well without spending your life setting up the ECU. Maybe it's really easy and I blanked out for a while reading the setup instructions and missed that part.

BC

I don't know Louie. The documentation is so scarce, and the support so foreign, sometimes I feel like I shouldn't do it with VEMS, but then I get an email from the actual developer himself, or the actual forum administrator for the UK site, and it all seems okay. Raceboy on this forum has set up several cars - if I have to I will fly him out on a rewards ticket from estonia! I don't expect to tune the car in a day, but I do expect to have it running in a short time after final assembly ( a pesky career change is getting all the time!)

That WIKI that they use is so ludicrous its almost laughable, but somehow people make it work, and i have my own member page there too now. I was planning on usuint the LC1 from innovate that heats its own, and hopefully there was a full spectrum input on the VEMS so it can just passively deal with the signal instead of my setting up the heater crap.

It will be a learning experience, but hopefully will make more sense when I am in it.

Louie928

Hi Brendan,
I think overall that the VEMS could be a good choice. It seems to me that it is sort of MS like in that it is always in some stage of development and you can't really be sure of getting a firmware version without some obscure bug in it. The web site could use a lot of organization too. Nothing is ever perfect and if the support is good and there is someone to answer questions, or have most of the zillion possible setup parameters already figured out for your needs, then it could be just fine. Good choice I think to use the LC-1 at least in the beginning. One of the problems I find with the DTA is that of documentation that is lacking explanation of some of the features. The unit works, but you can't figure out how to configure it to do what you want. The documentation was no doubt written by the development group who already knew everything about the unit. I think that is common. Sometimes you hope to get help in the Windows help file only to find there isn't any help file, or it's not of much help at all. The instructions should be used first by someone who knows nothing about it and then any problem areas will become immediately apparent. Probably won't happen with DTA, VEMS, or anything else. Thank goodness for the forums. That is one very positive thing about John Speake's Sharktuner documentation. It leaves little to your imagination with clear explanation on all the features.

John Speake

Hi Louie
Can you explain what Adam's set up will be ? Are his ITBs fed from an airbox with a MAF preceeding it ?

Louie928

Hi John,
Adam has my ITB intake system as well as the Devek B1 cams. He may use my air box with the MAF connected to the front of it, but I really don't know. He has some unique ideas of his own he may want to incorporate. He's got a 6cwt crank rather than the 8cwt that I have. Those are a bit lighter, but offset by his torque converter full of oil. For a street driven car with a slightly lumpy cam, rotating mass is your friend. Different pistons too, but the engines are basically the same.

John Speake

OK, thanks, mustn't hijack this thread.....

BC

Louie - this is a link to the wideband forum for VEMS:

http://www.vems.co.uk/forum/index.php?board=7.0

Fastest928

Louis - unless I did the heads, they are not the same

I have spent over 10 years with stand alone systems and still never have gotten any of them close to stock idle and all condition running quality. Louis, you know of my plight...

Good explanation and give understanding to my quest to use the stock EFI and custom intake to make power....Tom and I have made up to 550rwhp so far and we think we can get more....up to 600.

Engine build in process for 600 rwhp. NA

Reversion is a pain at idle...the B1 cams will idle well at around 1000-1100 rpm and with a larger, less sensitive maf, may work well all around. Try Bosch motorsports or modify the stock.

John, how about some additional rpm tuning???

Cheers,
Marc